CHEMOSPHERE
·
2019
·
IF 5.108
Yueyue Shi,Dazhen Xiong,Yangyang Zhao,Tiemei Li,Kaige Zhang,Jing Fan
Highly efficient and selective separation of Cr (VI) is great of importance in environmental pollution control . In this study, a novel family of hydrophobic DESs has been designed and synthesized by mixing parabens and quaternary ammonium, and then used to extract heavy metal Cr (VI) from water phase and the content of Cr (VI) is measured by 1,5-diphenylcarbazide spectrophotometry . It is found that the hydrophobic DESs exhibit excellent extraction performance towards Cr (VI). At the 1:1 M ratio of DES to Cr (VI), the extraction capacity is as high as 66.7 mg g −1 , the extraction efficiency is greater than 90% for ultra-trace Cr (VI) (0.51 μg L −1 ), and the preconcentration factor is up to 700. When the concentration of coexisting metal ions (Cd 2+ , Cu 2+ ) and organic compounds ((C 6 H 10 O 5 ) n , C 6 H 12 O 6 ·H 2 O) is 2000 times that of Cr (VI), the extraction efficiency is still above 90%. Compared with ionic liquid extractants, the preparation process of DES is very simple, the atomic utilization rate is 100%, and no waste is produced. These hydrophobic DESs have been used to separate and enrich Cr (VI) from actual water samples with satisfactory recoveries. The possible extraction mechanism is investigated by FT-IR and 1 H NMR.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Qian Chen,Yi Feng,Rongrong Tian,Jinghang Chen,Anqing Wang,Jianfeng Yao
Photosensitization is a promising way to make UiO-66 visible light responsive. In this work, zirconium (Zr) precursors and synthetic methods (solvent-assisted or nonsolvent-assisted) were found to significantly affect the electric charge and the defect sites of UiO-66. UiO-66 with enhanced adsorption and photosensitized photocatalytic ability was then obtained. When ZrOCl2·8H2O was applied as Zr-precursor in a nonsolvent method, defect rich UiO-66 (UiO–OCl–N) was achieved with higher Cr(VI) adsorbing ability and improved photosensitized photocatalytic ability. Moreover, with the coexistence of Rhodamine B in Cr(VI) solution, photocatalytic performance of UiO-66 can be further enhanced.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Chen Wang,Mingjie Huang,Wentao Hu,Wei Xiang,Tao Zhou,Juan Mao,Feixiang Zan,Xiaohui Wu
The carcinogenic and hard-to-dispose Cr(VI) in high-salinity industrial wastewater has caused severe environmental problems. Herein, a novel hollow spherical CuFe 2 O 4 spinel oxide with concentrated confined oxygen vacancies (HS/CuFe 2 O 4 -OVs) was developed for Cr(VI) decontamination. Such a fancy material delivers a remarkable removal rate of 0.041 min −1 , approximately-one order of magnitude higher than the commonly reported iron-based materials. The OVs in the confined space could exert dual effects on Cr(VI) removal from the aspects of enhanced stabilization via local electronic structure regulation and strengthened immobilization via electron conductivity modulation. Importantly, due to the highly sensitive response of Cr(VI) to the changed confined OVs content, the HS/CuFe 2 O 4 -OVs showed higher selectivity for Cr(VI) removal in the interference of high concentration salts than its nonhollow-structured counterpart and can successfully treat Cr(VI)-contaminated industrial wastewater with high salinity. This work opens up a new concept for rational design of robust spatial confined architectures for Cr(VI) treatment.
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Water Science and Engineering
·
2023
·
IF 4
Xiao-jie Guo,Wei-kang Fu,Jing-yuan Ma,Bo-jun Xi,Chen Wang,Meng-yao Guan
Lignocellulose has the potential to become a bio-based adsorbent due to its biodegradability and renewability. In this study, a novel polydopamine-functionalized-lignin (lignin@PDA), prepared via self-polymerization of dopamine (PDA) on lignin, was used as a bio-based adsorbent for rapid scavenging of hexavalent chromium (Cr(VI)). The morphology, functional groups, crystalline structure, and chemical composition of lignin@PDA were characterized with a scanning electron microscope–energy dispersive spectrometer, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The Cr(VI) adsorption process of lignin@PDA was studied using batch experiments as a function of pH, ionic strength, adsorbent dose, and contact time at room temperature. The adsorption rate of lignin@PDA was five times greater than that of the unmodified lignin, with a maximum adsorption capacity of 102.6 mg/g in an acidic medium. The adsorption of Cr(VI) on lignin@PDA fit the pseudo-second-order equation and the Freundlich model, indicating that the adsorption process was mainly dominated by chemisorption and surface complexation. The thermodynamic parameters showed that adsorption of Cr(VI) on lignin@PDA was an endothermic and spontaneous process. The X-ray absorption fine structure results showed that sorption and reduction of Cr(VI) into Cr(III) occurred simultaneously on lignin. Moreover, PDA coating not only improved the reactivity of lignin but also promoted the complete reduction of Cr(VI) by lignin. According to these results, polydopamine-functionalized-lignin is a promising bio-based adsorbent for immobilization of Cr(VI) from wastewater.
