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With the fast development of industrialization and urbanization, large amounts of organic pollutants are released into the natural environment. The efficient elimination of organic pollutants is thereby crucial for environmental pollution treatment and human health. In the last decades, photocatalytic degradation of persistent organic pollutants has attracted multidisciplinary interest because of its simple operation on a large scale. However, the whole processes for the photocatalytic degradation of organic pollutants are still unclear. In this perspective, the contribution of reactive species, the contribution of photocatalysts, the analysis of intermediate products, the charge transfer and fast carrier recombination are discussed on biochar-based photocatalysts.

Manganese dioxide (MnO2) is an environmentally friendly metal oxide. The characteristics of diverse morphology, rich crystal forms, and controllable particle size make MnO2 flexibly adaptive to mul...

With the growth of population and the rapid development of industry, a large amount of wastewater containing heavy metals has been produced. How to treat wastewater containing heavy metals effectively is an important problem. In this study, biochar derived from corn straw is prepared at different carbonization temperatures by oxygen-limited carbonization, and finally, biochar derived from the corn straw at different temperatures is obtained. Then, the adsorption characteristics of ionic heavy metal copper in aqueous solution were studied by biochar prepared at different temperatures. Adsorption kinetics of copper in aqueous solution by biochar from corn straw is discussed in detail. Experimental results show that the adsorption capacity of Cu2+ ions in solution by biochar prepared at different temperatures is significantly different. The prepared biochar derived from corn straw is a fragmentary and porous structure. A lot of functional groups appear on the prepared biochar. The pseudo second order kinetic equation can better describe the entire adsorption of Cu2+ ions in solution by biochar prepared under different temperatures. The adsorption process of Cu2+ ions by biochar is controlled by liquid diffusion and intraparticle diffusion.

Uranium (U) is a common radionuclide in soil and groundwater. Uranium contamination often results from uranium mining and processing, nuclear energy power plants, nuclear weapon tests and nuclear accidents. Due to its toxicity and bioaccumulation, it was necessary to treat it effectively. Biochar and FeS nanoparticles were prepared for the treatment of U(VI) in solution. The characteristics of biochar and FeS nanoparticles were determined by Scanning Electron Microscopy, Energy Dispersive Spectrum and Fourier Transform Infrared Spectroscopy and BET adsorption method. The results showed that a large number of functional groups were present on the surface of biochar and FeS nanoparticles. The influencing factors, such as contact time, pH of the solution, initial concentration U(VI) and solution temperature, had an important influence on the adsorption capacity of U(VI) by biochar and FeS nanoparticles.

The removal of uranium on various sorbents has been widely employed in recent times. However, the limited sorption capacities of these sorbents inhibit the actual application of the radionuclide in actual environments. The development of a novel material with high sorption capacity and superior regeneration for the removal of uranium is highly desirable. Therefore, a versatile class of crystalline carbohydrate polymers (COF) was prepared from organic compounds. Moreover, COF-functionalized graphene oxide (COF/GO) was synthesized and tested for the removal of U(VI) from aqueous solutions. The batch characterization showed that COF was vertically oriented on the surface of GO using diboronic acid as nucleation sites. The maximum removal capacity of U(VI) on COF/GO reached 117.67 mg g−1, and was attributed to a huge void ratio and various oxygen-bearing functional groups. In addition, the inner-sphere surface-complexation dominated the U(VI) removal, and the adsorption mechanism of inner-sphere surface-complexation was transferred into surface precipitation with increasing reaction time. COF/GO can be converted into conductive carbon and reduced GO (C/rGO) nanocomposite, which has high specific capacitance. These results suggested that GO-based materials can be considered as promising candidates for the enrichment of U(VI) and energy storage.

