Soil microbial fuel cells (SMFCs) are low-cost devices capable of converting chemical energy of organic matter into electricity through anodic microorganisms while simultaneously degrading organic pollutants in the soil. Therefore, they have promising applications in soil remediation and sustainable agriculture. However, the existing SMFCs still face limitations in terms of power generation and pollutant degradation efficiency. Moreover, many gaps are observed in their application for soil remediation of organic pollutants. Therefore, this article systematically reviews the research progress of SMFCs for degrading various organic pollutants in the soil, aiming to provide references for enhancing the power generation and degradation efficiency of SMFCs and guiding future research directions. First, the article elucidates the principles of SMFCs in degrading soil organic pollutants, analyzes the application of top-, insertion-, and U-type SMFCs, and deeply discusses the impacts of electrode materials and soil media on the SMFCs performance as well as the criteria for their selection. Second, it analyzes the different microbial species roles in the anode and their distribution changes in SMFCs. Accordingly, this article summarizes various methods to improve the power generation and degradation efficiency of SMFCs, such as optimizing electrode structures, adding electron mediators, and regulating environmental conditions. Future directions for developing SMFCs should focus on enhancing their stability and scalability, exploring highly efficient electrode materials and microbial strains, and expanding their applicability across different soil types and pollutants.

Land-use change, as a key driving force of the terrestrial ecosystem carbon cycle, plays a critical role in assessing carbon balance and promoting sustainable development. Based on the land-use change patterns in the source region of the Yellow River in the mountainous areas of the Qinghai-Xizang Plateau from 2000 to 2020, this study developed an integrated CA-Markov-InVEST-OPGD model to reveal the spatiotemporal evolution of land cover and carbon storage, analyze the driving mechanism of carbon-storage changes, and predict the characteristics of carbon storage changes in a natural change scenario in the source region of the Yellow River in 2030. The results showed that from 2000 to 2020, grasslands in the source region of the Yellow River declined, while unused land and water areas expanded, leading to an overall reduction in carbon storage, with high-value areas shifting toward the northwest. NDVI, elevation, and temperature were the main factors affecting carbon storage in the region, with NDVI interacting most significantly with temperature, precipitation, and population density. In the natural change scenario in 2030, the grassland area will continue to shrink while the water area will increase significantly. Carbon storage in the east and south will decline significantly, while carbon storage in some areas in the west and north will increase significantly. The overall spatial concentration of carbon storage will tend to decrease, with notable local increases and decreases. Therefore, it is essential to undertake grassland ecological protection and restoration efforts to enhance carbon sink capacity and promote regional carbon balance.

This study investigates the spatiotemporal variation characteristics of negative air ion (NAI) concentration and the primary factors influencing it across different seasons using Jiyuan Nanshan Forest as the research site. Based on continuous observations conducted from June 2021 to May 2022 using RR-9411A monitoring equipment and data obtained from an automatic weather station, this study analyzes the diurnal and seasonal variations in NAI concentration and its correlation with environmental factors. Results show that the order of seasonal average NAI concentrations is autumn (889 ion·cm^-3) > summer (756 ion·cm^-3) > winter (601 ion·cm^-3) > spring (430 ion·cm^-3). The diurnal variation patterns reveal that (i) in autumn, peak NAI concentration in appears at 11:00 (1 030 ion·cm^-3); (ii) in summer, a “double-peak and double-valley” pattern is observed; (iii) in winter, the peak lags behind noon; and (iv) in spring, fluctuations are minimal. Correlation analysis reveals significant seasonal differences in the relationships between NAI concentration and environmental factors, namely, wind speed, temperature, relative humidity, and particulate matter (PM)—specifically, PM with a diameter of ≤10 μm and PM with a diameter of ≤2.5 μm. In spring, the NAI concentration is primarily influenced by wind speed and humidity. Moreover, in summer, it is positively correlated with temperature and wind speed, and in winter, it is significantly correlated with PM levels and relative humidity. Furthermore, vegetation photosynthesis intensity, meteorological conditions (e.g., precipitation and inversion layer), and human activities are found to be the key drivers of the seasonal differentiation in NAI. This study provides a scientific basis for optimizing forest ecological management and improving air quality assessments.

The Xiaoqing River serves as a multifunctional waterway in Shandong Province, supporting flood control, irrigation, and navigation activities. Accurate evaluation of its water ecological quality is crucial for informing ecological restoration and guiding the resumption of navigation. This study conducted field monitoring to assess correlations between water quality parameters and biodiversity indices, aiming to identify appropriate biological indicators at the species, population, and community levels for the Jinan section. A hierarchical evaluation framework was developed by integrating indicators across three levels: physicochemical characteristics, habitat quality, and ecological structure. This system was applied for the first time to assess the water ecological quality of the Jinan section. The results aligned with the observed spatial trend of water quality, characterized by a “high-low-high” pattern from upstream to downstream. The study provides a scientific foundation for ecological restoration and navigation planning in the Xiaoqing River basin and offers a methodological reference for evaluating urban river ecosystems in China.

