Single Atom Catalyst in Persulfate Oxidation Reaction: From Atom Species to Substance.

With maximum utilization of active metal sites, more and more researchers have reported using single atom catalysts (SACs) to activate persulfate (PS) for organic pollutants removal. In SACs, single metal atoms (Fe, Co, Cu, Mn, etc.) and different substrates (porous carbon, biochar, graphene oxide, carbon nitride, MOF, MoS2 , and others) are the basic structural. Metal single atoms, substances, and connected chemical bonds all have a great influence on the electronic structures that directly affect the activation process of PS and degradation efficiency to organic pollutants. However, there are few relevant reviews about the interaction between metal single atoms and substances during PS activation process. In this review, the SACs with different metal species and substrates are summarized to investigate the metal-support interaction and evaluate their effects on PS oxidation reaction process. Furthermore, how metal atoms and substrates affect the reactive species and degradation pathways are also discussed. Finally, the challenges and prospects of SACs in PS-AOPs are proposed.

Highly efficient activation of periodate by a manganese-modified biochar to rapidly degrade methylene blue.

In this study, the manganese oxide/biochar composites (Mn@BC) were synthesized from Phytolacca acinosa Roxb. The Mn@BC was analyzed via techniques of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction analysis (XRD). The results show that MnOx is successfully loaded on the surface of BC, and the load of MnOx can increase the number of surface functional groups of BC. X-ray photoelectron spectroscopy (XPS) shows that MnOx loaded on BC mainly exists in three valence forms: Mn(Ⅱ), Mn(Ⅲ), and Mn(Ⅳ). The ability of Mn@BC to activate periodate (PI) was studied by simulating the degradation of methylene blue (MB) dye. The degradation experiment results showed that the MB removal rate by the Mn@BC/PI system reached 97.4% within 30 min. The quenching experiment and electron paramagnetic resonance (EPR) analysis confirmed that Mn@BC can activate PI to produce iodate (IO3•), singlet oxygen (1O2), and hydroxyl radical (•OH), which can degrade MB during the reaction. Response surface methodology (RSM) based on Box-Behnken Design (BBD) was used to determine the interaction between pH, Mn@BC and PI concentration in the Mn@BC/PI system, and the optimum technological parameters were determined. When pH = 5.4, Mn@BC concentration 0.56 mg/L, PI concentration 1.1 mmol/L, MB removal rate can reach 98.05%. The cyclic experiments show that Mn@BC can be reused. After four consecutive runs, the removal rate of MB by the Mn@BC/PI system is still 82%, and the Mn@BC/PI system also shows high performance in treating MB in actual water bodies and degrading other pollutants. This study provides a practical method for degrading dyes in natural sewage.

Exogenous spermidine elevating cadmium tolerance in Salix matsudana involves cadmium detoxification and antioxidant defense.

In this study, exogenous spermidine role on Salix matsudana tolerance to cadmium was evaluated. Spermidine and cadmium presented antagonistic effects on the biomass, copper and zinc concentrations in S. matsudana. cadmium mainly distributed in the cell wall of subcellular fraction; 46.97%-60.43% of cadmium existed in a sodium chloride-extracted form. Cadmium contents in roots, leaves, and twigs ranged from 2002.67 to 3961.00, 111.59 to 229.72, and 102.56 to 221.27 mg/kg, respectively. Spermidine application elevated cadmium concentrations in the roots, cuttings, and cell wall and the ratio of deionized water-extracted cadmium, but decreased cadmium levels in the twigs and leaves and the fractions of cadmium extracted by ethanol and sodium chloride, respectively. Putrescine and malondialdehyde were important indicators of cadmium-induced oxidative damage. Exogenous spermidine alleviated the accumulation of superoxide anion, hydrogen peroxide, malondialdehyde via promoting the levels of spermidine, soluble protein, superoxide dismutase, reductive ascorbate, glutathione reductase, and glutathione peroxidase in S. matsudana leaves under the corresponding cadmium stress. The results indicated that S. matsudana was a candidate for cadmium rhizoremediation and extraction in leaves; the spermidine application enhanced the cadmium tolerance of S. matsudana through promoting cadmium accumulation in roots, cell wall, and less bioactive chemical forms and the antioxidative ability.

Effects of cadmium on calcium homeostasis in the white-rot fungus Phanerochaete chrysosporium.

