Industrial Pollution Discharge Research Articles

Sustainable and efficient removal of phosphorus from wastewater through red mud residue after deep dealkalization

The increase phosphorus content in industrial wastewater can seriously deteriorate the water quality and correspondingly cause the eutrophication of rivers, lakes and underground water. The calcium silicate powder (CSP) was prepared from the red mud residue after deep dealkalization for phosphorus removal from wastewater, and the corresponding removal performance and adsorption mechanism were investigated in this work. Under the optimal conditions, a phosphorus removal efficiency of 96.32 % and a maximum immobilization capacity of 24.08 mg∙g−1 were achieved. The kinetic and isotherm data are well-fitted by the pseudo-second-order and Langmuir models, while the phosphorus is mainly removed by chemisorption, accompanied by the formation of a monolayer film on the heterogeneous surface. A novel Source-Parameters-Strategy-Demand architecture was proposed to evaluate the application potential of calcium silicate powder and environmental risk. The findings confirmed the validity of calcium silicate prepared from red mud residue for the phosphorus removal from wastewater, which has the unique advantages in simultaneously solving the industrial solid waste pollution and excessive phosphorus discharge.

A study on the economic loss estimation of industrial wastewater pollution discharges in the Yangtze River Delta urban agglomeration

ABSTRACT This study focuses on the industrial wastewater discharge of 27 cities in the Yangtze River Delta urban agglomeration. It selects five water pollutant indicators from industrial wastewater discharge, including chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), petroleum pollutants (PP), and major heavy metal content (HM). A shadow price model for industrial wastewater discharge pollutants in each city of the Yangtze River Delta urban agglomeration is constructed, and empirical research is conducted using government-provided statistical data. The study reveals that the economic losses associated with industrial wastewater discharge in the 27 cities of the Yangtze River Delta urban agglomeration range from 5.9296 billion to 6.448 billion yuan. Shanghai demonstrates the highest economic losses caused by industrial wastewater discharge, surpassing 0.45 billion yuan annually. In contrast, Anqing city experiences the lowest economic losses, approximately ranging from 93 million to 104 million yuan per year due to industrial wastewater discharge.

Nitrate Contamination of Groundwater in Selected Industrial and Non Industrial Sites, Coimbatore District, Tamil Nadu: Exposure and Health Risk Assessment

Groundwater resources are essential for sustaining human health, agricultural productivity, and industrial growth. In recent years, anthropogenic influences have caused a sharp decline in ground water quality, which is also having an impact on human health in many parts of India. It is crucial to analyze the risk of contamination to human health and the quality of the water supply. Coimbatore is one of the rapidly growing industrial areas in South India. The industrial areas of ground water have a significant impact on ground water quality due to anthropogenic activities such as discharge of Industrial waste, chemicals and pollutants into the ground which make water unsuitable for human and industrial use. Nitrate is the emerging contaminant which can cause a deadly disease methehemoglobinemia. Hence the present study is focused to analyze the ground water of selected industrial and non industrial sites of Coimbatore city. Nitrate concentration ranged from 32.90 to 88.13 mg/l in the samples industrial and non-industrial sites, and over 37% of both the sites had nitrate levels that above the Bureau of Indian Standards’ and WHO’s acceptable limits (45 mg/l and 50 mg/l, respectively). The USEPA human health risk assessment tool was used to examine the potential health hazards of increased nitrate intake for both adults and children.

