Journal of Materials Chemistry A
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2018
·Vol. 6
·期 45
·22580-22589
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IF 9.931
Xiu-Qing Qiao,Zhen-Wei Zhang,Qiu-Hao Li,Dongfang Hou,Qichun Zhang,Jian Zhang,Dong-Sheng Li,Pingyun Feng,Xianhui Bu
Exploiting novel photocatalysts with high efficiency and durability for reduction of hexavalent chromium (Cr(VI)) has gained attention from fundamental science and industrial research. In this work, we synthesized novel two-dimensional (2D) n–n Bi2MoO6 & Bi2S3 heterojunctions by a facile in situ anion exchange process for remarkably efficient removal of Cr(VI). Results show that Bi2MoO6 & Bi2S3 heterojunctions with core–shell structures are formed through the intimate contact of Bi2MoO6 core and Bi2S3 shell. The prepared Bi2MoO6 & Bi2S3 heterojunctions exhibit unprecedented photocatalytic activity for reduction of Cr(VI) under visible light irradiation. The optimized BMO-S1 heterojunction displays the highest reduction efficiency (κapp = 0.164 min−1) for Cr(VI) reduction. To the best of our knowledge, it is one of the highest reduction rate achieved among reported photocatalysts for Cr(VI) reduction under visible-light irradiation. Detailed studies show that strong selective adsorption for Cr(VI) enhances this unprecedented photocatalytic activity. Moreover, the intimate heterojunction between Bi2MoO6 core and Bi2S3 shell can efficiently deteriorate the charge carrier recombination and Bi2S3 content can boost visible light harvesting, thereby contributing to the remarkable photocatalytic catalytic activity, which were proven by PL, EIS and transient photocurrent responses. Characterization of Mott–Schottky plots and DRS prove that the Bi2MoO6 & Bi2S3 heterojunctions established a type-II band alignment with intimate contact, accounting for the efficient transfer and separation of photogenerated carriers. This work provides a simple route for facial synthesis of heterojunction photocatalysts for Cr(VI) reduction in industrial applications.
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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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2023
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IF 10.9
Chao Liu,Wen Xiao,Xingyu Liu,Qiang Wang,Jiawei Hu,Siyuan Zhang,Jianguang Xu,Qinfang Zhang,Zhigang Zou
As a highly toxic heavy metal, Cr(VI) reduction by developing high-efficiency photocatalysts is of great significance. Herein, we firstly design few-layer Ti 3 C 2 MXene (FTM) by the hand-operated shaking, showing dual advantages of structural stability and more exposed reactive sites. Then, a refluxed process is performed to fabricate FTM/CaIn 2 S 4 (FTC) composites, where 2D CaIn 2 S 4 (CIS) nanoplates are closely connected with 2D FTM to form Schottky junction. The optimal 1-FTC with the FTM/CIS mass ratio of 1 wt.% exhibits the highest activity toward photocatalytic Cr(VI) reduction under visible light. It is well elucidated that the broadened light absorption range and promoted charge carrier separation rate induced by the introduction of FTM are responsible for improving photocatalytic activity of CIS. During Cr(VI) photoreduction, 1-FTC possesses excellent photo-stability and reusability. The effects of catalyst mass, coexisting ions, water sources and pH values on the Cr(VI) photoreduction efficiency are investigated. Photogenerated • O 2 − and e − are the main radical species accounting for Cr(VI) photoreduction over 1-FTC. The photocatalytic mechanism along with Cr(VI) removal pathway is exploited. This work may provide some insights into constructing FTM-based Schottky junctions for the efficient water purification.
研究领域:
材料科学
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环境科学
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化学工程
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高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 11
·3122
·
IF 5.076
Rao Fu,Yinyan Gong,Can Li,Lengyuan Niu,Xinjuan Liu
The development of highly active and stable photocatalysts, an effective way to remediate environment pollution and alleviate energy shortages, remains a challenging issue. In this work, a CdIn2S4/In(OH)3nanocomposite was deposited in-situ on NiCr-LDH nanosheets by a simple hydrothermal method, and the obtained CdIn2S4/In(OH)3/NiCr-LDH heterostructure photocatalysts with multiple intimate-contact interfaces exhibited better photocatalytic activity. The photocatalytic H2evolution rate of CdIn2S4/In(OH)3/NiCr-LDH increased to 10.9 and 58.7 times that of the counterparts CdIn2S4and NiCr-LDH, respectively. Moreover, the photocatalytic removal efficiency of Cr(VI) increased from 6% for NiCr-LDH and 75% for CdIn2S4to 97% for CdIn2S4/In(OH)3/NiCr-LDH. The enhanced photocatalytic performance was attributed to the formation of multi-interfaces with strong interfacial interactions and staggered band alignments, which offered multiple pathways for carrier migration, thus promoting the separation efficiency of photo-excited electrons and holes. This study demonstrates a facile method to fabricate inexpensive and efficient heterostructure photocatalysts for solving environmental problems.
