JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2023
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IF 6.1
Nian Liu,Yuqi Zhang,Jiaoyan Huang,Sicong Liu,Taiping Qing,Peng Zhang,Bo Feng
In the realm of sensing, carbon dots (CDs) have exhibited remarkable fluorescence characteristics. In the field of catalysis, CDs can function concurrently as electron donors and acceptors and have substantial electron or hole transport capacities. In this study, both merits were integrated into one, and a one-step hydrothermal approach was used to create multifunctional CDs. On the one hand, CDs are employed as a fluorescence probe with good sensitivity and selectivity to detect Cr(VI). On the other hand, CDs exhibit strong photoreduction capabilities for Cr(VI) in the absence of any external cocatalysts or photosensitizers when acting as photoinitiators. The results show that Cr(VI) quenches the CDs fluorescence as a result of the combined effects of static quenching and the inner filter effect. At the same time, under the condition of illumination, the inner filter effect encourages the CDs electrons to move from the valence band to the conduction band, resulting in electron hole pairs. With the help of electrons' reducing power, Cr(VI) can be rapidly and effectively converted to Cr(III). The findings of this study suggest that CDs are a satisfying bi-functional carbon-based material with significant potential for the treatment of industrial wastewater.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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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.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
GEOCHIMICA ET COSMOCHIMICA ACTA
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2019
·
IF 4.258
Guojun Chen,Yanan Bai,Raymond Jianxiong Zeng,Liping Qin
Chromium isotopes are promising for monitoring and quantifying the extent of microbial Cr(VI) reduction. However, the mechanisms and factors that influence Cr isotope fractionation are not well understood. In the present study, we investigated the effects of different metabolic pathways and various environmental parameters on Cr isotope fractionation during Cr(VI) reduction by the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus . The Cr isotopic compositions were measured on unreacted Cr(VI) in the remaining solution. The reaction product is isotopically lighter than the reactant. The Cr isotope composition for remaining Cr(VI) in the solution followed a Rayleigh fractionation trend and thus became increasingly isotopically heavier as the reduction of Cr(VI) proceeded. Cr(VI) reduction mainly occurs on the cell surface by Ni–Fe hydrogenase; however, in the presence of CuCl 2 , the activity of Ni–Fe hydrogenase was inhibited, and Cr(VI) was reduced inside the cells. We found that despite different Cr(VI) reduction locations, Cr isotope enrichment factors ( ε = ( α − 1) × 1000, where α is the fractionation factor) were identical within uncertainty for experiments with and without CuCl 2 (−2.72 ± 0.67‰ and −2.92 ± 0.14‰, respectively). When added to the cell cultures, neutral red (NR) functioned as an electron carrier that enabled bacteria to drive the electron transfer processes. The ε values were also similar for experiments with and without NR (−2.53 ± 0.40‰ and −2.92 ± 0.14‰, respectively). We compared these ε values to investigate the effects of different electron transport pathways and cellular Cr(VI) transfer processes, including Cr(VI) transport across the cell envelope and binding to reacting enzymes, on Cr isotope fractionation. Furthermore, the effects of various environmental parameters on Cr isotope fractionation were tested, including temperature (50 °C and 70 °C), hydrogen concentration, and different electron donors (glucose and hydrogen). The ε values were similar at both tested temperatures and stayed within the previously observed range for mesophiles ; changes in hydrogen concentration also did not affect the ε values. However, the ε values were slightly higher with hydrogen as the electron donor (−3.64 ± 0.24‰) than those with glucose as the electron donor (−2.92 ± 0.14‰). In short, the Cr enrichment factors remained unchanged despite of changing microbial Cr (VI) reduction pathways and changing temperature conditions, but may be sensitive to the electron donor type.
