SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Liwen Zhang,Shaohua Chen,Shanyi Tan,Huizi Wen,Shuyu He,Fen Zhang,Xiangru Zuo,Ling Xiong
The inherent limitations of nano zero-valent iron (nZVI) severely limit its widespread application in heavy metal pollution remediation. To address this, Shewanella oneidenis MR-1 (MR-1) was utilized to counteract the iron oxide passivation layer on nZVI surface, however, this approach suffered from low electron transfer rate between MR-1 and the passivation layer. In this research, a novel PDA-modified nZVI composite (PDA-nZVI) was synthesized. Compared to unmodified nZVI, the proportions of Fe 0 and Fe(II) on the PDA-nZVI surface increased 2.06 % and 21.63 %, respectively. The electrochemical tests (e.g., a more negative corrosion potential, a lower charge-transfer resistance, a higher current density, and a 3.4-times larger electrochemical active surface area for PDA-nZVI compared to nZVI) confirm that PDA enhances electron transfer from iron core to the outside, thereby promoting Fe 0 availability and Fe(II) generation on the PDA-nZVI surface. Meanwhile, PDA modification successfully enhanced the material's dispersibility and hydrophilicity in aqueous solutions. Results demonstrate that the Cr(VI) elimination capacity of the PDA-nZVI and MR-1 combined system (PDA-nZVI/MR-1) was markedly superior to that of the nZVI/MR-1 system. Mechanism analyses demonstrate that PDA can act as an electron shuttle to accelerate electron transfer between MR-1 and the passivation layer, thereby promoting more Fe(III) transformation to Fe(II). This process enables more Cr(VI) to be reduced to Cr(III), which is subsequently adsorbed or complexed on the material surface as Cr 2 O 3 /FeCr 2 O 4 and Cr x Fe 1-x (OH) 3 , ultimately being removed from the solution via co-precipitation. The PDA-nZVI/MR-1 system successfully overcomes the inherent limitations and exhibits an exceptional Cr(VI) elimination capability
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Qianqian Tang,Hao Wu,Mingsong Zhou,Dongjie Yang
To remove Cr(VI) in water, a novel lignin-based anionic adsorption resin epichlorohydrin cross-linking lignin grafted by diethylenetriamine (E-DAL) was prepared by the direct cross-linking and curing of alkali lignin grafted by diethylenetriamine in aqueous solutions. Under the determined optimum synthesis conditions, E-DAL with higher nitrogen (7.46%) and lignin (32.78%) contents was obtained. Structural and physicochemical measurement results showed E-DAL was a macroporous resin, having a regular connected pore structure with porosity of 67.48% and pore size of 615.6 nm, also strong hydrophilicity, excellent acid-alkaline resistance and thermal stability. Adsorption experiment results indicated the adsorption isotherm of E-DAL to Cr(VI) was well-described by Langmuir model. E-DAL showed a higher adsorption capacity to Cr(VI), and the fitted maximum adsorption capacity reached up to 775.2 mg/g. Pseudo-second-order model could fit this adsorption process well, suggesting its chemisorption characteristics. The calculated thermodynamic parameters indicated a spontaneous and endothermic adsorption of E-DAL to Cr(VI). Dynamic column adsorption results showed E-DAL could completely remove Cr(VI) in wastewater. This whole preparation process only used a very small amount of cheaper amination agent and was relatively low-cost. This work provided efficient technical supports for the structural design of high-performance lignin-based anionic adsorption materials in water treatment field.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2022
·
IF 11.357
Dashi Lei,Chunli Gou,Chunli Wang,Juanqin Xue,Zhongshen Zhang,Weizhen Liu,Zhang Lin,Jing Zhang
The reduced chromite ore processing residue (rCOPR) deposited in environments is susceptible to surrounding factors and causes reoccurrence of Cr(VI). However, the impact of natural sunlight on the stability of rCOPR is still unexplored. Herein, we investigated the dissolution and transformation behaviors of Cr(III)–Fe(III) hydroxide, a typical Cr(III)-containing component in rCOPR, under visible light. At acidic conditions, the release rate of Cr(III) under illumination markedly increased, up to 7 times higher than that in the dark, yet no Cr(VI) was produced. While at basic conditions, only Cr(VI) was obtained by photo-oxidation, with an oxidation rate of ∼7 times higher than that by δ-MnO2 under dark conditions at pH 10, but no reactive oxygen species was generated. X-ray absorption near-edge structure and density functional theory analyses reveal that coexisting Fe in the solid plays a critical role in the pH-dependent release and transformation of Cr(III), where photogenerated Fe(II) accelerates Cr(III) produced at acidic conditions. Meanwhile, at basic conditions, the production of intermediate Cr(III)–Fe(III) clusters by light leads to the oxidation of Cr(III) into Cr(VI) through the nonradical “metal-to-metal charge transfer” mechanism. Our study provides a new insight into Cr(VI) reoccurrence in rCOPR and helps in predicting its environmental risk in nature.