Highly elastic photothermal nanofibrillated cellulose aerogels for solar-assisted efficient cleanup of viscous oil spill

Frequent oil spills and illegal industrial pollutant discharge cause ecological and resource damages, so it is necessary to establish efficient adsorption and recovery strategies for oils in wastewater. Herein, inspired by solar-driven viscosity-breaking, we propose a facile approach to fabricate multifunctional nanofibrillated cellulose-based aerogel with high elasticity, excellent photothermal conversion, efficient selective oil adsorption and antibacterial properties. Firstly, copper sulfide (CuS) nanoparticles were in situ deposited on the template of oxidative nanofibrillated cellulose (ONC), aiming at achieving efficient photothermal effect and antibacterial properties. Ethylene glycol diglycidyl ether (EGDE) was employed to establish multiple crosslinking network between CuS@ONC and polyethyleneimine (PEI). A thin hydrophobic PMTS layer deposited on the surface of aerogel via a facile gas-solid reaction ensured stable oil selectivity. The resulting composite aerogel can rapidly adsorb oil under solar self-heating, significantly reducing the adsorption time from 25 to 5 min. Furthermore, it exhibits excellent adsorption capacities for various oils, retaining over 92 % of its initial capacity even after 20 adsorption-desorption cycles, and the antibacterial properties extend its lifespan. This work offers a promising method for constructing multifunctional aerogels for efficient oil-water separation, especially beneficial for high-viscosity and high-melting-point oil cleanup.

Natural and anthropogenic factors regulating fluoride enrichment in groundwater of the Nansi Lake Basin, Northern China

Excess fluoride (F−) in groundwater can be hazardous to human health of local residents who rely upon it. Beside natural sources, anthropogenic input may be an additional source to be considered. Twenty surface water and 396 groundwater samples were collected from the Nansi Lake Basin, with hydrogeochemical and isotope techniques employed to clarify the spatial variability, source, and the natural and anthropogenic factors regulating the occurrence of high F− groundwater. The factors responsible for elevated F− levels in surface water and deep confined aquifers are discussed based on their hydraulic relationship. Also a conceptual model of F− enrichment with different aquifer systems is put forward based on the geomorphic units of the basin. The results show that F− concentration is between 0.1 and 6.9 mg/L in the west of Lake, while ranged from 0.03 to 1.74 mg/L in the east of Lake. The hydrogeological setting and lithology are the primary factor determining the provenance of high-fluoride groundwater in the basin. Fluoride mainly originated from the dissolution of fluorine-bearing minerals, and is affected by the alkaline groundwater environment, cation exchange, adsorption, and evaporation. The landforms on the east side of Nansi Lake are low hills and piedmont sedimentary plains, where the aquifers consist of karst fissure water and overlying porewater. High F− groundwater is not observed in this area due to its rapid flow and Ca2+-enriched hydrochemical characteristics. The anthropogenic input (such as fertilizer application on farms and illegal industrial pollutant discharge), contribute F− to groundwater in varying degrees, especially in the shallow aquifers east of the lake and in some parts west of the lake. This work is a clear example of how natural processes together with human activities can affect the chemical quality of groundwater, which is essential to safeguard the sustainable management of water resources in semi-arid areas.

Spatial correlation and coupling between industrial enterprise agglomeration and water pollutant discharge

Industrial wastewater discharge has become the main cause of water pollution in China. However, the spatial interaction mechanism between industrial structure and water pollution is still unclear. Accordingly, we evaluated and analyzed spatiotemporal changes of the agglomeration pattern of pollution-intensive industrial enterprises and the evolution of the water environmental pollution pattern, as well as the correlation between them. The study results show that the polluting industrial enterprises were located mainly along the Yangtze River and Taihu Lake Basin in southern Jiangsu in 2013 and 2018. However, we observed a spatial trend of pollution transfer to northern Jiangsu. The industrial water pollution discharge presents the distribution pattern of facing rivers, seas, lakes and cities. Papermaking and paper products industry are the leading factors of COD and NH3–N pollution, with explanatory power of 0.3666 and 0.6201 respectively. The spatial positive coupling effect between the concentration degree of polluting enterprises and the intensity of water environment pollution discharge is 94.95% of the region. The spatial agglomeration of polluting industrial enterprises is an important cause of water environment pollution. They promote and couple each other, proving the existence of “Pollution haven” and “Porter hypothesis".

