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Gasification is an effective technology for the thermal disposal of municipal solid waste (MSW) with lower dioxin emission compared to the prevailing incineration process. Nevertheless, the mechanism of dioxin formation in the reducing atmosphere during the gasification process was seldomly explored. Herein, the effects of the atmosphere, temperature, and chlorine source were systematically investigated in terms of dioxin distribution. With CO

Petrochemical industries are widely distributed in China. As a negative consequence, heavy metals in petrochemical area can result in soil contamination. However, the relevant research of heavy metals contamination in petrochemical area was few. In this study, a total of 103 topsoil samples (20 cm) and 25 profile soil samples were collected and examined in a retired petrochemical industrial area, South China. The results showed the mean contents of Hg, Cd, As, Pb, Ni and Cu were 0.18, 0.69, 16.22, 47.24, 31.62 and 93.06 mg kg

Per- and polyfluoroalkyl substances (PFAS) have concerned the public due to their worldwide distribution and the threat they pose to drinking water safety and human health. Temperature and DC field-induced electroosmotic flow (EOF) are powerful tools to regulate organic contaminant adsorption and control PFOS (as a typical PFAS) transport in porous media. However, the co-driven mechanisms of temperature–electrokinetic transport of contaminants are still unclear. Here, we investigated the synergistic mechanisms of temperature–electrokinetic co-driven PFOS adsorption on zeolite and activated carbon as model geo-adsorbents. We found that DC fields increased PFOS adsorption on activated carbon by up to 19.8%, while they decreased PFOS adsorption on zeolite by up to 21.4%. Increasing the temperature decreased the adsorption of PFOS by activated carbon and zeolite. The temperature and electrokinetic synergistically drive EOF velocity to control PFOS adsorption. Synergistic mechanisms of temperature–electrokinetic regulated kinetic and temperature-regulated thermodynamic (the Gibbs free energy change ΔG) and kinetic (liquid viscosity) under various temperatures and DC field situations were analyzed with models. A kinetic approach interlinking viscosity, EOF velocity, and the kinetic adsorption constants was established to interpret the synergistic mechanisms which can be further adopted to estimate temperature–electrokinetic induced PFOS adsorption benefits to mineral and carbonaceous adsorbents. We concluded that such kinetic regulation may provide support for controlling the transmission of PFOS.

Environmental microbiology has been an essential part of environmental research because it provides effective solutions to most pollutants. Hence, there is an interest in investigating microorganism behavior, such as observation, identification, isolation of pollutant degraders, and interactions between microbial species. To comprehensively understand cell heterogeneity, diverse approaches at the single-cell level are demanded. Thus far, the traditional bulk biological tools such as petri dishes are technically challenging for single cells, which could mask the heterogeneity. Single-cell technologies can reveal complex and rare cell populations by detecting heterogeneity among individual cells, which offers advantages of higher resolution, higher throughput, more accurate analysis, etc. Here, we overviewed several single-cell techniques on observation, isolation, and identification from aspects of methods and applications. Microscopic observation, sequencing identification, flow cytometric identification and isolation, Raman spectroscopy-based identification and isolation, and their applications are mainly discussed. Further development on multi-technique integrations at the single-cell level may highly advance the research progress of environmental microbiology, thereby giving more indication in the environmental microbial ecology.

Per- and polyfluoroalkyl substances (PFAS) is the emerging contaminants of critical concern. Comprehensive understanding of the transport and fate of PFAS in the vadose-zone, a type of water-unsaturated porous media, is key to determination of the risks of the PFAS contamination in the subsurface and to the development of the effective remediation strategies. PFAS transport in the unsaturated porous media is a complex process. In order to disclose the main factors controlling the PFAS transport in unsaturated porous media, we develop the theoretical model based on the dimensionless governing equations for the transient water flow and PFAS transport. The effects of the dimensionless parameters and numbers on the PFAS transport in 2D unsaturated porous media are uncovered based on the second order accurate finite volume method. We find that the retardation numbers and the dimensionless parameters relevant to the properties of porous media as well as the relation between the surface tension and the PFAS concentration play an important role in the PFAS transport in the unsaturated porous media. The effects of the Péclet numbe, Damköhler numbers, and fraction of instantaneous sorption are not significant, however. These findings provide a better understanding of the PFAS transport in vadose zone.