Due to the widespread application of white-rot fungi for the treatment of pollutants, it's crucial to exploit the special effects of pollutants on the microbes. Here, we studied the effects of cadmium on calcium homeostasis in the most studied white-rot fungus Phanerochaete chrysosporium. The response of P. chrysosporium to cadmium stress is concentration-dependent. A high concentration of cadmium caused the release of calcium from P. chrysosporium, while a hormesis effect was observed at a lower cadmium concentration (10 µM), which resulted in a significant increase in calcium uptake and reversed the decrease in cell viability. Calcium (50 µM) promoted cell viability (127.2% of control), which reflects that calcium can protect P. chrysosporium from environmental stress. Real-time changes in the Ca2+ and Cd2+ fluxes of P. chrysosporium were quantified using the noninvasive microtest technique. Ca2+ influx decreased significantly under cadmium exposure, and the Ca2+ channel was involved in Ca2+ and Cd2+ influx. The cadmium and/or calcium uptake results coupled with the real-time Ca2+ and Cd2+ influxes microscale signatures can enhance our knowledge of the homeostasis of P. chrysosporium with respect to cadmium stress, which may provide useful information for improving the bioremediation process.

Adsorption of Estrogen Contaminants by Graphene Nanomaterials under Natural Organic Matter Preloading: Comparison to Carbon Nanotube, Biochar, and Activated Carbon.

Adsorption of two estrogen contaminants (17ß-estradiol and 17α-ethynyl estradiol) by graphene nanomaterials was investigated and compared to those of a multi-walled carbon nanotube (MWCNT), a single-walled carbon nanotube (SWCNT), two biochars, a powdered activated carbon (PAC), and a granular activate carbon (GAC) in ultrapure water and in the competition of natural organic matter (NOM). Graphene nanomaterials showed comparable or better adsorption ability than carbon nanotubes (CNTs), biochars (BCs), and activated carbon (ACs) under NOM preloading. The competition of NOM decreased the estrogen adsorption by all adsorbents. However, the impact of NOM on the estrogen adsorption was smaller on graphenes than CNTs, BCs, and ACs. Moreover, the hydrophobicity of estrogens also affected the uptake of estrogens. These results suggested that graphene nanomaterials could be used to removal estrogen contaminants from water as an alternative adsorbent. Nevertheless, if transferred to the environment, they would also adsorb estrogen contaminants, leading to great environmental hazards.

Biochar pyrolyzed from MgAl-layered double hydroxides pre-coated ramie biomass (Boehmeria nivea (L.) Gaud.): Characterization and application for crystal violet removal.

A novel biochar/MgAl-layered double hydroxides composite (CB-LDH) was prepared for the removal of crystal violet from aqueous solution by pyrolyzing MgAl-LDH pre-coated ramie stem (Boehmeria nivea (L.) Gaud.). Pyrolysis played dual role for both converting biomass into biochar and calcining MgAl-LDH during the pyrolysis process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and zeta potential analysis were used to characterize the CB-LDH. The results of characterization suggested that the calcined LDH was successfully synthesized and coated on biochar. The resulted CB-LDH had higher total pore volume and more functional groups than the pristine biochar. Adsorption experimental data fitted well with the pseudo-second order kinetics model and the Freundlich isotherm model. The rate-controlled step was controlled by film-diffusion initially and then followed by intra-particle diffusion. Thermodynamic analysis showed that the adsorption of crystal violet was a spontaneous and endothermic process. The higher pH and temperature of the solution enhanced the adsorption performance. CB-LDH could also have excellent ability for the removal of crystal violet from the actual industrial wastewater and groundwater with high ionic strength. LDH adsorption, electrostatic attraction, pore-filling, π-π interaction and hydrogen bond might be the main mechanisms for crystal violet adsorption on CB-LDH. The results of this study indicated that CB-LDH is a sustainable and green adsorbent with high performance for crystal violet contaminated wastewater treatment and groundwater remediation.

Growth inhibition and oxidative damage of Microcystis aeruginosa induced by crude extract of Sagittaria trifolia tubers.

Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microcystis aeruginosa in the laboratory. Several physiological indices of M. aeruginosa, in response to the environmental stress, were analyzed. Results showed that S. trifolia tuber aqueous extract significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The highest inhibition rate reached 90% after 6 day treatment. The Chlorophyll-a concentration of M. aeruginosa cells decreased from 343.1 to 314.2µg/L in the treatment group. The activities of superoxide dismutase and peroxidase and the content of reduced glutathione in M. aeruginosa cells initially increased as a response to the oxidative stress posed by S. trifolia tuber aqueous extract, but then decreased as time prolonged. The lipid peroxidation damage of the cyanobacterial cell membranes was reflected by the malondialdehyde level, which was notably higher in the treatment group compared with the controls. It was concluded that the oxidative damage of M. aeruginosa induced by S. trifolia tuber aqueous extract might be one of the mechanisms for the inhibitory effects.

Effects of limonene stress on the growth of and microcystin release by the freshwater cyanobacterium Microcystis aeruginosa FACHB-905.

The effects of limonene exposure on the growth of Microcystisaeruginosa and the release of toxic intracellular microcystin (MCY) were tested by evaluating the results obtained from the batch culture experiments with M. aeruginosa FACHB-905. The time series of cell as well as intracellular and extracellular MCY concentrations were evaluated during 5d of the incubation. After exposure to limonene, the number of cells gradually diminished; the net log cell reduction after 5d of the exposure was 3.0, 3.6, and 3.8log when the initial cell densities were set at 1.6×10(7), 1.1×10(6) and 4.1×10(5)cell/mL, respectively. Limonene was found to significantly influence the production and release of MCY. As the limonene exposure could inhibit the increase in the number of cells, the increase in the total MCY concentration in the medium was also inhibited. In the presence of limonene, the intracellular MCY was gradually released into the medium through a gradual reduction in the number of cells. The extracellular MCY concentration in the medium was significantly higher in the limonene-exposed samples than in the control samples, which confirmed that limonene cannot decompose the extracellular MCY.

Bioaccumulation of zinc, lead, copper, and cadmium from contaminated sediments by native plant species and Acrida cinerea in South China.

This research was conducted to search and identify spontaneously growing heavy metal-tolerant plant species that are potentially useful for phytoremediation in contaminated sediment. Five sites were selected for collection of plants growing on polluted shore (river bank) sediment of the Xiang River, China. The concentrations of Zn, Pb, Cu and Cd in plants, sediments, and grasshoppers were determined using flame atomic absorption spectrophotometer (AAS700, Perkin-Elmer, USA). Considering translocation factor and bioaccumulation factor, Rumex crispus (Polygonaceae), Rumex dentatus (Polygonaceae), and Lagopsis supina (Labiatae) could be potentially useful for phytostabilization of metals. R. crispus can be considered potentially useful for phytoextraction of Cd. In light of the biomagnification factors, grasshoppers are deconcentrators for Pb and Cd, microconcentrators for Zn and macroconcentrators for Cu to the plants, respectively. To the best of our knowledge, the present study is the first report on Zn, Pb, Cu and Cd accumulation in R. crispus and L. supina, providing a pioneer contribution to the very small volume of data available on the potential use of native plant species from contaminated sediments in phytostabilization and phytoremediation technologies.

A restoration-promoting integrated floating bed and its experimental performance in eutrophication remediation.

Numerous studies on eutrophication remediation have mainly focused on purifying water first, then restoring submerged macrophytes. A restoration-promoting integrated floating bed (RPIFB) was designed to combine the processes of water purification and macrophyte restoration simultaneously. Two outdoor experiments were conducted to evaluate the ecological functions of the RPIFB. Trial 1 was conducted to compare the eutrophication purification among floating bed, gradual-submerging bed (GSB) and RPIFB technologies. The results illustrated that RPIFB has the best purification capacity. Removal efficiencies of RPIFB for TN, TP, NH(+)4-N, NO(-)3-N, CODCr, Chlorophyll-a and turbidity were 74.45%, 98.31%, 74.71%, 88.81%, 71.42%, 90.17% and 85%, respectively. In trial 2, influences of depth of GSB and photic area in RPIFB on biota were investigated. When the depth of GSB decreased and the photic area of RPIFB grew, the height of Potamogeton crispus Linn. increased, but the biomass of Canna indica Linn. was reduced. The mortalities of Misgurnus anguillicaudatus and Bellamya aeruginosa in each group were all less than 7%. All results indicated that when the RPIFB was embedded into the eutrophic water, the regime shift from phytoplankton-dominated to macrophyte-dominated state could be promoted. Thus, the RPIFB is a promising remediation technology for eutrophication and submerged macrophyte restoration.

