INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2022
·
IF 8.025
Shichen Wang,Yixuan Liu,Yue Hu,Weibo Shen
Metal-organic frameworks (MOFs) are gradually used since of their huge specific surface area and superior pore structure. However, there are problems such as easy aggregation and difficult separation in water treatment. In this study, we prepared composite microspheres (FMCS-1) by modifying MIL-125-NH 2 with Fe 3 O 4 and chitosan. The structural characterization and performance analysis of the materials showed that the introduction of chitosan effectively prevents the stacking of MOFs. The magnetic test manifested that Fe 3 O 4 solved the problem of the difficult separation of MOFs from water. The removal potential of toxic Cr(VI) was tested by adsorption experiments. The isotherm model indicated that FMCS-1 is a single molecular layer adsorbent with a maximum adsorption capacity of 109.46 mg/g at pH = 2. The adsorption kinetics showed that the adsorption of Cr(VI) by FMCS-1 was chemical adsorption. The acid resistance test demonstrated that FMCS-1 can exist stably in acid solutions. The recycling experiments proved that the adsorbent can be reused and the removal percentage still reaches 50 % after 5 cycles. This work expands the application of MOFs in water treatment and also provides an effective adsorbent for Cr(VI) removal.
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Catalysis Science & Technology
·
2022
·Vol. 13
·期 3
·705-713
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IF 6.177
Xu Zhang,Xiaoman Li,Senda Su,Mengyao Tan,Guodong Liu,Yingying Wang,Min Luo
The active sites of the catalyst and the charge transfer during the reaction are crucial for the photocatalytic nitrogen reduction reaction (PNRR). Here, ultrafine Ag Nanoparticles (Ag NPs) as the active sites and the electron transporters are successfully fixed in the cavities of the metal–organic frame MIL-101(Cr) by the “double solvent-photoreduction” method. The hydrophilic cages of MIL-101(Cr) could restrict and disperse the growth of Ag NPs, and the windows of the cages prevent them from being detached from the MOF carriers. The Schottky junction between Ag NPs and the MIL-101(Cr) leads to ligand–metal charge transfer (LMCT), while the localized surface plasmon resonance effect (LSPR) possessed by Ag NPs themselves generates hot electrons. Thus, N2 was converted to NH3 by the synergistic effect of the two mechanisms, which was 12 times higher than that of pure MIL-101(Cr) and reached 138.81 μmol g−1 h−1. Furthermore, the mechanism of nitrogen fixation and the reason for the stabilization of this catalyst were investigated, and the results were verified by density functional theory calculations.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 30
·期 10
·26889-26900
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IF 5.19
Jiang Chunlu,Zhou Shijia,Li Chang,Yue Fengdie,Zheng Liugen
A ZnCl 2 -modified biochar-supported nanoscale iron sulfide composite (FeS-ZnBC) was successfully prepared to address the easy oxidization of FeS and enhance Cr(VI) removal from water. The material was characterized by SEM, XRD, FTIR, and XPS. The effects of FeS:ZnBC mass ratio, FeS-ZnBC dosage, solution pH, initial Cr(VI) concentration, and reaction time on the adsorption performance were investigated. The results revealed that the optimum adsorption capacity of FeS-ZnBC (FeS:ZnBC = 1:2) for Cr(VI) was 264.03 mg/g at 298 K (pH = 2). A Box-Behnken design (BBD) was applied to optimize the input variables that affected the adsorption of Cr(VI) solution. The results revealed that the highest removal (99.52%) of Cr(VI) solution was achieved with a Cr(VI) initial concentration of 150.59 mg/L, FeS-ZnBC adsorbent dosage of 2 g/L, and solution pH of 2. The sorption kinetics could be interpreted using a pseudo-second-order kinetic model. The isotherms were simulated using the Redlich-Peterson isotherm model, indicating that Cr(VI) removal by the FeS-ZnBC composites was a hybrid chemical reaction-sorption process. The main mechanisms of Cr(VI) removal by FeS-ZnBC were adsorption, chemical reduction, and complexation. This study demonstrated that FeS-ZnBC has potential application prospects in Cr(VI) removal.