Organo-Montmorillonite Modified by Gemini Quaternary Ammonium Surfactants with Different Counterions for Adsorption toward Phenol

The discharge of industrial phenol pollutants causes great harm to the natural environment and human health. In this study, phenol removal from water was studied via the adsorption of Na-montmorillonite (Na-Mt) modified by a series of Gemini quaternary ammonium surfactants with different counterions [(C11H23CONH(CH2)2N+ (CH3)2(CH2)2 N+(CH3)2 (CH2)2NHCOC11H23·2Y-, Y = CH3CO3-, C6H5COO- and Br-, 12-2-12·2Y-]. The results of the phenol adsorption indicated that MMt-12-2-12·2Br-, MMt-12-2-12·2CH3CO3- and MMt-12-2-12·2C6H5COO- reached the optimum adsorption capacity, which was 115.110 mg/g, 100.834 mg/g and 99.985 mg/g, respectively, under the conditions of the saturated intercalation concentration at 2.0 times that of the cation exchange capacity (CEC) of the original Na-Mt, 0.04 g of adsorbent and a pH = 10. The adsorption kinetics of all adsorption processes were in good agreement with the pseudo-second-order kinetics model, and the adsorption isotherm was better modeled by Freundlich isotherm. Thermodynamic parameters revealed that the adsorption of phenol was a physical, spontaneous and exothermic process. The results also showed that the counterions of the surfactant had a certain influence on the adsorption performance of MMt for phenol, especially the rigid structure, hydrophobicity, and hydration of the counterions.

A study on the efficiency of the sequential batch reactor on the reduction of wastewater pollution from oil washing.

Industrial pollution discharges from washing fuel oils pose severe problems for the environment, particularly for the marine environment receiving these discharges. This work evaluates the biological treatment performance of wastewater (90 m3/h) rich in organic matter with low biodegradability using a sequential batch reactor (SBR) on a laboratory scale. The test using SBR was carried out for 25days on a continuous cycle of 24h (30min of filling, 17h of aeration, 4h of anoxia, 2h of settling, and 30min of emptying). The feasibility of alternative sources of microorganisms from urban wastewater. The performance of the batch sequencing reactor was evaluated using turbidity, total suspended solids, chemical oxygen demand (COD), biological oxygen demand (BOD), ammonium, nitrate, and phenol as indicators. The results obtained showed that the COD/BOD ratio and the pollutant load vary from one campaign to another. The removal efficiency of COD, BOD, TSS (Total suspended solids), ammonium, nitrate, and phenol varies from 81%, 91%, 72%, 100%, 52%, and 63%. Thus, SBR-type treatment could be an interesting way to reduce pollution due to its simplicity, less space occupation, low energy consumption, and not requiring highly qualified personnel.

An extended input-output analysis of links between industrial production and water pollutant discharge in the Yangtze River Economic Belt

Industrial production is key to economic development, yet it significantly influences the water environment. Recent literature has mainly focused on economic development and water pollution separately, lacking an integrated assessment. This study aims to clarify the links between industrial production and water pollution and its driving factors in the Yangtze River Economic Belt (YREB) in 2012–2017 based on environmentally-extended input-output analysis and structural decomposition analysis, thus identifying key regions and sectors for pollution reduction. The results revealed that manufacture of foods and tobacco (MFT) and chemical industry (CI) in Anhui, Jiangsu, Jiangxi, Hunan, and processing of petroleum, coking, processing of nuclear fuel (PPCN) in Chongqing were the primary sources of total chemical oxygen demand (COD), ammoniacal nitrogen (NH3–N), total nitrogen (TN), and total phosphorus (TP) discharges. The structural decomposition analysis (SDA) results demonstrated that the discharge intensity effect caused a decrease of 7.91 Mt, 0.22 Mt, 0.25 Mt, and 0.03 Mt of the indirect COD, NH3–N, TN, and TP discharge, while the scale effect led to an increase of 1.95 Mt, 0.26 Mt, 0.24 Mt and 0.03 Mt of them in 2012–2017. According to the analysis, water pollution reduction and industrial structure modernization are needed in the YREB. The technological upgrading of highly polluting industries and the structural adjustment between traditional highly polluting industries and high-tech industries were the focus for achieving green development of the YREB, especially in Anhui, Hubei, Guizhou and Yunnan. The establishment of green industrial parks, the development of environmental regulations, and the implementation of supply-side reform policies can benefit water pollution reduction and sustainable development.