In recent years, extreme precipitation events have become increasingly frequent in Shandong Province. To improve the monitoring, forecasting, and early warning of these short-duration events, this study analyzes minute-level precipitation data from 99 national meteorological stations in Shandong Province, covering the period from 1991 to 2020. Using the climate tendency rate, wavelet analysis, and empirical orthogonal function decomposition, we examine the spatiotemporal distribution and variability of annual maximum precipitation across different short durations. The results indicate that both the average and maximum values of annual maximum precipitation for all short durations increase progressively from central and eastern Shandong outward, peaking in southern Shandong. In most parts of southern Shandong, these annual maxima show a decreasing trend over time, whereas most other areas exhibit an increasing trend. For 5 min durations, the spatial variability trends are generally consistent, with intensity centers located in northwestern Shandong. For the 30 min and 60 min durations, eastern and southern Shandong, as well as the eastern Shandong Peninsula, show trends opposite to those in other regions, with negative intensity centers in central-western, northwestern, and southwestern Shandong. For the 90 min, 120 min, and 180 min durations, the eastern central region and the eastern Shandong Peninsula display opposite trends, with positive intensity centers in southwestern Shandong. Each duration shows significant 2 to 3 year periodicities. An abrupt change was detected in 2004 for the 5 min duration, leading to a marked decrease thereafter, whereas no abrupt changes were observed for other durations. Overall, most annual maximum short-duration precipitation events in Shandong exhibit an increasing trend. These findings underscore the importance of enhancing monitoring efforts and revising storm intensity formulas, particularly in southern and northwestern Shandong.

The section of the Yellow River from Bailongwan to the Lanjia River in Binzhou, China, is a curved section of the lower reaches of the Yellow River. In recent years, notable changes in the river regime have occurred due to alterations in water and sediment conditions. In certain sections, the mainstream lines have shifted leftward, posing a threat to the safety of the levees. Through data analysis, field investigations and measurements, and basic theoretical analysis, this study focuses on the channel evolution in this reach since the operation of the Xiaolangdi Reservoir and proposes corresponding management strategies. The study shows that the changes in the mainsteam lines are the primary cause of the leftward river regime migration and that flood events during the rainy season further intensify the river's swing. In response to the river regime changes, multiple management strategies are proposed, such as extending five spur dikes downstream of the Bailongwan risk control project and extending three spur dikes downstream of the Wangpingkou guiding structure, to enhance the project's flow-guiding capacity and reduce the hazards of the “cross-river” and “oblique-river” flows to the levees.

Persistent organic pollutants (POPs) generated during coal combustion have become a global focus of environmental governance because of their environmental persistence, bioaccumulation potential, and toxic effects. This study systematically reviews the formation mechanisms, emission characteristics, control technologies, and health risks of coal-derived POPs, such as polycyclic aromatic hydrocarbons (PAHs), halogenated PAHs (HPAHs), polychlorinated biphenyls (PCBs), and dioxins and furans. This study shows that POP formation is regulated by chemical kinetic pathways (precursor generation, halogenation, and surface-catalyzed synthesis) and the coupled effects of combustion conditions, coal properties, and fly ash catalysis. Their emission intensity is determined by the synergistic effects of combustion parameters, coal quality, and end-of-pipe control technologies. Remarkable heterogeneity exists in POP emissions from different combustion devices: PAHs are predominantly enriched in fine particles (particulate matter 2.5, PM_2.5), whereas emissions of HPAHs and PCBs are considerably influenced by coal chlorine content and combustion technologies. Current precombustion treatment, in-combustion control, and postcombustion technologies partially reduced POPs; however, breakthroughs are needed for identifying emerging pollutants, analyzing cross-media migration mechanisms, and improving global governance frameworks. Human exposure to POPs through inhalation and dietary intake may cause respiratory, immune, and reproductive system diseases, with health risks exceeding safety thresholds in some regions. Future research should focus on the characteristics of emerging pollutants, optimizing synergistic emission reduction technology systems, and improving multimedia risk assessment frameworks.

To investigate the characteristics of atmospheric composite pollution and meteorological driving mechanisms in medium-sized industrial cities, this study systematically analyzed the spatiotemporal variations and synergistic effects of PM_2.5 and ozone (O₃) based on air quality data from five national stations and eight county-level monitoring stations in Liaocheng City from 2019 to 2023. The results showed that the annual average PM_2.5 concentration exhibited a fluctuating downward trend but rebounded in 2023 with increased extreme values. O₃ concentrations displayed a “decline followed by rise” pattern, peaking at 230.0 μg/m³ in June during the summer pollution season. Correlation analysis revealed that PM_2.5 and O₃ pollution showed a positive correlation in summer and a negative correlation in winter,Among various meteorological factors, temperature exhibited a significant positive effect on O₃ formation. When humidity was in the 60%-70% range, the risk of simultaneous PM_2.5 and O₃ exceedance increased. Wind analysis further showed that O₃ exceedances predominantly occurred under the presence of southerly winds(0 to 7.5 m/s), displaying a distinct “red tongue” extension pattern, while calm and westerly winds exacerbated PM_2.5 concentration.

Spray-seeding technology can effectively restore the ecological environment of damaged mountain slopes. However，variations in the physicochemical properties of slope soil and vegetation growth conditions—resulting from technical measures and human factors—limit our understanding of carbon sequestration on slopes. This study analyzed the characteristics and influencing factors of carbon storage in damaged slopes in Zhangzhou restored using aggregate spray-seeding technology. The results showed that carbon storage decreased sequentially from the tree layer to soil，root system，and litter layer，with the dominant tree species Leucaena leucocephala in the tree layer contributing significantly to carbon storage. Although the soil layer of the slope is thin，its organic matter content reached 37.98 g/kg，demonstrating the potential of aggregate spray-seeding technology to improve soil quality and carbon storage. The physicochemical properties of the soil，particularly moisture，total phosphorus，and total potassium，significantly affected carbon storage in the ecological restoration area. This study highlights the key role of soil moisture in ecological restoration and carbon sequestration enhancement，providing valuable insights for optimizing slope management measures and improving ecological restoration effectiveness.