A biochar-supported nanoscale ferrous sulfide composite was prepared and applied for the treatment of Pb(II) ions in aqueous solution. The experimental results of SEM, EDS, XRD, and FT-IR spectroscopy clearly implied that the biochar was successfully modified with nanoscale ferrous sulfide composite. The maximum adsorption capacity of Pb(II) ions by FeS@biochar reached 88.06 mg g−1. Compared with other reported adsorbents, the removal rate of Pb(II) ions by FeS@biochar was higher. The pseudo-second-order kinetic model and Langmuir isotherm model could better fit the experimental adsorption results. The removal rate of Pb(II) ions by FeS@biochar was controlled by the chemical reaction and monolayer adsorption on the surface of FeS@biochar. The mechanisms of Pb(II) removal from aqueous solutions by biochar involved electrostatic attraction, hydrogen bonding, physical adsorption, ion exchange, and chemical precipitation. Additionally, the chemical stability and reusability of FeS@biochar were good. It is also an environment-friendly material for low-cost wastewater treatment.

Biochar was prepared from the peanut shell. Then, it was mixed with the clay mineral kaolinite and stirred under the magnetic stirrer. The biochar derived from peanut shell supported with clay mineral kaolinite (B@K) was obtained. Adsorption experiments of dye Acid Orange 7 by B@K were conducted. The characteristics of B@K were determined by the elemental analyzer, specific surface area meter, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer and the model axis-HS. The experimental results showed that a large number of oxygen-containing functional groups appear on the surface of B@K, which is beneficial for binding dye ions. The adsorption process fits well with the pseudo-second-order kinetic model. It indicated that the adsorption process was both physical adsorption and chemical adsorption. Chemical adsorption is the main adsorption process. Langmuir isotherm model can better describe the adsorption isothermal process of B@K on dye Acid Orange 7. The adsorption process is monolayer adsorption process.

Biochar shows significant potential to serve as a globally applicable material to remediate water and soil owing to the extensive availability of feedstocks and conducive physio-chemical surface characteristics. This review aims to highlight biochar production technologies, characteristics of biochar, and the latest advancements in immobilizing and eliminating heavy metal ions and organic pollutants in soil and water. Pyrolysis temperature, heat transfer rate, residence time, and type of feedstock are critical influential parameters. Biochar’s efficacy in managing contaminants relies on the pore size distribution, surface groups, and ion-exchange capacity. The molecular composition and physical architecture of biochar may be crucial when practically applied to water and soil. In general, biochar produced at relatively high pyrolysis temperatures can effectively manage organic pollutants via increasing surface area, hydrophobicity and microporosity. Biochar generated at lower temperatures is deemed to be more suitable for removing polar organic and inorganic pollutants through oxygen-containing functional groups, precipitation and electrostatic attraction. This review also presents the existing obstacles and future research direction related to biochar-based materials in immobilizing organic contaminants and heavy metal ions in effluents and soil. Graphical Abstract

It is becoming increasingly common in recent years that Chinese government officials visit companies on site and the news about this spread widely on the Internet. Official visits can bring various...

Due to mining, industrial wastewater discharge and agricultural fertilization and other human activities, heavy metal cadmium pollution in water bodies has become increasingly prominent. In this study, the sulfidated nanoscale zero-valent iron was prepared by the method of liquid-phase reduction. The removal behaviour of Cd(II) ion in aqueous solution and the effect of pH in solution on its removal rate were investigated. The synthesized materials before and after the adsorption reaction were characterized by scanning electron microscopy, X-ray diffraction and Zeta potential tester. The removal mechanism of Cd(II) ion in solution was explored in details. The results showed that the S-nZVI particles present a polymeric sheet. They contained Fe0, Fe3O4 and FeS. The removal rate of Cd(II) ion by the S-nZVI particles is higher than the nZVI particles. The reaction mechanism for S-nZVI particles to remove Cd(II) ion is that Cd(II) ion replaces Fe in FeS and then combines with S to form stable CdS compound. S has a significant effect on the oxidation process of iron.

