JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2017
·Vol. 85
·期 1
·121-131
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IF 1.575
Zhang Dong,Guo Qingjie,Ren Yanfang,Wang Changzheng,Shi Qiang,Wang Qinglin,Xiao Xia,Wang Wenjun,Fan Quli
ZnAl 2 O 4 :Cr 3+ crystals were synthesized by using sol–gel method at 1000 °C. The results showed that with the concentration of Cr 3+ in spinel lattices increasing, the x-ray diffraction peaks shifted toward lower diffraction angles, and the grain size revealed a rapid increase and became invariable when the Cr 3+ dopant concentration was above 0.7 mol%. All the samples showed a series of emission peaks ranging from 660 to 730 nm assigned to spin-forbidden 2 E g → 4 A 2g transition of Cr 3+ ions in spinel lattices. The intensity of emission peaks revealed a strong dependence on the Cr 3+ concentration. An additional emission peak at 740 nm was present when the Cr 3+ ions concentration was above 0.5%. All emission peaks were quenched when the Cr 3+ concentration reaches 1.3 mol%. The results of x-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) suggested that the Cr 3+ ions occupied the octahedral sites in spinel lattices, and with the Cr 3+ concentration increasing, the exchange interaction and coupling interaction between Cr–Cr were enhanced and the antisite defects related to Zn in octahedral sites increased. Graphical abstract
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Chemical Engineering Journal Advances
·
2025
·
IF 7.1
Wuxin Hou,Jizhuang Zuo,Yongle Gao,Yao Wang,Li Liu
The generation of humins by-products in biorefinery is often unavoidable. We here report the valorization of chitosan-derived humins for removal of heavy metal ions to enhance the atomic economy of the biomass conversion. Chitosan-derived humins were synthesized by catalysis of oxalic acid (OA), whereby the adsorption performance for Cd(II), Cr(III) and Cr(VI) was explored. The adsorption data were well fitted by the pseudo-second-order kinetic model, complemented by the Freundlich and Temkin isotherm models, revealing maximum adsorption capacities of humins for heavy metal ions as follows: 358.7 mg/g for Cr(VI), 152.6 mg/g for Cd(II), and 40.2 mg/g for Cr(III). The mechanistic studies revealed that the adsorption of Cd(II) and Cr(III) by humins mainly occurs through ion exchange (carboxyl groups) and surface complexation (hydroxyl, carbonyl, and amino groups). In comparison, the adsorption of Cr(VI) by humins involves electrostatic attraction, alongside ion exchange and surface complexation. After carbonization and activation, the specific surface area increased markedly, however the adsorption capacity decreased owing to reduced oxygen- and nitrogen-containing functional groups. Competitive adsorption studies, industrial wastewater experiments, and cyclic adsorption tests demonstrate that humins exhibit remarkable adsorption performance even in complex environments. This work highlights that chitosan-derived humins are promising adsorbents for the remediation of heavy metal ions.
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MICROCHEMICAL JOURNAL
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2025
·
IF 5.1
Jiajia Yuan,Yue Luo,Xinfeng Zhang
In this study, we developed a sensitive chemiluminescence (CL) method for the detection of Cr (Ⅲ) and Cr (VI), based on periodate (NaIO 4 )-hydrogen peroxide (H 2 O 2 )-terbium-based metal–organic frameworks (Tb-BTC MOF) system. Reactive oxygen species (ROSs) created from the reaction of NaIO 4 with H 2 O 2 , such as singlet oxygen ( 1 O 2 ), can effectively transfer energy to the Tb-BTC MOF, resulting in the characteristic emissions from Tb 3+ through the antenna effect. Compared to its bulk form, the nanoscale Tb-BTC MOF exhibited significantly enhanced CL intensity, which can be attributed to improved surface properties and reduced non-radiative decay. The presence of Cr (VI) led to a marked decrease in CL intensity due to energy competition with the H 3 BTC ligand. Additionally, Cr (III) was oxidized to Cr (VI) by NaIO 4 , thereby indirectly contributing to CL quenching. A linear correlation was observed between the concentrations of Cr (III)/Cr (VI) and the reduction in CL intensity, enabling quantitative analysis of both species. Following systematic optimization, the proposed method demonstrated good sensitivity, achieving detection limits of 33 nM for Cr (III) and 17 nM for Cr (VI), which are significantly lower than those obtained with fluorescence-based detection using Tb-BTC MOF. Furthermore, by employing a cation-exchange resin for pre-separation, Cr (III) and Cr (VI) could be individually quantified within mixed samples. This method was also successfully applied to real water samples, yielding satisfactory recoveries and demonstrating its practical applicability for chromium speciation analysis in environmental matrices. Overall, this work provides new insights into the design of advanced CL systems using nanostructured MOFs, offering a promising strategy for the selective and sensitive detection of metal ions in complex environmental matrices.