Environmental and economic effects of grassroots environmental protection agencies in China: An analysis based on the synthetic control method

Grassroots environmental protection agencies are the “last kilometer” of environmental supervision in China, but the effects of these agencies have not received sufficient attention from the economic community. This paper adopts the synthetic control method to estimate the impact of establishing grassroots environmental protection agencies on industrial pollution discharge. The results show that establishing grassroots environmental protection agencies reduces industrial pollution discharge, but the effects are only statistically significant in some regions. In addition, grassroots environmental protection agencies do not significantly impact local economic growth and the economic structure. Grassroots environmental protection agencies generally have problems such as inadequate managerial staff, which may cause the failure in fully executing their functions. The overall promotion of grassroots environmental protection work can hardly be facilitated by the government before these problems are resolved.

Research on the spatial correlation and drivers of industrial agglomeration and pollution discharge in the Yellow River Basin

The spatial auto-correlation analysis approach is used to examine the agglomeration features and geographical correlation of industrial agglomeration and pollutant discharge using 91 prefecture-level cities in the Yellow River Basin from 2005 to 2020 as the research target. The Yellow River Basin and the upper, middle, and lower reaches were investigated for the effects of industrial agglomeration on industrial pollution emissions. The Dubin model of the spatial panel is used to investigate the drivers of industrial pollution from both indirect effects and direct effects. The findings indicated that ① the spatial pattern of industrial pollution agglomeration and industrial agglomeration in the Yellow River Basin has spatial convergence; ② the global clustering characteristics of industrial pollution in the Yellow River Basin are apparent. The global correlations of the three pollutants are industrial wastewater > industrial smoke and dust > industrial SO2; there is a spatial association between industrial agglomeration and pollution agglomeration, and there are differences in the spatial interconnection between industrial agglomeration and the accumulation of different pollutants; ③ from the overall point of view of the Yellow River Basin, industrial agglomeration will reduce the pollution levels of industrial wastewater, industrial SO2, and industrial smoke and dust. From the perspective of different regions, industrial agglomeration in the upper, middle, and lower reaches is conducive to the decline of industrial pollution, and the role is in the middle, downstream, and upstream in order from large to small; and ④ the Yellow River Basin’s industrial pollution is primarily caused by population agglomeration, industrial structure, environmental regulation, opening to the outside world, and economic development. Their effects on industrial wastewater, industrial SO2, industrial smoke, and dust pollution vary.

Spatial temporal patterns and driving factors of industrial pollution and structures in the Yangtze River Economic Belt

The conflict between industrial development and environmental pollution is global. This study quantitatively analyzes the temporal and spatial changes, spatial effects and determinants of industrial pollution discharge in the Yangtze River Economic Belt through two main indicators: wastewater and SO2. Analyze the spatial coupling relationship between industrial agglomeration and pollution emission and the characteristics of industrial structure in different regions. The analysis shows that industrial emissions in the Yangtze River Economic Belt first increased and then decreased during the period 2003-2019. Industrial pollution spread from large to small and medium cities and shifted from downstream to upstream. Moreover, a positive correlation exists between industrial pollution discharge and per capita GDP, secondary industry proportion, population density, and energy use. Meanwhile, scientific and technological progress and environmental regulations are associated with industrial pollution reduction. Since the Yangtze River Economic Belt was still in the industrialization stage and had not yet reached a turning point on the Environmental Kuznets Curve. The "pollution refuge" phenomenon was evident in the Belt, where underdeveloped areas in the central and western regions accommodated portions of highly polluting industries from the eastern areas through "regional competition" and "policy depression." The industrial agglomeration and pollution antagonistic zones were dominated by polluting industries; environmental risks were greatest in these areas. The upstream and downstream of the YREB play the negative and positive environmental externalities of industrial agglomeration, respectively. Thus, differential control measures should be formulated according to different regions, industrial pollutants, and polluting industries to improve environmental quality.