This study investigated the effects of different coagulants—namely chitosan，polyaluminum chloride （PAC），and ferric chloride （FeCl₃）—on cyanobacterial cell breakage and microcystin-LR （MC-LR） anaerobic biodegradation in raw water containing algae during conventional drinking-water treatment. Analyses were conducted using three-dimensional excitation emission matrix （3D-EEM） fluorescence spectroscopy，scanning electron microscopy，and enzyme-linked immunosorbent assays. Results showed that coagulated flocs generated by the action of FeCl₃ had no significant effect on cyanobacterial cell breakage or total MC-LR degradation. Chitosan initially protected cyanobacterial cells and adsorbed extracellular MC-LR； however，its effectiveness declined over time. Meanwhile，PAC significantly exacerbated cyanobacterial cell breakage，leading to the massive release of intracellular toxins，which ultimately accelerated the degradation rate of total MC-LR. In addition，3D-EEM fluorescence spectroscopy revealed increasing concentrations of five substance types，such as the ammoniacal/tryptophan protein zone and tyrosine/tryptophan zone，indicating that the different coagulants had a significant effect on the production of extracellular polymers in the sludge. Further，the related substances increased in amount the fastest when PAC was used. This study is the first to systematically investigate the mechanisms by which coagulants affect cyanobacterial cells and MC-LR anaerobic degradation，providing an important reference for the efficient removal of cyanobacteria and their toxins from waterworks sludge.

Micro/nanoplastics (MNPs) and microalgae are widely distributed in water and MNPs that adhere to the surface of microalgae or enter their internal structures will enter the food chain in large quantities, posing a great threat to aquatic ecosystems. The physiological effects of MNPs on algae vary depending on their particle sizes. In this study, polystyrene micro/nanoplastics(PS-MNPs) particles were selected as target pollutants to investigate their toxicological effects on Microcystis aeruginosa (FACHB 905) at different concentrations (5, 10, 50 and 250 mg/L) and particle sizes (100 μm and 80 nm). Results showed that the inhibition effect of 80 nm PS-MNPs exerted a more potent inhibitory effect on the growth of algal, chlorophyll a and phycobiliprotein synthesis than 100 μm PS-MNPs, and the inhibitory effect was more obvious with the increase of PS concentration. In addition, the activities of catalase (CAT), malondialdehyde dehydrogenase (MDA) and glutathione (GSH) in microalgae cells were significantly increased under the stress of high concentration of PS-MNPs, indicating that high concentration of PS-MNPs caused oxidative damage to algal cells, and smaller PS-MNPs particles can lead to more severe oxidative damage. The toxicity of PS-MNPs with different particle sizes toward M. aeruviosa mainly led to cell destruction through surface adsorption, which affected photosynthesis and energy metabolism of algal cells, hindering normal physiological and biochemical reactions in algal cells. This study, by exploring the toxicity mechanism of PS-MNPs to microcystis aeruginosa, is of great significance for the risk assessment of PS-MNPs, and provides a theoretical basis for the prevention of M. aeruginosa bloom.

The effluent total nitrogen (TN) is one of the key indicators for assessing the biological denitrification performance of wastewater treatment plants(WWTPs). To mitigate the prevalent issue of excessive TN discharges from WTTPs, we proposed a real-time prediction model based on long short-term memory (LSTM) networks. We performed Pearson correlation analysis to determine model inputs and used grid search algorithm to optimize model hyperparameters. Then, we used the proposed model to predict the actual effluent TN in a WWTP in Chongqing and compared its predictive performance with that of traditional time-series models. Results indicate that the proposed model can effectively predict effluent TN with an average absolute error of 0.911 mg/L, an average root mean square error of 1.074 mg/L, and an average absolute percentage error of 11.28%. All of these performance indicators surpass those of the recurrent neural network and ARIMA models. The proposed model can serve as the foundation for effective monitoring of effluent TN.

Based on the monthly average global precipitation data from January 1982 to April 2022, this study discusses the spatial distribution and time series of mode one and mode two using the cyclostationary empirical orthogonal function (CSEOF) method; analyzes the spatial distribution, seasonal variation characteristics, and interannual variation characteristics of global marine precipitation at low and middle latitudes; and discusses the possible causes of these variations. Results show that the interannual variation of precipitation exhibits periodic characteristics, with the main areas experiencing variations being distributed in the tropical Pacific region; additionally, the spatial field of mode one demonstrates an east-west inverse phase distribution, which is stronger in winter than in summer. The seasonal variation of the spatial field of mode two is more complex than that of mode one, with the high-value positive and negative variability regions demonstrating an east-west inverse phase distribution in winter and negative variability regions dominating in summer with weaker intensity. ENSO has an important impact on the interannual variations of precipitation. The spatiotemporal variation characteristics of mode one are primarily affected by the ENSO phenomenon, while those of mode two are mainly affected by the El Niño Modoki phenomenon. The main precipitation variation characteristics are affected by the superposition of these two phenomena.

To ascertain the current status of plant resources and biodiversity in the Yellow River, Yishu River, Nansi Lake Basin and Weifang in Shandong Province, a comprehensive and detailed investigation was conducted by combining field investigation, specimen collection, indoor classification, and anatomical identification. The results identified 1 194 species of vascular plants belonging to 587 genera and 155 families. Among these, 6 species, namely Teucrium japonicum, Euphorbia heyneana, Echinochloa colona, Commelina diffusa, Braya humilis, and Bidens maximowicziana, were newly recorded in Shandong Province. The key identification characteristics of these species are described in this study, and the distribution status and application value are also discussed. The discovery of these plants not only enriches the background data of plant resources and plant diversity in Shandong, but also is significancant to the study of the systematic classification, floristic plant geography, and distribution patterns of related families and genera.

