CHEMICAL ENGINEERING JOURNAL
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2022
·
IF 16.744
Yanfang Li,Kang Xu,Huilin Hu,Lixia Jia,Yizhong Zhang,Ciren Zhuoga,Pengli Yang,Xin Tan,Wanqian Guo,Weichang Hao,Tao Yu,Jinhua Ye
Constructing atomic-level cation vacancies is an effective strategy to modulate the electronic properties of host materials, thus promoting charge transfer and redox reaction kinetics. Herein, ultrathin Bi 24 O 31 Br 10 nanosheets with cationic vacancy was synthesized via an inventive precipitation strategy by adding appropriate arginine. The difunctional arginine can changes the pH of the synthetic system and selectively deprive Bi atoms on the surface to form Bi vacancies through strong affinity between functional groups and cations. The abundant Bi vacancy decrease the Gibbs free energy change and provide channels to promote bulk adsorption of Cr(VI), thus effectively reduces the carrier migration distance during in situ bulk photocatalytic reduction of Cr(VI) and induces the formation of new impurity states to improve the utilization of visible light. Bi vacancy mitigates strong excitonic effects confined by significantly reducing exciton binding energies, thus effectively promote the separation of photo-generated charges and suppress reorganization of photon-generated carrier. Benefiting from these merits, these exclusive V Bi -Bi 24 O 31 Br 10 ultra-thin nanosheets exhibit superior reduction performance for Cr(VI), and the removal rate was more than 90% at universal pH (2–10). This work provides a new idea for the construction of cation vacancies and a feasible method for the removal of Cr(VI) under alkaline conditions.
研究领域:
材料科学
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环境科学
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化学
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纳米技术
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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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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2017
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IF 2.714
Shuang Li,Te Wei,Guojuan Ren,Fang Chai,Hongbo Wu,Fengyu Qu
A simple and highly practical colorimetric method has been proposed for detection of chromium ions (Cr 3+ and Cr 6+ ) synchronously by sodium hyaluronate functionalized gold nanoparticles (SH-AuNPs). The SH-AuNPs were synthesized and characterized by UV–vis spectra and transmission electron microscopy (TEM). The colorimetric response of Cr 3+ and Cr 6+ can be performed simultaneously by the same probe SH-AuNPs, based on the property of special localized surface plasmon resonance (LSPR). The interaction between chromium ions and sodium hyaluronate causes rapid aggregation of the SH–AuNPs conjugates and a concurrent color conversion from wine red to blue gray which is clearly detectable by the naked eye. By using SH-AuNPs as colorimetric probe, the color change with 3 μM Cr 3+ , 1 μM Cr 6+ , or 10 μM mixed chromium ions can be recognized easily by naked eye with highly selectivity. The detection limit calculated by the linear relationship of LSPR were at 0.78 nM (for Cr 3+ ), 2.90 nM (Cr 6+ ) and 0.69 nM (mixed chromium ions) respectively, which were all below the guideline value set by World Health Organization (0.962 μM). The practical applicability of the SH-AuNPs was also verified by the detection of chromium ions in natural lake water samples.
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POWDER TECHNOLOGY
·
2024
·
IF 4.5
Yuxiao Xue,Deqing Zhu,Jian Pan,Gen Li,Xuewei Lv
In this paper, two types of Ni-Cr bearing composite burdens including SP1 (79% Ni-bearing sinter and 21% Cr-bearing oxide pellets) and SP2 (84% Ni-bearing sinter and 16% Cr-bearing pre-reduced pellets) were used for the more efficient preparation of high-Cr ferronickel . Based on the metallurgical performance characterization, thermodynamic analysis and smelting parameters optimization, the qualified high-Cr ferronickel were prepared by the utilization of the Ni-Cr bearing composite burdens. The recovery rates of iron, chromium and nickel exceed 95%, 90% and 98% whereas their grades are 85.56–85.88%, 7.82–8.02% and 1.59–1.62%, respectively. Compared with SP1, SP2 possesses lower smelting duration, which indicates the appropriate proportioning of Cr-bearing pre-reduced pellets is beneficial for the smelting process. The obtained high-Cr ferronickel consisting of (Fe, Cr) 3 C and (Fe, Cr) 7 C 3 can be used as a low-cost substitute for the conventional raw materials of 200 or 300 series of stainless steel .
