Oxidation of emerging organic contaminants by in-situ H_(2)O_(2) fenton system

The existence and risk of emerging organic contaminants(EOCs)have been under consideration and paid much effort to degrade these pollutants.Fenton system is one of the most widely used technologies to solve this problem.The original Fenton system relies on the hydroxyl radicals produced by Fe(Ⅱ)/H_(2)O_(2) to oxidize the organic contaminants.However,the application of the Fenton system is limited by its low iron cycling efficiency and the high risks of hydrogen peroxide transportation and storage.The introduction of external energy(including light and electricity etc.)can effectively promote the Fe(Ⅲ)/Fe(Ⅱ)cycle and the reduction of oxygen to produce hydrogen peroxide in situ.This review introduces three in-situ Fenton systems,which are electro-Fenton,Photo-Fenton,and chemical reaction.The mechanism,influencing factors,and catalysts of these three in-situ Fenton systems in degrading EOCs are discussed systematically.This review strengthens the understanding of Fenton and in-situ Fenton systems in degradation,offering further insight into the real application of the in-situ Fenton system in the removal of EOCs.

Integrated risk assessment framework for transformation products of emerging contaminants:what we know and what we should know

The continuous input of various emerging contaminants(ECs)has inevitably introduced large amounts of transformation products(TPs)in natural and engineering water scenarios.Structurally similar to the precursor species,the TPs are expected to possess comparative,if not more serious,environmental properties and risks.This review summarizes the state-of-the-art knowledge regarding the integrated risk assessment frameworks of TPs of ECs,mainly involving the exposure-and effectdriven analysis.The inadequate information within existing frameworks that was essential and critical for developing a better risk assessment framework was discussed.The main strategic improvements include(1)non-targeted product analysis in both laboratory and field samples,(2)omics-based highthroughput toxicity assessment,(3)multichannel-driven mode of action in conjugation with effectdirected analysis,and(4)machine learning technology.Overall,this review provides a concise but comprehensive insight into the optimized strategy for evaluating the environmental risks and screening the key toxic products from the cocktail mixtures of ECs and their TPs in the global water cycle.This facilitates deciphering the mode of toxicity in complex chemical mixtures and prioritizing the regulated TPs among the unknown products,which have the potential to be considered a class of novel"ECs"ofgreatconcern.

Analysis of Emerging Contaminants in Surface Water,Aquaculture Ponds and Wastewater Treatment Facilities in the Taige Canal Basin

Emerging contaminants(ECs)have aroused great concerns due to their widespread presence as well as their potential health and ecological risks.Currently monitoring data about ECs in Chinese rural areas are still limited.In this study,Taige Canal basin was selected as a typical rural area for a pilot study.The occurrence of ECs,including pharmaceutical and personal care products(PPCPs),pesticides,plasticizers and flame retardants,in surface water and aquaculture ponds,as well as in wastewater treatment facilities,was comprehensively investigated.The effectiveness of rural decentralized wastewater treatment facilities and centralized wastewater treatment plant(WWTP)in removing ECs was also analyzed.Among 126 commonly used pesticides for target analysis,25 compounds were detected in surface water with high frequency of>80%.Besides,55 PPCPs,21 pesticides and 18 other industrial products were identified by non-target analysis using high resolution mass spectrometry(HRMS).Totally 18 compounds were detected in surface water with a frequency of>60%and 6 of them were found in all samples,including irbesartan,valsartan,propazine,buprofezin,bis(2-ethylhexyl)phthalate(DEHP)and tri-(2-chloroisopropyl)phosphate(TCPP),with mean concentrations of 3022,195,125,218,3738 and 545 ng/L,respectively.There are 29 compounds(11 PPCPs,8 pesticides and 10 other industrial products)detected in water samples from the aquaculture ponds,of which 13 compounds were found in all three ponds.The removal efficiencies of ECs in wastewater treatment facilities are generally limited,except valsartan(82%–86%),nobiletin(100%)and diisodecylphthalate(100%)were found to be significantly removed.