The large amounts of heavy metal from landscape wastewater have become serious problems of environmental pollution and risks for human health. It affects the growth of plant and aquatic, and leads to the destruction of landscape. Therefore, the development of efficient novel adsorbent is a very important for treatment of heavy metal. A low-cost and easily obtained agricultural waste (Peanut Shell) was modified by nanoscale Fe3O4 particles. Then, the functionalized porous nanoscale Fe3O4 particles supported biochar from peanut shell (PS-Fe3O4) for removal of Pb(II) ions from aqueous solution was investigated. The characterization of PS-Fe3O4 composites showed that PS from peanut shell was successfully coated with porous nanoscale Fe3O4 particles. The pseudo second-order kinetic model and Langmuir model were more fitted for describing the adsorption process of Pb(II) ions in solution. The maximum adsorption capacity of Pb(II) ions removal in solution by PS-Fe3O4 composites could reach 188.68 mg/g. The adsorption process of Pb(II) ions removal by PS-Fe3O4 composites was a spontaneous and endothermic process. The adsorption mechanisms of Pb(II) ions by PS-Fe3O4 composites were mainly controlled by the chemical adsorption process. They included Fe-O coordination reaction, co-precipitation, complexation reaction and ion exchange. PS-Fe3O4 composites were thought as a low-cost, good regeneration performance and high efficiency adsorption material for removal of Pb(II) ions in solution.

The large amounts ofheavy metal from landscape wastewater have become serious problems of environmental pollution and risks for human health. The development of efficient novel adsorbent is a very important for treatment of heavy metal. The functionalized porous nanoscale Fe

FeS nanoparticles were easily aggregated and oxidized in the natural environment due to van der Waals forces between nanoparticles. Biochar could be used as a carrier to inhibit the agglomeration and oxidization of FeS nanoparticles. An efficient bio-adsorbent (CFeS-WS) from walnut shell (WS) and cellulose composites stabilized iron sulfide nanoparticle was synthesized by the modified method. It also was determined by SEM, EDS, XRD and FT-IR, respectively. The removal of U(VI) ions from aqueous solution by CFeS-WS were conducted. The reaction mechanism between CFeS-WS and U(VI) ions also were discussed in details. The experimental results were showed that the biochar successfully was supported with cellulose/FeS composites (CFeS). CFeS-WS exhibited an excellent removal performance for U(VI) ions in solution. The adsorption process of U(VI) ions by CFeS-WS was more consistent with pseudo second-order kinetic model and Langmuir isotherm model. The proposed reaction mechanism of U(VI) ions removal by CFeS-WS mainly consisted of ion exchange reaction, reduction reaction, hydrogen bonding and functional group, and pore of adsorbent filling. Recycle experiment indicated that CFeS-WS was a cost-effective bio-adsorbent.

Bacteria may change the physicochemical properties of montmorillonite and further effect the disposal of high-level radioactive waste. Therefore, we explored the influence of Shewanella oneidensis MR-1 on the elimination of representative radionuclide U(VI) by montmorillonite (MMT). The batch experiments showed that MR-1 significantly enhanced the removal efficiency of U(VI), the adsorption capacity of MMT improved from 8.4 to 16.1 mg/g after addition of MR-1, and the adsorption type changed from Langmuir to Freundlich. FTIR and XPS analysis revealed that hydroxyl, phosphate, carbonyl and amine in MMT + MR-1 were primary actors in the elimination of U(VI). The U 4f high-resolution XPS spectrum of MMT + MR-1 showed U(VI) and U(IV) peaks at the same time, indicating that the adsorption process was accompanied by the reduction reaction, which may be due to the extracellular respiration of MR-1. These investigations are significant to insight the potential significance of microbial processes for the transport and elimination of U(VI) in repositories, which in return will contribute to their safe disposal.

Because the pollutants produced by human activities have destroyed the ecological balance of natural water environment, and caused severe impact on human life safety and environmental security. Hence the task of water environment restoration is imminent. Metal-organic frameworks (MOFs), structured from organic ligands and inorganic metal ions, are notable for their outstanding crystallinity, diverse structures, large surface areas, adsorption performance, and excellent component tunability. The water stability of MOFs is a key requisite for their possible actual applications in separation, catalysis, adsorption, and other water environment remediation areas because it is necessary to safeguard the integrity of the material structure during utilization. In this article, we comprehensively review state-of-the-art research progress on the promising potential of MOFs as excellent nanomaterials to remove contaminants from the water environment. Firstly, the fundamental characteristics and preparation methods of several typical water-stable MOFs include UiO, MIL, and ZIF are introduced. Then, the removal property and mechanism of heavy metal ions, radionuclide contaminants, drugs, and organic dyes by different MOFs were compared. Finally, the application prospect of MOFs in pollutant remediation prospected. In this review, the synthesis methods and application in water pollutant removal are explored, which provide ways toward the effective use of water-stable MOFs in materials design and environmental remediation.