Improving surface water quality of the Yellow River Basin due to anthropogenic changes.

Understanding of how changes in diverse human activities and climate contribute to water quality dynamics is crucial for sustainable water environment management especially in the arid and semi-arid regions. This study conducted a comprehensive estimation of the surface water quality change in the Yellow River basin during 2003-2017 and its responses to varied pollution sources and water volumes under socioeconomic and environmental influences. Basin-wide measurements of chemical oxygen demand (COD), ammonium nitrogen (NH+4-N) and dissolved oxygen (DO) concentrations were used in trend detection. Annual anthropogenic (covering six sectors) and natural (sediment-induced, flow-in from the upstream and stored last year) pollution sources and water components (inflow, natural runoff, water consumption, reservoir storage and evaporation) were compiled for each sub-basin. Bottom-up hierarchical analysis was then performed to differentiate individual contributions. Results showed significant decreasing trends in COD and NH+4-N concentrations and increasing trends in DO concentrations. The middle reaches that traverse the Loess Plateau however remained severely polluted with 11.3-39.0% inferior to level III in 2017. The pollutant load played major positive contributions that gradually increased from upper to lower reaches. Declines in urban, rural and industrial pollution discharges following environmental investments and rural depopulation contributed the most: 78-96% for COD and 55-100% for NH+4-N. The total surface water volume had dilution effects in the upper and middle reaches (3-28%) and condensing effects in the lower reaches (2-37%). Precipitation and vegetation dynamics contributed slightly. The primary unfavorable factors were the growing agricultural pollution discharges and water consumption in the upper and middle reaches that also threatened the lower reaches. This study is expected to provide in-depth insights for the systematic response of regional water quality to combined human interventions and references for water quality management in other arid and semi-arid river basins worldwide.

Spatial correlation and influencing factors of industrial agglomeration and pollution discharges: a case study of 284 cities in China.

Exploring the spatial correlation characteristics and influencing factors of industrial agglomeration and pollution discharge, which is of great significance to reduce industrial pollution discharge and promote China's construction of an ecological civilization. Taking 284 prefecture-level cities in China in 2017 as the research object, this study used spatial autocorrelation analysis method to explore the spatial agglomeration characteristics and spatial correlation of industrial agglomeration and industrial pollution discharge, and spatial econometric analysis method was used to explore the main factors affecting industrial pollution discharge. The research results showed that the level of industrial agglomeration in China exhibited a spatial distribution characteristic of "high in the east and low in the west". The total discharge and discharge intensity of industrial pollutants showed a spatial pattern of "high in the north and low in the south" in general, and industrial agglomeration, total discharge, and discharge intensity of industrial pollution showed significant spatial autocorrelation. Moreover, industrial agglomeration had a strong local spatial correlation with the total and intensity of industrial wastewater, industrial SO2, and industrial smoke and dust, and the main agglomeration types were high agglomeration-low pollution, low agglomeration-high pollution, and low agglomeration-low pollution. In addition, industrial agglomeration had a positive impact on the total industrial wastewater discharge, and had a negative impact on the total industrial smoke and dust discharge, industrial wastewater discharge intensity, industrial SO2 discharge intensity, and industrial smoke and dust discharge intensity.

Effects of Industrial Structure Adjustment on Pollutants Discharged to the Aquatic Environment in Northwest China.

