Coal fy ash:an emerging material for water remediation

Coal fy ash(CFA)is a byproduct of thermal power plant and collected from fue gases by separator.Composition of CFA depends on the type of coal used and it has both crystalline and amorphous character.It is considered to be an environmental pollutant and used in number of areas.CFA is a useful material and widely used in cement production and as a promising adsorbent for water remediation.CFA used for remediation of wastewater solves problems related to water quality issues and waste management.The physical properties such as porosity,surface area,morphology,and chemical composition(iron oxide,alumina,silica,titania,etc.)make CFA efcient material for wastewater treatment.CFA is also converted to geopolymer,which is used as an adsorbent and photocatalyst.Dye,organic compounds,toxic heavy metal ions,etc.have been removed using CFA and modifed CFA adsorbents.Diferent adsorption efciencies have been reported for diferent adsorbate and CFA adsorbents.Numbers of adsorption isotherm and kinetic models have been discussed.

Comparison and Selection of Water Restoration Techniques for Artificial Landscape Lakes in Nantong City

As an important part of urban infrastructure,urban water system is of great and far-reaching significance for ensuring urban flood control and waterlogging safety,protecting ecological environment and building livable homes.Taking the urban water system of Nantong as an example,Nantong Water Resources Bureau issued R evision of Nantong Urban Water System Planning in 2017,and put forward the construction of the"two circles,eight lakes and nine veins"water system layout,giving new vitality to the urban water system.In view of problems existing in newly excavated artificial landscape lakes,such as fragile water ecosystem,strong eutrophication trend,poor environmental sensory effect and unsatisfactory water landscape effect,it is urgent to study the in-situ water ecological restoration technique of"algae-controlling zooplankton+submerged plant community"to build a"grass-type clear water"ecosystem for artificial landscape lakes,so as to improve the water sensory index and self-purification ability and finally realize the double improvement of"sensory effect and water quality"of artificial landscape lakes.

Preparation of graphene-MoS_2 hybrid aerogels as multifunctional sorbents for water remediation

The increasing demand of clean water and ef- fective way to recycle industrial wastewater has offered a new application for carbon-based three-dimensional （3D） porous networks as sorbents due to their superior sorption abilities. Through the surface modification and hybridization with functional materials, the physical and chemical properties of the 3D carbon-based materials can be engineered. In this work, graphene-MoS2 aerogels （GMAs） with bulky shape are synthesized via a one-pot hydrothermal method. The obtained GMAs show quick sorption rate and high sorption capacity towards a wide variety of contaminants. The sorption covers not only organic solvents or organic dyes, but also toxic heavy metals ions such as Hg2＋ and Pb2＋. More importantly, the sorption capacity towards metal ions can be optimized by simply changing the loading amount of MoS2.

Fundamental Perspectives on the Electrochemical Water Applications of Metal-Organic Frameworks

Metal-organic frameworks(MOFs),a family of highly porous materials possessing huge surface areas and feasible chemical tunability,are emerging as critical functional materials to solve the growing challenges associated with energy-water systems,such as water scarcity issues.In this contribution,the roles of MOFs are highlighted in electrochemical-based water applications(i.e.,reactions,sensing,and separations),where MOF-based functional materials exhibit outstanding performances in detecting/removing pollutants,recovering resources,and harvesting energies from different water sources.Compared with the pristine MOFs,the efficiency and/or selectivity can be further enhanced via rational structural modulation of MOFs(e.g.,partial metal substitution)or integration of MOFs with other functional materials(e.g.,metal clusters and reduced graphene oxide).Several key factors/properties that affect the performances of MOF-based materials are also reviewed,including electronic structures,nanoconfined effects,stability,conductivity,and atomic structures.The advancement in the fundamental understanding of these key factors is expected to shed light on the functioning mechanisms of MOFs(e.g.,charge transfer pathways and guest-host interactions),which will subsequently accelerate the integration of precisely designed MOFs into electrochemical architectures to achieve highly effective water remediation with optimized selectivity and long-term stability.

