COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
·
IF 5.2
Zhixiang Cui,Shengnan Tian,Xiaolong Liu,Qianting Wang,Sen Zeng,Junhui Si
The efficient elimination of toxic dye and Cr(VI) from wastewater by photocatalysis is still a challenge due to the unsatisfactory photocatalytic efficiency and difficult separation of the photocatalyst . Herein, the thermoplastic polyurethane (TPU) fiber membrane was prepared by electrospinning and then titanium dioxide (TiO 2 ) nanoparticles were loaded on the fiber membrane by ultrasonic-assisted method, followed by in-situ polymerizations of polyaniline (PANI) on the surface of the membrane. The synergistic effect of TiO 2 and PANI results in faster charge migration and more efficient separation of photogenerated charge carriers. Photocatalytic experiments revealed that TPU/TiO 2 /PANI fiber membranes were highly efficient for dye degradation and Cr(VI) reduction under visible light irradiation. 99.7 % of Congo red was degraded by TPU/TiO 2 /PANI membrane within 30 min, and the reaction rate reached 0.2 min −1 . The Cr(VI) reduction efficiency was up to 99.0 % within 25 min with a reaction rate of 0.128 min −1 . Additionally, the TPU/TiO 2 /PANI membrane exhibited a low loss in catalytic activity even after recycling 10 times, suggesting superior recycling stability compared to TPU/TiO 2 membrane. The result of the electron spin resonance (ESR) experiment showed that superoxide radicals (-O 2 - ) and hydroxyl radicals (-OH - ) were involved in the photocatalytic degradation process. The prepared TPU/TiO 2 /PANI fiber membrane combined with excellent photocatalytic capacity, good stability and easy recovery makes it a good candidate for removing dye and Cr(VI) from wastewater.
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APPLIED CLAY SCIENCE
·
2023
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IF 5.6
Fang Wang,Pingxiao Wu,Meiqing Chen,Jiayan Wu,Leiye Sun,Zhongbo Shang,Nengwu Zhu
Green rust (GR), as one of mixed-valent iron [Fe(II)-Fe(III)] minerals, has received a significant attention in recent years because it is an intrinsic and essential part of biogeochemical cycling of heavy metals and DOM . The transformation of GR is a key factor in altering the environmental behavior of heavy metals, and therefore, prediction of such transformation is critical for managing environmental quality. DOM and heavy metals are recognized to have a significant impact on iron oxide transformation. However, detailed information on these phenomena and mechanisms are still limited. In this study, Cr(VI) and oxalic acid (OA) widely distributed in the natural environment were selected representatives of heavy metals and DOM. The mechanism of their influence on GR transformation and their environmental significance were clarified. GR transformed to feroxyhyte under the impact of Cr(VI) and OA, and feroxyhyte did not transform to more crystalline iron oxides after 7 days. However, OA enhanced Fe dissolution and Cr(VI) reduction while weakening the immobilization of Cr on GR. SEM results demonstrated that OA addition resulted in the collapse of the feroxyhyte structure. SEM-EDS data indicated that Cr and OA were adsorbed on GR, suggesting that this can be an essential pathway for C and Cr sequestration during GR transformation. This study reveals Cr(VI) not only favors the formation of feroxyhyte, but also stabilizes the mineral to prevent transformation and meanwhile indicates the mechanisms of organic matter interactions with iron oxide and the environmental behavior of C and Cr during the iron oxide transformation processes.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Huimin You,Changlin Cao,Xiaoli Sun,Baoquan Huang,Qingrong Qian,Qinghua Chen
Microplastics (MPs) are emerging contaminants with growing concerns due to their potential adverse effects on the environment. However, understanding the aging properties and adsorption behavior of MPs is still limited. In this study, we investigated the correlation between the adsorption capacity, aging stages, and aging properties of polyethylene MPs using a correlation equation. Our results revealed that the trends of O/C ratio and contact angle of polyethylene MPs with aging time were fitted to be linear under xenon lamp accelerated aging conditions. Conversely, the trends of other properties such as particle size, crystallinity , and molecular weight with time were fitted to conform to the Boltzmann equation. Moreover, the aging curve data for carbonyl index and molecular weight (M w ) perfectly matched, confirming M w play a crucial role in verifying the aging process. Additionally, the adsorption amount of polyethylene MPs increased sharply with the increase of aging ages, reaching up to 1.850 mg/g. The adsorption data fit well to the pseudo-second-order kinetics and Langmuir model, suggesting that the adsorption process is dominated by chemisorption . The low pH and low salt concentration is beneficial to the adsorption capacity of MPs onto Cr(VI). Further, a relationship equation was established to predict adsorption risk at different aging stages. These findings provide new insights into the impact of aging on pollutants transport and the fate of MPs, enabling the prediction of adsorption risk of MPs at different aging stages in water environments.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 29