Enhanced efficiency of cadmium removal by Boehmeria nivea (L.) Gaud. in the presence of exogenous citric and oxalic acids.

Boehmeria nivea (L.) Gaud. is a potential candidate for the remediation of Cd contaminated sites. The present investigation aims to explore Cd tolerance threshold and to quickly identify the role of exogenous organic acids in Cd uptake and abiotic metal stress damage. Elevated Cd levels (0-10mg/L) resulted in an obvious rise in Cd accumulation, ranging from 268.0 to 374.4 in root and 25.2 to 41.2mg/kg dry weight in shoot, respectively. Citric acid at 1.5 mmol/L significantly facilitated Cd uptake by 26.7% in root and by 1-fold in shoot, respectively. Cd translocation efficiency from root to shoot was improved by a maximum of 66.4% under 3 mmol/L of oxalic acid. Citric acid exhibited more prominent mitigating effect than oxalic acid due to its stronger ligand affinity for chelating with metal and avoiding the toxicity injury of free Cd ions more efficiently. The present work provides a potential strategy for efficient Cd remediation with B. nivea.

Low-cost eggshell-fly ash adsorbent for phosphate recovery: A potential slow-release phosphate fertilizer.

Fly ash (FA) and eggshells (ES) are common solid wastes with significant potential for the recovery of phosphorus from water. This study focuses on synthesizing a low-cost and environmental-friendly phosphate adsorbent called eggshell-fly ash geopolymer composite (EFG) using eggshells instead of chemicals. The CaO obtained from the high-temperature pyrolysis of eggshells provides active sites for phosphate adsorption, and CO2 serves as a pore-forming agent. The phosphate adsorption performance of EFG varied with the eggshell-fly ash ratios and achieved a maximum of 49.92 mg P/g at an eggshell-fly ash ratio of 40 %. The adsorption process was well described by the pseudo-second-order model and the Langmuir model. EFG also exhibited a good regeneration performance through six-cycle experiments and achieved the highest phosphate desorption at pH 4.0. The results of the column experiment showed that EFG can be used as a filter media for phosphorus removal in a real-scale application with low cost. Soil burial test indicated saturated EFG has a good phosphate slow-release performance (maintained for up to 60 days). Overall, EFG has demonstrated to be a promising adsorbent for phosphorus recovery.

Preparation of reed-based hydrothermal carbonized carbon photocatalyst and effective degradation of methylene blue and tetracycline.

Hydrothermal carbonation carbon (HTCC) is a promising semiconductor material for the photocatalytic degradation of pollutants. However, the poor charge transfer capability of HTCC and the unclear mechanism of photocatalysis limit its practical application. In this study, a novel Z-type heterojunction photocatalyst of silver carbonate (Ag2CO3) and HTCC (Ag2CO3/HTCC) was developed for the degradation of methylene blue (MB) and tetracycline (TC) from wastewater using a hydrothermal- coprecipitation method. Compared to Ag2CO3 and HTCC, 40% Ag2CO3/HTCC had excellent photocatalytic activity and stability. The free radical scavenger experiments showed that •O2- and h+ were the main substances for the degradation of MB and TC. The intermediates formed during the photodegradation were identified by HPLC-MS, and a possible mechanism and pathway for the degradation of MB and TC by Ag2CO3/HTCC was proposed. This study provides a new idea for the synthesis of Z-type HTCC heterojunction with a high-photocatalytic efficiency and its photocatalytic mechanism.

Generation and identification of 1O2 in catalysts/peroxymonosulfate systems for water purification.

Catalysts for peroxymonosulfate (PMS) activation are appealing in the purification of organic wastewater. Singlet oxygen (1O2) is widely recognized as a crucial reactive species for degrading organic contaminants in catalysts/PMS systems due to its adamant resistance to inorganic anions, high selectivity, and broad pH applicability. With the rapid growth of studies on 1O2 in catalysts/PMS systems, it becomes necessary to provide a comprehensive review of its current state. This review highlights recent advancements concerning 1O2 in catalysts/PMS systems, with a primary focus on generation pathways and identification methods. The generation pathways of 1O2 are summarized based on whether (distinguished by the geometric structures of metal species) or not (distinguished by the active sites) the metal element is included in the catalysts. Furthermore, this review thoroughly discusses the influence of metal valence states and metal species with different geometric structures on 1O2 generation. Various potential strategies are explored to regulate the generation of 1O2 from the perspective of catalyst design. Identification methods of 1O2 primarily include electron paramagnetic resonance (EPR), quenching experiments, reaction in D2O solution, and chemical probe tests in catalysts/PMS systems. The principles and applications of these methods are presented comprehensively along with their applicability, possible disagreements, and corresponding solutions. Besides, an identifying procedure on the combination of main identification methods is provided to evaluate the role of 1O2 in catalysts/PMS systems. Lastly, several perspectives for further studies are proposed to facilitate developments of 1O2 in catalysts/PMS systems.

