Hydrodynamic Cavitation Enhanced SR-Aops Degradation of Organic Pollutants in Water:A Review

SR-AOP(sulfate radical advanced oxidation process)is a novel water treatment method able to eliminate refractory organic pollutants.Hydrodynamic cavitation(HC)is a novel green technology,that can effectively produce strong oxidizing sulfate radicals.This paper presents a comprehensive review of the research advancements in these fields and a critical discussion of the principal factors influencing HC-enhanced SR-AOP and the mechanisms of synergistic degradation.Furthermore,some insights into the industrial application of HC/PS are also provided.Current research shows that this technology is feasible at the laboratory stage,but its application on larger scales requires further understanding and exploration.In this review,some attention is also paid to the design of the hydrodynamic cavitation reactor and the related operating parameters.

Applying molecular oxygen for organic pollutant degradation: Strategies, mechanisms, and perspectives

Molecular oxygen(O_(2))is an environmentally friendly,cost-effective,and non-toxic oxidant.Activation of O_(2) generates various highly oxidative reactive oxygen species(ROS),which efficiently degrade pollutants with minimal environmental impact.Despite extensive research on the application of O_(2) activation in environmental remediation,a comprehensive review addressing this topic is currently lacking.This review provides an informative overview of recent advancements in O_(2) activation,focusing on three primary strategies:photocatalytic activation,chemical activation,and electrochemical activation of O_(2).We elucidate the respective mechanisms of these activation methods and discuss their advantages and disadvantages.Additionally,we thoroughly analyze the influence of oxygen supply,reactive temperature,and pH on the O_(2) activation process.From electron transfer and energy transfer perspectives,we explore the pathways for ROS generation during O_(2) activation.Finally,we address the challenges faced by researchers in this field and discuss future prospects for utilizing O_(2) activation in pollution control applications.This detailed analysis enhances our understanding and provides valuable insights for the practical implementation of organic pollutant degradation.

Synergistic effect of CuO coupled with MoS_(2) for enhanced photodegradation of organic dyes under visible light

A series of MoS_(2)-modified CuO(CuO/MoS_(2))heterostructures were successfully fabricated.The photodegradation properties of organic dyes were explored in detail under visible light.The photocatalytic results demonstrate that the CuO/MoS_(2)-3 heterostructure delivers superior degradation rates towards methyl violet dye(MV)and rhodamine B(RhB),reaching 99.8%and 95.3%within 30 min,respectively.The decent photodegradation activity is due to improved visible light adsorption and faster transfer of electron-hole pairs.The radical trapping experiments show that superoxide radicals(O_(2)^(-))and holes(h+)are the main active species in the removal of MV.Furthermore,the CuO/MoS_(2)-3 composite possesses the prominent stability and recyclability.This work offers a highly sustainable technique for designing a high-efficiency photocatalyst to remove environmental pollutants.

A Review of Metal–Organic Framework-Based Compounds for Environmental Applications

Metal–organic framework-based compounds have recently gained great attention because of their unique porous structure,ordered porosity,and high specific surface area.Benefiting from these superior properties,metal–organic framework-based compounds have been proven to be one of the most potential candidates for environmental governance and remediation.In this review,the different types of metal–organic framework-based compounds are first summarized.Further,the various environmental applications of metal–organic framework-based compounds including organic pollutant removal,toxic and hazardous gas capture,heavy metal ion detection,gas separation,water harvesting,air purification,and carbon dioxide reduction reactions are discussed in detail.In the end,the opportunities and challenges for the future development of metal–organic framework-based compounds for environmental applications are highlighted.

Persulfate activation by single-atom catalysts for the removal of organic pollutants: A review

Single-atom catalysts(SACs)have received enormous attention in the field of catalysis due to their inherent mer-its,such as nearly 100%atomic efficiency,environmental friendliness,and unique physicochemical properties.The emerging SACs have facilitated the development and advancement of catalysis.The rapidly increasing ap-plications of SACs in various fields,including oxygen evolution reaction,organic synthesis,hydrogen evolution reaction,and CO_(2) reduction,reflect their enormous potential.Recently,SACs have been extensively used in per-sulfate(PS)activation for refractory organic pollutants degradation in the aqueous environment.SACs exhibit distinct advantages of both homogeneous and heterogeneous catalysis,demonstrating a prospective application in PS activation.This review first introduces the synthesis and characterization schemes of SACs in PS activa-tion.Second,the factors influencing PS activation by SACs,including coordination numbers,type of coordination atoms,the spin state of metal sites,type of carriers,and the loading amount of metal atoms,are described.Third,the applications and activation mechanisms of SACs are summarized.Finally,the opportunities and challenges confronted by SACs and their future development prospects in advanced oxidation processes(AOPs)are put forward.

