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•● Fe3O4@MoS2-X hybrids were successfully prepared by hydrothermal reactions.•● The degradation rate of SA in Fe3O4@MoS2-3/PMS system was improved by 86 times.•● Anions (Cl-, NO3− and ...SO42−) and humic acid had little effect on SA degradation.•● SO4•- and 1O2 are the main reactive oxygen species in Fe3O4@MoS2-3/PMS system.
By coating with MoS2 on the surface of Fe3O4 nanoparticles, a series of Fe3O4@MoS2-X catalysts were successfully synthesized to activate peroxymonosulfate (PMS) for sulfonamides (SA) degradation. Owing to the highly active Mo(IV) could efficiently improve the Fe(II)/Fe(III) cycle, the activity of the heterogeneous reaction was significantly enhanced. Compared with Fe3O4/PMS system, the degradation efficiency of SA in Fe3O4@MoS2-3/PMS system was improved by 4 times and the degradation kinetic rate was improved by 86 times. In addition to SA, Fe3O4@MoS2-3/PMS system also showed high efficiency in treating other representative emerging pollutants (phenols, endocrine disrupting chemicals, drugs or antibiotics). Fe3O4@MoS2-3/PMS is a system in which Fe3O4 and MoS2 are both active components. The main active free radical in Fe3O4@MoS2-3/PMS system is SO4•-, the generation of HO• may be suppressed after coating MoS2. Meanwhile, exposed Mo(IV) on the surface of MoS2 participates in the reduction of Fe(III) and further promotes the reaction rate. Furthermore, Mo(VI) participates in the generation of non-radical 1O2 which is also an important reactive oxygen species in the system. Fe3O4@MoS2-3 could be applied in a wide initial pH range (3.0 ~ 9.0). Anions (Cl-, NO3− and SO42−) and natural organic matter (humic acid, HA) had little effect on the degradation efficiencies of Fe3O4@MoS2-3. This study provides theoretical and experimental basis for the development and utilization of Fenton-like reaction catalysts.
Pharmaceuticals in surface waters have raised significant concern in recent years for their potential environmental effects. This study identified that at present a total of 477 substances (including ...66 metabolites and transformation products) have been analyzed in European surface waters. Around 60% (284) of these compounds belonging to 16 different therapeutic groups were positively detected in one or more of 33 European countries. To conveniently and effectively prioritize potential high-risk compounds, an optimized method that considers the frequency of concentrations above predicted no effects levels was developed on the basis of the traditional method, and it was then used to identify and screen candidate priority pollutants in European surface waters. The results proved the feasibility and advantages of the optimized method. Pharmaceuticals detected in European surface waters were classified into 5 categories (high, moderate, endurable, negligible and safe) depending on their potential environmental effects and the distribution of pharmaceuticals. Circa 9% (45 out of 477) analyzed compounds showed a potential environmental risk to aquatic ecosystems. Among these 45 compounds, 12 compounds were indicated to have high environmental risk in aquatic environments, while 17 and 7 compounds showed moderate and small-scale environmental risks, respectively.
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•An optimized method was developed to identify and screen candidate priority pollutants in surface waters.•Different therapeutic groups were positively detected in many European countries.•45 compounds showed potential environmental risks in European surface waters.
Emerging pollutants (EP) are increasingly studied and characterized worldwide to improve the understanding of their environmental and toxicological impacts and their occurrence and behaviors in ...different environmental systems. Latin America has been subject to both environmental and toxicological impacts due to EP. To better understand these impacts, studies concerning pollutants have increased for the last ten years. The current study presents a critical review on the occurrence of different emerging pollutants in various components of the urban water cycle (UWC) in Latin America. The review is based on studies performed in 11 different countries between 1999 and 2018. The countries where the higher number of investigations were conducted are Brazil (53%) and Mexico (15%). The EP most often studied within the literature are pharmaceuticals, followed by personal care products. The most common EP reported were 17β-estradiol, bisphenol A and estrone; The UWC component with the greatest number of measurements in the reported studies were effluents from wastewater treatment plants.