研究领域:
材料科学
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环境科学
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能源科学
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DOI
高影响因子
ENVIRONMENTAL RESEARCH
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2024
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IF 7.7
Shi-Wen Lv,Jialu Pan,Xiaoran Wang,Yifan Shao,Yanqing Cong,Lin Che
It is of great significance to establish an effective method for removing Cr(VI) from wastewater. Herein, Fe-doped g-C 3 N 4 (namely Fe-g–C 3 N 4 –2) was synthesized and then employed as photocatalyst to conduct the test of Cr(VI) reduction. Notably, the embedding of Fe ion in g-C 3 N 4 can offer the Fe 2+ /Fe 3+ redox couples, so reducing the interfacial resistance of charge transfer and suppressing the recombination of photogenerated electrons and holes. The impurity energy levels will form in g-C 3 N 4 after the introduction of Fe ion , thereby boosting the light absorption capacity of catalyst. Thus, Fe-g–C 3 N 4 –2 showed good performance in photocatalytic Cr(VI) reduction, and the reduction efficiency of Cr(VI) can reach 39.9% within 40 min. Different with many previous studies, current work unexpectedly found that the addition of p -benzoquinone (BQ) can promote the Cr(VI) reduction, and the reduction efficiency of Cr(VI) over Fe-g–C 3 N 4 –2 was as high as 93.2% in the presence of BQ (1.5 mM). Further analyses showed that BQ can be reduced to hydroquinone (HQ) by photogenerated electrons, and UV light can also directly induce BQ to generate HQ by using H 2 O as the hydrogen donor . The HQ with reducing ability can accelerate the Cr(VI) reduction. In short, current work shared some novel insights into photocatalytic Cr(VI) reduction in the presence of BQ. Future research should consider possible reactions between photogenerated electrons and BQ. For the UV-induced photocatalysis , the suitability of BQ as the scavenger of O 2 •‒ must be given carefully consideration.
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
ENVIRONMENTAL TECHNOLOGY
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2019
·
IF 1.918
Ying Li,Cheng Chen,Yao Wu,Yijie Han,Yeqing Lan
The synergism of CuS and tartaric acid (TA) in the reduction of Cr(VI) with an irradiation of simulated solar light was investigated through observing the effects of solution pH, temperature, CuS loading and TA concentration on the removal efficiency of Cr(VI). Approximately 32% and 54% of the initial Cr(VI) (100 µmol/L) were reduced within 180 min by TA and CuS with light, respectively. Under the same condition, however, almost a complete removal of the initial Cr(VI) was achieved within 130 min in the coexistence of CuS and TA. In the case, it is considered that Cr(VI) was rapidly reduced in two main pathways. One is that H2S produced from the dissolution of CuS in weak acidic solution directly reduced Cr(VI) to Cr(III). The other is that Cu(II) released from CuS reacted with TA to form complexes with photochemical activity, producing Cu(I) through ligand-to-metal electron transfer, and then the reduction of Cr(VI) was coupled with a conversion of Cu(I) to Cu(II). Thus, a cycle catalytic system was established for the reduction of Cr(VI). Moreover, it is observed that the reaction could be divided into two stages: the initial chemical reduction of Cr(VI) by H2S and the later photochemical reduction of Cr(VI) by Cu(II)–TA complexes.
研究领域:
环境科学
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化学
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
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2018
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IF 4.439
Chongfei Yu,Pengyan Yang,Luna Tie,Siyu Yang,Shuying Dong,Jingyu Sun,Jianhui Sun
Herein, we demonstrate the design and fabrication of β-Bi 2 O 3 @ Bi 2 S 3 hollow microspheres with sheet-like hierarchical nanostructures targeting an advanced visible-light-responsive photocatalytic system. In comparison with pure Bi 2 S 3 and β-Bi 2 O 3 , the as-obtained β-Bi 2 O 3 @Bi 2 S 3 heterojunction photocatalyst exhibits a markedly enhanced sunlight photocatalytic activity towards the photo-degradation of rhodamine B. Following, the property of the β-Bi 2 O 3 @Bi 2 S 3 on the Cr 6+ photocatalytic reduction was then evaluated. Operating conditions such as β-Bi 2 O 3 @Bi 2 S 3 mass, tartaric acid concentration, and initial Cr 6+ concentration were analyzed. The results showed that a suitable reduction condition was selected as, β-Bi 2 O 3 @Bi 2 S 3 dosage 25 mg, initial concentration 20 mg·L −1 and molar ratio of Cr 6+ /tartaric acid 1:20. The outstanding photocatalytic performances of the hybrid photocatalyst are mainly attributed to the reduced recombination rates of photo-generated electrons/holes, enhanced light harvesting, increased active sites as well as the improved photo/chemical stability. Moreover, the photocatalytic mechanism of β-Bi 2 O 3 @Bi 2 S 3 for oxidation of RhB and reduction of Cr 6+ was investigated in detail. The enhanced photocatalytic activity and excellent chemical stability render the thus-fabricated heterostructure a promising candidate to remediate aquatic contaminants and meet the demands of future photocatalytic materials.