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ENVIRONMENTAL POLLUTION
·
2022
·
IF 9.988
Jianhua Qu,Yang Liu,Jiao Meng,Fuxuan Bi,Shouyi Ma,Guangshan Zhang,Yifan Wang,Yue Tao,Zhao Jiang,Ying Zhang
Herein, magnetic porous pinecone-derived hydrochar (MPHC MW ) co-activated by KHCO 3 and K 2 FeO 4 through one-step microwave-assisted pyrolysis was innovatively synthesized for hexavalent chromium (Cr(VI)) and anthracene (ANT) removal from water. The analyses of characterization consequences and co-activation mechanisms not merely proved the high specific surface area (703.97 m 2 /g) and remarkable microporous structures of MPHC MW caused by the synergistic chemical activation of KHCO 3 and K 2 FeO 4 , but also testified successful loading of Fe 0 and Fe 3 O 4 on MPHC MW by the process of carbothermal reduction between K 2 FeO 4 and carbon matrix of hydrochar. The resultant MPHC MW possessed pH-dependence for Cr(VI), while adsorption for ANT was hardly impacted by the pH of solution. Moreover, the adsorption processes of MPHC MW could attain equilibrium within 60 min for Cr(VI) and 30 min for ANT with multiple kinetics, and the corresponding adsorption capacity for Cr(VI) and ANT was 128.15 and 60.70 mg/g, respectively. Additionally, the adsorption percentages of MPBC MW for Cr(VI)/ANT was maintained at 87.87/82.64% after three times of adsorption-desorption cycles. Furthermore, pore filling, complexation, electrostatic interaction, reduction and ion exchange were testified to enhance the removal of Cr(VI), while the ANT removal was achieved via π-π stacking, complexation, pore filling and hydrogen bonding force.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Hai-Tao Ren,Meng-Zhen Jing,Da-Shuai Li,Ting-Ting Li,Ching-Wen Lou,Jia-Horng Lin,Xu Han
Photocatalytic reduction of Cr(VI) in water environments attracts more attention; however, the mechanisms involved in this process have not been clearly elucidated yet. In this study, the photocatalytic reduction of Cr(VI) by polydopamine modified Bi 2.15 WO 6 (PDA/BWO) under visible light was conducted. Kinetics results show that PDA apparently accelerates the reduction of Cr(VI). The quasi-first-order kinetic constant of Cr(VI) reduction by 5PDA/BWO is 70.0 times that of the original BWO, reaching 0.070 min −1 . X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy , and Raman analyses confirm the formation of ligand-to-metal charge transfer (LMCT) complex [Bi(III) O C] between PDA and BWO. The formed Bi(III) O C complex enhances visible light response and narrows the bandgap of PDA/BWO. The photoelectrochemical and photoluminescent characterization further reveals that the formed Bi(III) O C complex inhibits the recombination of carriers, thus enhancing the photocatalytic reactivity of PDA/BWO. Electrons, are derived from three paths, including dye sensitization, LMCT and bandgap excitation, contribute to Cr(VI) reduction by PDA/BWO. This study provides new insights on the paths of Cr(VI) reduction by PDA/BWO under visible light.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Huizhen Shen,Li Chen,Cailong Zhou,Jingcheng Du,Chenyang Lu,Hao Yang,Luxi Tan,Xinjuan Zeng,Lichun Dong
Nanoscale zero-valent iron (NZVI, Fe 0 ) has been widely used for reduction of strong toxic Cr(VI) to low toxic Cr(III), however, given the easy aggregation of NZVI, developing new substrate support for NZVI is highly desirable. In this study, via a simple in-situ growth method, NZVI was immobilized on porous TpPa-1 covalent organic frameworks (COFs), making it an effective adsorbent for adsorption and reduction of Cr(VI) from aqueous solution. Meanwhile, to make the composite of NZVI and COFs a uniform system, dopamine (DOPA) was used as a connector to combine them. The COFs with porous crystal structure provides controlled anchors for Fe 0 loading as well as the reaction sites. Results verify that the Fe 0 / [email protected] exhibited an excellent performance in Cr(VI) removal due to synergistic effect of the composite, with the maximum removal capacity up to 516 mg/g. Furthermore, it maintained high removal capacity under acidic, neutral and alkaline environments. Therefore, the Fe 0 / [email protected] is a promising material for Cr(VI) removal from wastewater in practical application.