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PubMed
高影响因子
Journal of Water Process Engineering
·
2022
·
IF 7.34
Qi Jing,Wenhui You,Shuo Qiao,Yuheng Ma,Zhongyu Ren
In this study, nano zero-valent iron-reduced graphene oxide (NZVI-rGO) was successfully synthesized and applied for 2,4-DCP and Cr (VI) removal. Characterization results show that NZVI particles were successfully loaded on rGO nanosheets increasing the dispersibility of particles. Removal experiments indicate that the existence of rGO significantly enhanced the removal efficiency of 2,4-DCP and Cr (VI) compared with bare nano zero-valent iron. The removal rate of 2,4-DCP and Cr(VI) increased from 33.24 % and 63.14 % to 100 % and 98.40 %, respectively. Pseudo-second-order model and Langmuir isotherm model could better explain the 2,4-DCP removal process. The removal mechanism of 2,4-DCP in the process of simultaneous removal is adsorption, including π-π interaction, hydrogen bonding and n-π EDA interaction between Cr(VI) and 2,4-DCP. Cr(VI) is firstly fixed on the surface of NZVI-rGO by electrostatic interaction. The electrostatic interaction between γ-FeOOH and Cr(VI) and the strong connection formed by n-π EDA interaction between Cr(VI) and 2,4-DCP promote the adsorption of Cr(VI) in coexisting system. Subsequently, Cr(VI) is reduced to Cr(III) by accepting the electrons donated by NZVI, and Cr(III) interacts with OH − in the solution to generate Cr(OH) 3 precipitate. The existence of rGO accelerates the rate of electron transfer to Cr(VI) in NZVI. This study provides theoretical support for remediation of combined pollution of chlorinated organics and heavy metals.
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高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Xiaoming Zhang,Qi Li,Kai Nie,Kaiting Cao,Qi Liao,Mengying Si,Zhihui Yang,Weichun Yang
Effective remediation of Cr(VI)-contaminated soil with strong alkalinity and high Cr(VI) concentration is a severe challenge. Herein, a proton-buffering montmorillonite-supported sulfidated nano zerovalent iron (nFeS/Fe 0 @H–Mt) was developed for remediation of alkaline Cr(VI)-contaminated soil. The reductive efficiencies of water-soluble Cr(VI) reached 99.7%, 99.3% and 99.8% in three tested soils with initial concentrations of 439.6, 3307.5 and 4626.7 mg kg −1 , respectively, after 15 d of nFeS/Fe 0 @H–Mt treatment. Further speciation analyses demonstrated most available Cr species (exchangeable and carbonate-bound Cr) were transformed into more stable Cr species. The leachable Cr(VI) and total Cr obtained by toxicity leaching procedures decreased to extremely low levels and maintained long-term stability for 120 d. Such superior reductive immobilization performance of FeS/Fe 0 @H–Mt was attributed to the synergistic effect of sulfidated nano zerovalent iron and proton-buffering montmorillonite , which induced the coordination of proton donation and electron transfer . The proton-buffering montmorillonite (H–Mt) could prevent the aggregation of nanoparticles and provide protons to accelerate the corrosion of Fe 0 . In addition, the FeS component improved electron selectivity and facilitated electron transfer of Fe 0 to Cr(VI). Our study demonstrated that the coordination of proton donation and electron transfer significantly enhanced the Cr(VI) reduction under the alkaline condition thus leading to effective remediation of alkaline Cr(VI)-contaminated soil.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Hao Du,Ningyi Li,Lingxuan Yang,Qiang Li,Guoxiang Yang,Qi Wang
Environmental crisis caused by Cr(VI) pollution has gained remarkable attention. Developing efficient photocatalysts for Cr(VI) remediation remains a great challenge. Herein, the Ag@Ag 3 VO 4 /Ag 3 PMo 12 O 40 (Ag@Ag 3 VO 4 /AgPMo) S-scheme heterojunctions were prepared via the combination of hydrothermal and photodeposition methods for Cr(VI) reduction. The resultant S-scheme heterojunctions were characterized to investigate their morphological, structural, photoelectrochemical and optical properties. The synergy of surface plasmon resonance (SPR) effect of Ag and S-scheme hetero-structure improved their photo(electro)chemical performance. Upon visible light irradiation, the optimized Ag@Ag 3 VO 4 /AgPMo delivered superior photoreduction efficiency (94.8%) of Cr(VI) and stability with a slight loss of the performance (92.8% after 6 cycles). The enhancement of Cr(VI) reduction performance may be ascribed to the extended light absorption range and separation and migration pathway of photo-induced electron-hole pairs confirmed by the proposed photoreduction mechanism. This work not only confirms a highly active catalytic system for the light-driven environmental application, but pave a way for the construction of S-scheme heterojunction photocatalysts.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Na Wang,Qilin Liu,Bo Xie,Xuechun Huang,Dan Xiao