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JOURNAL OF MOLECULAR LIQUIDS
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2023
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IF 6
Guang Tian,Xiangxiang Li,Falin He,Shuqi Guo,Yaoyue Wang,Yuze Li,Wansong Zong,Rutao Liu
Chromium (Cr) poses potential threats on human and ecological health through both food and environmental pathways. However, the response mechanisms of Cr to function-related proteins in human subjects and the differential effects in the case of different valence states of Cr are still lacking. Herein, the binding interactions and mechanisms of lysozyme to Cr(III) and Cr(VI) were investigated by isothermal titration microcalorimetry, multi-spectroscopy, enzyme activity assay, and molecular simulations. Our results indicated that the binding of Cr in different valence states with lysozyme was a relatively affinity process and mainly driven by hydrophobic forces. Both Cr species induced the looseness of backbone for lysozyme and the enhancement of hydrophilicity around the backbone microenvironment. Otherwise, the α-helix of lysozyme was decreased with different valence states of Cr, while Cr(III) showed a greater degree of influence and a stronger regularity. Interestingly, no significant changes in the microenvironment around aromatic amino acid residues were observed under the exposure of different valence states of Cr. Differential structural changes of lysozyme resulted in activity alterations. At 80 mg·L −1 of Cr, Cr (VI) reduced the lysozyme activity to 81.44% of the control, while the lysozyme activity was significantly reduced to 24.45% under the exposure of Cr (III). Further molecular docking showed that amino acids near the binding sites of different valence states of Cr with lysozyme were not identical, but the enzyme active site, Asp52, was all within the binding pocket. This study elucidates the differential toxicity effects and interaction mechanisms of Cr in different valence states, and offers a comprehensive strategy for exploring the in vitro responses of toxicants exposure.
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CHEMOSPHERE
·
2023
·
IF 8.8
Aikui Chen,Yao Huang,Hui Liu
Sulfidated nanoscale zerovalent iron (S-nZVI) has been extensively studied for the reductive removal of Cr(VI), but its applicability is limited by agglomeration and unexpected efficiency reduction. In this study, chitin microsphere supported sulfidated nanoscale zero-valent iron (S-nZVI@Chi-M) was prepared by in-situ one-step reduction method and used to remove Cr(VI) from water. Compared to chitin and chitosan powder, Chi-M with nanofibrous structure and large surface area performed best in stabilizing S-nZVI with a Fe 0 loading content of 3.01 wt%. The S-nZVI particles were homogeneously distributed on the surface of Chi-M, effectively avoiding agglomeration. Compared with bare nanoparticles and supported nZVI, S-nZVI@Chi-M showed significantly enhanced Cr(VI) removal capacity (924.5 mg Cr(VI) for per gram of effective Fe 0 ). The influences of sulfidation degree, dosages, initial Cr(VI) concentration, pH, DO, humic acid and typical ions on Cr(VI) removal kinetics were further studied. S-nZVI@Chi-M could be recycled for at least 4 times with acceptable reactivity. The mechanism investigation results indicated that the Cr(VI) removal was a complex process of reduction, adsorption and co-precipitation under the synergistic effect of Chi-M and S-nZVI. This work provides new ideas for the continuous fabrication of highly reactive nanoparticles, hopefully expanding the application scope of biomass resources in pollution remediation.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Tong Zhang,Yuan Chen,Yurong Zhang,Bin Liu,Yuanyuan Liu,Jianwei Zhao
Cr(VI) and catechol are common pollutants in wastewaters of tannery industry. Cr(VI) reduction by catechol results in accumulation of Cr(V)-complex and toxic o -benzoquinone. Cr(VI) reduction can be enhanced by accelerating the electron transfer from catechol to Cr(VI) using Fe(III). This electron transfer allows the continuous production of reactive oxygen species (ROS) in advanced oxidation processes, which further degrades catechol. However, the effects of catechol on Fe(III)-based Cr(VI) reduction and ROS production are not clear. In this study, the electron transfer pathway between catechol, Fe(III) and Cr(VI) was investigated along with the catechol degradation by ROS. Results show that the process of Cr(VI) reduction follows well a pseudo-second-order kinetic model, and the activation energy decreases by 4189 J/mol after electrons are transferred by Fe(III). Aqueous chromium (50 mg/L) was completely precipitated as Cr(OH) 3 , Fe x Cr 1-x (OH) 3 or Fe(OH) 3 -Cr(OH) 3 at Fe(III) concentration of 10 mmol/L. Residual catechol and Fe(II) in wastewater activated percarbonate, thereby producing OH for over 480 min at pH 3.0 and generating OH and CO 3 − for over 5 min at pH 10.0. Catechol was degraded by these ROS to butenedioic, oxalic, and formic acids, which were then mineralized to H 2 O and CO 2 . Catechol (2 mmo/L) was fully removed from wastewater with TOC removal of 37%, and the degradation was not affected by SO 4 2− and Cl − . This study provides new insights into the removal of pollutants from wastewaters via electron transfer mediated by Fe(III), and may aid in controlling the toxic effects of Cr(VI) and catechol-like organics in natural and engineered aquatic systems.