Nonylphenol (NP), as one of the typical endocrine disrupter chemicals (EDCs), has a high detection concentration and frequency in reclaimed water. This research focused on the degradation of NP isomers in two typical reclaimed water irrigation fields in Daxing, China, and Florida, USA. The results showed that the half-lives of NP isomer degradation in the soil of China and Florida were 2.03–8.66 d and 5.16–11.83 d, respectively. The degradation of NP isomers was structure-specific. Isomers of NP5, NP2, NP11, and NP3 had the highest degradation rates in the two soils; NP12, NP7, and NP6 were the isomers with medium degradation rates; and NP4, NP1, NP10, NP9, and NP8 had the slowest degradation rates. Steric hindrance and mean information index for the magnitude of distance (IDWbar) were found to be the better indexes for measuring the degradation of NP isomers compared with the length of the side chain, the type of the substitute, and the molecular connectivity. This study offers insights into the characteristics of NP isomers and two reliable indicators for measuring the degradation of NP isomers, which could provide data support for the environmental fate and the health risk assessment of NP in the future.

Quantitative evaluation of different contaminated soil remediation technologies in multiple dimensions is beneficial for the optimization and comparative selection of technology. Ex situ thermal desorption is widely used in remediation of organic contaminated soil due to its excellent removal effect and short engineering period. In this study, a comprehensive evaluation method of soil remediation technology, covering 20 indicators in five dimensions, was developed. It includes the steps of constructing an indicator system, accounting for the indicator, normalization, determining weights by analytic hierarchy process, and comprehensive evaluation. Three ex situ thermal desorption technology—direct thermal desorption, indirect thermal desorption, and indirect thermal heap—in China were selected for the model validation. The results showed that the direct thermal desorption had the highest economic and social indicator scores of 0.068 and 0.028, respectively. The indirect thermal desorption had the highest technical and environmental indicator scores of 0.118 and 0.427, respectively. The indirect thermal heap had the highest resource indicator score of 0.175. With balanced performance in five dimensions, the indirect thermal desorption had the highest comprehensive score of 0.707, which is 1.6 and 1.4 times higher than the direct thermal desorption and indirect thermal heap, respectively. The comprehensive evaluation method analyzed and compared the characteristics of the ex situ thermal desorption technology from different perspectives, such as specific indicators, multiple dimensions, and single comprehensive values. It provided a novel evaluation approach for the sustainable development and application of soil remediation technology.

Thermal desorption (TD) is generally considered to be an effective but unsustainable technology. Decontamination performance, charring behaviors and physicochemical properties during TD of dibenzofuran-contaminated soil (DCS) are explored. After treatment at 300 °C for 20 min, the dibenzofuran concentration decreases from 3969.37 mg/kg to 17.29 mg/kg, lower than Chinese risk screening value. More than 99% of dibenzofuran in soil are removed at low temperature of 300 °C, meanwhile the organic carbon is partially retained in soil. Removal mechanism of DCS at 300 °C is proposed, including desorption, cracking, and charring. Char material of low H:C ratio is produced by the generation, polymerization and dehydrogenation of aromatic intermediates, and then increases carbon stocks and reduces the carbon footprint of contaminated soil. Meanwhile, due to the char generated, pH, cation exchange capacity and specific surface area of DCS heated at 300 °C are higher than those of raw DCS, promoting ecological restoration and enhancing carbon sink in soil ecosystems. The aforesaid saving energy, reducing carbon footprint and enhancing carbon sink are exactly the main innovative technologies for achieving carbon neutrality. Hence, it may be a contribution to climate change mitigation, in addition to a robust and sustainable remediation of organic contaminated soil.

Polycyclic aromatic hydrocarbons (PAHs) formation from the pyrolysis of waste tires is inevitable because of the complexity of tire formulations and the addition of certain chemicals. In this study, the formation behavior and distribution of PAHs in three-phases were investigated from waste tires under pyrolysis conditions. The influencing factors including the temperature, heating rate, holding time, particle size, catalyzer, and atmosphere, were systematically evaluated. The results showed that PAHs were mainly concentrated in pyrolysis oil (94.59-99.03%), followed by the gas phase (0.96-5.34%), and their content was very low in the solid phase (0.01-0.99%). A higher temperature and slower heating rate lead to partial PAHs decomposition, thus reducing their emissions. The overall formation of PAHs can be inhibited when pyrolyzing coarse-grained tire powder. Furthermore, the PAHs formation mechanisms in waste tires were determined through reaction molecular dynamics, electron paramagnetic resonance, and intermediate products. Tires were mainly decomposed into benzene series, *C