Advances in Nanomaterial-microbe Coupling System for Removal of Emerging Contaminants

Emerging contaminants are characterized by toxicity,environmental durability,and bioaccumulation.How to effectively remove them has attracted tremendous attention in the field of environmental science and engineering.Nanomaterial-microbe coupling systems driven by photo-electrochemistry have high degradation efficiency and low cost by combining the advantages of nanomaterials and microorganisms in pollutant treatment.This review summarizes the recent development of the nanomaterial-microbe system for the removal of emerging contaminants,which is divided into exogenous nanomaterial-microbe and endogenous nanomaterial-microbe.The interaction mechanism of materials and microorganisms is addressed from the particular perspective of extracellular electron transfer and redox reactions,and the advantages and challenges of the pollutants treatment are analyzed.Furthermore,future applications in the degradation of emerging contaminants in environmental fields have been prospected.

Fabrication of Bi-Bi3O4Cl plasmon photocatalysts for removal of aqueous emerging contaminants under visible light

Photocatalytic oxidation of emerging contaminants(ECs) in water has recently gained extensive attentions. In this study, bismuth oxychloride-based plasmon photocatalysts(BiBiOCl) exhibiting high performance were successfully developed by reducing Bion the surface of BiOCl. Consequently, the photocatalysts were used to remove ECs from water.The effects of developmental process and Bi metal plasmon resonance on the photoelectric performances of Bi-BiOCl were investigated through a series of characterizations. The UV-vis diffuse reflection and photoluminescence spectra revealed that the light absorption range of the photocatalyst gradually increased and the electron recombination rate gradually decreased with the introduction of Bi metals. The optimal removal rates of ciprofloxacin and tetrabromobisphenol A by Bi-BiOCl were 93.8% and 96.4%;the respective reaction rate constants were 5.48 and 4.93 times higher than that of BiOCl. The mechanism study indicated that main reactants in the photocatalytic system were ·O-2radicals and photogenerated holes, and the existence of oxygen vacancies and Bi metals promoted electron transfer in photocatalyst. In conclusion, this research produces a novel, green, highly efficient, and stable visible light photocatalyst for the removal of ECs from water.

New Takes on Emerging Contaminants:Preface

Since the 1990s,there has been a strong interest across the environmental science community in characterizing the threats to human health posed by emerging contaminants.Much of this research has focused on pharmaceuticals and personal care products in Europe and North America.However,the range of chemicals evaluated has expanded dramatically over the past three decades.This expansion raises a

Roadmap of environmental health research on emerging contaminants: Inspiration from the studies on engineered nanomaterials

Research on the environmental health of emerging contaminants is critical to understand their risks before causing severe harm.However,the low environmental concentrations,complex behaviors,and toxicology of emerging contaminants present enormous challenges for researchers.Here,we reviewed the research on the environmental health of engineered nanomaterials(ENMs),one of the typical emerging contaminants,to enlighten pathways for future research on emerging contaminants at their initial exploratory stage.To date,some developed pretreatment methods and detection technologies have been established for the determination of ENMs in natural environments.The mechanisms underlying the transfer and transformation of ENMs have been systematically explored in laboratory studies.The mechanisms of ENMs-induced toxicity have also been preliminarily clarified at genetic,cellular,individual,and short food chain levels,providing not only a theoretical basis for revealing the risk change and environmental health effects of ENMs in natural environments but also a methodological guidance for studying environmental health of other emerging contaminants.Nonetheless,due to the interaction of multiple environmental factors and the high diversity of organisms in natural environments,health effects observed in laboratory studies likely differ from those in natural environments.We propose a holistic approach and mesocosmic model ecosystems to systematically carry out environmental health research on emerging contaminants,obtaining data that determine the objectivity and accuracy of risk assessment.

Emerging contaminants as global environmental hazards.A bibliometric analysis

This paper presents a bibliometric analysis of peer-reviewed scientific literature on emerging contaminants published from 2000 through 2019.A total of 4968 documents(among research articles and review papers)collected from Scopus database were analyzed using the VOSviewer 1.6.11 software.According to our results,this topic has been capturing researchers’attention over the years and the latter five years of the analysis timespan corresponds to the period of highest scientific productivity on this subject,when a 70.4%of all analyzed documents were published.United States,China,Spain,Italy and Canada were the tope5 most productive countries in terms of number of published works,while Science of the Total Environment,Chemosphere,Environmental Science and Pollution Research,Environmental Pollution and Water Research stood out as the journals with the highest number of publications,gathering a 31%of papers and 34%of all citations.According to the frequency of author keywords,the main specific research topic assessed by the researchers are the occurrence of pharmaceuticals and personal care products in wastewater and the removal of such pollutants by the application of adsorption and advanced oxidation processes.