The novel biochar supported by starch and nanoscale iron sulfide (SFeS@Biochar) composites were successfully prepared through coupling of biochar derived from peanut shell with nanoscale ferrous sulfide and starch under nitrogen atmosphere. It had the advantages of biochar, starch, and nanoscale ferrous sulfide. Therefore, it could overcome some shortcomings. The nanoscale ferrous sulfide particles and starch were thought to be loaded successfully on the surface of the biochar by SEM, EDS, BET, XRD, FT-IR, and XPS techniques. High uptake capacity of U(VI) by SFeS@Biochar could be attributed to reactive reaction of FeS nanoparticles and adsorptive of a lot of functional groups. The proposed reaction mechanisms of the U(VI) uptake by SFeS@Biochar were electrostatic attraction, surface complexation, precipitation, and reductive reaction. It also might be an improved environmentally friendly material for U(VI) removal.

Herein, a potential bio-adsorbent (DACS-CA) was formed via immobilizing caffeic acid (CA) on dialdehyde corn starch (DACS) for Cr(VI) removal. The characterization techniques such as IR, Raman, XPS and 13C NMR were performed to analyze surface elements and functional groups on the as-prepared sorbents. Batch experiments revealed that the maximum Cr(VI) removal amount (96.45 mg/g) took place at a pH value of 3.0, adsorption temperatures of 333 K and solid-liquid ratio of 0.2. The isotherms studies found that the Cr(VI) removal of DACS-CA was monolayer adsorption, while the kinetics analysis revealed that chemisorption was the main power for removal process. Characterization analysis found that about Cr(VI) (53.02%) and Cr(III) (46.98%) species co-existed onto the surface of DACS-CA, which implied that a redox reaction may be occurred between Cr(VI) and the bio-adsorbent. Namely, Cr(VI) was first loaded on DACS-CA via electrostatic interaction, subsequently Cr(VI) was partially transformed into Cr(III) by reductive functional groups, meanwhile the resulting Cr(III) was immobilized by the carboxyl groups of DACS-CA. Thus, this bio-adsorbent could serve as an efficient sorbent for the removal of Cr(VI) from wastewater in environmental pollution cleanup.

Environmental pollution has accelerated and intensified because of the acceleration of industrialization, therefore fabricating excellent materials to remove hazardous pollutants has become inevitable. MXenes as emerging transition metal nitrides, carbides or carbonitrides with high conductivity, hydrophilicity, excellent structural stability, and versatile surface chemistry, become ideal candidates for water purification and environmental remediation. Particularly, MXenes reveal excellent sorption capability and efficient reduction performance for various contaminants of wastewater. In this regard, a comprehensive understanding of the removal behaviors of MXene-based nanomaterials is necessary to explain how they remove various pollutants in water. The eliminate process of MXene-based nanomaterials is collectively influenced by the physicochemical properties of the materials themselves and the chemical properties of different contaminants. Therefore, in this review paper, the synthesis strategies and properties of MXene-based nanomaterials are briefly introduced. Then, the chemical properties, removal behaviors and interaction mechanisms of heavy metal ions, radionuclides, and organic pollutants by MXene-based nanomaterials are highlighted. The overview also emphasizes associated toxicity, secondary contamination, the challenges, and prospects of the MXene-based nanomaterials in the applications of water treatment. This review can supply valuable ideas for fabricating versatile MXene nanomaterials in eliminating water pollution.