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Polymer-Plastics Technology and Materials
·
2023
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IF 2.7
Qianyong Liang,Ying Pan,Jia Du,Dong Zhang,Yan Zhang,Zhishun Zhong,Hongting Zhao
Carbon sphere@layered double hydroxides filled cellulose nanofibers (ACS@LDHs/CNF) aerogel was successfully synthesized. The removal rate of Cr(VI) using ACS@LDHs/CNFs aerogel at a solid-liquid ratio of 1 g/L was 89.4%, which was higher compared to the removal rate of 65.2% using LDHs alone. The adsorption capacity of ACS@LDHs/CNFs for Cr(VI) was determined to be 44.9 mg/g. The adsorption kinetics followed the pseudo-second-order kinetic equation, and the isotherm data showed good agreement with the Langmuir model. The adsorption mechanism of Cr(VI) onto ACS@LDHs/CNFs aerogel was also investigated. Additionally, the ACS@LDHs/CNFs aerogel demonstrated consistent high adsorption efficiency over 4 consecutive cycles of adsorption-regeneration.
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Polymers
·
2023
·Vol. 15
·期 13
·2918
·
IF 5
Cheng Tang,Tao Hu,Chengzhen Du,Ziqin Liao,Wenyan Cheng,Fen Wang,Xiaoli Hu,Kunpeng Song
A Fe-N conjugated organic polymer (SMP-Fr-Py) was prepared from ferrocene and pyrrole using a Scholl coupling reaction, which significantly improved the performance of Cr(VI) removal compared to the polymer (HCP-Fr-Py) prepared by adding the cross-linker formaldehyde dimethyl acetal (FDA). The results showed that at a pH of 2 and at 25 °C, the removal of Cr(VI) reached 90% for SMP-Fr-Py and only 58% for HCP-Fr-Py after 20 min of reaction. Subsequently, 99% and 78% were achieved after 120 min of reaction, respectively. The test results showed that the removal reaction followed a pseudo-second-order kinetic model. The removal efficiency decreased with increasing solution pH and initial Cr(VI) concentration, but increased with increasing SMP-Fr-Py dosage, reaching three cycles. The characterization of the reaction complexes and measurements of Cr species conversion revealed the near absence of Cr(VI) species in the solution. Approximately 38% of Cr(VI) was found to be adsorbed on the material surface, with another fraction present in solution (24%) and on the material surface (38%) in the form of Cr(III). The overall study showed that the direct connection of ferrocene and pyrrole in SMP-Fr-Py through C-C bonding increased the conjugated structure of the polymer backbone, which facilitated electron transfer and transport. Furthermore, the Fe-N elements worked synergistically with each other more easily, which improved the removal performance of Cr(VI) and provided a reference for the subsequent work.Keywords:organic polymers;Fe-N co-doping;Cr(VI) removal;conjugate structure
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Separations
·
2023
·Vol. 10
·期 6
·358
·
IF 2.6
Xiangfen Cui,Juan Wang,Qun Zhao,Chen Li,Jianhong Huang,Xuewei Hu,Jie Li,Mantao Li
Biochar adsorption has emerged as a favorable and environmentally friendly approach for removing metals such as chromium (Cr) from wastewater. However, the use of pristine biochar (PBC) is limited due to its finite adsorptive capacity, selectivity, and potential for secondary pollution. In this study, a novel bifunctionalized magnetic biochar (BMBC) was fabricated by incorporating cystamine as a ligand and glutaraldehyde as a crosslinker into alkali-treated magnetic biochar (MBC). This chemical modification introduced numerous amino groups and disulfide bonds onto the surfaces of BMBC. The biochar adsorbents’ surface morphologies, crystal structures, and texture properties were characterized using SEM, XRD, and N2adsorption-desorption techniques. The specific surface area was determined using the BET method. Furthermore, the surface functional groups and elemental compositions before and after adsorption were analyzed using FTIR and XPS, respectively. The results demonstrated higher Cr(VI) removal efficacy of BMBC (100%) than MBC (72.37%) and PBC (61.42%). Optimal conditions for Cr(VI) removal were observed at a solution pH of 2, a temperature of 50 °C, a reaction time