CHEMICAL GEOLOGY
·
2022
·
IF 4.685
Liyan Deng,Fu Liu,Zecong Ding,Yuzhen Liang,Zhenqing Shi
Fe(II)-bearing clay minerals are abundant in soils and are critical to control the fate of the highly toxic hexavalent chromium (Cr(VI)). Even though the reduction of Cr(VI) by Fe(II)-bearing clay minerals has been extensively studied, the effect of the commonly co-existing natural organic matter (NOM) on this process is poorly understood. This study aimed to understand the kinetics of Cr(VI) reduction by a typical Fe(II)-bearing clay mineral (i.e., reduced nontronite (rNAu-2)) in the presence of Suwannee River NOM and to unveil the possible mechanisms. Cr(VI) reduction experiments were conducted with different NOM concentrations in a range of 0 to 100 mg C L −1 under circumneutral pH. The time-course aqueous-phase measurements and solid-phase characterizations were performed with a combination of wet chemical methods, transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses. The results demonstrated that NOM inhibited Cr(VI) reduction overall, mainly due to the decrease of Cr(VI) sorption on rNAu-2 by mineral-bound NOM. Besides the predominant solid Cr(III) species, soluble and mobile Cr(III) complexes were formed during reduction. Interestingly, the reduction rate ( k ) decreased with the increase of NOM concentration from 0 to 20 mg C L −1 , but kept increasing when the concentration of NOM increased from 30 to 100 mg C L −1 . The contrary pattern is due to the increasing promotion effects that offset the inhibitory effect caused by competitive sorption between Cr(VI) and NOM. The promotion effects may include weakening the mineral passivation by forming stable aqueous NOM-Cr(III) complexes, accelerating the electron transfer rate by dissolving rNAu-2, and donating electrons through NOM-Fe(II/III) complexes and/or NOM-Cr(V) complexes. This study extends our knowledge of Cr(VI) reduction by clay minerals in organic matter-rich soils and sediments and has important implication for understanding the transport and long-term behavior of Cr in the environment.
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Jian Gao,Yuqi Shi,Minglu Tang,Yuancai Chen
Chromate bioreduction is a promising bioremediation strategy, but its application in wastewater treatment is limited by the Cr(VI) biotoxicity, particularly due to the generation of Cr(VI)-induced reactive oxygen species (ROS). To mitigate these adverse effect, this study synthesized bio-Pd 0 in Citrobacter freundii to modulate distinct Cr(VI) aerobic/anaerobic reduction pathways. With the incorporation of bio-Pd 0 , aerobic and anaerobic Cr(VI) specific removal rate increased by 18.1–21.2 and 51.5–87.9 times, respectively. The genomics, RT-qPCR, respiratory inhibition experiments, ROS levels and antioxidant enzyme activity assays demonstrated that bio-Pd 0 enhanced intracellular Cr(VI) aerobic bioreduction mainly via upregulating the chromate multi-electron reductase (Cr-MER) (related with YieF, NfsA and NemA), together with the energy-dependent resistance system (antioxidant enzyme superoxide dismutase and catalase, efflux pump Emr, DNA repair protein RecG). Cr-MER and resistance system effectively reduced the generation and accumulation of ROS, respectively. For anaerobic conditions, bio-Pd 0 facilitated hydrogenase-mediated short respiratory chain (S-chain) to reduce Cr(VI) extracellularly (related with HypE, RutF and OmcG), avoiding ROS generation and the energy consumption of the intracellular detoxification system, and maximized the energy utilization for Cr(VI) extracellular reduction. This study provides a new strategy for Cr(VI) bioreduction and elucidates the underlying mechanism.