The calorific value of household refuse (HR) is greatly improved after classification, which includes the implementation of sufficient pyrolysis conditions. Therefore, a better pyrolysis effect can be achieved by co-pyrolysis with industrial solid waste (ISW) with high calorific value. In this work, HR and ISW were used as raw materials for co-pyrolysis experiments. The influence on the distribution of three-phase products after co-pyrolysis, the concentration of heavy metals and dioxins in the flue gas, and the distribution of PCDD/Fs isomers were studied. The results showed that, at a temperature of 600 °C and H/C = 1.3, of the formed material, the quantity of pyrolysis gas was approximately 27 wt.%, and the quantity of pyrolysis oil was approximately 40.75 wt.%, which mainly contained alkanes, olefins, and aromatic hydrocarbons. When S/C = 0.008, pyrolysis gas accounted for 25.95 wt.% of the formed material, and pyrolysis oil for 41.95 wt.% of the formed material. The ignition loss rate of pyrolysis coke was approximately 20%, and the maximal calorific value was 14,217 KJ/kg. According to the thermogravimetric experiment, the co-pyrolysis of HR and ISW can promote the positive reaction of pyrolysis, and the weight loss reached 62% at 550 °C. The emission of gaseous heavy metals was relatively stable, and the concentration of heavy metals slightly decreased. The main heavy metals in the ash were Cu, Fe, and Zn. The emission of dioxins could be effectively reduced by the pyrolysis of HR with ISW, and the produced dioxins were mainly synthesized from de novo synthesis. After pyrolysis, the toxic equivalent of dioxins in the flue gas was reduced from 0.69 to 0.29 ng I-TEQ/Nm3, and the distribution of dioxin isomers in the flue gas had little influence. The experimental results provide a theoretical basis for the application of co-pyrolysis technology with HR and ISW.

Uranium and arsenic are two pollutants commonly found in groundwater near uranium mines. However, the reactivity of U(VI) and As(V) need to be carefully investigated to better understand their fate and transport in the environment. In this study, the reactivity of U(VI) and As(V) were studied under various pH, bicarbonate, and Ca2+ levels. In air-equilibrated systems, the reactivity of U(VI) and As(V) generally decreased with the increase in pH, as evidenced by the solubility of U(VI) and As(V) increasing along with the elevation of pH. At pH = 8, 44.70% and 37.81% of initially added U(VI) and As(V) remained soluble. The addition of 1 mM of bicarbonate increased the reactivity of U(VI) and As(V) at mild acidic to neutral pH; however, the presence of bicarbonate significantly increased the solubility of U(VI) at mild alkaline condition, as nearly all U(VI) remained soluble at pH values of 8 and 9. After the addition of Ca2+, the solubility of both U(VI) and As(V) decreased at mild acidic to neutral pH ranges; however, the addition of Ca2+ markedly increased the soluble percentages of U(VI) at neutral pH, in which the condition 97.81 ± 2.95% of U(VI) remained soluble. Comparatively, only 36.13 ± 4.98% and 1.69 ± 1.08% of U(VI) were soluble at the same pH in air-equilibrated and bicarbonate systems. Our study demonstrated that U(VI) and As(V) are less reactive at neutral to alkaline conditions. Furthermore, the addition of bicarbonate and Ca2+ can further reduce the reactivity of U(VI) and As(V) at neutral to alkaline conditions. The findings of this study contribute to a deeper understanding of the fate and transport of U(VI) and As(V) in groundwater and could aid in better designing of U(VI) and As(V) removal processes.

Nonylphenol (NP) and bisphenol A (BPA) are two typical endocrine disrupter chemicals (EDCs) in reclaimed water. In this study, the adsorptions of NP, a branched NP (NP7) and BPA on reclaimed water-irrigated soils were studied by isothermal experiments, and the different environmental factors on their adsorptions were investigated. The results showed that the adsorptions of NP and NP7 on soils conformed to the Linear model, and the adsorption of BPA conformed to the Freundlich model. The adsorptions of NP, NP7 and BPA on soils decreased with increasing temperatures and pHs. Adsorption equilibrium constant (Kd or Kf) were maximum at pH = 3, temperature 25 °C and As(III)-soil, respectively. The adsorption capacity of NP, NP7 and BPA to soils under different cation valence were as follows: neutrally &gt, divalent cations &gt, mono-cations. Kd of NP7 on soil was less than that of NP under different pH and temperatures, while under different cation concentrations it was the inverse. Fourier Transform Infrared Spectrometer (FTIR) analysis showed alkyl chains of NP and BPA seemed to form van der Waals interactions with the cavity of soil. Results of this study will provide further comprehensive fundamental data for human health risk assessment of NP and BPA in soil.