研究领域:
微生物学
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地球化学
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DOI
高影响因子
Environmental Science-Nano
·
2024
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IF 5.8
Shengnan Zhang,Lingyi Li,Junxue Li,Wei Cheng
Hematite displays diverse crystal structures and often coexists with Fe(II), both of which are crucial in controlling the fate and mobility of Cr(VI). However, the mechanisms underlying Cr(VI) removal in the presence of Fe(II) on various hematite facets remain elusive. This study aims to elucidate the facet-dependent reactivity of hematite nanocrystals in conjunction with Fe(II) for the removal of Cr(VI) from aqueous solutions. Hematite nanoplates (HNPs), predominantly composed of {001} facets, and nanorods (HNRs), exposing both {001} and {110} facets, were synthesized and characterized. Their Cr(VI) removal capabilities were evaluated in hematite–Cr(VI) and hematite–Fe(II)–Cr(VI) systems, as well as the Fe(II)–Cr(VI) system. The adsorption of Fe(II) and Cr(VI) on hematite surfaces was highly dependent on the crystal facets and pH, with HNRs demonstrating superior Cr(VI) adsorption over HNPs, especially under acidic conditions. Neutral pH favored Fe(II)–Cr(VI) redox reactions and Fe(II) adsorption. The hematite–Fe(II) couple displayed a synergistic effect in removing Cr(VI) under acidic conditions, which was not observed under neutral conditions. The presence of Fe(II) notably enhanced Cr(VI) adsorption onto hematite, and bound Fe(II) facilitated electron transfer, accelerating Cr(VI) reduction. HNRs–Fe(II) exhibited higher Cr(VI) removal efficiency than HNPs–Fe(II) due to their lower free corrosion potential and improved electron transport properties. This research underscores the potential of facet engineering in optimizing hematite nanocrystals for environmental remediation, specifically in Cr(VI)-contaminated environments.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
CHEMOSPHERE
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2022
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IF 8.943
Xiaofeng Jiang,Wenjun Long,Liangqiong Peng,Teng Xu,Faming He,Yuling Tang,Wenhua Zhang
The rapid reductive immobilization of Cr(VI) from the aqueous solution was achieved by reduction to Cr(III) using tannic acid (TA), and subsequent pH-triggering precipitation of the organo-Cr(III) complexes formed in the redox reaction. The effects of TA concentration, temperature, and solution pH on the reduction of Cr(VI) were examined by batch experiments, and the rapid redox reduction followed a second-order kinetics with respect to Cr(VI) concentration in the pH range of 2.0–3.0. UV–visible spectra, FTIR, and XPS confirmed the complete detoxification of Cr(VI) concomitant with carboxylation of partial phenolic hydroxyls in TA. Synchronously, the reduced Cr(III) coordinated with carboxyl groups in oxidized TA (OTA) to form complexes, which exhibited remarkable pH-dependent size distribution characteristics as illustrated by SEM images and sequential filtration/ultrafiltration. The resulted Cr(III) complexes could aggregate into colloids with larger size and precipitate out at pH range of 6.0–8.0 via cross-linking, thereby leading to 93% Cr and 89% TOC immobilization. An eco-friendly and cost-effective method for Cr(VI) elimination and immobilization is provided because polyphenols are natural polymers derived from plants.
研究领域:
环境科学
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化学
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2019
·Vol. 27
·期 15
·17446-17457
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IF 2.914
Gao Zhao,Yang Hanpei,Fu Xiaofei,Jin Qiu,Wu Qiangshun,Kang Li,Wu Junming
Slow and random transfer of pollutants and photo-induced carriers on photocatalysts causes loss of efficiency in photodegradation of contaminants. Enhancing and directing mass transfer of them are considered as two major methods for improving the photodegradation of pollutants over photocatalysts. Here in this work, we focused on the design of a novel photocatalyst which not only accelerated the transfer rate of Cr(VI) and electrons but also provided specific transfer routes for them. By careful characterizations, it is indicated that 2-((2-(2-aminoethylamino)ethylimino)methyl)phenol (AEMP) was covalently attached onto activated carbon (AC), which enhanced Cr(VI) transfer from bulk solution to AC through electrostatic or coordinative interactions. The external mass transfer coefficient ( K f ) of Cr(VI) over TiO 2 /AC-AEMP was estimated as 1.75 × 10 −6 m s −1 , which was ~ 12.79 and ~ 5.96 times that of TiO 2 and TiO 2 /AC, respectively. Dense and homogeneous heterojunctions between AC and TiO 2 were acquired synchronically by forming Ti–O–C linkages, which increased traveling of electrons from TiO 2 to AC. Accordingly, Cr(VI) can capture photo-induced electrons on the surface of AC via concrete routes and then be reduced efficiently. The results showed that the photoreduction rate of Cr(VI) on TiO 2 /AC-AEMP reached to ~ 92.7%, and the overall photocatalytic activity of this well-designed TiO 2 /AC-AEMP has been enhanced significantly by 5.5 times compared to TiO 2 /AC. The enhanced photocatalytic activity of TiO 2 /AC-AEMP was mainly attributed to an improved synergetic process of mass transfer–induced adsorption–photoreduction by forming specific transfer routes for accelerative motion of Cr(VI) and electrons. This work provides a feasible strategy to improve the photoactivity of photocatalysts for the degradation of pollutants by effective mass transfer.