Emerging contaminants in biosolids:Presence,fate and analytical techniques

Emerging contaminants(ECs)represent a small fraction of the large chemical pollution puzzle where a wide variety of potentially hazardous chemicals reach the environment,and new compounds are continuously synthesized and released in wastewater treatment plants and ultimately in effluent and biosolids.ECs have been classified into various categories;however,this article focuses on the fate of major categories,namely pharmaceutical and personal care products(PPCPs),per-and poly-fluoroalkyl substances(PFAS),flame retardants,surfactants,endocrine-disrupting chemicals(EDCs),and microplastics(MPs).These ECs when discharged to sewer and downstream wastewater treatment plants can undergo further transformations and either degrade,persist or convert into by-products which have the potential in some cases to be more hazardous.Because of potential dangerous impacts of the availability of these contaminants in the environment,information on the fate and behavior of these pollutants is highly important to develop new strategies,such as the regulation of chemicals imported into Australia and Australian consumer goods and environmental policies to mitigate them in a sustainable way.Moreover,advanced technologies are required for the detection and identification of novel contaminants emerging in the environment at ultra low levels.The application of chromatographic techniques coupled with mass spectroscopy has provided attractive breakthroughs to detect new emerging contaminants.However,it is crucially important to understand the sensitivity and robustness of these analytical techniques when dealing with complex matrices such as biosolids.In addition,most of the literature was focused on selected compounds or a family of compounds and the existing reviews have paid less attention to examine the formation of metabolites during the wastewater treatment process and their impacts on the ecosystem.This review presents an overview of the presence of different classes of ECs around the world,their quantification from different sources like wastewater(influents or effluents),sludge and biosolids.In addition,the transformation of ECs during the treatment process,the formation of intermediate products and their impacts on the environment are also critically discussed.Three major steps of ECs analysis include sample preparation,extraction and clean-up,and analysis;hence,different methods employed for extraction and clean-up,and analytical techniques for identification are thoroughly discussed,their advantages and limitations are also highlighted.This comprehensive review article is believed to enhance the understanding of ECs in sewage sludge and would be useful to the readers of the relevant communities and various stakeholders to investigate potential technologies to maximize destruction of ECs.

Emerging Organic Contaminants in Chinese Surface Water:Identification of Priority Pollutants

The occurrence and impacts of emerging organic contaminants(EOCs)in the aquatic environment have gained widespread attention over the past two decades.Due to large number of potential contaminants,monitoring campaigns,treatment plants,and proposed regulations should preferentially focus on specific pollutants with the highest potential for ecological and human health effects.In the present study,a multi-criteria screening approach based on hazard and exposure potentials was developed for prioritization of 405 unregulated EOCs already present in Chinese surface water.Hazard potential,exposure potential,and risk quotients for ecological and human health effects were quantitatively analyzed and used to screen contaminants.The hazard potential was defined by contaminant persistence,bioaccumulation,ecotoxicity,and human health effects;similarly,the exposure potential was a function of contaminant concentration and detection frequency.In total,123 compounds passed the preselection process,which involved a priority index equal to the normalized hazard potential multiplied by the normalized exposure potential.Based on the prioritization scheme,11 compounds were identified as top-priority,and 37 chemicals were defined as high-priority.The results obtained by the priority index were compared with four other prioritization schemes based on exposure potential,hazard potential,or risk quotients for ecological effects or human health.The priority index effectively captured and integrated the results from the more simplistic prioritization schemes.Based on identified data gaps,four uncertainty categories were classified to recommend:①regular monitoring,derivation of environmental quality standards,and development of control strategies;②increased monitoring;③fortified hazard assessment;and④increased efforts to collect occurrence and toxicity data.Overall,20 pollutants were recommended as priority EOCs.The prioritized list of contaminants provides the necessary information for authoritative regulations to monitor,control,evaluate,and manage the risks of environmentally-relevant EOCs in Chinese surface water.