Catalytic degradation of organic pollutants for water remediation over Ag nanoparticles immobilized on amine-functionalized metalorganic frameworks

Developing efficient catalysts for organic pollutants degradation is crucial for remediating the current severe water environment,yet remains a great challenge.Herein,we report silver nanoparticles immobilized on an amine-functionalized metal-organic framework(MOFs)(Ag/UiO-66-NH_(2))as a robust catalyst for the reduction of 4-nitrophenol(4-NP).The fabricated Ag/UiO-66-NH_(2)catalyst exhibits the merits of superior activities(high turnover frequency(TOF)3.2×10^(4)h^(-1)and k value 6.9×10^(-2)s^(-1)),costeffectiveness under the lowest NaBH4 concentration(n[NaBH_(4)]/n[4-NP],200),outstanding cyclability(10 recycling runs),and observable long-term durability,significantly outperforming previously reported catalytic system.The excellent degradation efficiency is ascribed to the favorable microenvironment modulation of unique MOF structure,which regulates the intrinsic properties of active sites and improves the electron-transfer process.Notably,the Ag/UiO-66-NH_(2)also promotes the catalytic degradation of several organic pollutants at room temperature and hence could find a broad application for water remediation.This work offers a new avenue for the development of high-performance MOF-based catalysts with excellent activity and durability.

Photocatalytic removal of heavy metal ions and antibiotics in agricultural wastewater:A review

In recent years,the treatment of agricultural wastewater has been an important aspect of environmental protection.The purpose of photocatalytic technology is to degrade pollutants by utilizing solar light energy to stimulate the migration of photocarriers to the surface of photocatalysts and occur reduction-oxidation reaction with pollutants in agricultural wastewater.Photocatalytic technology has the characteristics of high efficiency,sustainability,low-energy and free secondary pollution.It is an environmental and economical method to recover water quality that only needs sunlight.In this paper,the mechanism and research progress of photocatalytic removal of heavy metal ions and antibiotics from agricultural water pollution were reviewed by combining photocatalytic degradation process with agricultural treatment technology.The mechanism of influencing factors of photocatalytic degradation efficiency was discussed in detail and corresponding strategies were proposed,which has certain reference value for the development of photocatalytic degradation.

Ecological filter walls for efficient pollutant removal from urban surface water

Urban surface water pollution poses significant threats to aquatic ecosystems and human health.Conventional nitrogen removal technologies used in urban surface water exhibit drawbacks such as high consumption of carbon sources,high sludge production,and focus on dissolved oxygen(DO)concentration while neglecting the impact of DO gradients.Here,we show an ecological filter walls(EFW)that removes pollutants from urban surface water.We utilized a polymer-based three-dimensional matrix to enhance water permeability,and emergent plants were integrated into the EFW to facilitate biofilm formation.We observed that varying aeration intensities within the EFW's aerobic zone resulted in distinct DO gradients,with an optimal DO control at 3.19±0.2 mg L^(-1) achieving superior nitrogen removal efficiencies.Specifically,the removal efficiencies of total organic carbon,total nitrogen,ammonia,and nitrate were 79.4%,81.3%,99.6%,and 79.1%,respectively.Microbial community analysis under a 3 mg L^(-1) DO condition revealed a shift in microbial composition and abundance,with genera such as Dechloromonas,Acinetobacter,unclassified_f__Comamonadaceae,SM1A02 and Pseudomonas playing pivotal roles in carbon and nitrogen elimination.Notably,the EFW facilitated shortcut nitrification-denitrification processes,predominantly contributing to nitrogen removal.Considering low manufacturing cost,flexible application,small artificial trace,and good pollutant removal ability,EFW has promising potential as an innovative approach to urban surface water treatment.