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高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2023
·Vol. 87
·期 9
·2061-2078
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IF 2.7
Su Ya,Kang Yumeng,Huang Qinya,Zhang Jiahao,Liu Jinhua,Hu Zhaoyong,Liu Zhanchao,Liu Yan
View large Download slide View large Download slide Close modal The novel Cr(VI) anion-imprinted polymer (Cr(VI)-IIP) was prepared by a surface imprinting technique with bifunctional monomers pre-assembly system based on mesoporous silicon (SBA-15). The synthesized Cr(VI)-IIP was characterized by Fourier transmission infrared spectra (FT-IR), energy dispersive spectrometer (EDS), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray powder diffractometer, N 2 adsorption–desorption and thermogravimetric analysis (TGA), proving to be with a highly ordered mesoporous structure, as well as favorable thermal stability. The saturated adsorption amount was 96.32 mg/g, which was 2.7 times higher than that of non-imprinted polymer (NIP). Kinetic experiments showed that the adsorption equilibrium state was obtained within 70 min. In addition, in the selectivity experiments, Cr(VI)-IIP exhibited strong specific recognition ability for Cr(VI) and could realize the separation of Cr(VI) and Cr(III) from an aqueous solution. The dynamic adsorption experiments exhibited that the dynamic adsorption efficiency of Cr(VI)-IIP was as high as 71.57%. Meanwhile, the dynamic regeneration experiments showed that the adsorption amount of Cr(VI)-IIP did not decrease significantly after repeating for five times. All of the findings suggested that Cr(VI)-IIP could achieve precise identification as well as efficient separation of Cr(VI) from aqueous solution. Preparation of Cr(VI) anion-imprinted polymer (Cr(VI)-IIP) by bifunctional monomers pre-assembly system. The Cr(VI) imprinted sites formed by the coordination of bifunctional monomers and template ions could realize the separation of Cr(VI) and Cr(III). Cr(VI)-IIP exhibited superior selectivity compared to other common adsorbents and Cr(VI) imprinted polymers prepared by a single functional monomer.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2026
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IF 5.4
Pei Yu,Yulong Xiang,Xiaoli Dong,Yu Wang,Jialin Niu
The development of heterojunction photocatalysis provides an efficient, cost-effective, and environmentally sustainable approach to mitigating heavy metal contamination in the ecosystem. In this work, ZnIn 2 S 4 /H 2 Ti 3 O 7 heterojunctions have been successfully constructed via the in-situ growth of ZnIn 2 S 4 on H 2 Ti 3 O 7 nanowires. This rational structure enhances the separation efficiency of photogenerated carriers and suppresses carriers recombination. The ZnIn 2 S 4 /H 2 Ti 3 O 7 heterojunction exhibits significantly enhanced performance in the photoreduction of Cr(VI), and under 8 min illumination, it can achieve 100% photoreduction efficiency. The active species capture experiment confirmed that electrons served as the primary active species in the photocatalytic reduction of Cr(VI). This work offers support for the rational design of highly efficient heterojunction photocatalyst dedicated to environmental remediation.
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高影响因子
CHEMICAL ENGINEERING SCIENCE
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2026
·
IF 5.1
Yinze Yang,Yan Du,Wen Yang,Yueru Yan,Yipeng Wang,Rujin Zhang,Huishan Shang,Lili Zhang,Yafei Zhao,Bing Zhang
Reasonable design core@shell heterostructures is essential for efficient photocatalytic reduction of Cr(VI) in water, as such architectures not only enhance light absorption but also facilitate light-induced charge separation and transfer. Herein, ZnIn 2 S 4 (ZIS) nanosheets were grown in situ on NiCo 2 O 4 hollow nanospheres to construct a NiCo 2 O 4 @ZIS heterostructured photocatalyst for efficient Cr(VI) reduction. The optimal 6 wt% NiCo 2 O 4 @ZIS achieves 100 % photocatalytic reduction efficiency for Cr(VI) within 10 min at pH 3, along with excellent cycling stability, outperforming pure ZIS and most previously reported ZIS-based catalysts. The improved photocatalytic activity is attributed to the unique heterostructure and composition of NiCo 2 O 4 @ZIS, where intimate interfacial contact facilitates charge separation and transfer while suppressing charge recombination. Additionally, homogeneous arrangement of ZIS nanosheets over NiCo 2 O 4 raises the quantity of active sites and enhances light harvesting. This study presents a viable strategy for constructing core@shell heterostructured photocatalysts based on ZIS toward highly efficient Cr(VI) reduction.
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高影响因子
Carbohydrate Polymer Technologies and Applications
·
2026
·
IF 7.6
Jiarui Wang,Fan Zhang,Xiaona Huang,Xiaotong Dong,Hang Jiang,Yungang Bai,Kun Xu,Pixin Wang
1 The development of natural polymer-based materials for the efficient and rapid removal of hexavalent chromium (Cr (VI)) from water remains a persistent global challenge. In this study, hyperbranched polyvinylamine (H-PVAm 1 ) was prepared via copolymerization and hydrolysis using N-vinylformamide (NVF) and the branching agent dipentaerythritol hexaallyl ether (DPHAE, 1 wt% relative to NVF) as raw materials. Subsequently, using epichlorohydrin (ECH) as the crosslinking agent, H-PVAm 1 was grafted onto the surface of microcrystalline cellulose (MCC) to obtain the functionalized cellulose adsorbent H-PVAm 1 -MCC. Benefiting from the high primary amine content and three-dimensional branched structure of H-PVAm 1 , H-PVAm 1 -MCC exhibited high primary amine density (19.06 mmol/g), high specific surface area (13.5 m²/g), and good salt resistance. The maximum adsorbed amount of H-PVAm 1 -MCC for Cr (Ⅵ) reached 538 mg/g, which was higher than that of most reported amine-modified cellulose-based adsorbents. Moreover, H-PVAm 1 -MCC exhibited rapid Cr (VI) adsorption kinetics, even at low concentrations (1 ppm). Within 2 min of adsorption, the residual Cr (VI) concentration satisfied the WHO drinking water guideline (≤0.05 ppm). Even in the presence of coexisting ions, H-PVAm 1 -MCC maintained a high Cr (VI) removal rate. Moreover, H-PVAm 1 -MCC exhibited good stability, maintaining 90% adsorbed amount after eight adsorption-desorption cycles. This study provides a strategy for the further development of cellulose-based Cr (VI) adsorbents.