Graphical abstract
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2025
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IF 6.9
Mimi Sun,Jiahui He,Wanting Xiang,Wei Zou,Wenfei Song,Yating Xi,Jun Yan,Meimei Zhou,Pingping Luo
The design and construction of diverse heterojunction architectures have emerged as an effective strategy for enhancing the photocatalytic performance of semiconductors. In this study, ZIF-8/TiO 2 composite nanofibers were successfully fabricated by combining electrospinning technology with a facile in-situ solvothermal method, followed by ZIF-8 sulfurization to form ZnS/TiO 2 nanofiber heterostructures. Comprehensive characterization confirmed that ZIF-8 on the surface of TiO 2 nanofibers was completely converted into ZnS, establishing a robust and intimate interface with TiO 2 . The resulting ZnS/TiO 2 heterojunction exhibited remarkable photocatalytic reduction activity for Cr(VI), achieving 100% removal efficiency within 20 min under visible light irradiation. The photocatalytic reaction rate constant of the ZnS@TiO 2 nanofibers was approximately 10 and 319.5 times higher than those of pristine ZnS and TiO 2 nanofibers, respectively. This enhanced photocatalytic performance is attributed to the formation of the heterojunction, which effectively narrows the bandgap of the composite, optimizes photogenerated charge transfer pathways and significantly improves electron-hole pairs separation. Furthermore, mechanistic studies identified photogenerated electrons (e − ) and superoxide radicals ( O 2 − ) as the dominant active species involved in the photocatalytic reduction process. This work provides both fundamental understanding and practical methodology for developing high-performance TiO 2 -based photocatalytic systems, highlighting their potential for advanced water purification technologies.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
FUEL
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2022
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IF 8.035
Chenxi Lu,Yuanzhuo Zhou,Liangzhi Li,Hongwei Chen,Lishi Yan
Catalytic production of 5-hydroxymethylfurfural (5-HMF) from glucose is a promising routine for generation of varied value-added chemicals. Herein, Mixed-Metal metal–organic frameworks (MOFs)–Fe/MIL-101(Cr) and MIL-101(Cr, Fe) obtained from post-synthesis modification and one-pot synthesis approach respectively were applied for catalytic converting glucose to 5-HMF. The synthesized Mixed-Metal MOFs were characterized by PXRD, SEM, N 2 adsorption–desorption analysis, TGA, XPS and NH 3 -TPD. Cr-and Fe-containing Mixed-Metal MOFs Fe/MIL-101(Cr) and MIL-101(Cr, Fe) presented synergistic effect with enhanced catalytic ability for glucose transformation to 5-HMF compared with typical single-metal MOFs and sulfonic acid-functionalized MOFs. Moreover, these two Mixed-Metal MOFs also presented better thermal stability than single-metal MOFs like MIL-101(Cr). Fe/MIL-101(Cr) was found to possess higher catalytic performance than MIL-101(Cr, Fe). 55.8 % 5-HMF yield was obtained with Fe/MIL-101(Cr) at 170 °C for 2 h in DMSO/water system. In addition, Fe/MIL-101(Cr) demonstrated desired recyclability for five times without incredible loss in its activity. This study provides a Mixed-Metal strategy on MOFs for improving catalytic efficiency of glucose conversion to 5-HMF.