·13952-13962
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IF 3.3
Dehong Bai,Ziyu Xue,Shaohui Li,Ran Meng,Dongxia Zhang,Xibin Zhou
Chromate (Cr(VI)) is a highly toxic heavy metal ion that not only endangers human health but also causes environmental pollution. To control and remove Cr(VI) from water more effectively, we report a simple, novel, and rapid detection technique for Cr(VI) in water based on an iron-manganese bimetal-metal organic framework (FexMny-MOF). Firstly, the synthesized FexMny-MOF has a large specific surface area and porosity; for the first time, an MOF with dual mimic enzyme properties is reported, which can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to the blue product in the presence or absence of H2O2. Interestingly, the mimic enzyme properties of FexMny-MOF are enhanced than those of Fe-MOF and Mn-MOF. The free energies of elementary reactions and adsorption energies (Eads) of H2O2 and O2 adsorbed on different materials were calculated by density functional theory (DFT) to verify the mechanism of action of FexMny-MOF. The Fe1Mn1-MOF mimics oxidase-like oxidation of TMB; 8-hydroxyquinoline (8-HQ) is used as the inhibitor of TMB oxidation, and the specific interaction between 8-HQ and Cr(VI) weakens the inhibition of 8-HQ on TMB oxidation to achieve the detection of Cr(VI). The established method has high sensitivity and selectivity with a detection limit of 51 nM and a linear range of 80–3500 nM. This method has been successfully applied to the determination of Cr(VI) in tap water and the Yellow River, showing its great potential in environmental monitoring.
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CHEMICAL ENGINEERING SCIENCE
·
2023
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IF 4.7
Wen Wang,Liqiang Qi,Song Han,Hejin Yuan
A new chitosan-trithiocyanuric composite (CS@TMT) was synthesized by graft copolymerization using chloroacetyl chloride as the cross-linking agent. Using response surface analysis, the optimal conditions for the synthesis of CS@TMT were determined as: chloroacetyl chloride concentration of 2.0 mol/L, trithiocyanuric acid (TMT) addition of 7.0 g, and reaction temperature of 70 °C. The successful preparation of CS@TMT was confirmed FTIR spectrum, 13C NMR spectrum, SEM mapping, EDS, XRD and XPS. At ambient temperature (25 °C, pH=6.0, Catalyst dosage=1.0 g/L), the maximum Cr(VI) and Pb(II) adsorption amount of CS@TMT were 194.76 and 101.39 mg/g, respectively, compared to CS (97.15 and 69.76 mg/g). The Cr(VI) and Pb(II) removal process of CS@TMT was better fitted by the pseudo-second-order kinetic model and Langmuir model, and the adsorption process was spontaneous, endothermic and disordered. Under the reduction mechanism, 69.32% of Cr(VI) was reduced to Cr(III) by -SH and –OH group on CS@TMT.
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WATER AIR AND SOIL POLLUTION
·
2022
·Vol. 233
·期 12
·1-14
·
IF 2.984
Li Weiquan,Li Mingxi,Yin Weizhao,Zhang Weinan,Zhong Jiawei,Li Ping,Deng Hong,Wu Jinhua
The removal of Cr(VI) from groundwater by zero-valent iron (Fe 0 ) and microorganisms under different nutrients and electron-accepting conditions was investigated using continuously-flowed column reactors with an abiotic Fe 0 column as the control. Both abiotic and biotic Fe 0 columns were operated at low and relatively high concentrations of organic substrates (sodium acetate and humic acid) and electron acceptors (nitrate and sulfate). Sodium acetate and humic acid were found to be effective substrates for the biotic Fe 0 system to remove Cr(VI) since microorganisms were able to gain extra reducing capacity from two nutrients and simultaneously avoid the passivation effect of humic acid on Fe 0 by metabolizing it. For nitrate and sulfate, varied influences were observed in the biotic Fe 0 system. The former showed apparent inhibition on Cr(VI) removal as it competed with Cr(VI) for electrons, and the inhibition became more severe while nitrate concentrations increased. Differently, highly reactive minerals such as green rusts and iron sulfide could be generated on the biotic Fe 0 surface under sulfate-reducing condition. They significantly enhanced Cr(VI) removal by providing more adsorptive and reductive sites. Overall, though the biotic Fe 0 column exhibited a longer life-span and higher Cr(VI) removal capacity than the abiotic Fe 0 column, the effects of organic substrates and electron acceptors should still be taken into account when applying biotic Fe 0 systems for Cr(VI)-contaminated groundwater remediation.