The effects of temperature and CaO introduction on polycyclic aromatic hydrocarbons (PAHs) contents, distribution patterns and toxicity of the products from hydrothermal carbonization (HTC) of swine manure (SM) were investigated in this study for the first time. The results indicated that increasing temperature decreased total PAHs content of the hydrochar, while the PAHs toxicity firstly decreased and then increased during HTC of SM. For the aqueous product, the total PAHs content and toxicity gradually decreased with increasing temperature. CaO introduction during HTC of SM significantly suppressed the PAHs formation and promoted the transformation from higher molecular weight PAHs into lower molecular weight PAHs in HTC products, resulting in the remarkably decreased content and toxicity of PAHs. The lowest total PAHs content (1428.57 μg/kg) and TEQ value (21.33 μg/kg) of the hydrochar were obtained by 15% CaO introduction at 200 °C and 180 °C, respectively, and compared to SM, they were decreased by 73.73% and 79.51%, respectively. Moreover, 3-ring PAHs were the predominant PAHs in HTC products regardless of CaO introduction. The present study demonstrated that CaO assisted HTC at temperature lower than 220 °C was effective to reduce the total content and toxicity of PAHs in SM, and the prepared hydrochar was a promising soil amendment in view of the elimination of PAHs toxicity.

Noble-metal-free heterometallic Ni–Cu nanoparticles (NPs) supported on hydrochar have been developed for CO2 sorption-enhanced steam reforming of acetic acid (AC) to enhance H2 production. Among al...

The modified hydrochar was prepared by a facile one-pot lime-assisted hydrothermal synthesis approach and the modified hydrochar and pristine hydrochar were investigated to immobilize the heavy metals (HMs) of Pb and Cd in contaminated soils. The results showed that the modified hydrochar exerted significantly enhanced effectiveness in immobilizing Pb and Cd comparing to pristine hydrochar, resulting from the increased surface functionality and non-crystalline properties, increased pH value and enhanced electronegativity of hydrochar. By introduction with 5% modified hydrochar, the contaminated soils showed the highest value of 34.5% (Pb) and 8.1% (Cd) reductions in leaching toxicity, and significant improvements of 95.1% (Pb) and 64.4% (Cd) were observed. In addition, the concentrations of acid soluble fraction were remarkably reduced by 54.0% (Pb) and 27.0% (Cd), and the reductions were much higher than that of 29.5% (Pb) and 8.3% (Cd) for 5% pristine hydrochar treatment. The enhanced surface complexation, precipitation and cation-π interaction played an important role in the immobilization of HMs in soils. The present study offered a novel and cost-effective approach to prepare soil amendment from waste biomass towards HMs immobilization in contaminated soils.

The emerging contamination of pathogenic bacteria in the soil has caused a serious threat to public health and environmental security. Therefore, effective methods to inactivate pathogenic bacteria and decrease the environmental risks are urgently required. As a century-old technique, bacteriophage (phage) therapy has a high efficiency in targeting and inactivating pathogenic bacteria in different environmental systems. This review provides an update on the status of bacteriophage therapy for the inactivation of pathogenic bacteria in the soil environment. Specifically, the applications of phage therapy in soil-plant and soil-groundwater systems are summarized. In addition, the impact of phage therapy on soil functioning is described, including soil function gene transmission, soil microbial community stability, and soil nutrient cycling. Soil factors, such as soil temperature, pH, clay mineral, water content, and nutrient components, influence the survival and activity of phages in the soil. Finally, the future research prospects of phage therapy in soil environments are described. Keywords: Bacteriophage therapy, Pathogenic bacteria, Targeted inactivation, Soil, Review

Pyrolysis is one of the most important approaches to convert waste biomass into renewable energy and biomaterials, and the tar is the inevitable by-product of this process. In this study, carbon foams were prepared innovatively with biomass tar as the precursor through spontaneous gas foaming approach and used for dicamba removal from aqueous solution. The results showed that prepared carbon foams had unique properties including rich microporous structure and high specific surface area (reaching 1667 m2/g). In addition, the prepared carbons had high thermal stability due to the high graphitic degree. The adsorption results indicated that pH showed a great effect on the adsorption of dicamba onto the prepared carbon foams. The carbon foam exhibited ultra-fast dicamba removal and ultra-high adsorption capacity of 891.74 mg/g at room temperature. The adsorption process was well described by pseudo-second-order kinetics and Langmuir isotherm models. The thermodynamic study indicated dicamba adsorption onto the prepared carbon foams was a spontaneous and exothermic process. In addition, the good reusability from recovery test demonstrated that the prepared carbon foams had promising potential for dicamba removal from aqueous solution.