The recovery of uranium from wastewater and safe treatment of U(VI)-containing wastewater are of great important to ensure the sustainable development of nuclear-related energy. Although abundant studies of U(VI) sorption on various adsorbents have been widely achieved, U(VI) sorption at extreme pH and trace concentration is challenging issues due to limited sorption activity of natural adsorbents. The development of novel materials with highly efficient and excellent selectivity for capturing U(VI) from nuclear-related wastewater and seawater is highly desirable. In this study, amidoxime/carbon nitride (AO/g-C3N4) was fabricated and captured U(VI) under a variety of water chemistry. We demonstrated that AO/g-C3N4 exhibited the high adsorption capacities (312 mg/g at pH 6.8), fast removal equilibrium (>98% at 10 min) and superior selectivity for U(VI) compared with the other radionuclides (e.g., 19.76 mg/g of Cs(I)). In addition, AO/g-C3N4 exhibited the high uranium extraction capacity from natural seawater (9.55 mg/g at saturation time of 5.5 days) compared to vanadium (1.85 mg/g). U(VI) adsorption behavior at different pH can be excellently fitted by the surface complexation modeling with three inner sphere surface complexes (i.e., SOUO2(CO3)23−, SO(UO2)3(OH)50 and SOUO2+ species). According to XPS (X-ray Photoelectron Spectroscopy) analysis, the strong complexation of U(VI) with AO groups retained in C3N4 nanosheet. The split of U-Oeq2 subshell and the occurrence of U–C shell further demonstrated inner-sphere surface complexation by EXAFS (X-Ray Absorption Fine Structure) spectra analyses. These results revealed that the high potential of AO/g-C3N4 materials for selective U(VI) capture from wastewater and seawater.

Summary Covalent organic frameworks (COFs) are a new type of crystalline porous polymers known for chemical stability, excellent structural regularity, robust framework, and inherent porosity, making them promising materials for capturing various types of pollutants from aqueous solutions. This review thoroughly presents the recent progress and advances of COFs and COF-based materials as superior adsorbents for the efficient removal of toxic heavy metal ions, radionuclides, and organic pollutants. Information about the interaction mechanisms between various pollutants and COF-based materials are summarized from the macroscopic and microscopic standpoints, including batch experiments, theoretical calculations, and advanced spectroscopy analysis. The adsorption properties of various COF-based materials are assessed and compared with other widely used adsorbents. Several commonly used strategies to enhance COF-based materials’ adsorption performance and the relationship between structural property and sorption ability are also discussed. Finally, a summary and perspective on the opportunities and challenges of COFs and COF-based materials are proposed to provide some inspiring information on designing and fabricating COFs and COF-based materials for environmental pollution management., Graphical Abstract, Public summary • Covalent organic frameworks (COFs) are a new type of crystalline porous materials known for chemical stability, high specific surface area, and orderly porous channels.With the rapid growth of industrialization, water pollutants remain a serious issue of public health and environmental protection • COFs as superior adsorbents for the efficient removal of toxic heavy metal ions, radionuclides, and organic pollutants in water is becoming a hot topic • Information about the interaction mechanisms between various pollutants and COFs materials are summarized.The perspectives and challenges are proposed to provide some useful inspiration for the application of COFs in environmental pollution management

Carbon materials derived from metal organic frameworks (MOFs) have excellent properties of high surface area, high porosity, adjustable pore size, high conductivity and stability, and their applications in catalysis have become a rapidly expanding research field. In this review, we have summarized the synthesis strategies of MOF-derived carbons with different physical and chemical properties, obtained through direct carbonization, co-pyrolysis and post-treatment. The potential applications of derived carbons, especially monometal-, bimetal-, nonmetal-doped and metal-free carbons in organo-catalysis, photocatalysis and electrocatalysis are analyzed in detail from the environmental perspective. In addition, the improvement of catalytic efficiency is also considered from the aspects of increasing active sites, enhancing the activity of reactants and promoting free electron transfer. The function and synergy of various species of the composites in the catalytic reaction are summarized. The reaction paths and mechanisms are analyzed, and research ideas or trends are proposed for further development.