•Research on emerging pollutants in Latin America have not considered the full urban water cycle.•Reported studies have focused on pharmaceuticals in surface and wastewaters.•Occurrence data is growing, but evaluation of risks and control strategies are limited.•Regulatory structures for emerging pollutants in Latin America are almost non-existent.•Research efforts in this area must emphasize the integrated urban water cycle.
•The advantages of polyaniline (PANI)-based adsorbents are discussed;•PANI-based adsorbents and their properties are summarized;•Adsorption mechanisms of PANI-based adsorbents are evaluated;•The ...future of pollutants removal by PANI-based adsorbents is viewed.
Water contamination by a variety of pollutants, such as conventional pollutants (e.g. heavy metals and organics) and emerging micropollutants (e.g. personal care products and endocrine disrupting compounds) is of great concern. Various technologies have been developed to address this critical challenge. Among them, adsorption by polyaniline (PANI)-based nanocomposites, has gained growing research interest recently due to their unique electrical characteristics and many other benefits, such as facile synthesis, low cost, excellent environmental stability, simple acid-base doping/dedoping process, reactive NH– groups, and tunable properties. This paper provides a comprehensive review of the typical PANI-based adsorbents and their properties. Moreover, the removal of various aqueous contaminants (including heavy metals and metalloids, organic dyes and emerging pollutants) by PANI-based adsorbents is discussed and assessed. The unique doping/dedoping of PANI-based adsorbents alters the morphology, pore size, surface charge and functional groups of the adsorbents, leading to enhanced adsorbent-adsorbate interactions and thus adsorption performance. The adsorption mechanisms of aqueous pollutants by PANI-based adsorbents include electrostatic interactions, van der Waals forces, π–π interactions, hydrogen bonding, chelating and/or complexation effects. Finally, the future outlooks on aqueous pollutants removal by PANI-based adsorbents are presented.
The evolution of modern technology and industrial processes has been accompanied by an increase in the utilization of chemicals to derive new products. Water bodies are frequently contaminated by the ...presence of conventional pollutants such as dyes and heavy metals, as well as microorganisms that are responsible for various diseases. A sharp rise has also been observed in the presence of new compounds heretofore excluded from the design and evaluation of wastewater treatment processes, categorized as “emerging pollutants”. While some are harmless, certain emerging pollutants possess the ability to cause debilitating effects on a wide spectrum of living organisms. Photocatalytic degradation has emerged as an increasingly popular solution to the problem of water pollution due to its effectiveness and versatility. The primary objective of this study is to thoroughly scrutinize recent applications of titanium dioxide and its modified forms as photocatalytic materials in the removal and control of several classes of water pollutants as reported in literature. Different structural modifications are used to enhance the performance of the photocatalyst such as doping and formation of composites. The principles of these modifications have been scrutinized and evaluated in this review in order to present their advantages and drawbacks. The mechanisms involved in the removal of different pollutants through photocatalysis performed by TiO2 have been highlighted. The factors affecting the mechanism of photocatalysis and those affecting the performance of different TiO2-based photocatalysts have also been thoroughly discussed, thereby presenting a comprehensive view of all aspects involved in the application of TiO2 to remediate and control water pollution.
•TiO2 and their modified forms used as catalysts in various processes discussed.•Modifications done by immobilization, doping, compositing, forming nanostructures.•Positives and Negatives of TiO2 are discussed.•Applications in degrading emerging pollutants are elaborated.
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•Cyclodextrins nanosponges for the emerging pollutants removal from water.•Fast Ciprofloxacin adsorption and desorption.•Recyclable adsorbent material and pollutant recovery.