As the second most abundant element on earth, silicon plays an important role in soil biogeochemical processes. However, the geochemical characteristics of soil silicon in different forms in coastal wetlands still need further investigation. In this study, we selected four typical coastal wetlands (nonflooding Phragmites australis, tidal P. australis, freshwater P. australis, and tidal Suaeda salsa wetlands) as sampling sites and collected soils from 0 to 20 cm depth. Furthermore, we determined oxalate-extractable silicon, dithionite-citrate-extractable silicon, pyrophosphate-extractable silicon and analyzed their soil physical and chemical properties, distribution patterns, and influencing factors in typical coastal wetlands. Results showed that dithionite-citrate-extractable silicon and pyrophosphate-extractable silicon showed no significant differences among four wetlands (p>0.05), while oxalate-extractable silicon in nonflooding P. australis wetlands was significantly lower than tidal P. australis wetlands (p<0.05). As for the profile distribution, the three types of extractable silicon in soils from 0 to 10 cm were generally higher than in soils from 10 cm to 20 cm. Additionally, the correlation analysis revealed that soil organic matter, total nitrogen, bulk density, pH, silt and moisture were important factors influencing these three types of extractable silicon.

Based on MOD17A3 product data for Shandong Province from 2010 to 2022, this study uses univariate regression trend analysis, the coefficient of variation method, partial correlation analysis, and the Hurst index method to investigate the spatiotemporal distribution of vegetation net primary productivity (NPP) for the ecosystem of Shandong Province and analyze the impact of climate factors. Results demonstrate the fluctuating upward trend of vegetation NPP for Shandong Province in recent years, with an annual average of (398.03±150.20) g/(m²·a), higher than the national average and comparable with that of the Beijing-Tianjin-Hebei region. Vegetation NPP varies considerably across different areas. The vegetation NPP in the eastern coastal hilly area is higher than that in the inland plain area. With respect to interannual variation, the overall vegetation NPP in Shandong Province is relatively stable. With regard to the variation trend of vegetation NPP, the areas of positive and negative trends are equivalent. The trend analysis shows that 27.86% of the areas show an increasing trend, whereas 33.49% show a decreasing trend. However, the areas that have shifted from the increasing trend to the decreasing trend are mostly in woodland areas with high vegetation NPP levels, and further research is needed. In general, a positive correlation exists between vegetation NPP and climate factors. Temperature has a wider and more considerable impact on vegetation NPP than precipitation; moreover, the correlation between vegetation NPP and climate factors is poor in plain agricultural areas.

Nitrogen fertilizers provide the nitrogen necessary for crop growth in modern agricultural production, but their excessive use in the long term leads to waste of resources, economic losses and profound negative environmental impacts. Microorganisms play a critical role in the nitrogen cycle; therefore, there is a significant need for further research in this field. Here, we summarize our findings on the mechanisms and processes by which microorganisms drive the soil nitrogen cycle, including nitrogen fixation, nitrification, denitrification, ammonification, and nitrogen assimilation/dissimilation. We further summarize microbial technologies and strategies for mitigating agricultural nitrogen loss and improving agricultural sustainability, such as nitrogen fixation, greenhouse gas emission reduction, nitrogen bioretention, and ammonia volatilization. These strategies illustrate the potential of microorganisms in reducing the dependence on nitrogen fertilizers and increasing crop yields, while also highlighting the challenges of research and effective field application of these technologies.

In this study, the hot water extraction method was utilized to extract polysaccharides from persimmon peel, and the persimmon peel polysaccharides were combined with trivalent chromium ions to prepare persimmon peel polysaccharide chromium. Considering the adsorption rate of chromium as the index, the adsorption process of persimmon peel polysaccharide chromium was optimized using single factor and response surface methodology. The results showed that the optimal preparation process of persimmon peel polysaccharide chromium consisted of the following steps, such as the mass ratio of persimmon peel polysaccharides to chromium chloride was set at 6.7∶1; the reaction time was 150 min; the temperature was set at 82 ℃; and the pH of the adsorption liquid was fixed at 5. Under these conditions, the maximum adsorption rate reached 92.81%. Therefore, this study has shown that persimmon peel polysaccharides can efficiently bind trivalent chromium ions, which can further provide technical support for the development of green pollution-free heavy-adsorption chromium adsorbents or animal nutritional supplements.

This study analyzed the climate change characteristics and causes of foggy days in Qingdao and Jinan using meteorological observation data from 1961 to 2020 in Qingdao and Jinan, as well as sea surface temperature data near Qingdao. Results showed that the average annual foggy days in Qingdao were 50.4 d, 3.1 times more than that in Jinan. The peak fog seasons were substantially different in the two cities; Qingdao experiences more foggy days in spring and summer, accounting for about 78.4% of the whole year, whereas Jinan experiences more foggy days in autumn and winter, accounting for about 70.7% of the whole year. Furthermore, remarkable differences in the annual and seasonal variations of foggy days were observed. Qingdao shows an increasing trend in annual foggy days, i.e., less foggy days in spring and summer, but significantly more in autumn and winter. Alternatively, Jinan exhibits a decreasing trend in annual foggy days, where the number of foggy days is lowest in autumn. Moreover, considerable climate variability and abrupt change in the number of annual foggy days between the two cities were noticed. The climate variability of Qingdao showed an increasing trend and remained at a high level, while Jinan witnessed a decreasing trend; this indicates a higher probability of extreme foggy weather in Qingdao than in Jinan. Qingdao witnessed an increase in the number of foggy days in 1969, while Jinan encountered a decrease in 1995. The increase in the number of foggy days in Qingdao during autumn and winter was closely related to the substantial increase in the sea surface temperature near the city. This increase promoted sea surface evaporation and subsequently increased the atmospheric water vapor content. However, the decrease in foggy days in Jinan during autumn and winter was closely associated with a substantial increase in the minimum temperature and the dew point temperature difference as well as reduced humidity.