Co-hydrothermal carbonization (co-HTC) is recognized as a promising pretreatment for upgrading fuel quality of high moisture biomass prior to further thermal conversion. The properties of the hydrochar derived from co-HTC of sewage sludge (SS) and sawdust (SD), and CO2 gasification characteristics of the hydrochar were investigated. The results showed that the hydrochar had enhanced aromatic degree and increased metals content compared to raw sludge. The hydrochar also exhibited an enhanced gasification reactivity, resulting in high carbon monoxide content in the syngas than that from SS under identical conditions. The temperature and SD/SS mass ratio had a significant influence on the syngas composition mainly by the Boudouard reaction and water gas reaction. The gasification reactivity was strongly associated with the inorganic elements, and the KAlSi3O8 inhibited while the K2CO3 promoted the gasification reaction of hydrochars. Under optimal conditions, a high gasification efficiency of 77.73% was obtained, and the lower heating value of the syngas reached 8.15 MJ/Nm3. This study indicated that co-HTC of SS and SD combined with subsequent gasification had promising potential towards syngas production with high quality.

The hydrochars derived from swine manure were prepared by CaO assisted hydrothermal carbonization (HTC), and their properties were investigated for the first time. The results showed that the pH and yield of the hydrochar were largely increased by CaO addition. HTC of swine manure increased the phosphorus (P) content in the hydrochar, and appropriately 100% of P as apatite-P was enriched in the hydrochar by CaO assisted HTC. Additionally, the CaO addition during HTC improved the porosity of the hydrochar. The FTIR analysis revealed that substantial functional groups were present on the surface of the hydrochar, indicating the facilitated exchange between the hydrochar and hydrophilic soil when the hydrochar was used for soil amendment. This study demonstrated that CaO assisted HTC was a novel strategy to quickly convert swine manure to the promising soil amendment especially for acidic soils.

The synthesis of carbon-based nanomaterials, ideally produced via facile, inexpensive approaches, using sustainable resources as precursors, with modulated structures, morphologies and functionalities is still challenging for energy applications. This work developed a mild one-step hydrothermal synthesis route for the fabrication of highly dispersed metallic nickel nanoparticles on hydrothermal carbons derived from waste biomass. The roles of precursor nickel ion concentration and calcination temperature in modulating the morphology, location and crystalline size of the nickel nanoparticles as well as the metal-support interactions have been delineated. The average grain size of the metallic nickel nanocrystals on the resultant Ni0.5@HCOp nanocatalysts could be tuned to 8–13 nm by varying the preparation conditions. The catalytic abilities of the Ni-based nanocatalysts towards hydrogen-rich syngas production and tar reduction were then tested in a two-stage reactor system using sewage sludge as biomass feedstock. The catalytic tests showed that the Ni0.5@HCOp catalyst calcined at 700 °C was shown to have stronger metal-support interactions compared to other Ni-based nanocomposites, which provided better suppression of coke deposition and resistance of nickel agglomeration during the catalytic gasification process. This highly active catalyst promoted formation of hydrogen-rich syngas, with up to 109.2 g H2/kg sludge, and tar yields as low as 2.12 mg g−1.

Disposal of organic-contaminated soil through ceramsite production can not only generate ceramsite with acceptable properties but also completely remediate the organic-contaminated soil owing to high treatment temperature. However, the removal mechanism of organic pollutants and the gas-solid phase distribution of the pollutants remain unclear. In this study, coking contaminated soils with high concentrations of polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbon (PHC) were used to prepare ceramsite at 1160 °C. The quality of ceramsite met the required product standard when the disposal ratio of contaminated soil was up to 60%. The concentration of PAHs and PHC in the soil was 57.7 mg kg

Formation and emission of dioxins is a great concern during thermal desorption remediation of organic contaminated soil. The differential formation of dioxins from chlorine organic contaminated soil (COCS) and non-chlorine organic contaminated soil (NCOCS) is still unclear and the control technique for the dioxins generated is an urgent need. In this study, the formation and distribution characteristics of dioxins were investigated in the thermal desorption unit combined with flue gas purification system during COCS and NCOCS treatments. Although organic contaminates were well desorbed, de-novo formation of dioxins was observed for both COCS and NCOCS, as well as synthesis from precursors for NCOCS. The gas-phase dioxin in the flue gas purification system continuously decreased during NCOCS thermal desorption, while the dioxin concentration in the quench tower sharply increased from 0.46 to 2.13 ng/Nm