This ...study was developed inside the European Project Life “Clean up” (LIFE 16 ENV/ES/000169) to search for suitable adsorbents to purify treated water from emerging pollutants. Notably, among pollutants, the attention was focused on Ciprofloxacin removal, selecting as recyclable adsorbent Cyclodextrin-based nanosponges, characterized by using FTIR-ATR, DSC, TG, SEM, EDX, gas-volumetric analysis, and XRD analyses. Indeed, the in-batch adsorption process was quite complete removing, in a few minutes, 90% of the pollutant from water, with a maximum adsorption capacity of 2 mg/g. A better comprehension of the adsorption mechanism was obtained by studying the effect of various experimental parameters on the process, i.e. ionic strength, pH values, adsorbent/pollutant ratio, and temperature values. The thermodynamics (ΔG°<0 ΔH°<0 and ΔS°>0), the adsorption isotherms (Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich), and kinetics of the process were also investigated. In particular, the applicability of all the proposed isotherms, except the Langmuir model, was observed, and the finding highlighted the heterogeneous character of the adsorption process. The pseudo-second-order kinetic model well described the process and the application of the Weber-Morris model suggested that two main consecutive steps constituted the adsorption. Despite the relatively low adsorption capacity, desorption experiments, recycling 80% of the pollutant for each cycle, were performed, and for the purpose, 0.1 M NaCl was used, lowering the environmental impact. Moreover, other contaminants, such as Diclofenac, Carbendazim, Furosemide, and Sulfamethoxazole were successfully removed from the water, also if present in a quaternary mixture, opening the possibility to use this adsorbent for real water treatments.
Emerging pollutants (EPs) are prevalent in aquatic environments globally. Researchers strive to understand their occurrence and behavior prior to their release into the environment. In this study, we ...examined five wastewater treatment plants (WWTPs), collected 50 wastewater samples and 10 sludge samples. We explored the sources and destinations of phthalic acid esters (PAEs) within these WWTPs using mass balance equations. Wastewater treatment diminished the frequency and concentration of PAEs, and decreased the fraction of short-chain PAEs. We confirmed the increased concentration of PAEs post-primary treatment and modified the mass balance equation. Calculations suggest that weaker “the mix” in winter than in summer and stronger sedimentation in winter than in summer resulted in high efficiency of PAEs removal by winter wastewater treatment. The mass flux of biodegradation was influenced by the combination of biodegradation efficiency and the strength of the particular type of PAEs collected, with no seasonal differences. Mass fluxes for sludge sedimentation were mainly influenced by season and were higher in winter than in summer. This study enhances our understanding of emerging pollutants in manual treatment facilities and offers insights for optimizing wastewater treatment methods for water professionals.
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•Modified mass balance equations are used to study the behaviors of compounds.•Add “mix in” to sources of PAEs in wastewater treatment plants.•PAEs biodegradation flux lacks seasonal variation due to a combination of efficiencies and collection intensity.•Both short- and long-chain PAEs showed higher sedimentation efficiency and flux in winter than in summer.
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•A historical perspective of MOFs as a unique adsorbent was presented.•The synthesis routes, properties and structure of MOFs were critically discussed.•Recent progress on the ...adsorptive sequestration of pollutants by MOFs was reviewed.•The mechanism and effect of operational factors on the performance of MOFs was also reviewed.•Challenges associated with MOFs were elucidated and and suggestions for future progress.
Interest in the use of metal–organic frameworks (MOFs) for the sequestration of pollutants from aqueous media has been increasing in recent times because of the very desirable properties of MOFs, such as eco-friendliness, large surface area and pore volume, hierarchical structures, and tunability of its properties. This work presents a critical and comprehensive review of recent progress in the synthesis and deployment of MOFs-based adsorbents for the sequestration of common pollutants such as heavy metals, dyes, antibiotics, and some emerging pollutants from aqueous solutions. Although some previous reviews explained the adsorptive sequestration of pollutants from wastewater using MOFs, the present review comprehensively compiled the dominant pollutants with up-to-date progress for the simple understanding of their removal from wastewater. Thus, this review takes a critical look at the significant synthesis routes for preparing MOFs-based adsorbents and the essential properties of MOFs that give them an advantage over conventional adsorbents. Furthermore, the mechanism of interaction between MOFs and pollutants in solution and the parametric effect of operational variables on the performance of MOFs were elucidated. Some challenges currently associated with the use of MOFs and the future prospects of this unique adsorbent were highlighted.