Northwest China is located along China’s Belt and Road Initiative routes and represents the frontier and core region for China’s construction and development of the Silk Road Economic Belt. In recent years, the conflict between economic development and environmental pollution has become increasingly intense in this region, with the latter mainly caused by disorderly industrialization brought about by rapid urbanization processes. Inappropriate industrial structure is the primary reason for environmental degradation in Northwest China, which has limited precipitation and available water. Due to its fragile aquatic environment and unsustainable use of water resources, the pollution and degradation of the aquatic environment has become a bottleneck that severely restricts the sustainable development of China’s northwest region. In the present study, five provinces or autonomous regions in Northwest China were selected as the study objects. Based on the vector autoregressive (VAR) model, quantitative research methods, such as impulse response function and variance decomposition analysis, were applied to quantify the dynamics between industrial structure adjustment and changes in industrial pollutant discharges to the aquatic environment, so that the impact of industrial structure adjustment on pollutants discharged to the aquatic environment could be quantified and characterized. Therefore, the present study has both theoretical and practical significance. The conclusions are as follows: (1) In general, industrial structure in most provinces in Northwest China imposes a positive effect over the discharge of pollutants to the aquatic environment. Adjusting industrial structure and reducing the proportion of secondary industry present can to some extent promote reductions in the discharge of pollutants to the aquatic environment. However, such beneficial effects may vary among different provinces. (2) Specifically, for Gansu, province industrial structure adjustment could help reduce the discharge of pollutants to the aquatic environment effectively during the early stages, but this positive effect gradually weakens and disappears during the later stages. In Qinghai province, industrial structure adjustment could not help reduce the discharge of pollutants to the aquatic environment effectively during the early stages, but a positive effect gradually increases and continues to function later. The performance in Shaanxi and Xinjiang provinces was quite similar, with industrial structure adjustment helping to effectively reduce the discharge of pollutants to the aquatic environment over a long period of time. This positive effect can play a more sustained and stable role. For Ningxia province, industrial structure adjustment can not only help significantly reduce the discharge of pollutants to the aquatic environment but also displays a significant positive effect. (3) Given the specific conditions and characteristics of the region under study, relevant policies for industrial structure adjustment should be formulated and implemented.

Does Green Credit Policy Move the Industrial Firms Toward a Greener Future? Evidence From a Quasi-Natural Experiment in China

How to utilize financial instrument to deal with environmental issues has been a focal topic. Taking the introduction of green credit program as a “quasi-natural experiment,” the propensity score matching and difference-in-difference approach (PSM-DID) are used to investigate the impact of the green credit policy implemented by Chinese government on firm-level industrial pollutant emissions. The estimation results indicate that the green credit policy significantly reduces corporate sulfur dioxide emissions. Heterogeneity analysis shows this impact is more pronounced for large-scale enterprises and enterprises located in the eastern region. The estimated mediation models reveal that after the implementation of the green credit policy, reduction in sulfur dioxide emissions can be attribute to the increased environmental investment and improved energy consumption intensity. Moreover, the green credit policy is also significantly effective in mitigating the discharge of other common industrial pollutants. Our findings highlight the importance of green credit policies in achieving greener industrial production and more sustainable economic development.

Analysis on the causes of the change in the north-south gap of industrial pollution discharge in China.

What are the causes of the change in the north-south gap of industrial pollution discharge in 2008 and 2016? In order to solve this problem, this paper makes theoretical and empirical research. The results show that (1) the difference in economic growth pattern transformation is the root cause of the change in the north-south gap of industrial pollution discharge.(2) The international financial crisis is the direct cause of the change in the north-south gap of industrial pollution discharge in 2008. The international financial crisis forced the industrial transformation and upgrading of the southern region, which made the TFP of the southern region relatively improve, and then led to the relative reduction of industrial pollution discharge in the southern region. (3) The supply-side structural reform is the direct cause of the change in the north-south gap of industrial pollution discharge in 2016. However, the supply-side structural reform proposed by the central government in 2016 is essentially a further continuation of the policy of “resolving overcapacity” implemented in 2013. In fact, the north-south gap in the growth rate of industrial discharge has changed since 2013.