Efficient removal of per- and polyfluoroalkyl substances from biochar composites: Cyclic adsorption and spent regenerant degradation.

In order to solve the problem of efficient desorption of per- and polyfluoroalkyl substances (PFAS) and regeneration of adsorbents, a novel biochar composite was prepared based on the quaternary ammonium groups and hydrophobicity of sulfobetaine polymer, which can be used for the efficient removal of various PFASs and has great regeneration ability. Through adsorption, regeneration and degradation experiment, the comprehensive effect of the novel biochar composite on the whole process of removal of PFAS was systematically investigated. The results showed that the maximum adsorption capacity of PFOS, PFOA, PFBS, and PFBA reached 634 mg/g, 536 mg/g, 301 mg/g and 264 mg/g, respectively. The adsorption process involved hydrophobicity, electrostatic, pore diffusion and complexation. The NaI + NaOH solution was used at 50 °C to achieve efficient regeneration of the adsorbent, which can be recycled more than 4 times. When the vacuum-ultraviolet (VUV)/sulfite reduction system was used for deep degradation of the regenerated solution, the effect of hydrated electrons on PFAS was enhanced due to the inclusion of NaI and NaOH in the regeneration reagent, resulting in an increase in the degradation efficiency (89.1%-99.9%) and defluorination efficiency (63.3%-84.1%). Based on the performance of BC-P(SB-co-AM) and the treatment efficiency of PFAS, the design idea of the whole process treatment technology of PFAS proposed in this work is expected to hold great promise in environmental applications. This work provides a novel idea and system for the efficient adsorption removal and desorption of PFAS, and subsequent deep degradation.

Developing self-floating N-defective graphitic carbon nitride photocatalyst for efficient photodegradation of Microcystin-LR under visible light.

The frequent occurrence of algal blooms in water bodies leads to a significant accumulation of microcystin-LR (MC-LR). In this study, we developed a porous foam-like self-floating N-deficient g-C3N4 (SFGN) photocatalyst for efficient photocatalytic degradation of MC-LR. Both the characterization results and DFT calculations indicate that the surface defects and floating state of SFGN synergistically enhance light harvesting and photogenerated carrier migration rate. The photocatalytic process achieved a nearly 100 % removal rate of MC-LR within 90 min, while the self-floating state of SFGN maintained good mechanical strength. ESR and radical capture experiments revealed that the primary active species responsible for the photocatalytic process was OH. This finding confirmed that the fragmentation of MC-LR occurs as a result of OH attacking the MC-LR ring. LC-MS analysis indicated that majority of the MC-LR molecules were mineralized into small molecules, allowing us to infer possible degradation pathways. Furthermore, after four consecutive cycles, SFGN exhibited remarkable reusability and stability, highlighting the potential of floating photocatalysis as a promising technique for MC-LR degradation.

Responses of Phanerochaete chrysosporium to toxic pollutants: physiological flux, oxidative stress, and detoxification.

The white-rot fungus Phanerochaete chrysosporium has been widely used for the treatment of waste streams containing heavy metals and toxic organic pollutants. The development of fungal-based treatment technologies requires detailed knowledge of the relationship between bulk water quality and the physiological responses of fungi. A noninvasive microtest technique was used to quantify real-time changes in proton, oxygen, and cadmium ion fluxes following the exposure of P. chrysosporium to environmental toxic (2,4-dichlorophenol and cadmium). Significant changes in H(+) and O(2) flux occurred after exposure to 10 mg/L 2,4-dichlorophenol and 0.1 mM cadmium. Cd(2+) flux decreased with time. Reactive oxygen species formation and antioxidant levels increased after cadmium treatment. Superoxide dismutase activity correlated well with malondialdehyde levels (r(2) = 0.964) at low cadmium concentrations. However, this correlation diminished and malondialdehyde levels significantly increased at the highest cadmium concentration tested. Real-time microscale signatures of H(+), O(2), and Cd(2+) fluxes coupled with oxidative stress analysis can improve our understanding of the physiological responses of P. chrysosporium to toxic pollutants and provide useful information for the development of fungal-based technologies to improve the treatment of wastes cocontaminated with heavy metals and organic pollutants.