The development of new photocatalyst towards the highly efficient photo-reduction of U(VI) was highly desirable. In this study, ZIF-8/g-C

Among many separation membranes reported to date, the favorable polymer affinity and unique physio-chemical performances of metal-organic frameworks (MOFs) including ultra-high surface area, regular and highly controlled porosity have drawn widespread attention in industrial and academic communities. In this comprehensive review, the developmental timeline of MOF containing membranes for water treatment were clarified. The removal efficiencies, elimination mechanisms, as well as possible influencing factors of various MOF containing membranes that applied to water treatment were systematically summarized. The excellent removal performances of MOF containing membranes for various pollutants were determined by the size-exclusion, π-π stacking interaction, electrostatic interaction, hydrogen bonding and so on. Since the progress of engineered MOF containing membranes for practical wastewater treatment applications lags, we further analyzed the potential environmental application of MOF containing membranes from four aspects (stability of MOFs, antifouling performance of membranes, compatibility between MOF fillers and polymer matrix, dispersity of MOF nanoparticles in matrix), hoping to provide some meaningful insights.

Nanoscale zero valent iron (NZVI) modified MCM zeolite composites (NZVI/MCM) were obtained by reduction and in-situ growth process, and were characterized by SEM, TEM, XRD, HRTEM, TEM-EDS, and XPS techniques. Investigation results showed that the surface of NZVI/MCM were coated with NZVI particles mainly in the range of 10–100 nm, and only part of NZVI particles > 100 nm or

In this paper, nanoscale zero-valent iron (NZVI), which has great potential in environmental purification is introduced. However, NZVI is easy to accumulate and oxidize, which limits its ability to remove pollutants. Hence several modified NZVI are proposed to overcome its shortcomings in this paper. The heavy metal ions, radionuclides and organic pollutants in the environment are removal by NZVI based materials, and their removal behaviors had been analyzed. This paper also reviews the factors affecting the removal of pollutants by NZVI-based materials, such as pH, ionic strength, contact time, reaction temperature, interfering ions and humic acids. In addition, it is also introduced that NZVI is toxic in the environment, and it also can be recovered and has different removal effects in different water environment. In short, this paper gives a comprehensive summary of NZVI, including its modification methods, pollutants removal, influencing factors of pollutants removal and implication to environment. It provides a strong theoretical basis for the future development of NZVI based materials.

Photocatalysis as one of the most important routes for the utilization of solar energy has been extensively investigated due to its inexhaustibility, low-cost, cleanliness and high efficiency. Perovskite-based materials (ABX3, third generation photocatalysts) have been recently utilized in photovoltaic industries, whereas the state-of-the-art progress of perovskite photocatalysts in environmental remediation were not available nowadays. In this review, the recent advances of A-, B- and X-substituted perovskites and photocatalytic removal of deleterious gases, organic contaminants, heavy metals as well as radionuclides on various perovskites are comprehensively reviewed. Then, suggestive comments concerning current and future challenge are summarized. The main objective of this review paper is to provide some beneficial guidelines for future utilization of perovskite-based materials in environmental cleanup.

Various kind of organics are toxic and detrimental, resulting in eutrophication, black, odorous water and so on. Photocatalysis has been deemed to be a promising technology which can decompose different kinds of organic pollutants under visible light irradiation, finally achieving non-poisonous, harmless CO2, water and other inorganic materials. Bismuth oxychloride (BiOCl) is considered as a promising photocatalyst for the efficient degradation of organic pollutants due to its high chemical stability, unique layered structure, resistance to corrosion and favorable photocatalytic property. However, BiOCl can only absorb UV irradiation because of its wide band gap of 3.2 eV–3.5 eV that limits its photocatalytic performance. Herein, a lot of methods have been reviewed to improve its photocatalytic activity. We introduced the unique and special layered structure of BiOCl, the typical and common synthesis methods that can control the morphology, and the most important part is varies of modification routes of BiOCl and the application of BiOCl-based materials for photocatalytic degradation of organic pollutants. Besides, we summarized the crucial issues and perspectives about the application of BiOCl in pollution management.