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Electrocatalysis
·
2022
·Vol. 14
·期 1
·78-87
·
IF 2.933
Gu Ying-ying,Xiang Ding-tao,Cai Ke,Wang Yuan-hao,Mei Yong,Han Jun,Pan Hongzhi
The rapid determination of Cr(VI) in workplace air can provide technical support for daily monitoring of occupational hazard factors in enterprises. In this paper, a bismuth film/carboxylated multi-walled carbon nanotube modified glassy carbon electrode (Bi/CMWCNTs/GCE) electrochemical sensor had been used to establish a new method for detection of Cr(VI) in workplace air. Carboxylated multicycle carbon nanotubes (CMWCNTs) were modified onto glassy carbon electrode (GCE), and bismuth (Bi) film was precoated on the modified electrode by electrodeposition. The morphology and electrochemical properties of Bi/CMWCNTs modified electrodes were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. The results showed that the formation of stable bismuth films and sensor’s high sensitivity were due to CMWCNTs. The differential pulse stripping voltammetry (DPSV) response of Cr(VI) at Bi/CMWCNTs modified electrode outcomes with a low detection limit of 0.18 μg/L and wider linear 0.50 ~ 25.0 μg/L. In comparison to standard spectrophotometry, the newly designed electrochemical sensor had exhibited more sensitive, convenient, and environmentally friendly, which was satisfactory in analytical application to real air samples. Therefore, the Bi/CMWCNTs/GCE electrochemical sensor has the potential applications in the rapid detection of Cr(VI) in workplace air. Graphical abstract
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EUROPEAN POLYMER JOURNAL
·
2022
·
IF 5.546
Wen-bo Tan,Dan Luo,Wei Song,Yan-yan Lu,Nuo Cheng,Jia-bin Zhang,Ting Huang,Yong Wang
Highly efficiently removing hazardous heavy metal ions from water is very important from a viewpoint of maintaining the sustainable development of ecological environment. In this work, a novel adsorbent based on the cellulose acetate (CA) was developed, which was fabricated through the blend electrospinning of CA and titanium dioxide (TiO 2 ) nanoparticles, surface modification by polydopamine (PDA) and then grafted by polyethyleneimine (PEI). The composite CA/TiO 2 electrospun fibers exhibit the porous structure, while the surface modification by PDA-assisted PEI grafting has no apparent effect on morphology of the electrospun fibers. The CA/TiO 2 @PDA@PEI composite fibers show the large number of amine groups, and the surface of the fibers can be positively charged in the acidic solution. Adsorption measurements show that the fibrous membrane samples exhibit excellent adsorption ability toward Cr(VI), and the maximum adsorption capacity is as high as 357.1 mg g −1 at solution pH value of 2, solution temperature of 25 °C. Specifically, about 72.1 % Cr(VI) can be directly reduced to harmless Cr(III) during the adsorption measurement, which is much higher than those of the almost adsorbents reported in literatures. The excellent adsorption/reduction ability endows the fibrous membranes with great potential application in removing highly hazardous Cr(VI) from wastewater.
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CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Taotao Qiang,Boqiang Qiu,Lu Chen,Longfang Ren
In this work, a novel adsorbent for the removal of hexavalent chromium (Cr(VI)) in aqueous solution was successfully prepared by altering the 2D Ti 3 C 2 /chitosan composite with disodium ethylenediaminetetraacetate (EDTA·2Na) agent. The successful surface loading of chitosan on Ti 3 C 2 was demonstrated by various characterization methods, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The adsorption of Cr(VI) by Ti 3 C 2 -based composite under various circumstances was evaluated using batch adsorption experiments. The adsorption performance of the optimal sample for Cr(VI) was investigated in detail through different influencing factors, and the adsorption process was analyzed by adsorption kinetics and isotherm model. In addition, XPS analysis of adsorbents before and after adsorption showed that some Cr(VI) was reduced to Cr(III) during the whole process, which was conducive to reducing the biological toxicity of Cr(VI). The mechanism analysis showed that the adsorption was mainly electrostatic physical adsorption, supplemented by chemical reduction adsorption. Finally, through the regeneration cycle experiment, it was found that the adsorption rate of Cr(VI) remained above 80% after six repeated adsorptions, indicating that the composite material had good stability and might have certain practical application value in the treatment of Cr(VI)-containing wastewater.