Highly efficient degradation of emerging contaminants by magnetic CuO@Fe_(x)O_(y) derived from natural mackinawite(FeS) in the presence of peroxymonosulfate

In this study,natural mackinawite (Fe S),a chalcophilic mineral,was utilized to prepare iron/copper bimetallic oxides (Cu^(O)@Fe_(x)O_(y)) by displacement plating and calcination process.Various characterization methods prove that Cu;is successfully coated on the surface of Fe S,which were further oxidized to Cu^(O),Fe_(3)O_(4)and/or Fe_(2)O_(3)during calcination process,respectively.Cu^(O)@Fe_(x)O_(y)performed highly efficient capacity to activate PMS for the degradation of various emerging pollutants including sulfamethoxazole(SMX),carbamazepine (CBZ),bisphenol A (BPA),2,4-dichlorophenol (2,4-DCP) and diclofenac (DCF) in aqueous solution.Complete removal of the above pollutants was observed after 8 min of Cu^(O)@Fe_(x)O_(y)/PMS treatment.Taking SMX as an example,the key parameters including Cu^(O)@Fe_(x)O_(y)dosage,PMS dosage and initial p H were optimized.The results show that the catalytic system can be worked in a wide p H range (3.0-9.0).The quenching experiments and electron spin resonance (ESR) test demonstrated that the main reactive oxygen species in Cu^(O)@Fe_(x)O_(y)/PMS system were hydroxyl radicals (^(·)OH) and sulfate radicals(SO_(4)^(·ˉ)),and SO_(4)^(·ˉ)was the primary reactive species.Besides,the influence of coexisting anions (i.e.,Cl^(ˉ),NO_(3)^(ˉ),HCO_(3)^(ˉ)and H_(2)PO_(4)^(ˉ)) for the degradation of SMX was explored.Cu^(O)@Fe_(x)O_(y)/PMS system can maintain good catalytic activity and reusability in different water bodies and long-term running.This work provided a green strategy to fabricate the efficient catalyst in PMS-based advanced oxidation processes.

Guidelines for rational design of high-performance absorbents:A case study of zeolite adsorbents for emerging pollutants in water

Rational design is important to achieve high-performance sorbents used to remove the contaminants of emerging concern(CECs) from water.However, it is hard to propose effective design guidelines due to the lack of a clear understanding of the interaction mechanisms. By means of systematic quantum chemical computations, as a case study, we investigated the interactions between zeolite X/M^(n+)-zeolite X(Si/Al=1,M^(n+)=Cu^(2+) and Ni^(2+)) and three commonly used CECs(namely salicylic acid, carbamazepine and ciprofloxacin) in water to clarify the adsorption mechanisms. Our computations found that anionic salicylic acid cannot be adsorbed by neither zeolite X nor M^(n+)-zeolite X in neutral water due to the high electrostatic repulsion. In comparison, carbamazepine and ciprofloxacin have favorable binding energies with both zeolite X and M^(n+)-zeolite X, and their interactions with M^(n+)-zeolite X are stronger due to the joint effects of H-bond, metal complexation and electrostatic interaction. The adsorption loading of ciprofloxacin, which has a large molecular size, on M^(n+)-zeolite X is limited due to the steric hindrance. In general, steric hindrance, electrostatic interaction, H-bond and metal complexation are dominant factors for the examined systems in this study. Thus, for the design of high-performance absorbing materials, we should fully consider the molecular properties of pollutants(molecular size, surface electrostatic potential and atomic type, etc.), and properly enhance the favorable effects and avoid the unfavorable factors as much as possible under the guidance of the interaction mechanisms.

PFAS: Ecological Implications, Remedial Actions and Ethical Considerations

The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals that include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Thermal stability, surface activity, dielectric characteristics, chemical resistance, and inertness are just a few of the technical advantages that this group has over hydrocarbons, and since the 1950s, these chemicals have been largely utilized in a variety of domestic and industrial endeavors. The hydrophilic and lipophilic nature of this class of chemicals accounts for its uniqueness. Up until today, the chemistry and ecotoxicology of these chemicals continue to emerge. Issues concerning the destructive power of ignorance expedited by an ineffective regulatory institution continue to show that manufacturing chemicals are insufficient without giving serious thought to issues of openness and humanity’s awareness of its own safety. When discussing the nature of humanity and how it can be defined or redefined, it is important to allude to the significance of integrating business with ethics in its various forms. This paper highlights the importance of holding polluters accountable for PFAS contamination cleanup costs while emphasizing the need for chemical manufacturers to test and disclose the health and environmental effects of PFAS compounds. In addition, the sources, types, properties, applications, distribution, toxicological implications, regulations, and analytical methods associated with PFAS (per- and polyfluoroalkyl substances) are explored. The effectiveness of the remedial methods described in this paper needs to be progressively tested while exploring other sustainable approaches.