A systematic review was conducted on the current status and causes of the ecological degradation of wetlands in the Yellow River Delta (YRD), and the ecological restoration technologies were summarized. The results revealed that the wetland areas in the YRD are currently in a serious state of degradation, with the total area of wetlands shrinking year by year. Along with the shrinking of the wetland area, the wetland composition has changed, natural wetlands are decreasing while artificial wetlands are gradually increasing, the pattern of the landscape shows a trend toward fragmentation, and the service function of the ecosystem has been seriously degraded. The main causes of wetland ecological degradation in the YRD include the reduction of water and sediment fluxes from the Yellow River, increased sea-land interactions, intensified salinization of the soil, climate change, invasive species, and human activities. Current ecological restoration techniques for wetland restoration include biocomponent restoration, water body restoration, soil improvement, and comprehensive habitat restoration. This study will utimately provide specific recommendations for wetland restoration in the YRD, which is of great significance for the national strategy of ecological protection and the high-quality development of the YRD.

The industrial production process produces large quantities of high-salinity wastewater comprising complex water-quality components, including a large amount of Na⁺, Cl^-, SO₄^2-, and other salts as well as toxic substances. Traditional high-salinity wastewater treatment technology has low efficiency and high operating cost. The freeze concentration method for high-salinity wastewater treatment has received widespread attention as a highly efficient and clean treatment technology without secondary pollution. However, the problem of impurities in the ice crystals prepared via freeze concentration should be solved urgently. This article summarizes the research progress of freeze concentration technology in high-salinity wastewater treatment in recent years. The key parameters such as freezing time, freezing temperature, and initial solution concentration were discussed, and various methods for removing impurities from ice crystals, including immersion, gravity, and water addition purification methods, were investigated. To accelerate the desalination process and improve the desalination effect, nucleating agent and ultrasonic-assisted freeze concentration methods were investigated. Furthermore, the energy consumption of the freeze concentration technology was economically analyzed. Moreover, the development of the technology is summarized and a prospect is proposed to provide specific references for the development and application of freeze concentration method in high-salinity wastewater treatment.

Recently, circulating cooling water systems have been widely used to alleviate water shortage.However, cooling water usually contains various mineral ions,such as calcium and magnesium, which can easily form insoluble salts and scale on the surface of the equipment. The use of scale inhibitors in cooling water systems is one of the most effective methods to solve the scaling problem. In this paper, the recent research progress on green scale inhibitors at home and abroad was reviewed. The development and applications of green scale inhibitors were introduced here. The characteristics and scale inhibition performance of different types of scale inhibitors are also analyzed.Moreover,the scale inhibition mechanism was explained from different aspects,such as chelation and solubilization, coagulation and dispersion, and lattice distortion.Therefore,this review would provide an excellent reference for future research and development of green scale inhibitors.

Using the monitoring data of 34 air negative oxygenion stations and Moderate Resolution Imaging Spectroradiometer vegetation index product data of 13 counties in the western and southern mountainous areas of Henan Province, correlation analysis and random forest regression model were used to analyze the main meteorological and environmental factors affecting the concentration of negative oxygenion in these areas to establish a negative oxygenion concentration forecasting model. Results showed that temperature and relative humidity were the main meteorological factors affecting the diurnal variation of negative oxygenion concentration, concentration of PM_2.5, PM₁₀ and vegetation coverage were the main environmental factors.By establishing the negative oxygen ion concentration forecasting model, the quantification of negative oxygen ion prediction was realized. This study provides reference for regional air quality evaluation.

During oilfield workover, it is necessary to control the gel breaking speed of the temporary plugging agent, so that the gel is not broken during the workover to ensure the completion of the operation and is broken quickly after the workover to resume production. For traditional gel breakers, it is difficult to achieve a slow release at the initial stage and a fast release at the late of the workover. This paper describes a cellulose-based sustained-release encapsulated gel breaker with a double-layer film. This gel breaker is evenly mixed with molted Carnauba wax and the solid dispersion pellet is made using the extrusion-speronization method. In the Wurster fluidized bed, a double-layer film with different components is put on the pellet to prepare the sustained-release encapsulated gel breaker. The result of the orthogonal test shows that this method is reliable, the yield of the pellet is 93.2%. SEM result shows that the film on the surface of the pellet is smooth and uniform, and the sealing and unblocking of the film pores are crucial to sustained-release. The results of sustained-release test and simulation test of reservoir gel breaking exhibit that the sustained-release encapsulated gel breaker has an excellent controlled-release effect and reservoir permeability recovery effect. Herein, the preparation method is simple and efficient. The sustained-release of drugs is mainly controlled by the double-layer film.

To reveal the multiscale variation law of extreme precipitation events under climate warming, based on the daily precipitation data of the National Meteorological Station from 1961 to 2020, the spatiotemporal variation characteristics of extreme precipitation events on the monthly scale in Shandong Province were analyzed using the percentile relative threshold method. The results show that the monthly-scale extreme precipitation events in Shandong Province mainly occurred in July and August with the annual frequency bigger than 40%. The annual frequency showed a decreasing trend as one moves from southeast to northwest regions. The annual frequency and precipitation of extreme precipitation events increased in most areas for all seasons except autumn and considerably increased in winter. After the mid-1980s, extreme precipitation events have generally increased and intensified, and their interannual changes have increased significantly. The intensity of extreme precipitation in summer and winter increased significantly by 10 mm to 20 mm during 10 years in summer in the central, southwestern, and peninsular areas of Shandong and 20% to 50% in winter months in Shandong province. The precipitation instability generally increases under climate warming in Shandong, and it is necessary to strengthen early warning and defense services for disaster risks such as rainstorm, flood, and blizzard.