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Linshan Zhang,Guozong Yue,Luming Yang,Deshun Huang
Ultra-thin MXene nanosheets (Nss) were facilely prepared via delaminating and intercalating the multi-layered MXene using tetramethylammonium hydroxide (TMAOH). Electron-rich characteristics, abundant surface active sites and the negative charges made MXene Nss having both good reduction ability and adsorption capacities, which would effectively remove anion Cr(VI) via reduction and remove cation Cr(III) via adsorption. Batch adsorption tests were carried out to study the pH impact, adsorption kinetics and isotherms. Upon adsorption, the well dispersed MXene Nss suspension was aggregated to form flocs and sediment at the bottom. The maximum Cr(VI) and Cr(III) removing capacities are calculated to be 554.9 mg/g at 318 K and 283 mg/g at 298 K, respectively. The mechanisms on Cr(VI)/Cr(III) adsorption were well studied employing SEM, TEM , XPS and FT-IR. In addition, the MXene Nss also showed good adsorption capacity towards other metal cations (such as Cu 2+ , Cd 2+ , and Pb 2+ ), manifesting that the current MXene Nss has the potential to be used as a general-purpose adsorbent.
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JOURNAL OF MOLECULAR LIQUIDS
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2023
·
IF 6
Guang Tian,Xiangxiang Li,Falin He,Shuqi Guo,Yaoyue Wang,Yuze Li,Wansong Zong,Rutao Liu
Chromium (Cr) poses potential threats on human and ecological health through both food and environmental pathways. However, the response mechanisms of Cr to function-related proteins in human subjects and the differential effects in the case of different valence states of Cr are still lacking. Herein, the binding interactions and mechanisms of lysozyme to Cr(III) and Cr(VI) were investigated by isothermal titration microcalorimetry, multi-spectroscopy, enzyme activity assay, and molecular simulations. Our results indicated that the binding of Cr in different valence states with lysozyme was a relatively affinity process and mainly driven by hydrophobic forces. Both Cr species induced the looseness of backbone for lysozyme and the enhancement of hydrophilicity around the backbone microenvironment. Otherwise, the α-helix of lysozyme was decreased with different valence states of Cr, while Cr(III) showed a greater degree of influence and a stronger regularity. Interestingly, no significant changes in the microenvironment around aromatic amino acid residues were observed under the exposure of different valence states of Cr. Differential structural changes of lysozyme resulted in activity alterations. At 80 mg·L −1 of Cr, Cr (VI) reduced the lysozyme activity to 81.44% of the control, while the lysozyme activity was significantly reduced to 24.45% under the exposure of Cr (III). Further molecular docking showed that amino acids near the binding sites of different valence states of Cr with lysozyme were not identical, but the enzyme active site, Asp52, was all within the binding pocket. This study elucidates the differential toxicity effects and interaction mechanisms of Cr in different valence states, and offers a comprehensive strategy for exploring the in vitro responses of toxicants exposure.
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FUEL PROCESSING TECHNOLOGY
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2016
·
IF 3.847
Ting-Ting Zhao,Wen-Zhi Ge,Fen Yue,Ying-Xiong Wang,Christian Marcus Pedersen,Fan-Gui Zeng,Yan Qiao
Lignite showed high capacity for reducing Cr(VI) to Cr(III) and hence removed Cr(VI) from aqueous solution, but the reduced Cr(III) cannot be released from adsorbent afterwards especially under acidic condition. In order to know why Cr(III) ions are immobilized within lignite adsorbent and how to recovery Cr species, the interaction of Cr(III) ions with lignite oxidized by Cr(VI) was studied by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The data obtained from these studies indicate that Cr(III) ions are bonded to oxygenic functional groups in lignite oxidized by Cr(VI) and electrons are delocalized over -O-Cr-O- domain. It is also revealed that the O atoms of C = O and C-O groups in the adsorbent matrix are bonded to Cr(III) ions along with the decrease of electron density, while the O atoms of O -C = O group are along with the increase of electron density. Based on these important structural information, we developed a method to treat Cr-loaded lignite further and to recover the Cr species.