Nanosized magnetite in low cost materials for remediation of water polluted with toxic metals, azo- and antraquinonic dyes

Nanosized magnetite has emerged as an adsorbent of pollutants in water remediation. Nanoadsor- bents include magnetic iron oxide and its modifiers/ stabilizers, such as carbon, silica, clay, organic moieties （polymers, aminoaeids, and fatty acids） and other inorganic oxides. This review is focused on the recent developments on the synthesis and use of magnetic nanoparticles and nanocomposites in the treatment of contaminated water. The emphasis is on the influence of the iron oxide modifiers on some properties of interest such as size, BET area, and magnetization. The characteristics of these nanomaterials are related to their ability to eliminate heavy metal ions and dyes from wastewater. Comparative analysis of the actual literature was performed aiming to present the magnetic material, its preparation methodology and performance in the elimination of the selected pollutants. Vast information has been properly summarized according to the materials, their properties and preferential affinity for selected contaminants. The mechanisms governing nanomaterial＇s formation as well as the interactions with heavy metals and dyes have been carefully analyzed and associated to their efficiency.

Nanobubbles produced by hydraulic air compression technique

The anoxia of coastal water has already been a serious problem all over the word.Nanobubbles are proved to have great applications in water remediation because they could effectively increase the oxygen content and degrade organic matters in water.But the existing methods to produce nanobubbles are complicated and high cost to operate,especially in deep sea.In this paper,we presented a low-cost method,hydraulic air compression(HAC),to produce a large number of nanobubbles and proved that nanoscale gas bubbles could be produced by HAC for the first time.Nanoparticle tracking analysis was used to measure the size and concentration of produced nanobubbles.It indicated that the concentration of nanobubbles would increase as the downpipe height increases.Degassed measurements proved that produced“nanoparticles”are gas nanobubbles indeed.More dissolved oxygen in water would provide the source for larger number of nanobubble formation.Those results are expected to be very helpful for water remediation in ocean in the future.

Rapid Elimination of Black Odor in Rivers by Oxygen Aeration

Laboratory research and engineering applications demonstrated that oxygen aeration can rapidly increase the level of dissolved oxygen in the water of severely polluted rivers. This method was capable of eliminating the odorous substances from black odorous water and reducing the color shade of water, but could not remove the NH3-N, COD, TP or other common pollutants. Therefore, oxygen aeration can be implemented to rapidly eliminate black odorous from rivers, lakes and reservoirs, but cannot be used as a permanent method for treating pollution of rivers.

MoS_(2)的氧化还原特性综述:从污水治理到肿瘤治疗

环境污染及其衍生出的生物毒性是当今世界面临的两大挑战,寻找环境友好型材料是解决这类问题的有效策略之一.作为备受关注的类石墨烯纳米材料,二硫化钼(MoS_(2))性质优越,来源广泛,在污水处理领域具有强大的实际应用价值.与此同时,MoS_(2)还具有良好的生物相容性,因此研究学者们进而开发了其在生物应用领域的潜力,包括杀菌及肿瘤治疗等方面.本文总结了MoS_(2)在水处理及肿瘤治疗方面的应用及进展,并关注MoS_(2)在这两种应用场景下的创新.此外,我们还根据成本、回收效率对MoS_(2)的未来应用进行了展望.

Through converting the surface complex on TiO_(2) nanorods to generate superoxide and singlet oxygen to remove CN^(−)

Cyanide(CN−)is extensively used in the process of plating devices and for surface treatment in the electroplating industry and is extremely hazardous to humans and the environment.Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)hold considerable promise for CN−removal.However,the activity of sulfate radical and hydroxyl radical generated in the PMS activation process is low in the base condition,leading to a drop in its efficiency in CN−removal.Thus,a photo-electrocatalytic system(PEC),developed using a TiO_(2) photoanode and a carbon aerogel cathode,was used to activate PMS for the removal of CN−from wastewater through the generation of radicals and non-radicals.The PEC/PMS system could effectively remove CN^(−),with the removal efficiency reaching 98.5%within 2 min,when PMS concentration was at the 0.25 mmol/L level,and the applied bias voltage was-0.5 V.The main active species in the PEC/PMS system were superoxide radicals and singlet oxygen,which was proved through electron paramagnetic resonance detection and quenching experiments.Results obtained through in-situ Raman measurements,photocurrent tests,and electrochemical impedance spectroscopy measurements indicated that the TiO2 could activate PMS to generate active species.Following many cycles of experimentation,it was discovered that the system displayed high catalytic performance and possessed satisfactory stability to remove CN−economically and efficiently.