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Journal of Cleaner Production
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2022
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IF 11.072
Lu Zhang,Jianhao Qiu,Dingliang Dai,Yichen Zhou,Xi Liu,Jianfeng Yao
MIL-101(Cr)@ZnIn 2 S 4 hierarchical heterojunction was delicately designed and fabricated through the in-situ growth of ZnIn 2 S 4 on MIL-101 and electrostatic self-assembly. It is affirmed that the Cr–S interface bonding between MIL-101 and ZnIn 2 S 4 in their composite was established based on the characterization results of X-ray photoelectron spectroscopy, Raman and zeta potential . Thus, a high-speed channel for charges transfer is offered due to the Cr–S bond, intimate interface contact and hierarchical structure of MIL-101@ZnIn 2 S 4 , which largely inhibits the recombination of photo-induced charge carriers and promises a remarkable photocatalytic activity . Choosing visible-light-driven reduction of Cr(VI) as a model, the optimal MIL-101@ZnIn 2 S 4 sample can reduce 95% of Cr(VI) within 30 min, corresponding to a rate constant of 0.107 min −1 , which is 2.9-fold compared with blank ZnIn 2 S 4 counterpart (MIL-101 has a negligible performance). Additionally, a conspicuous apparent quantum yield of 9.7% can be achieved at a wavelength of 420 nm. Eventually, to reinforce the practicability of MIL-101@ZnIn 2 S 4 , the composite powders were manufactured as aerogels utilizing bacterial cellulose as a substrate. The MIL-101@ZnIn 2 S 4 aerogel still exerts an enviable performance for photocatalytic reduction of Cr(VI) and stability. This work could inspire the material design and environmental remediation based on MOFs.
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Processes
·
2024
·Vol. 12
·期 5
·905
·
IF 2.8
Tianji Liu,Huawei Guo,Qing Yu,Yajun Wang,Huan Liu,Yanan Zeng,Yitong Wang,Chunyu Liu,Junguo Li
In this study,Chlorella pyrenoidosawas cultured with different concentrations of Cr(III) and Cr(VI), and the changes in biomass, lipid content, protein content and total sugar content ofChlorella pyrenoidosaunder different culture conditions were detected. The effects of Cr(III) and Cr(VI) on the intracellular antioxidant system and related key enzymes of lipid synthesis were analyzed. The results showed that appropriate Cr(III) and Cr(VI) concentrations could makeChlorella pyrenoidosaregulate the contents of SOD, POD, ASA, CAT and GSH in cells, improve the enzyme activity of ACC and promote lipid synthesis. The aim was to investigate the mechanism of lipid synthesis by analyzing the distribution of Cr(III) and Cr(VI) in algal cells. The lipid content ofChlorella pyrenoidosareached its highest level at 50.43 wt% and 38.00 wt% when both Cr(III) and Cr(VI) concentrations in the culture environment were 0.5 mg/L. These values were 1.37 and 1.03 times higher than the control group, respectively. The addition of appropriate Cr(III) and Cr(VI) concentrations can increase ME enzyme activity and decrease PEPC enzyme activity, shorten the biomass accumulation cycle and prolong the lipid synthesis cycle.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2025
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IF 6.3
Zhongyu Tong,Jiamin Li,Yuqing Yan,Feifeng Huang,Guanyu Zhu,Huanping Wang,Hua Yu,Degang Deng
The development of tunable broadband near-infrared (NIR) fluorescent materials with excellent luminescent properties is still a challenge for the next generation of intelligent NIR light sources. Here, a series of Cr 3+ doped magnetoplum type NIR phosphors were prepared by the high-temperature solid-state method. Their luminescent properties and the methods to broaden the luminescence bandwidth were discussed in detail. In BaAl 12 O 19 : Cr 3+ phosphor, Cr 3+ -Cr 3+ ion pair was constructed based on heavily doped Cr 3+ ions, so as to broaden its spectral emission range. With the increase of Cr 3+ doping concentration, the full width at half maximum (FWHM) of BaAl 12 O 19 : Cr 3+ sample increased from 18.5 nm to 93.7 nm. Furthermore, the crystal field environment of Cr 3+ ions in BaAl 12 O 19 : Cr 3+ phosphors was changed by cationic substitution (Sr 2+ substituted Ba 2+ ion site). The FWHM of NIR emission increases from 49.37 nm to 123.78 nm, and the internal quantum efficiency (IQE) increases from 65.6 % to 76.2 %, with good thermal stability ( I 373 K / I 298 K = 77.3 %). An intense NIR emission of 31.3 mW at 100 mA is produced by the phosphor-converted light-emitting diode (pc-LED), exhibiting a photoelectric efficiency of 15.3 %.
