摘要:
Antibiotic residues in soil may cause potential risks to human health and soil ecosystems. To avoid these potential risks, comprehensive study of the adsorption, transport and biodegradation of antibiotics in soil is very imperative. This review provided current views about the most recent studies, which have been conducted toward the adsorption, transport and biodegradation of antibiotics in soil. The influencing factors affecting the adsorption behaviors of antibiotics in soil, including the antibiotics properties (e.g., molecular structure, hydrophobicity, polarity, polarizability, and spatial configuration) and the soil characteristics (e.g., soil type, soil pH, coexisting ions, and soil organic matter), were discussed. The effects of fertilizer colloids, porous media, and pH of soil on the transport behaviors of antibiotics were analyzed. The biodegradation of antibiotics in soil were also highlighted by investigating the effects of soil microbiome, soil pH, soil temperature, and interactions between antibiotics. Prospects of antibiotics adsorption, transport and biodegradation were also proposed.
关键词:
Advanced oxidation processes;Biochar-supported;Density functional theory;Nanoscale zero-valent iron
摘要:
Ciprofloxacin has been frequently detected in water environment, and its removal has become a significant public concern. Biochar-supported nanoscale zero-valent iron (BC/nZVI) to activate hydrogen peroxide (H2O2) has many advantages on promoting the removal of organic contaminants. In this paper, the BC/nZVI activating H2O2 degradation of ciprofloxacin was systematically investigated by experimental and theoretical approaches. The morphologies and property analysis showed that nZVI particles distributed uniformly on the biochar surface, which mainly include (-)OH, >CO and COC and CO groups. Different reaction conditions were compared to define the optimal conditions for ciprofloxacin removal in BC/nZVI/H2O2 system. More than 70% of ciprofloxacin was removed in the optimal conditions: acidic condition (pH 3 approximately 4), low doses of H2O2 (20 mM), and temperature of 298 K. The hydroxyl radical ((*)OH) oxidation was the primary pathway in BC/nZVI/H2O2 degradation of ciprofloxacin process. The theoretical calculation indicated that hydrogen atom abstraction (HAA) pathways were the dominant oxidation pathways contributing 92.3% in overall secondorder rate constants (k) of (*)OH and ciprofloxacin. The current results are valuable to evaluate the application of BC/nZVI activating H2O2 degradation of ciprofloxacin and other fluoroquinolone antibiotics in water treatment plants.
关键词:
Heavy metal;Microbial community;Microbiological indicator;Soil diagnosis
摘要:
Heavy metal contamination of soil has become a serious global issue because of their persistence in the environment and the non-biodegradable nature leading to their accumulation to toxic levels. In order to achieve early warning and prevent soil quality from deteriorating, it is necessary to select suitable indices to diagnose heavy metal pollution. Microbiological indices for monitoring soil pollution by heavy metals are gaining attention. However, the related researches are scattered, and critical review is imperative. This review is mainly to provide readers with an in-depth understanding of the merits and limitations of microbiological indices for heavy metals contaminated and remediated soils. Microbiological indicators include microbial abundance, community diversity and structure, functional activity. The changes of different microbiological indices and the mechanism of microbial response to heavy metal stress in soils are comprehensively summarized. Furthermore, research gaps and future directions of the microbial ecotoxicological diagnosis of soil contamination by heavy metals are also proposed and discussed.
摘要:
In this study, the oxidized multiwalled carbon nanotube (O-MWCNTs) was obtained by a simple method, and investigated by various techniques (SEM, TEM, FT-IR, XPS and zeta potential) for the removal of pefloxacin and Cu (II). The mutual effects of their adsorption onto O-MWCNTs were comprehensively clarified with sole and binary systems with adsorption kinetics, sorption thermodynamic and sorption isotherm models. The results indicated that there are site enhancement and competition of pefloxacin and Cu(II) on O-MWCNTs. According to mechanism investigation on the adsorption of pefloxacin and Cu(II) by XPS analysis, pH impact study, electrostatic interaction and pi-pi interactions, the low concentration of Cu(II)/pefloxacin could act as a bridge between pefloxacin/Cu(II) and O-MWCNTs, which significantly enhances the adsorption of pefloxacin/Cu(II). This study provided effective method and valuable reference for the elimination of pefloxacin/Cu(II) from aquatic environments. (C) 2018 Elsevier B.V. All rights reserved.