An unprecedented increase in municipal solid waste (MSW) is increasingly attractive in response to waste-to-energy. MSW pretreatment is an essential step due to the inherent properties of MSW. Hydrothermal carbonization (HTC) offers an efficient approach for converting MSW into carbonaceous hydrochars. In this chapter, the formation and transformation of heavy metals and polycyclic aromatic hydrocarbons (PAHs) during HTC of MSW were determined. The results indicated that HTC can homogenize the density and size of MSW and also increase carbon content. Moreover, the concentrations of heavy metals in the leachates of the hydrochars were lower than the United States Environmental Protection Agency (US EPA) maximum limits. Compared to MSW, the concentrations of Cr, Cd, Hg, and Zn in the hydrochars were low and the concentrations of Pb, As, Ni, and Cu were high. The concentrations of PAHs in the hydrochars increased with increasing temperature in the range of 1298.71–177698.20 μg/kg, which were much higher than that in MSW, except for H-160. The dominant PAH rings in MSW and the hydrochars were four-ring PAHs and three-ring PAHs, respectively. These findings suggest that 180°C is an appropriate hydrothermal temperature to reduce heavy metals and the toxicity PAHs of MSW.

Sulfate radical-based advanced oxidation processes have been applied in the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil, during which sulfate can be activated in different ways. In this work, effects of four different ways (FeSO4, NaOH, H2O2, and Heat) activated sodium persulfate (PS) on PAHs removal and soil physicochemical properties (pH, organic matter, functional groups, surface morphology, and partial heavy metal elements) were compared, and the influencing factors and mechanism of soil PAHs removal by thermally activated PS were also studied. The results showed that at the dosage of 3% of persulfate, the removal efficiency of PAHs followed the sequences of Heat (91.4%) > FeSO4 (86.6%) > H2O2 (86.2%) > NaOH (72.9%). However, thermal activation decreased the soil pH and organic matter content more significantly than other treatments. The reaction tended to reach equilibrium at 6 h when the dosage of persulfate was 3% and the activation temperature was 60 °C, and the reaction obeyed pseudo-first-order kinetics. Through quenching experiments, it was found that the free radicals playing a dominant role in the oxidation process were sulfate radicals. Compared with pH, liquid to soil (L/S ratio) and the temperature had more significant impacts on the degradation efficiency of PAHs.

Nonylphenol (NP) and bisphenol A (BPA) are two typical endocrine disrupter chemicals (EDCs) in the reclaimed water. The adsorptions of NP, a branched NP (NP7) and BPA on reclaimed water-irrigated soils were studied by isothermal experiments, and the different environmental factors on their adsorptions were investigated. The results showed that the adsorptions of NP and NP7 on soils conformed to Linear model, and the adsorption of BPA conformed to Freundlich model. The adsorptions of NP, NP7 and BPA on soils decreased with the increasing temperatures and pHs, while increased with the cation valence. Adsorption equilibrium constant (Kd or Kf) were maximum at pH=3, temperature 25℃ and As (Ⅲ)-soil, respectively; The adsorption capacity of NP, NP7, and BPA to soils increased in accordance with cation valence: trivalent cations > divalent cations > mono- cations. Kd of NP7 on soil was less than that of NP under the different pH and temperatures; while under different cations concentrations, it was inverse. Fourier Transform Infrared Spectrometer (FTIR) analysis showed alkyl chains of NP and BPA seemed to form van der Waals interactions with the cavity of soil. Results of this study will provide further comprehensive fundamental data for human health risk assessment of nonylphenol in the soil.

Modeling and prediction of soil hydrologic processes require identifying soil moisture spatial-temporal patterns and effective methods allowing the data observations to be used across different spatial and temporal scales. This work presents a methodology for combining spatially- and temporally-extensive soil moisture datasets obtained in the Shale Hills Critical Zone Observatory (CZO) from 2004 to 2010. The soil moisture was investigated based on Empirical Orthogonal Function (EOF) analysis. The dominant soil moisture patterns were derived and further correlated with the soil-terrain attributes in the study area. The EOF analyses indicated that one or two EOFs of soil moisture could explain 76&ndash, 89% of data variation. The primary EOF pattern had high values clustered in the valley region and, conversely, low values located in the sloping hills, with a depth-dependent correlation to which curvature, depth to bedrock, and topographic wetness index at the intermediate depths (0.4 m) exhibited the highest contributions. We suggest a novel approach to integrating the spatially-extensive manually measured datasets with the temporally-extensive automatically monitored datasets. Given the data accessibility, the current data merging framework has provided the methodology for the coupling of the mapped and monitored soil moisture datasets, as well as the conceptual coupling of slow and fast pedologic and hydrologic functions. This successful coupling implies that a combination of diverse and extensive moisture data has provided a solution of data use efficiency and, thus, exciting insights into the understanding of hydrological processes at multiple scales.