Cr(VI) pollution severely threatens the water environment and human health. One of the effective ways to solve this problem is to develop environmentally friendly and efficient adsorbents. This paper proposes a highly efficient Cr(VI) adsorbent based on tannic acid coating PVA/PVP/PEI nanofibrous membrane. The adsorbent is environment-friendly and has satisfying water stability and adsorption performance. The optimum preparation conditions, adsorption conditions, and the influence of ionic strength and coexisting ions were investigated comprehensively. Through the study of adsorption kinetics and isotherms, the adsorption of Cr(VI) on the nanofibrous membrane was found following the pseudo-second-order kinetics model, and the adsorption isotherm model following the Langmuir model. The maximum adsorption capacities were 631.97 mg/g, 667.52 mg/g, and 695.04 mg/g at 298 K, 308 K, and 318 K, respectively. After adsorption of Cr(VI), the membrane can be converted to high purity Cr 2 O 3 by calcination. The tannin-coated PVA/PVP/PEI nanofibrous membrane is a promising adsorbent because it can efficiently adsorb Cr(VI) and convert highly toxic Cr(VI) into hypotoxic Cr(III).
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高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Jiabao Gu,Chaogang Ban,Jiazhi Meng,Qianwen Li,Xuanyu Long,Xiaohan Zhou,Nan Liu,Zequan Li
Rapid recombination of the photogenerated carrier, a limited range of photoexcitation, and unsatisfactory photocatalytic activity are the limiting factors in photocatalytic applications. Accelerating photogenerated carrier transfer and constructing surface active sites have become critical tasks. In this study, a dual Z-scheme UNiMOF/BiVO 4 /S-C 3 N 4 (NBSCN) photocatalyst with a 2D/3D/2D structure was successfully constructed. Under visible-light irradiation, NBSCN outperforms single and binary composites in photocatalytic tetracycline photodegradation and Cr(VI) photoreduction due to the synergistic effect of adsorption and photocatalysis. The maximum photocatalytic efficiency of tetracycline (90.1 %) and Cr(VI) (93.6 %) in 120 min was achieved by NBSCN-20 %. The exceptional photocatalytic activity of NBSCN-20 % can be attributed to the large specific surface area, increased active sites, improved visible-light absorption ranges, and the construction of heterojunctions. The fabricated dual Z-scheme heterojunction at the interface of NBSCN reduces the recombination rate of photogenerated carriers and widens the range of light absorption. NBSCN-20 % exhibits excellent stability in the process of cyclic experiments. On the basis of the results, the feasibility of the dual Z-scheme mechanism is proposed. This work demonstrates that NBSCN-20 % photocatalyst has promising application prospects in removing heavy-metal ions and organic pollutants from aqueous environments.
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高影响因子
Gels
·
2022
·Vol. 8
·期 9
·546
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IF 4.432
Xiaolei Ma,Duomo Duan,Jinbin Chen,Baolong Xie
Hydrogels with polysaccharides as high polymer substrates have surprising advantages in wastewater treatment with complex components. Therefore, in this study, polysaccharides named EPS were extracted fromEnteromorpha prolifera, a coastal pollutant with a wide range of sources, and cationic modification was performed to obtain CAEPS, the hydrogel with a double network structure was prepared based on EPS and CAEPS. Meanwhile, the structural characteristic of EPS and CAEPS-based hydrogel were identified by HPLC, AFM, FT-IR, TGA, SEM-EDS, Pore size distribution, and WCA, which showed that the porosity, apparent (skeletal) density, and hydrophilicity of CAEPS-hydrogels. We used nonlinear isotherms to uncover the adsorption mechanism of hydrogel applied to the water environment containing three typical pollutants (Methylene blue, Cefuroxime, and Cr (VI)). The results showed that the adsorption isotherm of the two hydrogels fit the Langmuir isotherm model, which indicated the monolayer adsorption of the pollution factor onto EPS- and CAEPS-hydrogels. The maximum adsorption capacities of CAEPS-hydrogels were higher than EPS-hydrogels, which indicated the microstructure and adsorption performance of the CAEPS-hydrogel are strengthened.Keywords:cationic enteromorpha polysaccharide;hydrogel;structural;adsorption
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Jianhao Qiu,Dingliang Dai,Lu Zhang,Guanglu Xia,Jianfeng Yao
Oxygen vacancy-rich Bi 2 MoO 6 nanoflakes were uniformly anchored on cuboid MIL-121 via benign solvothermal and thermal-reduction methods. Benefiting from the efficient light capture and rich electron traps triggered by oxygen vacancies, intimate interface contact and intrinsic heterostructure, the enhanced separation and transportation rates of photo-induced charge carriers are achieved. Consequently, Bi 2 MoO 6 /MIL-121 with rich oxygen vacancies performs excellent photocatalytic activities, which are 4.8, 7.1, 1.4 times higher for Cr(VI) reduction, and 6.1, 5.4, 1.2 times higher for 2-nitrophenol degradation compared with those of Bi 2 MoO 6 , MIL-121 and Bi 2 MoO 6 /MIL-121 without oxygen-vacancies, respectively. Furthermore, thanks to the timely consumption of photo-induced electrons and holes by Cr(VI) reduction and 2-nitrophenol degradation, respectively, the corresponding photocatalytic efficiencies are further boosted in their coexistent environment. This work would enlighten the design of metal-organic framework-based (photo)catalysts for the treatment of complicated pollution.