研究领域:
材料科学
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环境科学
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化学工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Qiaoyuan Gao,Dagang Lin,Yongjie Fan,Qin He,Qi Wang
Visible-light-active Fe-2MI assemblies were prepared at room temperature using 2-Methylimidazole (2MI) as organic ligand to form complex with Fe(II) or Fe(III). TGA and XRD characterizations indicated that Fe(II) can form more stable complex and higher coordinating percentage with 2MI relative to Fe(III). Besides, Fe(II)-2MI displayed amorphous state with larger BET surface area and higher photocurrent response. At very low catalyst dosage (0.1 g/L), highest activity for Cr(VI) reduction can be achieved using Fe(II)-2MI as photocatalyst. The estimated pseudo-first-order rate constant (0.021 min −1 ) was 1.4 and 2.1 times that on Fe(III)-2MI and Fe(II)-NaOH, respectively. The well-known ZIF-67 (Co-2MI), ZIF-7 (Zn-2MI) and Fe-MOFs with other organic ligands (H 2 BDC, NH 2 -H 2 BDC or FA) were also used as control samples. Optimal activity for photocatalytic reduction of Cr(VI) was achieved by Fe(II)-2MI. The operating factors was optimized at acidic pH (2.0), higher catalyst dosage (0.3 g/L) and appropriate concentration of coexisting organics (2.0 mM) within the tested range. The stability of Fe(II)-2MI was investigated at different pH values (2, 3 and 4.64), which all displayed good stability. Mechanism study indicated that Fe(II)-2MI has adequate conduction and valence band positions for Cr(VI) reduction and organics oxidation, respectively. Therefore, the as-prepared amorphous Fe(II)-2MI assemblies may be cheap, stable and easy available candidate for the photocatalytic disposal of Cr(VI)-containing wastewaters.
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
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2023
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IF 6.8
Xiaofeng Jiang,Wenjun Long,Teng Xu,Jiayu Liu,Yuling Tang,Wenhua Zhang
Polyphenols, as an important category of natural organics, are ubiquitous in plants and structurally diverse. Batch experiments were conducted to investigate the role of natural polyphenol, such as gallic acid (GA) and tannic acid (TA), in the biochemical behavior of Cr(VI) in soil media. GA and TA can effectively convert Cr(VI) to Cr(III) under neutral conditions (pH 7.0). However, there are significant differences in the transport, leaching toxicity, and bioavailability of reduced Cr(III) between the two systems. UV–vis spectra, chromium (Cr) mass balance, speciation distribution, and X-ray photoelectron spectroscopy were used to explore the intrinsic mechanisms of Cr(VI) reduction and (im)mobilization in the presence of GA or TA. Results showed that the reduction of Cr(VI) by GA was accompanied by poor immobilization of reduced Cr(III), especially at high GA concentrations (4–10 g/L), which was associated with the formation of soluble Cr(III) complexes. After treatment with 4 g/L GA, 51.49 ± 3.04% of the Cr in GA system was mobilized as complexes into aqueous phase. In contrast, the reduction of Cr(VI) and the subsequent precipitation of reduced Cr(III) was dominant in the TA system. After treatment with 4 g/L TA, 97.24 ± 0.31% of the total Cr in the TA system was immobilized into soil phase and transformed into more stable fractions. Our findings provide new insights into how natural organics shape the fate and transport of Cr in soils, which also have substantial implications for the development of Cr sequestration technology.