Cerium and carbon-sulfur codoped mesoporous TiO_(2)nanocomposites for boosting visible light photocatalytic activity

Ce and C-S codoped mesoporous TiO_(2)nanocomposites were synthesized via a sol-gel method integrated with an evaporation-induced self-assembly approach.The basic physicochemical characteristics of the synthetic samples were analyzed via a series of characterization techniques.The results reveal that C-S and Ce codoping on mesoporous TiO_(2)enhances the photocatalytic activity owing to the synergistic effect caused by narrowing the band gap,enhancing adsorption,trapping and transferring the excited e^(-)/h^(+)pairs and suppressing the recombination of e^(-)/h^(+)pairs.Furthermore,the obtained C,S-TiO_(2)/CeO_(2)materials exhibit large specific surface areas and numerous pores which not only effectively improve the adsorption-enrichment capability,but also supply multi-dimensional mass and electron transfer channels.The photodegradation efficiency of RhB by C,S-TiO_(2)/CeO_(2)within 40 min is nearly 100%,and its degradation efficiency is 6.63 times that of undoped TiO_(2).Recycling experiments show that mesoporous C,S-TiO_(2)/CeO_(2)shows excellent recoverability and stability.Furthermore,by trapping experiments,·O_(2)e^(-)/h^(+)and·OH are the predominant active species and a possible reaction mechanism is proposed.

H_(3)PO_(4) activated biochars derived from different agricultural biomasses for the removal of ciprofloxacin from aqueous solution

Biochars were prepared by the pyrolysis of various H_(3)PO_(4) activated agricultural biomasses at 600℃and subsequently used as adsorbents for the removal of ciprofloxacin(CIP)from aqueous solution.Peanut shell-based biochar(PSBC),corncob-based biochar(CCBC)and cotton-based biochar(CTBC)had high surface areas(571.0-1006.3 m^(2)/g),well-developed pore structures(mesopores with large pore volumes)and available adsorption functional groups(C=C,C-N and C-O-C).The CIP adsorption onto the biochars was investigated by batch experiments(kinetics,isotherms,thermodynamics,pH,etc.).Thermodynamics calculations showed the spontaneous(ΔG^(θ)<0)and endothermic(ΔH^(θ)>0)nature of the mechanism.In particular,CCBC exhibited high adsorption capacity(120.6 mg/g)of CIP in real lake water and it also had significant removal efficiency of other common pharmaceutical contaminants from real lake environ-ment,and even in a coexisting quintuple system.Finally,multiple interaction mechanisms of CIP adsorption onto aromatized biochar were explored combining characterization analysis and theoretical calculations.Elucidation of the mechanism of CIP adsorption onto biochar provides new insights into the assessment of the removal of pharmaceuticals from the aqueous environment.

Enhanced catalytic degradation of organic pollutants by multi-stimuli activated multiferroic nanoarchitectures

Smart catalysts that can simultaneously utilize multiple energy sources will have a significant positive impact on the inefficiencies of conventional environmental remediation approaches,and will address their high energy demands.In this work,we have manufactured multiferroic magnetoelectric photocatalysts that can be simultaneously activated using multiple energy sources for the degradation of organic pollutants.The catalysts are composed of CoFe2O4@BiFeO3(CFO@BFO)nanooctahedrons(NOs),CFO@BFO nanocubes(NCs),and CFO@BFO nanowires(NWs),and were successful in harnessing energy from three different energy sources,including UV-vis light,acoustically mediated mechanical vibrations and magnetic fields.The CFO@BFO NOs displayed the most enhanced degradation,reaching 93%,96%,and 99%degradation of RhB dye within 1 h under light,ultrasound,and magnetic fields,respectively.When these energy sources were used simultaneously,significantly increased reaction rates were observed compared to the single-energy source stimulation.Results of radical trapping experiments indicate that radical species i.e.,OH·and O2·^-play a dominant role in catalytic degradation of organic pollutant,RhB,under all three stimuli.These results will contribute significantly to the development of new environmental technologies that are highly versatile in nature and able to adapt to changing environments to deliver efficient environmental remediation.