Using the datasets of major air pollutants and meteorological observations during the winter from 2016 to 2018 in Jinan, the characteristics of air pollution were analyzed to identify the major transport pathway of airmass. The results showed that during the winter from 2016 to 2018 in Jinan, about 63.8% and 34.7% of the major pollutants were PM_2.5 and PM₁₀, respectively. Of the total number of days, 58.6% had a pollution level worse than good polluted. The annual average concentration of PM_2.5 increased by 7.5 μg/m³ due to its high concentration in the winter. In terms of spatial distribution, the concentrations of PM₁₀ and PM_2.5 were high inTianqiao District, Huaiyin District, and Pingyin County; the concentration of SO₂ was high in Shanghe County and Jiyang District; and the concentrations of NO₂ and CO were high in Jiyang District, Tianqiao District and Huaiyin District. The results also showed that ρ(NO₂), ρ(CO), ρ(PM₁₀), and ρ(PM_2.5) had a positive correlation, with all r >0.7. It was inferred that traffic source, industrial combustion source, and burning coal were the major sources of particulate matter. The airmass in the winter of Jinan came from south, northwest, north, and east, and the airmass from south and east were the major transport pathway of air pollution. Further analyses of the potential source contribution and concentration weight showed that the air pollution in Jinan City was affected by the local and surrounding cities, and the current air pollution presents the characteristics of cross-contamination across regions. Therefore, a supervision and coordination mechanism for the joint prevention and control of air pollution in the region should be established to coordinate research and solve growing problems of air pollution.

This study reviews the speciation analysis methods of antimony indifferent environmental media in recent years. Inductively-coupled plasma mass spectrometry is widely used in the antimony speciation analysis because of its advantages such as low detection limit, high sensitivity, and good stability. Before the speciation analysis, extracting different forms of antimony from a complex matrix and maintaining its valence stability are essential. This can be achieved by combining the sensitive detection technology, efficient sample pretreatment techniques, and separation methods. In recent years, the combined techniques have been widely used for the determination of antimony in various environmental samples. Moreover, the challenges in this field and the development prospect of antimony speciation analysis method are discussed.

In this study, common plant-fiber agricultural wastes (corn stalks, peanut shells, and straw) were mixed to storage sludge as bulking agents to study their biodrying performance. Four experimental groups were used, namely, corn stalks, peanut shells, straw, and a control group. Results showed that plant-fiber agricultural wastes could be used as bulking agents in the biodrying process of storage sludge, and the straw group performed best. The straw pile reached a maximum temperature of 57.5 ℃, and the moisture content decreased from 71.83% to 60.01%. The mass fraction of volatile solids (VS) decreased from 62.01% to 52.02%, and the mass ratio of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) showed a decreasing trend with the largest decrease. The w(DOC)/w(DON) gradually decreased during the biodrying process, and the ratio of the straw pile decreased from 4.29 to 2.53, indicating that biodrying could stabilize the materials.

Natural gas is an environmentally friendly energy source that can be used in various chemical raw materials. However, the presence of CO₂ in natural gas has a significant impact on the heat value and transportation performance of natural gas. Therefore, effective CO₂ removal from natural gas is critical. In this study, Mg-MOF-74 was selected as an adsorbent and its effect on CO₂/CH₄ adsorption and separation performance was investigated using a molecular dynamics simulation method. Based on the simulation results, at certain pressure and temperature settings, CO₂ is more likely to bind to the metal sites of Mg-MOF-74 than CH₄. Moreover, Mg-MOF-74 exhibits a stronger interaction force with CO₂ gas, indicating a higher capacity for CO₂ adsorption. To verify the accuracy of the simulation results, Mg-MOF-74 was prepared and its CO₂/CH₄ adsorption performance was tested.The experiment results is consistent with the simulation,that proved Mg-MOF-74 is more attractive to CO₂.

In order to ensure the rapid, timely, and effective treatment of water pollution, based on the excellent coagulation effect of poly-Si-Fe(PSF) and the rapid precipitation performance of flocculation, and with simulated domestic sewage as the experimental water sample, we studied the flocculation and precipitation time parameters of the shortened coagulation precipitation process (shortened process) and their impacts on filtration through beaker experiments, compared the removal effects of PSF and polyaluminum chloride (PAC) under the shortened and conventional processes of coagulation filtration, and analyzed the flocs by scanning electron microscopy (SEM). Finally, we observed the treatment effect of the shortened process on actual domestic sewage. The results show that in the coagulation sedimentation experiment, the PSF shortened process with 2 min of flocculation and 3 min of precipitation can reach the pollutant removal level close to that of the conventional process. With a dosage of 0.162 mmol/L, the turbidity and average COD_Cr removal rate are 0.59% and 11.5%, respectively. In the actual water treatment experiment, when the dosage reaches 0.162 mmol/L, the removal efficiencies of turbidity and COD_Cr by the PSF shortened process are 27.88% and 11.11% higher than that by PAC shortened process respectively. In the filtration experiment, the filtered water quality of the PSF shortened process was stable, and the average COD_Cr removal rate reached about 85%, 7% higher than the PAC shortened process. The SEM picture shows that the flocculation of PSF in the shortened process has a more compact structure and larger particle size than PAC catkins, thus better flocculation and precipitation effect.

Owing to the problems of drying high-humidity and high-viscosity sludge, this paper analyzes the water characteristics and drying characteristics of municipal sludge to optimize the design of the key components of ordinary rotary cylinder dryer and conduct industrial simulation test. The results show that the self-cleaning and dispersing rotary cylinder dryer with internal self-cleaning components such as chains, scraping plates, and dispersing shafts has better a antisticking and antiagglomeration effect as well as higher drying power and more ideal drying effect than the ordinary rotary drum dryers. It provides useful theoretical support for the development and application promotion of municipal sludge deep dewatering processes and devices.