Soil polycyclic aromatic hydrocarbons (PAHs) contamination caused by factory relocations is a serious environmental issue across the world. Electrical resistance heating (ERH) and chemical oxidation are two promising in-situ methods for treating volatile and semi-volatile organic pollutants in contaminated soil. Coupling of ERH and chemical oxidation technologies to improve the remediation efficiency for PAH-contaminated soil was estimated in this study. PAH removal ratio in contaminated soils using ERH treatment were significantly negatively correlated with the boiling point of the pollutants (P = 0.002), and 21.63% (DBA high boiling point) to 71.53% (Nap low boiling point) of PAHs in the contaminated soil were removed in 120 min. With oxidant Na

Recently, emerging contaminants (ECs) in soil and groundwater have received intensive attention due to their potential impacts on ecological systems and on human health in the long run. To address the concern we confronted, some essential aspects on ECs were discussed here including the source, occurrence, pathways, adverse effects, ecological risk assessment, regulation, and remediation technologies. ECs enter soil and groundwater via both point and non-point sources, such as the discharges from livestock and poultry farming, the pharmaceutical industry, medical and health care industry, and the run-off from contaminated soil, etc. Inevitably these pollutants migrate, permutate, and transport between soil zone and groundwater and part of them reach surface water. They have shown detrimental influences on the quality of soil and groundwater directly and adverse effects on the inhabited living organisms. Risks for human beings come from the contaminated soil and groundwater and surface. The risks need to be assessed comprehensively through the exposure concentration analyses, effect concentration analyses, and risk characterizations. However, the mismatching between current regulatory approaches and the rapid surge of chemicals is becoming a huge challenge for researchers, managers, and politicians. Remediation of ECs in soil and groundwater has attracted extensive attention and is an urgent call for the research community and for governors. However, traditional disposal and treatment methods used for conventional organic chemicals are mainly adapted and employed for ECs due to slow-paced progress on ECs management. Generally, these technologies aim to reduce the concentration/activity of EC pollutants through physical, chemical, biological, and ecological principles and combination methods. Several novel treatment methods which we employed in our work were introduced here with schematic diagrams. Moreover, the effects of the remediation methods on the expected EC detoxification effects are also discussed.

Activated carbon is commonly used to remove dioxins from flue gas via adsorption. Improving the targeted adsorption capacity of activated carbon for dioxins can reduce the consumption of adsorbents and help achieve emission standards for target pollutants. Here, commercial coal-based activated carbon was used as a raw material and modified by urea impregnation along with treatment at high temperature under a nitrogen atmosphere. It was found that modification with urea effectively improved the pore structure of activated carbon while incorporating a certain amount of nitrogen. The best modification effect was achieved at a modification temperature of 600 °C, an impregnation ratio of urea to activated carbon of 1:1, and with high-temperature treatment for 2 h. The mesopore volume of the modified activated carbon (AC600) reached 0.38 cm3/g, accounting for 57.58% of the total pore volume. With an impregnation ratio of urea to activated carbon of 1:1, high-temperature treatment for 2 h, and a modification temperature of 800 °C, a certain amount of nitrogen was introduced into the carbon rings to form a modified activated carbon (AC800) rich in pyridine and pyrrole groups (atomic percentage = 4.84%). The activated carbon modified by urea and the unmodified activated carbon were subsequently selected for dioxin adsorption experiments using a dioxin generation and adsorption system. AC600 showed the highest adsorption efficiency for dioxins, reaching 97.65%, based on toxicity equivalents. Although AC800 has poor pore properties, it has more pyridine and pyrrole groups than AC600. Consequently, the efficiency of AC800 at adsorbing low-concentration dioxins reached 85.24% based on toxicity equivalents. Overall, this study describes two mechanisms for effectively modifying activated carbon with urea based on (1) optimizing the pore structure of activated carbon and (2) incorporating nitrogen.