PFAS: Ecological Implications, Remedial Actions and Ethical Considerations

The C-F bond is one of the strongest in organic chemistry. It is responsible for the great stability of perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as “PFAS”, a group of man-made chemicals that include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Thermal stability, surface activity, dielectric characteristics, chemical resistance, and inertness are just a few of the technical advantages that this group has over hydrocarbons, and since the 1950s, these chemicals have been largely utilized in a variety of domestic and industrial endeavors. The hydrophilic and lipophilic nature of this class of chemicals accounts for its uniqueness. Up until today, the chemistry and ecotoxicology of these chemicals continue to emerge. Issues concerning the destructive power of ignorance expedited by an ineffective regulatory institution continue to show that manufacturing chemicals are insufficient without giving serious thought to issues of openness and humanity’s awareness of its own safety. When discussing the nature of humanity and how it can be defined or redefined, it is important to allude to the significance of integrating business with ethics in its various forms. This paper highlights the importance of holding polluters accountable for PFAS contamination cleanup costs while emphasizing the need for chemical manufacturers to test and disclose the health and environmental effects of PFAS compounds. In addition, the sources, types, properties, applications, distribution, toxicological implications, regulations, and analytical methods associated with PFAS (per- and polyfluoroalkyl substances) are explored. The effectiveness of the remedial methods described in this paper needs to be progressively tested while exploring other sustainable approaches.

Construction of MoFs-based nanocomposite membranes for emerging organic contaminants abatement in water

Presence of emerging organic contaminants(EOCs)in water is one of the major threats to water safety.In recent decades,an increasing number of studies have investigated new approaches for their effective removal.Among them,metal-organic frameworks(MOFs)have_attracted increasing attention since their first development thanks to their tunable metal nodes and versatile,functional linkers.However,whether or not MOFs have a promising future for practical application in emerging contaminants-containing wastewater is debatabie.This review summarizes recent studies about the removal of EOCs using MOFs-related material.The synthesis strategies of both MOF particles and composites,including thin-film nanocomposite and mixed matrix membranes,are criticaily reviewed,as well as various characterization technologies.The application of the MOF-based composite membranes in adsorption,separation(nanofiltration and ultrafiltration),and catalytic degradation are discussed.Overall,literature survey shows that MOFs-based composite could play a crucial role in eliminating EOCs in the future.In particular,modified membranes that realize separation and degradation might be the most promising materials for such application.

Photodegradation and Removal of Diclofenac by the Green Alga Nannochloropsis oculata

The emerging contaminants(ECs)are organic compounds including pharmaceuticals.These products are consumed in large quantities,favoring their continuous entrance to the environment and affecting the health of living beings.Diclofenac is a non-steroidal anti-inflammatory drug with analgesic properties of prolonged release.It is the commonest postoperative analgesic,and it is highly consumed without prescription.In recent years,the capability of microalgae to remove pharmaceuticals in water has been tested as a promising tool.In this work,the removal efficiency of diclofenac(16µg/mL)by the microalga Nannochloropsis oculata CCAP 186/7 was evaluated.The major nutrient concentrations in Bold’s Basal Medium were modified(nitrogen and carbon:50 and 100%of their original concentration)to know their effect in the removal of diclofenac.Drug degradation by light was also evaluated.The maximum removal capacity of diclofenac in the medium was 68.8%.The percentage of diclofenac adsorbed on the cell wall was between 6 and 12.7%.Around 23.6%of diclofenac was degraded by light after 18 days.N.oculata did not show growth inhibition due to the presence of diclofenac.The results obtained point to the promissory application of N.oculata as a bioremediation system for diclofenac removal.

A review of the role of emerging environmental contaminants in the development of breast cancer in women

The incidence of breast cancer is on a rise worldwide;it is a disease having a complex etiology.Besides genetics,environmental and other lifestyle factors play a role in the development of the disease.There has been a keen interest in studying associations between breast cancer and exposures to emerging environmental chemicals,which mimic estrogens or influence estrogen levels and signaling in the human body.The common consequence of an endocrine disrupting chemical exposure is that it may have an impact on breast cancer etiology by stimulating formation as well as progression of breast cancer.Exposures to selected emerging environmental contaminants such as alkylphenols(APs),bisphenol A(BPA),parabens,perfluoroalkyl substances(PFASs),phthalates,polybrominated diphenyl ethers(PBDEs),synthetic musks and triclosan,and their probable role in breast cancer development are reviewed.Studies evaluated include the experimental in vitro and in vivo studies as well as human population based studies.In vitro and in vivo evidences indicate that a number of emerging environmental contaminants may play a role in the initiation and/or progression of breast cancer.Although exposures have been assessed in some human populations,breast and other cancer risks associated with these exposures are largely unknown.Efforts should be focussed on the evaluation of these environmental exposures in human populations and their interactions with each other and other genetic and lifestyle risk factors.