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Environmental Science & Technology Letters
·
2017
·
IF 5.308
Jun-Cheng Han,Guo-Jun Chen,Li-Ping Qin,Yang Mu
Cr isotope fractionation during microbial reduction processes is commonly recognized as a promising tool in biogeochemistry and bioremediation. However, the mechanism of Cr isotope fractionation during microbial reduction is poorly understood. In this work, the relationship between the bacterial respiratory pathway and Cr isotope fractionation was investigated in Shewanella oneidensis MR-1. For comparison with the wild type, a mutant strain (ΔomcA/ΔmtrC) with a deficiency in extracellular Cr(VI) reduction was constructed by deleting the omcA and mtrC genes, which encode the terminal reductase during extracellular reduction. The magnitudes of Cr isotope fractionation (ε) for Cr(VI) reduction by the wild type and ΔomcA/ΔmtrC were −2.42 ± 0.68‰ and −2.70 ± 0.22‰, respectively. Surprisingly, the ε values were not significantly different between the two strains. This suggests that isotope fractionation is independent of the metal respiratory pathway during Cr(VI) reduction by S. oneidensis MR-1. Moreover, a three-step Cr isotope fractionation model that includes uptake, reduction, and efflux was proposed to exist during intracellular Cr(VI) reduction by S. oneidensis MR-1. The developed model provides a better understanding of Cr isotope fractionation during microbial reduction.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
·
IF 4.539
Wei Zhang,Xinyue Ma,Rui Li,Wenzheng Yang,Qiao Li,Xiuyun Sun,Jiansheng Li,Jinyou Shen
Purification of various types of industrial wastewater containing chelated heavy metals (CHMs) remains a challenging task due to the easy dissolution, poor biodegradation and extremely high stability over a wide pH range. Compared with the common CHMs, the attention of Cr(III) complexes is greatly insufficient. Especially, Cr(III) of the wastewater is easily reoxidized and converted into Cr(VI) with high biotoxicity during the transferring process, so the treatment of Cr(III) complexes needs to be treated more strictly. Obviously, compared with previous advanced oxidation and replacement-coprecipitation technologies, adsorption method could directly remove Cr(III) complexes in one step, thus avoiding the accumulation of secondary toxic Cr(VI). Considering that ferrihydrite (Fh) materials are widely distributed on the nature, excellent adsorption performance, low cost, and environmentally friendly, this paper proposes a novel strategy that uses the common Fh as an efficient adsorbent to realize one-step elimination of typical EDTA-Cr(III) complexes without introducing secondary pollution. Batch experiment results illustrated that more than 93% of EDTA-Cr(III) was removed at pH = 3 or 6 (a final concentration of <1 mg/L EDTA-Cr(III) was detected in the residual solution within one hour). In particular, Fh retained good performance for the removal of EDTA-Cr(III) after desorption reactions in 2 g/L Na 2 SO 4 solution. A series of experiments and characterization results suggested that EDTA-Cr(III) was adsorbed on Fh materials mainly through electrostatic interactions and surface complexation. In general, this study also demonstrated Fh for the outstanding remediation of various Cr(III)-organic complexes from multicomponent environment.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Yun Guo,Hong-Yi Li,Jie Cheng,Shuo Shen,Jiang Diao,Bing Xie
The V-Cr-bearing reducing slag (VCBRS) is solid waste, which cannot be treated at present. This work proposes an effective approach to separately recover its major elements of V, Cr and Si and fully utilize the VCBRS with added-values. Flocculation desiliconization is used to extract Si from the acid solving liquid of VCBRS and Si is recovered as white carbon black with purity of 94.60% and recovery of 93.04%. After desiliconization, V in the solving liquid is selectively oxidized by H 2 O 2 and extracted by microemulsion extraction, which is recovered as V 2 O 5 whose purity is 99.60% with recovery at 96.32% from the stripping liquor of loaded microemulsion . Cr in the raffinate is recovered by alkaline precipitation as final product of Cr 2 O 3 with purity of 98.83% and recovery of 92.68%. The principles are discussed in detail and the operation conditions are optimized systematically. The microemulsion and wastewater are both cyclically utilized, which eliminates the secondary wastes. This work efficiently recovers all valuable elements with increased values from the solid waste, which can not only solve the environmental pollution problem, but also realize the efficient recovery of valuable elements to achieve comprehensive utilization.