A Z-scheme LaFeO_(3)-CuFe_(2)O4 composite for sulfate radical-based photocatalytic process:Synergistic effect and mechanism

The sulfate radical-based photocatalytic process is supposed to be the most promising way to degrade organic pollutants.However,the development of a suitable and efficient photocatalyst is very challenging.The 40LaFeO_(3)-CuFe_(2)O_(4)(40LFO-CFO)nanocomposite was constructed and its catalytic performance was studied using Rhodamine B(RhB)as the target pollutant.40LFO-CFO exhibited excellent RhB degradation by the persulfate(PS)-assisted photocatalytic process compared to the pristine LFO and CFO.The degradation rate constant for RhB by 40LFO-CFO in the Vis/PS system was 2.22h^(-1)which is 3.04 times and 5.05 times higher than the pristine LFO(0.73 h^(-1))and CFO(0.44h^(-1)),respectively.Furthermore,the trapping experiments and EPR spectra proved that h^(+) plays a leading role in the bleaching of RhB for the 40LFO-CFO/PS/Vis system.The enhanced photocatalytic oxidation activity of 40LFO-CFO could be attributed to the unique charge carriers flow in 40LFO-CFO due to the Z-scheme and the cooperation effect between photocatalysis and PS activation.The recycle tests confessed the stability of 40LFO-CFO.Additionally,the intermediates and products of RhB are detected by liquid chromatographymass spectrometry(LC-MS),and the photocatalytic degradation routes of RhB for the 40LFO-CFO/Vis/PS system were proposed.Moreover,the 40LFO-CFO nanocomposite has a superior catalytic performance for other organics,suggesting that it is a promising heterocatalyst because of its high catalytic activity and stability for the PS-assisted photocatalytic process.

Phytoremediation and its models for organic contaminated soils

Soil pollution has been attracting considerable public attentions over the last decades. Sorts of traditional physiochemical methods have been used to remove the organic pollutants from soils. However, the enormous costs and low efficiencies associated with these remediation technologies limit their availabilities. Phytoremediation is an emerging technology that uses plants to cleanup pollutants in soils. As overwhelmingly positive results have been shown, phytoremediation is a most economical and effective remediation technique for organic contaminated soils. In this paper phytoremediation and its models for organic contaminated soils are viewed. The mechanisms of phytoremediation mainly include the direct plant uptake of organic pollutants, degradation by plant-derived degradative enzymes, and stimulated biodegradation in plant rhizosphere. Phytoremediation efficiency is close related to physicochemical properties of organic pollutants, environmental characteristics, and plant types. It is no doubt that soil amendments such as surfactants improve the solubilities and availabilities of organic pollutants in soils. However, little information is available about effects of soil amendments on phytoremediation efficiencies. Phytoremediation models have been developed to simulate and predict the environmental behavior of organic pollutants, and progress of models is illustrated. In many ways phytoremediation is still in its initial stage, and recommendations for the future research on phytoremediation are presented.

Novel SiO2 nanoparticle-decorated BiOCl nanosheets exhibiting high photocatalytic performances for the removal of organic pollutants

Novel SiO2/BiOCl composites were fabricated by decorating BiOCl nanosheets with SiO2 nanoparticles via a simple hydrothermal process. The as-prepared pure BiOCl and SiO2/BiOCl composites were intensively characterized by various techniques such as XRD, FT-IR, SEM/TEM, BET, UV-vis, DRS, XPS, and photocurrent measurements. The SiO2/BiOCl composite nanosheets displayed high photocatalytic activity and excellent stability in the degradation of organic pollutants such as phenol, bisphenol A (BPA), and rhodamine B (RhB). With respect to those over bare BiOCl, the degradation rates of RhB, BPA, and phenol over 1.88% SiO2/BiOCl increased 16.5%, 29.0%, and 38.7%, respectively. Radical capturing results suggested that h^+ is the major reactive species and that hydroxyl (·OH) and superoxide (·O2^-) radicals could also be involved in the degradation of organic pollutants. The enhanced photocatalytic performances of SiO2/BiOCl composites can be mainly attributed to the improved texture and the formation of intimate SiO2/BiOCl interfaces, which largely promoted the adsorption of organic pollutants, enhanced the light harvesting, and accelerated the separation of e^– and h^+.