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POLYMER BULLETIN
·
2022
·Vol. 80
·期 2
·2099-2118
·
IF 2.843
Liu Xiaoqi,Zhang Yanyun,Liu Yan,Zhang Ting′an
Magnetic red mud/chitosan (MRM/CS) based bionanocomposites were prepared by the neutralization method, and this method had the advantages of simplicity, low-cost and eco-friendly. The adsorbents were characterized by XRD, FTIR and VSM analysis. The effects of various parameters, such as RM addition amounts, pH, concentration, temperature, time and co-existing metal ions, on the adsorption of Cr(VI) were studied. Moreover, adsorption kinetic, isotherm and thermodynamic of the Cr(VI) adsorption were analyzed. The results show that the MRM/CS composite has good recoverability (8.56 emu·g −1 ) and adsorption performance (7.79 mg·g −1 , 303 K, pH = 3). The process of the adsorption reaction conforms to the Langmuir model and the pseudo-second-order kinetic model, suggesting that the adsorption of Cr(VI) ions on the surface of CS-based adsorbents are monolayer adsorption and chemisorption. Thermodynamic study reveals that the adsorption is spontaneous and endothermic.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2022
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IF 4.831
Brian Musikavanhu,Yujie Zhang,Dongwei Zhu,Zhaoli Xue,Rui Yuan,Shengjun Wang,Long Zhao
A thiophene substituted naphthyl hydrazone derivative NHT was synthesized using a one-step route for the detection of trivalent chromium (Cr 3+ ). UV–visible absorption and emission spectra, density functional theory calculations as well as 1 H NMR titration confirmed that the probe underwent a turn-off response via the chelation enhanced fluorescence quenching effect upon exposure to Cr 3+ and the NHT -Cr 3+ complex was formed at a 1:1 binding stoichiometry. NHT exhibited a fast response rate of 2.3 min in buffer solution and a relatively low limit of detection of 41 nM. In addition, the Schiff base chemosensor exhibited excellent selectivity with high affinity towards Cr 3+ in the presence of other competing cations. Bioimaging of the probe in PC3 cells further demonstrated the potential real life application of the probe in detecting Cr 3+ .
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高影响因子
MICROCHEMICAL JOURNAL
·
2022
·
IF 5.304
Yaqian Feng,Ruxue Li,Peng Zhou,Chunying Duan
A novel fluorescence carbon dots (CS-CDs) were prepared via a one-step hydrothermal approach using chitosan and urea as precursors. CS-CDs exhibited good selectivity and sensitivity of fluorescence response to Cr (VI) in a wide range with a detection limit of 0.59 μM. More interestingly, CS-CDs-based fluorescent hydrogel sensors were further developed for quantitative detection of Cr (VI) in water. The fluorescence signals of the composite were recorded by a smartphone and converted to grayscale parameters linearly related to concentration of Cr (VI) by Image J software. This composite showed a broad linear range of 10–300 μM and a low detection limit of 2.83 μM. All results demonstrate the great potential for the portable, low-cost and green detection of Cr (VI) in practical application.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 47
·72058-72073
·
IF 5.19
Gao Jingqing,Liu Xiaobang,Ren Peng,Gao Jianlei,Chen Yong,Chen Zhijun
The novel iron-based reductive particles, functionalized with amino and carboxylic functional groups, were synthesized to remove Cr(VI) and Cd(II) ions from aqueous solutions. The morphological structure and surface functional groups of new composites were characterized with SEM, XRD, FTIR, BET, and other techniques. The influence of pH, initial concentration, adsorbent dosing, and temperature on removal efficiencies were explored by batch experiments. The adsorption capacity of Cr(VI) and Cd(II) increased by 159.95% and 76.60%, respectively, compared with Fe 0 , reaching 47.638 and 62.047 mg/g. EDS and XPS analysis showed most of Cr(VI) was reduced to Cr(III) and precipitated as ferrochrome oxide, and Cd(II) was mainly precipitated as hydroxide. Reduction-precipitation and complexation may predominate in the removal process of Cr(VI), which fitted well with Langmuir and Freundlich models and pseudo-second-order kinetics. While hydrolysis and complexation may prevail for Cd(II), which was suited with Langmuir model and pseudo-second-order kinetics. Having good magnetic properties, the A/C-Fe@SiO 2 particles exhibited excellent reusable stability after four times regeneration experiments, promising a prospect for in-situ remediations of groundwater contaminated by Cr(VI) and Cd(II).