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CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 12.5
Ting Zhao,Yanjing Wang,Lei Li,Pengyu Gong,Mingrui Yang
An oxalic acid-based remediation method enables deep Cr(VI) reduction and Cr removal. • Oxalic acid dissolves refractory Cr(VI) species and removes Fe Cr associated Cr(III). • Cr(VI) speciation-guided processes achieve efficient remediation of diverse soils. • One-step and two-step treatments address different Cr(VI) contamination scenarios. • Plant-derived oxalic acid provides an environmentally benign reagent. The complex distribution of Cr(VI) species in contaminated soils limits the effectiveness of conventional reduction methods, which often fail to achieve regulatory targets and result in the accumulation of substantial Cr(III) residues. In this study, a thermally activated oxalic acid reduction strategy was developed based on the molecular characteristics of Cr(VI) and Cr(III) species in soils, enabling deep Cr(VI) reduction and simultaneous total chromium removal. For soils with high proportions of adsorbed Cr(VI) but limited water-soluble Cr(VI), a one-step thermally activated oxalic acid treatment reduced Cr(VI) concentrations below the regulatory limit (5.7 mg kg −1 ) and removed approximately 80% of total chromium. In contrast, soils dominated by water-soluble Cr(VI) were effectively remediated through a two-step process involving water washing followed by thermally activated oxalic acid reduction, achieving regulatory compliance and substantial total chromium removal. Mechanistically, oxalic acid enables near-complete reduction of stably coordinated Cr(VI) via a dissolution-release-reduction pathway, while other adsorbed Cr(VI) species are reduced through dissolution-reduction or direct reduction pathways. Meanwhile, the predominant Cr(III) species Fe Cr coprecipitate in the soil is simultaneously dissolved by oxalic acid. After remediation, residual Cr is mainly retained as highly stable residual Cr(III) species with minimal environmental risk. The oxalic acid filtrate can be regenerated via ion exchange treatment and reused for subsequent reduction, and oxalic acid itself, as a common plant root exudate, serves as an environmentally benign reagent. Moreover, this method is applicable to different soils with varying textures and Cr(VI) speciation, providing a potentially sustainable approach for the remediation of Cr(VI)-contaminated soils. Download: Download high-res image (265KB) Download: Download full-size image
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JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Kang Li,Yang Hanpei,Wang Lina,Chai Siqi,Zhang Ruichen,Wu Junming,Liu Xiaona
In this study, a novel composite composed of iron monosulfide nanoparticles (FeS NPs) and titanate nanotubes (TNTs) was hydrothermally synthesized. Characterizations revealed the encapsulation and homogenous dispersion of FeS NPs into the interlayers of TNTs. Significant performance in removal of aqueous total Cr was acquired by efficient conversion of Cr(VI) to Cr(III) on FeS and simultaneous adsorption of Cr(III) on TNTs. Moreover, the high activity of FeS-TNTs in reduction of Cr(VI) can maintain at high oxicity or alkalinity of its solution. The synergistic effect between FeS and TNTs was derived from sheltering of FeS NPs from their self-aggregation, O 2 -oxidation and the affinity of Cr(III) to TNTs. The unique properties, e.g. the solid acidity, the hollow and interlayered configuration of TNTs played important roles in high activity, good stability and reusability of FeS-TNTs.
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PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Minzi Liao,Shengxi Zhao,Kai Wei,Hongwei Sun,Lizhi Zhang
Cr(III)-organic complexes removal from wastewater is challenging to decompose the complexes without producing toxic Cr(VI). Herein we demonstrated that oxalated zero-valent iron (Ox-ZVI) could one-step decomplex 95.4% of Cr(III)-EDTA with 94.2% removal of total Cr and 60.5% removal of TOC without generating Cr(VI) at pH 6.0. Ox-ZVI with FeC 2 O 4 shell preferred to adsorb and activate O 2 to produce more reactive species than ZVI with iron oxide shell, while the generated 1 O 2 could selectively break the Cr-O and Cr-N bond to precisely decomplex Cr(III)-EDTA without producing Cr(VI). The released Cr(III) was in-situ precipitated on the surface of ZVI in Cr(OH) 3 form. Interestingly, •OH preferred the effective degradation of the released EDTA ligand to the oxidation of the chelated Cr(III) at pH 6.0. This study offers a green and facile method for the Cr(III)-organic complexes treatment, and also sheds light on the importance of reactive species adjustment for the precise pollutant control.
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