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高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 12
·2087
·
IF 5.719
Xinman Tu,Linhong Ge,Lamei Deng,Li Zhang
Metal sulfide is often utilized as a catalyzed material to form colorimetric response system for some heavy metal detection. While the aggregation effect and conventional morphology limited the catalyzed efficiency. Herein, a robust method based on morphology adjustment was proposed to improve the dispersibility and catalytic performance of CuS. The results demonstrated when the solvent ratio of ethylene glycol and dimethyl sulfoxide arrived at 3:1, it displayed an optimal structure which is like a patulous flower. Meanwhile, an optimal surface binding energy (ΔE) of 120.1 kcal/mol was obtained via theoretical calculation model. The flower-like structure caused a 2-fold increase in the catalytic level. Subsequently, the CuS was employed to make colorimetric detection of Cr(VI) in water. The assay results exhibited a linear range of the Cr(VI) from 60 to 340 nM, the limit of detection was 1.07 nM. In the practical tests for Qianhu lake water, the spiked recoveries were 93.6% and 104% with the RSD of 4.71% and 3.08%. Therefore, this CuS-based colorimetric method possesses a satisfactory application prospect for the Cr(VI) determination in water.Keywords:CuS;morphology adjustment;solvent ratio;Cr(VI);colorimetric detection
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高影响因子
Biomass Conversion and Biorefinery
·
2022
·
IF 4.05
Qu Qiang,Guo Xiaohui,Shao Zhijiang,Wang Xiuzhang,Zhu Mingqiang,Qiu Ling
Zanthoxylum branch became agricultural waste without proper utilization, and the pristine biochar (PB) had the limited removal capacity of Cr(VI) (21.75 mg g −1 ). In this study, zanthoxylum branch was fabricated to modified biochar (MZB) through impregnating with 0.4, 0.6, 0.8, and 1.0 mol L −1 Fe (NO 3 ) 3 solution and then pyrolyzing at 500 and 900 ℃. After sieving by batch adsorption experiment of Cr(VI), the optimal MZB was prepared with impregnating solution concentration of 0.4 mg L −1 and pyrolysis temperature of 900 ℃ (900MZB4), and displayed the outstanding Cr(VI) removal capacity (110.43 mg g −1 ). Besides, the effect of initial solution pH was evaluated, and removal process of Cr(VI) was a reaction of consuming protons. The fitting results of Langmuir model and pseudo-second-order kinetic model confirmed that the Cr(VI) removal reaction was a homogeneous chemisorption. Thermodynamic parameters demonstrated that the adsorption of Cr(VI) was an endothermic spontaneous process. The results of SEM and XRD suggested that zero-valent iron (Fe 0 ) particles were located on 900MZB4 surface and participated in the removal reaction of Cr(VI). The XPS analysis indicated 78.37% of Cr(VI) was reduced to Cr(III) by the cooperation of oxygen-containing functional groups (OFG) and Fe 0 . More OFG and higher surface area (130.36 m 2 g −1 ) revealed by FTIR and BET also contributed to the better characteristic of 900MZB4. In addition, 900MZB4 maintained removal efficiency at 81.22% after sixth regeneration cycles. Therefore, it is feasible to prepare high-efficient adsorbent from zanthoxylum branch for wastewater treatment. Graphical abstract
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高影响因子
危险品化学品经营许可证（带存储）