of around 1440 min, and an initial adsorbate concentration of 300 mg/L. The sorption process followed a chemical mechanism and was controlled by monolayer adsorption, with a maximum adsorption capacity of 66.10 mg/g at 50 °C and a pH of 2, as indicated by the larger fitting values of the pseudo–second-order and Langmuir models. The positive ∆Hoand ∆Sovalues and negative ∆G0 values suggested a spontaneous and endothermic Cr(VI) adsorption process with high randomness at the solid/liquid interface. The removal of Cr(VI) was attributed to the reduction of Cr(VI) into Cr(III) facilitated by the introduced amino acids, sulfur, and Fe(II), electrostatic interaction between Cr(VI) in the solution and positive charges on the adsorbent surface, and complexation with functional groups. The presence of co-existing cations such as Cu(II), Cd(II), Mn(II), and K(I) had little effect on Cr(VI) removal efficiency. At the same time, the co-existence of anions of Cl−, NO3−, SO42−, and HPO42−resulted in a 7.58% decrease in the Cr(VI) removal rate. After five consecutive adsorption/desorption cycles, BMBC maintained a high Cr(VI) removal rate of 61.12%. Overall, this novel BMBC derived from rice straw shows great promise as a biosorbent for treating Cr(VI) in wastewater.Keywords:magnetic biochar;bifunctionalization;chemical modification;hexavalent chromium;adsorption
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Linshan Zhang,Guozong Yue,Luming Yang,Deshun Huang
Ultra-thin MXene nanosheets (Nss) were facilely prepared via delaminating and intercalating the multi-layered MXene using tetramethylammonium hydroxide (TMAOH). Electron-rich characteristics, abundant surface active sites and the negative charges made MXene Nss having both good reduction ability and adsorption capacities, which would effectively remove anion Cr(VI) via reduction and remove cation Cr(III) via adsorption. Batch adsorption tests were carried out to study the pH impact, adsorption kinetics and isotherms. Upon adsorption, the well dispersed MXene Nss suspension was aggregated to form flocs and sediment at the bottom. The maximum Cr(VI) and Cr(III) removing capacities are calculated to be 554.9 mg/g at 318 K and 283 mg/g at 298 K, respectively. The mechanisms on Cr(VI)/Cr(III) adsorption were well studied employing SEM, TEM , XPS and FT-IR. In addition, the MXene Nss also showed good adsorption capacity towards other metal cations (such as Cu 2+ , Cd 2+ , and Pb 2+ ), manifesting that the current MXene Nss has the potential to be used as a general-purpose adsorbent.
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Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 8
·2088-2094
·
IF 5.976
Xiran Shen,Xudong Yang,Chunyan Su,Jinghua Yang,Long Zhang,Binghui Liu,Siyu Gao,Fangyuan Gai,Zhubao Shao,Guanghui Gao
Stimuli-sensitive nanocomposites have received special attention because of their potential applications in various fields. In this work, we report a novel thermo-responsive photoluminescent silver clusters/hydrogel nanocomposite with red emission, as a probe for highly sensitive and selective detection of Cr(VI) in aqueous solutions. The hydrogel nanocomposites integrate the advantages of p(NIPAM-co-AAc) hydrogel submicron particles and Ag clusters: the p(NIPAM-co-AAc) hydrogel submicron particles can act as templates for Ag nanoclusters and exhibit thermo-responsive properties. In addition, Ag nanoclusters endow excellent photoluminescent properties to our nanocomposites, resulting in photoluminescent sensors. As a result, we obtained novel thermo-responsive Ag clusters/p(NIPAM-co-AAc) hydrogel nanocomposites through photoreduction process. The photoluminescence (PL) intensity of as-prepared nanocomposites exhibited a linear and reversible response from 2 to 85 °C and displayed a high PL quenching for the sensitive and selective detection of Cr(VI), rather than Cr(III). The limit of detection could reach as low as 1 ppb, which indicates that it is an ideal sensor tool for environmental monitoring, laboratory detections and various other applications.
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