There is less research on the hydrological system and its destruction processes mechanism in the mining areas, especially combined application of isotope technology and chemical signals, which is a key scientific problem that need to be solved. This study takes Jinci spring area in Shanxi as a case study. It is based on the data of hydrology and mining condition from 1954 to 2015, combining monitoring experiments, O18, D, S34 and N15 tracing, chemical and model simulation. This study investigates the hydrological regularity and impacts of mining activities on water quantity and quality, and reveals the destruction process of hydrological system. The results show that: (1) Water chemical type shows an evolutionary trend of HCO3−-Ca2+-Mg2+→SO42--HCO3--Ca2+-Mg2+→SO42--Ca2+-Mg2+, due to the influence of exploitation and fault zones. Isotope tracer shows that mine pit water is formed by a mixture of pore water, karst water and surface water. (2) Although precipitation and seepage have a certain impact on the reducing of groundwater quantity, over-exploitation of water resource is still the main reason for reducing of groundwater quantity. Under the conditions of keeping the exploitation intensity at the current level or reducing it by 10%, groundwater level shows a declining trend. Under the condition of reducing it by 30%, groundwater level starts to rise up. When reducing by 50%, groundwater level reaches its highest point. Coalmining changes the runoff, recharge and discharge paths. (3) From 1985 to 2015, Water quality in the mining area is worsening. Ca2+ increases by 35.30%, SO42− increases by 52.80%, and TDS (Total Dissolved Solid) increases by 67.50%. Nitrates come from the industrial and domestic wastewater, which is generated by mining. The percentage of groundwater coming from gypsum dissolusion is 67.51%, and the percentage from coal measure strata water is 34.49%. The water qualities of river branches are generally deteriorated.

The hydrological and pollution processes are an important science problem for aquatic ecosystem. In this study, the samples of river water, reservoir water, shallow groundwater, deep groundwater, and precipitation in mining area are collected and analyzed. δD and δ18O are used to identify hydrological process. δ15N-NO3- and δ18O-NO3- are used to identify the sources and pollution process of NO3−. The results show that the various water bodies in Fenhe River Basin are slightly alkaline water. The ions in the water mainly come from rock weathering. The concentration of SO42- is high due to the impact of coal mining activity. Deep groundwater is significantly less affected by evaporation and human activity, which is recharged by archaic groundwater. There are recharge and discharge between reservoir water, river water, soil water, and shallow groundwater. NO3− is the main N species in the study area, and forty-six percent of NO3−-N concentrations exceed the drinking water standard of China (NO3−-N ≤ 10 mg/L content). Nitrification is the main forming process of NO3−. Denitrification is also found in river water of some river branches. The sources of NO3− are mainly controlled by land use type along the riverbank. NO3− of river water in the upper reaches are come from nitrogen in precipitation and soil organic N. River water in the lower reaches is polluted by a mixture of soil organic N and fertilizers.

The cleaning-up of viscous oil spilled in ocean is a global challenge, especially in Bohai, due to its slow current movement and poor self-purification capacity. Frequent oil-spill accidents not only cause severe and long-term damages to marine ecosystems, but also lead to a great loss of valuable resources. To eliminate the environmental pollution of oil spills, an efficient and environment-friendly oil-recovery approach is necessary. In this study,1expanded graphite (EG) modified by CTAB-KBr/H3PO4 was synthesized via composite intercalation agents of CTAB-KBr and natural flake graphite, followed by the activation of phosphoric acid at low temperature. The resultant modified expanded graphite (M-EG) obtained an interconnected and continuous open microstructure with lower polarity surface, more and larger pores, and increased surface hydrophobicity. Due to these characteristics, M-EG exhibited a superior adsorption capacity towards marine oil. The saturated adsorption capacities of M-EG were as large as 7.44 g/g for engine oil, 6.12 g/g for crude oil, 5.34 g/g for diesel oil and 4.10 g/g for gasoline oil in 120min, exceeding the capacity of pristine EG. Furthermore, M-EG maintained good removal efficiency under different adsorption conditions, such as temperature, oil types, and sodium salt concentration. In addition, oils sorbed into M-EG could be recovered either by a simple compression or filtration-drying treatment with a recovery ratio of 58–83%. However, filtration-drying treatment shows better performance in preserving microstructures of M-EG, which ensures the adsorbents can be recycled several times. High removal capability, fast adsorption efficiency, excellent stability and good recycling performance make M-EG an ideal candidate for treating marine oil pollution in practical application.