In Situ Coupling Carbon Defective C3N5 Nanosheet with Ag2CO3 for Effective Degradation of Methylene Blue and Tetracycline Hydrochloride.

The development of novel catalysts for degrading organic contaminants in water is a current hot topic in photocatalysis research for environmental protection. In this study, C3N5 nanosheet/Ag2CO3 nanocomposites (CNAC-X) were used as efficient photocatalysts for the visible-light-driven degradation of methylene blue (MB), and tetracycline hydrochloride (TC-HCl) was synthesized for the first time using a simple thermal oxidative exfoliation and in situ deposition method. Due to the synergistic effect of nanosheet structures, carbon defects, and Z-scheme heterojunctions, CNAC-10 exhibited the highest photocatalytic activity, with photodegradation efficiencies of 96.5% and 97.6% for MB (60 mg/L) and TC-HCl (50 mg/L) within 90 and 100 min, respectively. The radical trapping experiments showed that ·O2- and h+ played major roles in the photocatalytic effect of the CNAC-10 system. Furthermore, intermediates in the photodegradation of MB and TC-HCl were investigated to determine possible mineralization pathways. The results indicated that C3N5 nanosheet/Ag2CO3 photocatalysts prepared in this work could provide an effective reference for the treatment of organic wastewater.

Simultaneous cadmium removal and 2,4-dichlorophenol degradation from aqueous solutions by Phanerochaete chrysosporium.

Phanerochaete chrysosporium has been recognised as an effective bioremediation agent due to its unique degradation to xenobiotic and biosorption ability to heavy metals. However, few studies have focused on the simultaneous removal of heavy metals and organic pollutants. The aim of this work was to study the feasibility of simultaneous cadmium removal and 2,4-dichlorophenol (2,4-DCP) degradation in P. chrysosporium liquid cultures. The removal efficiencies were pH dependent and the maximum removal efficiencies were observed at pH 6.5 under an initial cadmium concentration of 5 mg/L and an initial 2,4-DCP concentration of 20 mg/L. The removal efficiencies for cadmium and 2,4-DCP reached 63.62% and 83.90%, respectively, under the optimum conditions. The high production levels of lignin peroxidase (7.35 U/mL) and manganese peroxidase (8.30 U/mL) resulted in an increase in 2,4-DCP degradation. The protein content decreased with increasing cadmium concentration. The surface characteristics and functional groups of the biomass were studied by scanning electron microscopy and a Fourier-transformed infrared spectrometer. The results showed that the use of P. chrysosporium is promising for the simultaneous removal of cadmium and 2,4-DCP from liquid media.

A novel preparation of S-nZVI and its high efficient removal of Cr(VI) in aqueous solution.

The chitosan-stabilized biochar supported S-nZVI (CS@BC/S-nZVI) composite with low aggregation and superior antioxidation were successfully synthesized by liquid-phase reduction method for the outstanding removal of Cr(VI) from wastewater and characterized by SEM, BET, FTIR, XRD, and XPS. The optimized synthesis parameters of CS@BC/S-nZVI were determined as a 0.14 molar ratio of S/Fe and a 0.25 mass ratio of BC/Fe. The CS@BC/S-nZVI possessed a specific surface area of 199.246 m2/g and an average pore size and pore volume of 1.186 nm and 0.272 cc/g. The CS@BC/S-nZVI could remain reductive activity after Cr(VI) removal and present a remarkable tolerance to the coexisting ions during Cr(VI) removal. The adsorption data were fitted well by the pseudo-second order model and the Langmuir model. The removal of Cr(VI) by CS@BC/S-nZVI was an exothermic process with prominent Cr(VI) removal capacities of 244.07 mg/g at 120 min and 221.84 mg/g at 15 min at 25 â„ƒ. Further mechanism analysis proved that the binding of Cr(VI) to CS@BC/S-nZVI was mainly a synergistic effect of reduction and electrostatic attraction. Overall, these findings shed new light on the research of a novel S-nZVI compound and revealed the potential practical application of CS@BC/S-nZVI in the future heavy metal removal from wastewater.