As one of the three plains in China, the North China Plain is prone to large-scale and long-term pollution processes during the heating season due to its special geographical location, large number of heavy industry enterprises and higher pollution emissions in the season. The PM_2.5 concentration in the North China Plain is significantly higher than that in the surrounding areas during the heating season. To better understand the impact of weather system and meteorological elements on urban air quality in the North China Plain during the heating season, 50 cities in the North China Plain (32° to 40° N and 114° to 120° E) were selected as the research objects to analyze the impact of meteorological conditions on large-scale high pollution processes during the heating seasons from 2015 to 2021. Results show that when high pollution occurred in the North China Plain, the curvature of 500 hPa circulation decreases and is straighter. Due to the increased probability of temperature inversion, the horizontal and vertical directions were more stable, and the diffusion ability of pollutants was weakened. Near the surface, the abnormal southerly winds in Henan and central and southern Shandong led to regional warming and humidification, which was conducive to the growth of particle moisture absorption and secondary transformation. The abnormal easterly or northeasterly winds in central and western Hebei led to the accumulation of pollutants on the east side of Taihang Mountain, causing widespread pollution processes in the piedmont. They also formed wind convergence with the abnormal southerly winds in Henan and central and southern Shandong, diffusion conditions were unfavorable. The analysis of a pollution process from January 20, 2021 to January 28, 2021 shows that the upper air circulation in the North China Plain during the pollution was relatively straighter., the ground was mainly controlled by the pressure equalization field, and the main type was calm wind, and the humidity was continuously high. Unfavorable diffusion conditions were the main cause of this pollution process.

This paper proposes a field calibration method via standard weights accumulation to study the variation trend of the measurement error of the weighing precipitation sensor in an automatic meteorological station. Herein, the field calibration data of sensors from 2019 to 2021 are analyzed. Further, a calculation method is presented for measuring the error deviation degree and its variation trend with respect to the weighing precipitation sensor. The variation model of sensor deviation is obtained on the basis of the historical calibration data. The results show that the measurement error range and observation data quality are controllable. The overall deviation degree of the sensor is 2.1% of the standard value and its increase is 0.1% per year. This study can provide reference for predicting measurement errors and durability of meteorological sensors.

Based on the bibliometric analysis method, with the help of CiteSpace and VOSviewer visualization analysis software, this study, by combining quantitative and qualitative methods, systematically classifies the results of material stock research performed at home and abroad and analyzes the knowledge base, development context, and research progress of material stocks. Metals and buildings are found to be essential in material stock research and lay the basic foundation for this research. The research topics of material stocks include simple materials accounting to resource prediction, socioeconomic metabolism analysis, greenhouse gas emission reduction, and urban mineral development. The research methods are constantly enhanced, and life cycle assessment, decoupling analysis, and scenario analysis are introduced to expand the scope of this research. Furthermore, the research content of material stocks is enhanced, which involves greenhouse gas emission, circular economy, urban mineral resources, resource efficiency, and other sustainable development content. The existing problems in the development of material stock research are discussed, such as the difficulty in obtaining key data, data with different qualities, and practical guidance still need to be strengthened. The future development of material stock research should be actively integrated with other disciplines to improve the data accuracy and strengthen the ability of decision support services..

Based on the monitoring data of national geoinformation, this study analyzes the distribution pattern and change characteristics of natural ecosystems, including forest land, grassland, wetland, and bare land, from 2015 to 2019 in eight cities and one county along the Yellow River in Henan Province, China. Results show that the coverage rates of forest land, grassland, wetland, and bare land along the Yellow River are 36.12%, 2.61%, 2.01%, and 0.56%, respectively. Forest land was dominated by broad-leaved forests and broad-leaved shrub forests. The land coverage of coniferous forests, arbor-shrub-mixed forests, afforested land, and artificial young forests increased, and the land coverage of broad-leaved, coniferous, and broad-leaved shrub-mixed forests decreased during the study period. Grassland was dominated by high-coverage grassland, accounting for 81.47% of the grassland area. During the study period, the area of high-coverage grassland, artificial green grassland, and slope-protected shrub grassland increased and the area of medium-coverage grassland and herbage grassland decreased. The wetland was dominated by rivers, occupying 97.63% of the total wetland area. During the study period, the area of rivers and canals increased. The gravel surface was dominant, accounting for >60% of the total bare land. During the study period, the coverage area of all types of bare land showed a downtrend. Overall, in the Yellow River region of Henan Province, the distribution characteristics of different natural ecosystems differed; forest land was mainly distributed in the middle reaches, while the grassland was mainly distributed in the low reaches; the spatial distribution of the wetland area in the low reaches was higher than that in the middle reaches,while the area of bare land in the middle reaches was higher than that in the low reaches. During the study period, the coverage of forest land and bare land decreased, while that of grassland and wetland increased.

To handle inaccurate observations and errors in data analysis and assimilation, a single prediction is only one possible solution. To solve this problem, this study proposes an O₃ prediction model based on an artificial neural network ensemble prediction. To construct the artificial neural network forecast model, 8 types of meteorological factors and 2 types of pollutant factors are considered. Furthermore, the random disturbance method is used to create 15 sets of mutually independent random disturbance weather fields using data from May to September of each year, starting from 2013 and ending with 2019 as the training set and those from May to September 2020 as the test set. Results show that compared with a single artificial intelligence network prediction model, the proposed ensemble model clearly shows higher accuracy. The O₃ pollution hit rate is improved obviously, the nonresponse rate is remarkably reduced, and the empty rate is slightly higher than that of the single model. The O₃ pollution is predicted to happen more often using the proposed ensemble model, whereas that using the single model tends to be less. Considering a heavy O₃ pollution condition that occurred on July, 3 to 9, 2020 as an example, the proposed ensemble model can reflect the rapid cumulative increase and continuous process of O₃ pollution better than the single model. The proposed ensemble model can facilitate the probability of various occurrence, uncertainties and other more forecast information by providing quantitative probabilistic forecasts, which have certain practical application values.