Uptake and translocation of organic pollutants in plants:A review

Organic pollutants, such as polychlorinated dJbenzo-p-dioxins and polychlofinated dibenzofurans （PCDD/Fs）, polychlodnated biphenyls （PCBs）, antibiotics, herbicides, and bisphenol A （BPA）, are commonly found in agricultural environments. They are released into the environment as a result of their use for human health purposes and farm management activities, and are often discharged as waste-water effluents. Most of these organic pollutants are taken up by plants through roots and leaves, and when they enter the tissue, they cause serious damage to the plants. Although the toxicity of organic pollutants to plants, especially to plant cells, has been intensively studied, a systematic review of these studies is lacking. Here we review researches on the toxicity of organic pollutants, their uptake, and translocation in plants. Our objective is to assemble existing knowledge concerning the interaction of organic pollutants with plants, which should be useful for the development of plant-based systems for removing pollutants from aquatic and agricultural environments.

Peroxymonosulfate activation by Mn_3O_4/metal-organic framework for degradation of refractory aqueous organic pollutant rhodamine B

An environmentally friendly Mn‐oxide‐supported metal‐organic framework(MOF),Mn3O4/ZIF‐8,was successfully prepared using a facile solvothermal method,with a formation mechanism proposed.The composite was characterized using X‐ray diffraction,scanning electron microscopy,transmission electron microscopy,X‐ray photoelectron microscopy,and Fourier‐transform infrared spectroscopy.After characterization,the MOF was used to activate peroxymonosulfate(PMS)for degradation of the refractory pollutant rhodamine B(RhB)in water.The composite prepared at a0.5:1mass ratio of Mn3O4to ZIF‐8possessed the highest catalytic activity with negligible Mn leaching.The maximum RhB degradation of approximately98%was achieved at0.4g/L0.5‐Mn/ZIF‐120,0.3g/L PMS,and10mg/L initial RhB concentration at a reaction temperature of23°C.The RhB degradation followed first‐order kinetics and was accelerated with increased0.5‐Mn/ZIF‐120and PMS dosages,decreased initial RhB concentration,and increased reaction temperature.Moreover,quenching tests indicated that?OH was the predominant radical involved in the RhB degradation;the?OH mainly originated from SO4??and,hence,PMS.Mn3O4/ZIF‐8also displayed good reusability for RhB degradation in the presence of PMS over five runs,with a RhB degradation efficiency of more than96%and Mn leaching of less than5%for each run.Based on these findings,a RhB degradation mechanism was proposed.

Genotoxicity evaluation and a primary risk assessment of organic pollutants in the drinking water sources of Nanjing, China

An increasing number of industrial, agricultural, and commercial chemicals in the aquatic environment leads to various deleterious effects on organisms, which is becoming an increasingly serious problem in China. In this study, the comet assay was conducted to investigate the genotoxicity to human body caused by organic concentrates in the drinking water sources of Nanjing City from Yangtze River of China, and health and ecology risk due to expose to these organic pollutants were evaluated with the multimedia environmental assessment system （MEAS）. For all the water samples, they were collected from four different locations in the drinking water sourcr samples, es of Nanjing City. The results of the comet assay showed that all the organic concentrates from the water samples could induce different levels DNA damages on human peripheral blood lymphocytes, and a statistically significant difference （p〈0.01） was observed compared with the solvent control, which demonstrated the genotoxicity was in existence. According to the ambient severity （AS） of individual compound, we had sorted out the main organic pollutants in the drinking water source of the four waterworks, and the results showed that there was some potential hazard to human body for all the source water, namely the total ambient severity （TAS） of health for each water source was more than 1. However, the TAS of ecology for each water source was less than 1, which indicated that it was safe to ecology. The results of this investigation demonstrate the application of the comet assay and the MEAS in aquatic environmental monitoring studies, and the comet assay found to be fast, sensitive, and suitable for genotoxicity monitoring programs of drinking water source.