Photo enhanced degradation of contaminants of emerging concern in waste water

Emerging contaminants are posing serious global threats to the environment due to their diversity,recalcitrant nature and bioaccumulation.More disturbing is the fact that current wastewater treatment systems do not have the capacity to deal with these class of compounds.The quest to develop new technologies to mitigate the adverse effects of these contaminants has engendered new research interest on photo-enhanced processes.Photo-enhanced processes,with the potential of mineralizing environmental pollutants,currently appears to be the main viable technology for dealing with emerging contaminants.The process of contaminant degradation could either proceed via oxidation or reduction routes,referred to as advanced oxidation processes(AOPs)and advanced reduction processes(ARPs)respectively.Recently,different processes have been incorporated into a single system in order to explore the synergy that ensue from the combination of these processes.These processes that are currently at the front line in dealing with various classes of emerging contaminants,whose presence in the environment continues to grow on a daily basis,are the focus of this review.

Effects of the sunscreen ultraviolet filter,oxybenzone,on green microalgae

Ultraviolet(UV)filters are widely used in sunscreen and personal care products due to their ability to give protection to our skin from UV radiation.Oxybenzone,commonly known as benzophenone-3,is one type of UV filter found as the active ingredient in many pharmaceutical products.Although oxybenzone has been extensively studied as an environmental toxicant in the ecosystem,little is known about its toxicity effects on microalgae.The effects of oxybenzone on growth(measured as OD620 nm,chlɑand carotenoids)and macromolecular composition of polar microalgae(Chlorella UMACC 400 and Chlorella UMACC 401)and temperate microalgae(Chlorella sp.,Chlamydomonas reinhardtii,Scenedesmus quadricauda)were investigated.These microalgae were cultured in triplicate and exposed to different oxybenzone concentrations(0,100,200,300 and 400 mg·L-1),at 4℃and 18 for polar and temperate species respectively,for 96 h.The oxybenzone concentrations used℃represent a range from environmental to extreme concentrations to understand the impact of this toxicant on microalgae.The results showed that the highest concentration of oxybenzone(300 and 400 mg·L-1)had adverse effects on growth rate and biomass of these microalgae.However,exposure to oxybenzone concentrations ranging from 200 mg·L-1 to 400 mg·L-1 did not have significant effects on S.quadricauda growth.The exposure to oxybenzone at higher concentrations also led to changes in cell structure after 96 h.Generally,protein and carbohydrate content of all microalgae except S.quadricauda increased with increasing oxybenzone concentrations.Protein content increased significantly when cells were exposed to oxybenzone,though effects were greater in the polar species,suggesting that it could be one of the adaptive strategies that enabled these microalgae to tolerate oxybenzone.Further investigation is required to determine the effects of oxybenzone on other features of microalgal performance at relevant environmental concentrations.

Engineering carbon nanocatalysts towards efficient degradation of emerging organic contaminants via persulfate activation:A review

The engineering of carbon nanocatalysts for the persulfate activated elimination of emerging organic contaminants(EOCs)demonstrates promising potential compared with metal-based counterparts due to their unique advantage of high stability and low toxicity.The early reviews introduced the theoretical background of persulfate activation together with a detailed summary of different mechanisms responsible for degradation of EOCs.To further unify the state of knowledge,identify the research gaps,and prompt new research in this area,we present a thorough review on current trends in research on metal-free carbon nanocatalysts(e.g.,0D nanodiamond,1D carbon nanotubes and carbon nanofibers,2D graphene and graphitic carbon nitride,and 3D carbon nanocatalysts),with emphasis on their applications in persulfate activation and EOCs decontamination.We also discuss the current challenges and future perspectives in practically relevant applications.Last,we highlight that the development of sustainable carbon nanocatalysts/persulfate systems lies at the interface of multiple disciplines,which calls for future in-depth interdisciplinary collaborations.