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2018
·
IF 6.434
Qiang Liu,Qinze Liu,Bingsi Liu,Tao Hu,Weiliang Liu,Jinshui Yao
Newly developed adsorbents, poly(tannin-hexamethylendiamine) (PTHA), were fabricated by varying the mole ratio of tannin (TA) and hexamethylendiamine (HA) under one-pot reaction. The specific forming process of the adsorbent which had undergone the transition from hydrogen bonds to covalent bonds was subsequently explored. Based on the efficiency of Cr(VI) removal from aqueous solution over all prepared adsorbents, the PTHA-4 (mole ratio of TA/HA = 1:12.5) exhibited an excellent adsorption behavior. Adsorption experiments affected by contact time and ionic strength have been conducted successively by PTHA-4, and the equilibrium was reached at 24 h. The kinetic data revealed that the adsorption was good agreement with pseudo-second order model and needed to undergo the rate-controlling step. The maximum adsorption capacity was 283.29 mg/g at 30 °C, relying on the isothermal curve suitably described by Langmuir model. Furthermore, toxic Cr(VI) had been reduced to the low toxic Cr(III) during adsorption process. The structures and adsorption performance of adsorbent were confirmed by means of SEM, FT-IR, XPS etc. Thus, the cheap-sustainable adsorbents have a superior feature for Cr(VI)-wastewater purification in future.
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高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Hongbo He,Zhuangzhu Luo,Zhen-Yu Tang,Changlin Yu
Structure controlled ZnWO 4 nanomaterials were fabricated by a facile hydrothermal reaction . The nanorod-like ZnWO 4 with exposed (111) facets exhibits significant promoting effect for Cr 6+ reduction than that of noncrystalline ZnWO 4 nanoparticles . Specifically, the photocatalytic performance of ZnWO 4 -T14 for Cr 6+ reduction is 9.8 times higher than that of ZnWO 4 -T0. The effect of Zn 2+ on the concentration-absorbance (C-A) curve of K 2 Cr 2 O 7 solution was evaluated and investigated systemically, and adding Zn 2+ can improve the UV–vis spectrum detection sensitivity of K 2 Cr 2 O 7 solution. Methylene blue (MB) as a photosensitizer to enhance the photocatalytic activity of ZnWO 4 for Cr 6+ reduction is reported for the first time. In particular, the photocatalytic activity of ZnWO 4 -T14 for Cr 6+ reduction is 96.7% in 10 mg/L MB solution, which is 65.1% higher than that in aqueous solution. Moreover, the ZnWO 4 -T14/MB possesses excellent stability, and the reduction rate of Cr 6+ remains above 90% after four cycles. We believe that the photosensitized strategy is a promising methodology in the treatment of heavy metal ion due to its superior photocatalytic activity and stability.
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高影响因子
WATER ENVIRONMENT RESEARCH
·
2019
·Vol. 91
·期 7
·565-572
·
IF 1.24
Jingge Shang,Jie Gao,Junting Xi,Yingjie Wang,Fangyu Ji,Ruijun Li
A graphene oxide (GO)—nanoscale zerovalent iron (nZVI)—biochar composite (GO-nZVI/BC) was synthesized prior to characterization by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy analyses. Batch experiments were performed at different initial Cr(VI) concentrations, contact times, and solution pH values. The effects of coexisting anions and chelating agents were also examined. The results indicated that the removal of Cr(VI) was highly pH-dependent and reached a maximum capacity at pH of 2. The equilibrium data were fitted well with the Langmuir isotherm model, and the kinetic data fitted better with the pseudo-second-order kinetic model. The increasing concentrations of EDTA in aqueous solutions were favorable to the removal of Cr(VI), while significantly inhibited adsorption. Furthermore, the GO-nZVI/BC maintained ~84.5% of its original capacity after aging in the air for 25 weeks. Based on the removal efficiency, GO-nZVI/BC can be considered to be an effective material for water treatment applications. Practitioner points Biochar-supported graphene oxide-coated nanoscale zerovalent iron (GO-nZVI/BC) was synthesized and used to treat Cr(VI) from solution. Cr(VI) removal was pH-dependent and obeyed the Langmuir isotherm model and pseudo-second-order model. GO-nZVI/BC maintained ~84.5% of its original capacity after aging for 25 w in the air. Graphical TEM and Magnetic Field of GO-nZVI/BC and its removal capacity of Cr(VI).