Ecological Efficiency of Urban Industrial Land in Metropolitan Areas: Evidence from China

Industrial land is an indispensable strategic resource in urban development that plays an indispensable role in ensuring the industrial space of urban construction and development. Measuring and analyzing the eco-efficiency of industrial land utilization (ECILU) can provide insights into how to maximize the input–output ratio of industrial land and ensure the sustainable development of land resources and economies. Based on the undesirable output slacks-based measure (SBM) model, choosing land, capital, and labor as input indicators, and the industrial added value and carbon emissions as desirable and undesirable output indicators, this study measured the ECILUs in 78 cities and 13 metropolitan areas in four Chinese major economic zones from 2007 to 2018, analyzed their spatial and temporal evolution characteristics and regional differences, and constructed a Tobit regression model to test the influence mechanism of each variable on the ECILUs in different regions. This has important theoretical and practical significance for the Chinese government in formulating relevant policies and realizing the green utilization of urban land in the future. Empirical results showed that the ECILUs in most cities were low and that the differences between regions were large. The ECILU in the Western Economic Zone was relatively high, followed by the Eastern, Central, and Northeastern Economic Zones. According to the ECILU value and urban synergy degree of each metropolitan area, this study divided the 13 metropolitan areas into four categories. The regression analysis results showed that the variables had different effects on the ECILUs of all cities and the four economic zones in China. It is suggested that all economic zones should reinforce the optimization of industrial structure, control industrial pollutant discharge, and solve the phenomenon of labor surplus. The Eastern Zone should maintain the growth of its economy while focusing on soil quality. The Central Zone should focus on the efficient use of infrastructure, and the Western, Northeastern, and Central Zones should balance the green coverage area and the industrial land area to ensure the efficient use of urban industrial land.

Superhydrophobic fibers with strong adhesion to water for oil/water separation

BackgroundIn recent years, frequent oil spills and the discharge of industrial organic pollutants have caused long-term damage to the ecological environment and human safety. It is still a challenge to develop low-cost, stable, and reusable materials for highly efficient oil/water separation. MethodsHerein, the steady, recyclable and economical silica-based fibers were fabricated via self-assembly method (based on electrostatic attraction) and hydrophobic modification, which possess superhydrophobicity and petal effect. FindingsThe composite fibers had a high water contact angle of approximately 160 ° and high adhesion to water which can be utilized to adhere droplets without loss. The composite fibers can not only adsorb but also filter oil from water environment, and the separation efficiency reached up to 99.2% even after 10 cycles of dichloromethane/water separation. The fibers have great application potential in oil spill adsorption and oil/water separation.

Characteristics of biochar and its role in the remediation of heavy metals in soil

With the increasing threat of soil heavy metal pollution to the quality of agricultural products and human health, biochar has been widely studied as a substance that can effectively adsorb heavy metals. This study reviewed the preparation of biochar as well as its types and properties and discussed the role and potential risks of biochar in the remediation of heavy metals in soil. Heavy metal pollution in the soil mainly comes from industrial pollution discharge, good drainage, the usage of chemical fertilizers, pesticides and other illegal applications, and it has great influence on plants, human health and soil environment. Biochar can not only adsorb heavy metals in the soil effectively, but also keep the soil fertile and improve crop yields. In addition, different properties of biochar are controlled by different raw materials and production conditions, such as pH, specific surface area and cation exchange capacity. These properties also determine their different interaction mechanisms. The direct effects mainly include complexation, reduction, ion exchange, electrostatic attraction and precipitation, while the brief effects affect the mobility and bioavailability of heavy metals in soil. The risk of biochar application that provides the basis for the production and utilization of biochar in the future was also discussed in the end.