To study the characteristics of heavy-air pollution process of Jinan in winter, a typical heavy-air pollution process that occurred during December 8 to 13 in 2020 was taken as an example to comprehensively analyze the characteristics and causes from the perspectives of pollution process, meteorological conditions, and chemical composition of fine particles. The results were shown as follows: During the heavy pollution process, the primary pollutant was PM_2.5, with an average mass concentration of 137 μg/m³. The pollution peak was reached at 21:00 on the December 11, and the mass concentration of PM_2.5 was as high as 235 μg/m³. During heavy pollution, the high-altitude circulation was relatively straight; the low 850 hPa was affected by the southwest airflow, which was conducive to the formation of temperature inversion stratification; the ground pressure field was controlled, and advection and radiation fogs occurred alternately. The static and stable meteorological conditions worsened the accumulation of PM_2.5 concentration and the secondary conversion of particulate matter under high-humidity conditions. During the observation period, the mass concentration of SNA was 85.4 μg/m³, accounting for 52.0% of the PM_2.5 concentration. The average values of R_S and R_N were 0.44 and 0.33 respectively, the secondary oxidation of SO₂ and NO₂ in the atmosphere was relatively high. R_S was higher than R_N, indicating that the secondary conversion efficiency of $SO^{2-}_{4}$ is higher than $NO^{-}_{3}$. The average value of $\rho_{NO^{-}_{3}}$ / $\rho_{SO^{2-}_{4}}$ was 2.1, indicating that the contribution of mobile sources to PM_2.5 pollution is dominant. The average ratio of OC/EC was 6.5, which indicated that there was SOC pollution in the atmosphere of Jinan during the heavy pollution period. Using the ρ_OC/ρ_EC minimum ratio method, the mass concentrations of POC and SOC during the heavy pollution period were estimated to be 11.9 μg/m³ and 4.3 μg/m³, respectively. The mass concentration of POC was higher than SOC, and it indicated that the primary combustion source has a greater contribution to the pollution process.

To explore the salt tolerance ability of different varieties of willow species, three new varieties of willow species were used to study the change characteristics of their growth and related physiological indicators under different concentrations of NaCl(20, 40, 60, and 80 mmol/L).We measured 15 parameters associated with growth physical and chemical characteristics, and the salt tolerance of three varieties of willow seedlings was evaluated comprehensively by four objective analysis methods: equal weight grey correlation analysis, entropy weight grey correlation analysis, principal component analysis and principal component-grey correlation analysis. The results showed that combining with cluster analysis the contents of soluble protein, free proline, soluble sugar, H₂O₂ and relative water content of leaves could be considered as the main indexes for the identification of salt tolerance of willow seedlings. According to four analysis methods, Salix matsudana 'Wuxu1' (cultivated code A34), Salix matsudana 'Shidi1' (cultivated code A42) present the better performance in resisting salt stress. It can be used as alternative germplasm material for exploitation and utilization of saline soil. As a scientific and reasonable evaluation method, principal component-grey correlation analysis can be one more useful appraisement method to provide theoretical support for screening and breeding of salt tolerance of willow seedlings.

High-concentration brine exists in the northern part of the Bailang River catchment aquifer.In recent years,the brine has flowed southward and potentially impacts the water supply in the southern plain area.Correct understanding of its hydrochemical characteristics and the evolution of Bailang River catchment is important for the reasonable management of groundwater resources and safety of water supply.Based on the previous research results,through groundwater sampling and a variety of hydrochemical analysis,including Piper Diagram,Gibbs Diagram,and inorganic ion tracer,groundwater hydrochemistry characteristics and its controlling factors in both freshwater area and brine area were studied.The total dissolved solids of groundwater in freshwater area and brine area are 1 098.1 and 115 669.3 mg/L,respectively,which indicates that the formation of groundwater chemical composition in the two areas is controlled by different factors.The chemical composition of groundwater in freshwater area is mainly decided by the water-rock interaction.The salt in the brine area comes from three seawater intrudings,but the groundwater in brine area is no longer the original seawater; it has been replaced by new water from precipitation in the southern mountain area under the driving force of the natural hydraulic gradient.The distribution of hydrochemical field is the result of water-salt interaction during the groundwater recharge,runoff,and discharge processes.The main minerals dissolved in the water-salt interaction process are NaCl,MgCl₂,Na₂SO₄,and MgSO₄.

The concentrated liquid behind a landfill leachate membrane is a type of high-concentration organic wastewater generated during the leachate membrane treatment of landfills. It has a complex composition and is difficult to process via biodegradation. Because of its high chemical oxygen demand (COD), high ammonia nitrogen, high salt content, and other characteristics, the salt cannot crystallize and precipitate smoothly after reaching the saturated state, making it difficult to execute the follow-up mechanical vapor recompression process. To execute the follow-up treatment process smoothly, ferric chloride, aluminum chloride hexahydrate, polyaluminum chloride, and polyaluminum ferric chloride were used as coagulants; polyacrylamide was used as a coagulant aid; and the removal rate of COD was used as an evaluation parameter to coagulate the post-membrane concentrated liquid of a waste treatment plant in Jinan, and the optimal operating conditions were obtained. Results show that ferric chloride is the best coagulant. When FeCl₃ dosage was 0.64 g/L, polyacrylamide dosage was 4 mg/L, and pH was 6, the removal rate of COD was the highest (80.6%).