研究领域:
环境科学
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土壤化学
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污染修复
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DOI
PubMed
高影响因子
LANGMUIR
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2023
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IF 3.9
Wenjing Zhu,Zhinan Xia,Bingfeng Shi,Changli Lü
A series of 2D M(Cu, Zn, Co, and Mn)-TCPP MOFs/TiO2 binary nanocomposites (TCPP = tetrakis(4-carboxyphenyl)porphyrin) were constructed by solvothermal in situ loading of flaky TiO2 on the surface of 2D metal–organic frameworks (MOFs). The influence of different coordination metals on the catalytic activity was studied, and it was found that the 2D Cu-TCPP MOFs/TiO2 nanocomposite exhibited the best photo-Fenton performance. The superior property can be attributed to the high absorption coefficient and ultrathin two-dimensional structure of the 2D Cu-TCPP MOFs nanosheets. Meanwhile, the 2D Cu-TCPP MOFs/TiO2 II heterostructure can effectively promote the separation and transfer of photoformed carriers. Moreover, under visible irradiation, the optimized 2D Cu-TCPP MOFs/TiO2 composite can convert 99.9% of Cr(VI) to Cr(III) within 60 min with methanol as the hole scavenger at pH 3.14. Also, the photocatalytic performance of 2D Cu-TCPP MOFs/TiO2 was maintained after five reaction cycles. Furthermore, the proposed visible-light-driven photocatalysis mechanism of the 2D Cu-MOFs/TiO2 composite was reasonably derived according to experimental results. This study demonstrates the potential of building efficient TiO2-based visible light photocatalysts with 2D metal-porphyrin MOFs.
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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DOI
PubMed
高影响因子
Desalination and Water Treatment
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2024
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IF 1
Jing Yang,Siyuan Yang,Jing Zhang,Jian He,Wei Jiang
ABSTRACT The recovery of Cr(VI) from the solution and the utilization of by-products are significant for waste-water treatment and environmental protection. In this study, the amorphous ZrO 2 was prepared using a solvothermal method and used to treat the wastewater containing Cr(VI). Amorphous ZrO 2 is effective for the photocatalytic reduction of Cr(VI). Without a sacrificial agent, 20 mL potassium dichromate solution (20 mg/L) is reduced to almost 0 mg/L within 10 min. Moreover, the by-products obtained from this process exhibit good performance in the catalytic dehydrogenation of ethane coupled with the reverse water–gas reaction. The maximum yield of ethylene is 12.9%, and the service life of the catalyst reached 160 min. Catalyst deactivation is caused by carbon deposition, and the deactivated catalyst is regenerated by roasting in the air. The feasibility of this green process is demonstrated, including the one-step photocatalytic reduction of Cr(VI) and utilization of the by-product as an ethane dehydrogenation catalyst.
研究领域:
环境科学
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催化化学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Ousmanou Njoya,Shengxin Zhao,Xingyu Kong,Jimin Shen,Jing Kang,Binyuan Wang,Zhonglin Chen
The treatment of industrial wastewater containing Cr(VI)–organic compounds is a long-term concern in the field of environment. In order to realize the high-efficient reduction of Cr(VI) and solve the problem of Cr(III) residue in water environment, a novel catalytic chemical reduction/membrane filtration method was developed for the removal of total Cr (TCr) in a system with coexisting Cr(VI) and oxalate (Ox). The effects of the concentrations of Ox, Fe(III), and Al(III), the dosage of NaBH 4 , and sedimentation time on the removal of Cr(VI) containing Ox by NaBH 4 were investigated. Additionally, the simultaneous removal of turbidity and TCr using a microfiltration membrane was investigated, and the reason for the enhanced TCr removal was clarified. The results of ion chromatography (IC), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) suggested that when Cr(VI) and Ox coexist, low concentrations (0.3 mM) of Fe(III) or Al(III) contributed significantly to the high turbidity caused by the formation of suspended solids (SS) following the reduction of Cr(VI) by NaBH 4 . However, almost all the Cr(III) could be removed by a 1-μm microfiltration membrane. The high turbidity system formed by Ox and Cr(III) is unstable, and some Ox will gradually release their binding sites with Cr(III) with the extension of the natural settling time. For 24 h, 53.75% of Ox was involved in the formation of SS, while in the presence of Fe(III) or Al(III), only 11.28% and 6.30% of Ox were involved, respectively. High concentrations of Fe(III) and Al(III) enhanced the reduction of Cr(VI) by NaBH 4 . The removal of TCr was close to 100% after natural sedimentation for 15 min and combined with a microfiltration membrane. This result is caused because Fe(III)–Cr(III) or Al(III)–Cr(III) can form larger SS, which is easily intercepted by the microfiltration membrane. The development of a novel combined method of catalytic chemical reduction and membrane filtration will be beneficial for reducing the retention of TCr in the environment.
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
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
·
化学
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产品关联
DOI
PubMed
高影响因子
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