研究领域:
材料科学
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光学材料
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固态化学
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光子学
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发光光谱学
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TRANSACTIONS OF TIANJIN UNIVERSITY
·
2025
·
IF 8.5
Huang Xiaorui,Zhang Wei,Xiao Liyang,Han Chunyan,Liu Ying,Zhang Jingtong,Tan Haiwen,Yin Pengfei,Zhang Rui,Dong Cunku,Liu Hui,Du Xiwen,Yang Jing
NiFe(oxy)hydroxide (NiFeOOH) has been widely studied as a catalyst for oxygen evolution reaction (OER), but its activity is still not satisfactory. Although metal doping has been employed as a promising strategy for addressing this issue, the instability and leaching of the high-valence dopant metals remain considerable challenges. Herein, an array of Cr-doped NiFeOOH nanosheets was in situ synthesized on nickel foam via a one-step hydrothermal method. The doping of NiFeOOH with Cr was found to induce partial electron transfer from Ni and Fe to Cr atoms, thereby modulating the electronic structure of the catalyst and enhancing its intrinsic activity. Electrochemical and in situ Raman spectroscopy analyses showed that Fe active sites with lower charge density enhance the adsorption of *OH and reduce the formation energy barrier of the *OOH intermediate during OER, thereby accelerating the OER. Moreover, Fe was found to promote the transfer of additional electrons to Cr, leading to electron accumulation at Cr sites. This electron accumulation effectively prevents Cr from excessive oxidation and leaching under anode potentials, thereby maintaining the structural stability of the catalyst. The optimized Cr-doped NiFeOOH self-supported electrode exhibited a current density of 50 mA/cm 2 with an overpotential of only 239 mV and remained stable for 100 h at 600 mA/cm 2 in 1 mol/L KOH.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Yaxi Zhang,Mengjiao Xu,Hao Li,Hao Ge,Zhenfeng Bian
The photocatalytic reduction efficiency of hexavalent chromium (Cr 2 O 7 2− (Cr(VI)) is suffering from high recombination of photoinduced charges, poor adsorption capacity of Cr(VI), and slow desorption of product trivalent chromium (Cr 3+ (Cr(III))) from photocatalyst surface. In this work, carbon dots (CDs) was coupled with TiO 2 mesocrystals (MT), where CDs displayed both the electron collectors and the active sites. During photoreduction of Cr(VI), the as-prepared CD/MT exhibited activity about 5.4 times higher than the pure TiO 2 mesocrystals. The positive charges on the CD/MT surface favored the selective adsorption of Cr(VI) and rapid desorption of Cr(III), which has an obvious promotion on the photocatalytic reduction of Cr(VI) and retention of photoreduction activity. Meanwhile, the CDs coupled on TiO 2 mesocrystals facilitated the separation of photogenerated charges. This work provides a simple and effective adsorption-photoreduction-desorption mechanism for the photocatalytic reduction of Cr(VI).
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DALTON TRANSACTIONS
·
2015
·Vol. 45
·期 20
·8347-8354
·
IF 4.197
Chen Dong,Genhua Wu,Zhuqing Wang,Wenzhi Ren,Yujie Zhang,Zheyu Shen,Tianhua Li,Aiguo Wu
A colorimetric assay is proposed for the selective detection of Cr(III) and Cr(VI) via the aggregation-induced color change of gallic acid capped gold nanoparticles (GA-AuNPs). The AuNPs are characterized using UV-vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and Fourier-transform infrared spectrometry (FT-IR). To detect Cr(III) and Cr(VI) coexisting in a sample, citrate and thiosulfate were applied to mask Cr(VI) for the detection of Cr(III), and ethylenediaminetetraacetic acid disodium salt (EDTA) was applied to mask Cr(III) for the detection of Cr(VI). At optimized experimental conditions, the selectivity of these AuNPs-based detection systems is excellent for Cr(III) and/or Cr(VI) compared with other types of metal ions. The limit of detections (LODs) of a mixture of Cr(III) and Cr(VI), Cr(III) and Cr(VI) by eye vision are 1.5, 1.5 and 2 μM, respectively, and those by UV-vis spectroscopy are 0.05, 0.1 and 0.1 μM, respectively. The minimum detectable concentrations for Cr(III) or Cr(VI) are all below the guideline value set by the US Environmental Protection Agency (EPA). The applicability of the AuNPs-based colorimetric sensor is also validated by the detection of Cr(III) and Cr(VI) in electroplating wastewater and real water samples with high recoveries.
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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
·
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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