研究领域:
化学工程
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材料科学
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催化
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DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2017
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IF 3.648
Qianwei Liang,Junjie Geng,Hanjin Luo,Wei Fang,Yuwei Yin
In the present study, a novel magnetic Cr(VI) ion-imprinted polymer (MGOIIP) was prepared by a sol-gel process for fast and selective adsorption of Cr(VI) anions from aqueous solutions. In the synthesis process, 4-vinyl pyridine (4-VP) and 2-hydroxyethyl methacrylate (HEMA) were used as functional monomer and co-monomer; ethylene glycol dimethacrylate (EGDMA) and N , N -azoisobisbutyronitrile (AIBN) were used as cross-linker and initiator, respectively; acetone was selected as solvent. Fe 3 O 4 @SiO 2 nanoparticles were introduced for separating adsorbents from the aqueous solution conveniently, and graphene oxide (GO) could prevent Fe 3 O 4 @SiO 2 particles from aggregating. Some different techniques including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), SEM-energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to confirm the successful synthesis of ion-imprinted polymer on the surface of Fe 3 O 4 @SiO 2 /GO nanoparticles. The obtained magnetic ion-imprinted polymer has a high adsorption capacity (up to 311.95 mg/g) for Cr(VI) anions at an optimal pH of 2.0, and the adsorption equilibrium can be reached within 3 min. The adsorption process can be fitted well with Langmuir isotherm model and the pseudo-second-order kinetic model . Moreover, the results showed that MGOIIP has excellent selectivity and good regeneration ability. The prepared MGOIIP exhibited a satisfactory recovery for Cr(VI) anions in tap, river and lake water samples.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2014
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IF 0.987
Ruihua Huang,Bo Wang,Bingchao Yang,Dongsheng Zheng,Zengqiang Zhang
An adsorbent was prepared from bentonite modified by hexadecyltrimethylammonium bromide (HDTMAB) and N-2-hydroxypropyl trimethyl ammonium chloride chitosan (HTCC). This adsorbent was named as HDTMAB–HTCC bentonite. It would be used for the simultaneous adsorption of phenol and Cr(VI) from aqueous solution. By the method of single-factor experiment, the optimum preparation conditions of HDTMAB–HTCC bentonite were obtained. For bentonite (5 g), 1.0 g HDTMAB and 0.5 g HTCC were adopted as the modifying reagents. The reaction was carried out for 2 h at 80°C. The removals towards phenol and Cr(VI) enhanced with the increase in the amount of adsorbent dosage. The relatively high removals towards phenol and Cr(VI) occurred at a pH value of 1.5 or so. During the simultaneous adsorption process of phenol and Cr(VI), phenol was adsorbed by the partition from the organic phase formed by HDTMAB, while Cr(VI) was mostly adsorbed by the electrostatic interactions between HTCC and Cr(VI). No direct competition was observed due to different adsorption sites.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2013
·Vol. 131
·期 4
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IF 1.395
Ruihua Huang,Bingchao Yang,Qian Liu,Yanping Liu
Activated carbon/chitosan composite has been used as an adsorbent to remove aniline and Cr(VI) ions from aqueous solutions simultaneously. The effects of preparation conditions such as the ratio of activated carbon to chitosan, crosslinking reagents, crosslinking time, and adsorption conditions including adsorbent dosage, pH value of solution, and contact time on simultaneous adsorption of aniline and Cr(VI) ion were investigated. Experimental results showed that epichlorohydrin was the proper crosslinking reagent, and the ratio of activated carbon to chitosan was kept at 1. When the adsorbent dosage was 4.0 g/L, and the concentrations of aniline and Cr(VI) were lower than 50 and 100 mg/L, respectively, both aniline and Cr(VI) were simultaneously removed at natural pH with high removals (>95%). The presence of Cr(VI) enhanced the adsorption of aniline, while the presence of aniline almost had no influence on the adsorption of Cr(VI). The adsorption processes of both aniline and Cr(VI) followed the pseudo-second-order kinetics model, but the sorption of Cr(VI) was preferential to that of aniline by this composite. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 39903.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2022
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IF 7.139
Meigeng Gao,Elena Yu Konysheva,Jun Yang
The La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) ceramics with the porosity of 20% (LSCF-20) and 50% (LSCF-50) were fabricated through temperature variation. Kinetics of the Cr-adsorption has been studied at 700 °C over 345 h under air. Different dominant mechanisms of Cr chemisorption over the ceramics with different porosities were identified. The Cr–substitution into the LSCF perovskite grains will dominate in the denser LSCF-20 ceramics, whereas the growth of SrCrO 4 crystals over the LSCF perovskite phase will occur preferably in the more porous LSCF-50 ceramics. The Cr penetrates into a more porous LSCF-50 ceramics up to 12–17 μm and the total Cr amount adsorbed after 345 h over the LSCF-50 ceramics is larger by about 10 times than over the denser LSCF-20 ceramics. The revealed remarkable differences could be associated with the increase in the surface area and with a higher volume of macro- and mesoporosity.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）