17 global Sustainable Development Goals (SDGs) were established through the adoption of the 2030 Agenda for Sustainable Development by all United Nations members. Clean water and sanitation (SDG 6) ...and industry, innovation, and infrastructure (SDG 9) are the SDGs focus of this work. Of late, various new companies delivering metal-organic frameworks (MOFs) have blossomed and moved the field of adsorption utilizing MOFs to another stage. Inside this unique circumstance, this article aims to catch recent advancements in the field of MOFs and the utilizations of MOFs relate to the expulsion of arising contaminations that present huge difficulties to water quality because of their steadiness and possible damage to environments and human wellbeing. Customary water treatment techniques regularly neglect to eliminate these poisons, requiring the advancement of novel methodologies. This study overviews engineering techniques for controlling MOF characteristics for better flexibility, stability, and surface area. A current report on MOFs gathered new perspectives that are amicably discussed in emergent technologies and extreme applications towards environmental sectors. Various applications in many fields that exploit MOFs are being fostered, including gas storage, fluid separation, adsorbents, catalysis, medication delivery, and sensor utilizations. The surface area of a wide range of MOFs ranges from 103 to 104 m2/g, which exceeds the standard permeability of several material designs. MOFs with extremely durable porosity are more significant in their assortment and variety than other classes of porous materials. The work outlines the difficulties encountered in the synthesis steps and suggests ways to make use of MOFs' value in a variety of contexts. This caters to creating multivariate systems enclosed with numerous functionalities, leading to the synthesis of MOFs that offer a synergistic blend of in-built properties and exclusive applications. Additionally, the MOF-related future development opportunities and challenges are discussed.
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•Metal-organic frameworks (MOFs) have emerged as promising materials for removing emerging contaminants.•MOF’s are versatile owing to its stability, better flexibility, porous nature and surface area.•MOF’s possess extraneous applications in fluid separation, contaminant treatment, gas storage, catalytic functions and advanced sensing/functional materials etc.,•This review focuses on implications of MOF’s in water pollution technology and purification processes in depth.
In this study, ionizing radiation was used to induce the in-situ formation of highly dispersed nanosized cobalt oxide on the surface of graphene oxide (R-Co-GO), which was highly effective for ...activating PMS to degrade sulfamethoxazole (SMX). R-Co-GO had the highest catalytic activity when 150 μL cobalt chloride hexahydrate solution was used in the precursor, and the pseudo first-order kinetic constant of SMX degradation was 0.07 min−1 with high mineralization efficiency (63.1 %) and high PMS utilization efficiency. The sulfate radicals and high-valent cobalt oxo were mainly responsible for SMX degradation. Mechanism analysis showed that cobalt active site dominated in PMS activation, which was responsible for the formation of sulfate radicals and high-valent cobalt oxo; while the carbon framework contributed to the formation of singlet oxygen. The R-Co-GO-150 had good catalytic activity and stability in five cycling experiments, in which SMX was completely degraded and the concentration of dissolved Co was below 0.1 mg/L. In addition, the R-Co-GO-150/PMS system could also degrade phenol, bisphenol A, atrazine and nitrobenzene effectively, confirming its wide applicability. This study provided a facile method to uniformly disperse the metal oxides on the surface of carbon materials, and an effective system for the removal of emerging organic pollutants from the actual wastewater.
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•Radiation induced the in-situ formation of highly dispersed nanosized CoO on GO.•Sulfate radicals and high-valent cobalt oxo are responsible for SMX degradation.•Cobalt active sites dominated the PMS activation.•R-Co-GO/PMS could effectively degrade various emerging organic pollutants.
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