Removal of Nitrogen, Phosphorus, and Organic Pollutants From Water Using Seeding Type Immobilized Microorganisms

Objective To study the possibility of removing nitrogen, phosphorus, and organic pollutants using seeding type immobilized microorganisms. Methods Lakes P and M in Wuhan were chosen as the objects to study the removal of nitrogen, phosphorus, and organic pollutants with the seeding type immobilized microorganisms. Correlations between the quantity of heterotrophic bacteria and the total nitrogen （TN）, total phosphorus （TP）, and total organic carbon （TOC） in the two lakes were studied. The dominant bacteria were detected, inoculated to the sludge and acclimated by increasing nitrogen, phosphorus and decreasing carbon source in an intermittent, time-controlled and fixed-quantity way. The bacteria were then used to prepare the seeding type immobilized microorganisms, selecting diatomite as the adsorbent cartier. The ability and influence factors of removing nitrogen, phosphorus, and organic pollutant from water samples by the seeding type immobilized microorganisms were studied. Results The coefficients of the heterotrophic bacterial quantity correlated with TOC, TP, and TN were 0.9143, 0.8229, 0.7954 in Lake P and 0.9168, 0.7187, 0.6022 in Lake M. Ten strains of dominant heterotrophic bacteria belonging to Pseudomonas, Coccus, Aeromonas, Bacillus, and Enterobateriaceae, separately, were isolated. The appropriate conditions for the seeding type immobilized microorgansims in purifying the water sample were exposure time=24 h, pH=7.0-8.0, and quantity of the immobilized microorganisms=0.75-1g/50 mL. The removal rates of TOC, TP, and TN under the above conditions were 80.2%, 81.6%, and 86.8%, respectively. Conclusion The amount of heterotrophic bacteria in the two lakes was correlated with TOC, TP, and TN. These bacteria could be acclimatized and prepared for the immobilized microorganisms which could effectively remove nitrogen, phosphorus, and mixed organic pollutants in the water sample.

Organobentonites as adsorbents for some organic pollutants and its application in wastewater treatment

Two organobentonites were synthesized by placing quaternary ammonium cationscetyltrimethylammonium bromide (CTMAB) and cetylpyridinium chloride (CPC) on bentonite bycation exchange. Their ability to adsorb phenol, aniline. nitrobenzene and p-nitrophenol were examined.The optimal conditions for organobentonites to remove the organic pollutants from waterwere studied. The removal rates for organobentonites to treat the organic compounds in water werefound to be over 8 times for the original mineral (untreated bentonite).The removal rates of organic pollutants and COD of wastewater were further improved by organobentonites in the presence of aluminum sulfate. The structure of organobentonites and the mechanism for their adsorption were investigated by X-ray diffraction (XRD) analysis, infrared spectra and BET surface area.

Design of metal-organic frameworks(MOFs)-based photocatalyst for solar fuel production and photo-degradation of pollutants

Metal organic frameworks(MOFs)is a research hotspot in the solar fuel production and photo-degradation of pollutants field due to high surface area,rich metal/organic species,large pore volume,and adjustability of structures and compositions.Therefore,in this review,we first summarized the design factors of photocatalytic materials based on MOF from the perspective of"star"MOF.The modification strategies of MOFs-based photocatalysts were discussed to improve its photocatalytic activity and specific applications were summarized as well,including photocatalytic CO_(2)reduction,photocatalytic water splitting and photo-degradation of pollutants.Finally,the advantages and disadvantages of MOFs-based photocatalysts were discussed,the current challenges were highlighted,and suggestions for future research directions were proposed.