研究领域:
环境科学
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材料科学
·
水处理技术
·
污染物修复
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高影响因子
JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2023
·Vol. 31
·期 7
·2999-3014
·
IF 5.3
Song Jie,Chen Lijun,Niu Yuhua,Wei Zhiqiang,Sun Yonghui
From the perspective of environmental protection, high removal rate, reusable and degradable, amino-functionalized porous hydrogel material P-(EA-β-CD/KHA/AC) was synthesized by introducing ethylamino cyclodextrin, humic acid, and activated carbon, using polyacrylic acid as the carrier. MB and Cr (VI) are common wastewater pollutants, thus, Such contaminants must be removed from the water. The gel materials before and after adsorption were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The removal of MB and Cr(VI) showed high adsorption capacity. At 298 K and pH 8, the adsorption capacities of P-(EA-β-CD/KHA/AC) hydrogel for MB and Cr(VI) were as high as 262.31 and 170.12 mg/g, respectively, and the removal rates were 98.96% and 70.27%, respectively. The adsorption behavior follows the pseudo-second-order kinetic equation, conforming to the Langmuir model; and through intermolecular forces, π–π conjugation, chelation, and other interactions, entropy-increasing, endothermic, and spontaneous process is formed. The regeneration and degradability experiments of P-(EA-β-CD/KHA/AC) hydrogel were conducted and its recycling performance was verified.
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Qiang Li,Hao Zhou,Meng Tan,Lingxuan Yang,Xiao Hu,Guoxiang Yang,Hao Du,Qing Wei,Qi Wang
High visible light utilization and rapid charge separation are of great importance for environmental photocatalysis . Single photocatalyst always suffers from high recombination of photogenerated electron-hole pairs and low redox ability. Elemental doping and heterojunction construction are effective approaches to improve the photocatalytic performance. Herein, we designed and synthesized a novel Bi x Fe y VO 4 /g-C 3 N 4 (BFC) binary heterojunction via facile coprecipitation followed by calcination processes. The doping of Fe endows BiVO 4 with narrower bandgap, which boosts its light response and redox ability. The construction of heterojunction facilitates charge separation that makes BFC heterojunction displaying much higher photocatalytic activity than those of single semiconductors. The highest Cr(VI) photoreduction rate ( k ) of BFC binary heterojunction is 78 (45) times of BiVO 4 (FeVO 4 ). Additionally, the binary heterojunction can still maintain high photoreduction efficiency (98%) of Cr(VI) even after five cycling tests showing excellent photocatalytic stability. This research provides novel idea for synergistic application of doping and heterojunction in environmental photocatalysis.
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高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Tao Yang,Cui Huang,Linqian An,Ge Zeng,Juan Li,Changyu Liu,Xiaolong Xu,Jianbo Jia,Jun Ma
Hexavalent chromium (Cr(VI)) is ubiquitous in natural environments, whereas its role in the transformation of coexisting contaminants may have been overlooked. In this work, it was reported for the first time that the irradiation of Cr(VI) by solar light (solar light/Cr(VI) system) could effectively degrade various micropollutants with different structures. The removal efficiency of selected micropollutants was increased by 13.3–64.8% by the solar light/Cr(VI) system compared to that by direct solar photolysis. Meanwhile, the oxidation rates were enhanced by 2.2–21.5 folds, while they were negligible by Cr(VI) oxidation alone. Experiments by specific scavengers, probe compounds, fluorescence absorbance, and electron spin resonance analysis demonstrated that hydroxyl radical (•OH) was the major reactive species in the solar light/Cr(VI) system. Further experiments showed that the generation of •OH was closely related to the intermediate Cr(V) generated from Cr(VI) reduction, and Cr(V) could be re-oxidized back to Cr(VI). Increasing solution pH negatively affected model micropollutant (carbamazepine (CBZ)) degradation by the solar light/Cr(VI) system, mainly due to the decreased quantum yield of •OH at higher pH. Coexisting sulfate ions showed negligible effect on CBZ degradation in the solar light/Cr(VI) system, while the presence of bicarbonate , chloride, and humic acid inhibited CBZ degradation to varying degrees, owing to their diverse scavenging effects on •OH. Furthermore, moderate CBZ degradation was also achieved by natural solar light photolysis of Cr(VI). This study demonstrated the pivotal role of Cr(VI) in the transformation of micropollutants under solar irradiation, which advances the understanding of the fate of micropollutants in natural environments.
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高影响因子
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