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CHEMOSPHERE
·
2022
·
IF 8.943
Hongwei Wang,Fang Wu,Zhiheng Wang,Yang Wang,Shufang Zhang,Haijun Luo,Zhiqin Zheng,Liang Fang
Chromium (VI) removal is crucial to the safety of water resources, but there is still a lack of effective and fast dislodge methods, especially the on-site rapid remediation and emergency removal technology . Herein, the monolayer (ML) Ti 3 C 2 T x nanosheets (NSs) were prepared to remove Cr (VI) from water. The solution sample of the two-dimensional (2D) Ti 3 C 2 T x NSs demonstrate ultrafast adsorption kinetics (the concentration decreasing from 300 to 3 mg L −1 in 10 min) and impressively high capacity (1483 mg g −1 ), which is several times higher than that of the most reported Cr (VI) adsorption by Ti 3 C 2 T x . The analysis of the adsorption kinetics and isotherm models indicates that the adsorption reaction is endothermic, with physical and chemical adsorption coexisting (mainly monolayer chemical adsorption). The joint study of the experimental analysis and theoretical calculation based on the density functional theory (DFT) demonstrates that the extraordinary removal performance of Cr (VI) is due to the synergetic effect of reduction reaction removal and electrostatic adsorption. It is found that the Cr (VI) is mainly reduced by the OH- terminals on Ti 3 C 2 , and the detoxified Cr (III) is anchored on the surface of Ti 3 C 2 T x through complexation reaction with O terminal. The advantages of ultrafast adsorption kinetics and extra-high adsorption capacity of the single-layered Ti 3 C 2 T x for Cr (VI) removal make it a remarkable candidate for rapid and urgent removal of Cr (VI) wastewater.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Yuhan Zhu,Jia Wei,Jun Li
Biochar is a well-known material for pollutant removal owing to its low cost and rich surface functionality. A kind of highly active substance, called environmentally persistent free radicals (EPFRs), can be produced in the preparation process of biochar, playing an important role in the removal of pollutants. In this study, sludge-derived biochars (SBC 120 and SBC 270 ) were prepared by the hydrothermal carbonization under two temperatures (120 °C and 270 °C) to investigate their removal abilities of Cr(VI). The maximum removal amounts of Cr(VI) by SBC 120 and SBC 270 were 16.58 and 22.93 mg·g −1 , respectively. It was further revealed that the appearance of Cr(III), as a result of EPFRs on sludge-derived biochar (SBC) transferred electrons to Cr(VI) in neutral solutions. That is to say, oxygen-centered (O-centered) EPFRs on SBC 120 and carbon-centered (C-centered) EPFRs on SBC 270 all could be used as electron donors to Cr(VI) to make it become Cr(III). This study not only provides a theoretical basis for the mechanism of pollutants removal by sludge-derived biochar but also offers a new perspective on the direct effect of EPFRs on pollutants.
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ENVIRONMENTAL TECHNOLOGY
·
2022
·
IF 3.475
Mingxing Chen,Qinming Guo,Jinping Cui,Weiyang Lv,Yuyuan Yao
Developing high-performance adsorbent for hexavalent chromium (Cr(VI)) elimination presents an enticing prospect in environmental remediation. Herein, three-dimensional flowerlike nanospheres composed of molybdenum disulphide and polypyrrole (MoS2@PPy) were successfully prepared via a one-pot hydrothermal and subsequent carbothermal reduction process for the removal of Cr(VI). The effects of pH, adsorbent dosage, co-existing ions, initial Cr(VI) concentration and temperature were investigated systematically by batch experiments. Benefiting from the incorporation of MoS2, the obtained MoS2@PPy composites showed a dramatic increase of specific surface area (149.82 m2·g−1) and adsorption capacity (230.97 mg·g−1) when compared with the pure PPy nanoparticles. Based on the thermodynamics study and X-ray photoelectron spectroscopy analyses, the removal process of Cr(VI) was proved to be exothermic and spontaneous, and accessible under-coordinated Mo(IV) and pyrrolic N groups coupled with redox reactions were conducive to the efficient removal of Cr(VI). Attractively, the MoS2@PPy acted as the electron donor could also activate peroxymonosulphate for the efficient degradation of organic contaminants. These results suggested that the MoS2@PPy was promising in Cr(VI) elimination and other kinds of organic pollutants removal in wastewater.
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