Modified g-C_(3)N_(4) derived from ionic liquid and urea for promoting visible-light photodegradation of organic pollutants

In this work,modified g-C_(3)N_(4) was fabricated successfully by calcination of ionic liquid(IL) and urea.The addition of IL changed the polymerization mode of urea,induced the self-assembly of urea molecules,modified the morphological structure of the tightly packed g-C_(3)N_(4),and extended the electron conjugation system.When using 1-butyl-3-methylimidazolium chloride([Bmim]Cl) as a modifier,the heteroatom Cl could be inserted into the g-C_(3)N_(4) to optimize the electronic structure.The results of characterizations indicate that the unique structure of modified g-C_(3)N_(4) has an expanded electron delocalization range,introduces an interlayer charge transmission channel,promotes the charge transmission,reduces the band gap,enhances the absorption of visible light,and inhibits electron-hole recombination.Modified g-C_(3)N_(4) showed excellent photocatalytic performance for the degradation of rhodamine B and tetracycline.Furthermore,the effect of different anions in 1-butyl-3-methylimidazolium salts([Bmim]Cl,[Bmim]Br,[Bmim][BF_(4)],and [Bmim][PF_6]) on the structure and function of g-C_(3) N_(4) are discussed.

Persistent organic pollutants control strategy in China

The development of Persistent Organic Pollutants(POPs) control policy in China in the context of international concerns on POPs was reviewed. The aspects of the Chinese POPs control strategies were analyzed, and compared with those of developed counterparts (e.g. US, EU, Japan). Currently, while the legal framework on POPs management, which complies with international guidelines has been established, it should be improved in the areas of special POPs management, risk assessment, the precautionary principle, life-cycle management and technical support capacity. The analysis of Chinese POPs policy and suggestions for strengthening the science-based decision making capacity are not only useful for Chinese decision-makers, but also a case study for developing world and make a great contribution for the global elimination of POPs to make a toxic-free future.

Research progress on aging of organic pollutants in geosorbents:a review

Geosorbents are the main host of anthropogenic organic pollutants and play a vital role in their fate and transport in the natural environment.Soil and sediment are the most common and abundant geosorbents in the natural environment;their interactions with organic pollutants,especially sorption and desorption processes,have been extensively studied from the perspectives of thermodynamics and kinetics.Recently,the aging of organic pollutants in geosorbents has drawn increased attention,leading to an improved understanding of interactions between organic pollutants and geosorbents and informing remediation criteria.Aging has been deemed important in accurately assessing ecologic and health risks of organic pollutants,and both positive and negative impacts have been reported in studies of natural and artificial sorbents.This paper summarizes recent research progress on organic pollutant aging in geosorbents,including related mechanism research,influence factors,bioavailability assessments,and biological and physicochemical remediation of aged organic pollutants.We also discuss issues in the current research and bring forward suggestions for future study.

Side－effects of organic and inorganic pollutants on soil nitrification and respiration

Side-effects of heavy metals(Cd and Zn)and organic pollutants(phenanthrene and paclobutrazol)on nitrification and respiration in a loam soil were investigated with its air-dried and fresh conditions. Critical levels for these test pollutants were derived from this investigation.Bioavailable concentrations of Cd and Zn were also determined. It was concluded that such critical levels as NOEL and LOEL of heavy metals should be expressed using bioavailable concentrations rather than total ones since different soil has different properties,especially different absorption ability to heavy metals.

Effects of extra-cellular polymeric substances on organic pollutants biodegradation kinetics for A-step of adsorption-biodegradation process

The features of organic pollutants degradation mainly characterized by bio-flocculation for step-A of adsorption-biodegredation（AB） process were studied. By investigating the relationship of extracellular polymeric substances（EPS） with bioflocculation and introducing kinetic model of organic pollutant degradation into EPS, the kinetic model of organic pollutant degradation for step-A hioflocculation was deducted. And through the experiments, the kinetic constants were calculated as follows： k1 =0. 005 3; kc1 =1 710.7 and vmax1=10 min^-1.

Determining organic compounds in coking wastewater by SPME-GC /MS

The solid-phase microextraction （SPME） combined with gas chromatography/mass spectrometry （GC/MS） was used to determine and analyze organic pollutants in coking wastewater. Based on the fact that the main compounds in the wastewater were organics, some key parameters of the SPME were optimized. The method has good linearity （ its correlation coefficients 〉 0.99） in the range determined,its relative standard deviations （RSD） are less than 15%, and its recovery is from 87.9% to 128.1% with the lowest quantification limit of 5 ~g/L. This method has been used to measure 15 organic pollutants in wastewater from a certain coking plant. The results show that compared with the conventional method,it can save an hour in pretreatment time. It is a fast, low-cost, accurate, simple and efficient analytical method indeed.