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Frontiers in Energy Research
·
2022
·
IF 3.858
Wang Hongfei,Zhao Xiqiang,Yang Xinfei,Sun Shuang,Wang Wenlong,Mao Yanpeng,Song Zhanlong
In this paper, two types of adsorption materials SA-C-Fe and SA-C-Fe(C) were prepared using bagasse biochar produced by one-step microwave pyrolysis and activation for Cr(VI) removal of wastewater. The adsorption materials were characterized, and Cr(VI) adsorption performance, kinetics and thermodynamics on adsorption materials were studied. Results show that microwave pyrolysis/activation contributes to developed pore structure and abundant active functional groups, resulting in high Cr(VI) adsorption capacities. The optimal preparation conditions for biochar is: microwave power 500 W, ZnCl2/bagasse ratio 2.5:1 and pyrolysis/activation time 15 min, and the specific surface area of biochar is 1,787.64 m2/g. The Cr(VI) adsorption of the two materials is more in line with the pseudo-second-order kinetic model, and the adsorption process is dominated by chemical adsorption. The static removal experiment of Cr(VI) using SA-C-Fe and SA-C-Fe(C) has the best removal effect at pH = 2, and the whole adsorption process is more in line with the Langmuir-Freundlich isotherm model. Calculated by the pseudo-two-order kinetic model and the Langmuir-Freundlich isothermal model, the maximum adsorption rate for Cr(VI) of SA-C-Fe and SA-C-Fe(C) are 211.87 mg/g and 388.92 mg/g, respectively. The removal process is mainly dominated by three mechanisms: electrostatic adsorption, ion exchange and redox reactions. The improvement of Cr(VI) adsorption capacity is attributed to more developed pore structure. The results offer beneficial reference for the application of low-cost carbon-based adsorption materials for pollutants separation, and effectively realize the utilization of bagasse pyrolysis by-products.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Jiangli Sun,Jinhang Yang,Jiaxiang Liang,Lingli Tu,Yuejing Bin,Yanping Hou
It is crucial to design efficient photocatalysts for elimination of combined pollutants in wastewater. Herein, the S-scheme Zn 3 In 2 S 6 -BGQDs/AgBr (ZBA) heterojunction was synthesized through co-modification of Zn 3 In 2 S 6 with B-doped graphene quantum dots (BGQDs) and AgBr nanoparticles using solvothermal method for synchronous removals of nitrofurazone (NFZ) and Cr (VI). Characterization results revealed that ZBA showed superior photocatalytic activity than the counterparts. In NFZ-Cr (VI) coexistence environment, removal efficiencies towards NFZ and Cr (VI) were 95.23% and 99.39% using the ZBA photocatalyst within 2 h of visible light irradiation. Results demonstrated that ∙OH, h + and ∙O 2 − played major role for NFZ removal, while mainly e - and ∙O 2 − contributed to Cr (VI) reduction. The S-scheme heterojunction mechanism of ZBA was confirmed by energy band structure analysis, ESR and calculated work function. Possible pathways and mechanisms of NFZ degradation were proposed according the identified intermediates. Besides, the ecotoxicity of intermediates was analyzed. This study advances the development of photocatalytic treatment of combined-polluted wastewater.
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