摘要:
Perfluorinated substances are global and ubiquitous pollutants. The persistent organic pollution of perfluorochemicals (PFCs) have drawn attentions worldwide. In view of the current need for sustainable development, many researchers began to study the remediation techniques for PFCs. Due to its unique hydrophobic and oil-phobic characteristics, the requirements for the PFCs removal process are different, so that their remediation techniques are still under continuous exploration. Hence, this review summarized the removal behaviors of various PFCs on different materials which supply a good foundation for future investigations in this field. It is evident from previous literature that every remediation techniques for PFCs has its own advantages. Among various currently evaluated removal methods, adsorption seems to be one of the most commonly used and recognized techniques for PFCs pollution control. Other innovative and promising techniques, such as physical and/or chemical methods, have also been tested for their effectiveness in removing perfluorinated compounds.
摘要:
Triclosan (TCS) has been frequently detected in water environment, causing potential threats to the aquatic ecosystem and human health. Although TCS contamination has attracted increasing attentions, its prevention and treatment are still crucial projects for safeguarding the environment. This review covers the most recent studies towards the latest development of treatment techniques of TCS from wastewater. Various techniques for TCS removal were introduced, evaluated and compared, including oxidation (e.g., chlorination, ozonation, Fenton processes, photolysis/photocatalysis, and electrochemical oxidation), reduction-oxidation, biodegradation, adsorption, and combined processes. The oxidation techniques are always efficient for TCS removal, but some disadvantages of them still exist, such as formation of halogenated species (chlorination), relatively low mineralization degree (ozonation), and relatively high energy consumption (electrochemical oxidation). TCS biodegradation needs pre-treatment steps to degrade the toxic pollutants into less toxic by-products. Adsorption has satisfactory TCS removal efficiencies ((>)80%), but the solid residue needs further treatment/disposal upon the end of service life. The combined processes seem to be the most promising technique for TCS removal in wastewater owing to their potential to overcome several intrinsic limitations of each single process. This review provides insight into the control of TCS and other organic pollutants in wastewater. (C) 2019 Elsevier B.V. All rights reserved.
关键词:
Metal NP;Oxide-based Materials;Supercapacitors;Lithium-ion Batteries (LIBs);Layered Double Hydroxides (LDHs)
摘要:
Nanoporous metals and nanoporous metal oxide-based materials are representative type of porous and nanosized structure materials. They have many excellent performances (e.g., unique pore structure, large clear surface area and high electrical conductivity) to be prodigiously promising potentials, for a variety of significant applications (e.g., energy storage, sensing and catalysis). Therefore, this review summarized the recent advances in the development of nanoporous metals/metal oxide-based materials, with special emphasis on superior electrochemical applications: supercapacitors, lithium ion batteries, sensing, electrocatalysis and photocatalysis. The significant and representative studies in each area are comprehensively reviewed and discussed as a reference for researchers working in related areas. We also outline the key challenges and future opportunities in this exciting field.
关键词:
Adsorption modeling;Adsorption sites;Modified biochar;Site energy distribution;Tetracycline
摘要:
As a widely used antibiotic, tetracycline has a huge hidden danger to human health. Municipal sludge rich in organic substances has the potential to produce biochar. In this work, the municipal sludge biochar from solid waste was modified by the alkali-acid binding method, and tetracycline was efficiently removed from the aqueous solution, the adsorption removal efficiency reached to 86% at initial concentration of 200mg/L. The activation energy was determined by analyzing the adsorption kinetics at different temperatures and tetracycline concentrations. The results showed that tetracycline adsorption on modified biochar was endothermic reaction. Presenting the Langmuir-Freundlich model, adsorption site energy distributions was reckoned. The average adsorption site energy and corresponding standard deviation of the adsorption site energy distribution were deduced emphatically to inquiry the strength of tetracycline adsorption on modified biochar and the adsorption site heterogeneity. The method proposed of research further proves that modified biochar from sewage sludge remove tetracycline from contaminated water has great potential, and exploration of tetracycline adsorption mechanisms by quantifying average site energy. The results and methods of this work can be transferred to study water treatment systems.
摘要:
Chlorinated volatile organic compounds (Cl-VOCs) contamination has been recognized as one of the major problem in worldwide due to natural and anthropogenic activities. Recently, several treatment technologies (e.g., adsorption for broader concentration Cl-VOCs, catalytic combustion for high concentration (>500 ppm), advanced oxidation, electrochemical method, metal method and photo catalytic method for low concentration (<500 ppm)) have been applied for Cl-VOCs elimination. In this review, an extensive list of every method from literatures is compiled, and their capacities under various conditions are presented. However, there is still need to find out the practical technologies on commercial scale, leading to improvement of environmental pollution control. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.