Multi-functional polyethersulfone nanofibrous membranes with ultra-high adsorption capacity and ultra-fast removal rates for dyes and bacteria

The adsorption technology has been widely applied in water remediation for contamination removal of dyes and bacteria,by virtue of the advantages of adsorption technology including high efficiency,energy conservation and ease of operation.Simultaneous removal of dyes and bacteria has been realized by some reported materials,but to achieve satisfactory adsorption amounts and rates remain an unmet goal for decades.Herein,a poly(methacrylatoethyl trimethyl ammonium chloride-co-methyl methacrylate)copolymer was synthesized,and then blended with polyethersulfone for the fabrication of nanofibrous membranes via electrospinning for the use of fast and massive removal of dyes and bacteria.Owing to the introduction of abundant quaternary ammonium groups,the maximum adsorption amount for methyl orange was up to 909.8 mg g^(-1).In addition,the modified nanofibrous membranes showed good recyclability,broad applications in severe environments,selective adsorption ability,and excellent dynamic removal performance.Especially,thanks to the abundant functional groups,the membranes showed fast adsorption ability for bacteria through electrostatic interaction.It should be noted that the clearance ratio for Staphylococcus aureus or Escherichia coli by 6 min of static adsorption could reach 93%or 90%for each.Additionally,dynamic removal ratio via filtration with the nanofibrous membranes could reach 99.7%for Staphylococcus aureus or 98.7%for Escherichia coli in 90 s.Therefore,the proposed approach towards the quaternary ammonium modified polyethersulfone nanofibrous membranes creates a new route for ultra-high adsorption capacity and ultra-fast removal rates for dyes and bacteria in water remediation.

Porous β-cyclodextrin nanotubular assemblies enable high-efficiency removal of bisphenol micropollutants from aquatic systems

The performance of water purification by adsorption method has been limited owing to the fact that most of current available adsorbents fail to achieve satisfactory removal performance for organic micropollutants.Herein,we report the design and synthesis of novel porous polymeric adsorbent built fromβ-cyclodextrin(B-CD),in whichβ-CD molecules are arranged in an ordered bis(β-CD)tubular assemblies.The induction of bis(B-CD)units renders them high adsorption affinity toweard bisphenols(bisphenol A and its analogues bisphenol B,bisphenol F and bisphenol S),the typical endocrine disruptors,via the formation of stable host-guest inclusion complexes in aquatic systems.In combination with their high porosity(Brunauer-Emmett-Teller(BET)surface area of 150 m2·g-1),abundantβ-CD content and fast sorption kinetics,the obtained adsorbent outperforms commercial water purifier in elimination of bisphenol micropollutants from potable water.Our work may open a new avenue for designing highly eficient adsorbents for removal of organic micropollutants from aquatic systems.

Kinetics and thermodynamic studies of Methyl Orange removal by polyvinylidene fluoride-PEDOT mats

We report the preparation of poly(3,4-ethylene dioxythiophene)(PEDOT)-modified polyvinylidene fluoride electrospun fibers and their use as a novel adsorbent material for the removal of the anionic dye Methyl Orange(MO)from aqueous media.This novel adsorbent material can be used to selectively remove MO on a wide p H range(3.0-10.0),with a maximum capacity of 143.8 mg/g at p H 3.0.When used in a recirculating filtration system,the maximum absorption capacity was reached in a shorter time(20 min)than that observed for batch mode experiments(360 min).Based on the analyses of the kinetics and adsorption isotherm data,one can conclude that the predominant mechanism of interaction between the membrane and the dissolved dye molecules is electrostatic.Besides,considering the estimated values for the Gibbs energy,and entropy and enthalpy changes,it was established that the adsorption process is spontaneous and occurs in an endothermic manner.The good mechanical and environmental stability of these membranes allowed their use in at least 20 consecutive adsorption/desorption cycles,without significant loss of their characteristics.We suggest that the physical-chemical characteristics of PEDOT make these hybrid mats a promising adsorbent material for use in water remediation protocols and effluent treatment systems.