CHEMOSPHERE
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2021
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IF 7.086
Baiyan Zeng,Wenbin Xu,Sher Bahadar Khan,Yanjie Wang,Jing Zhang,Jiakuan Yang,Xintai Su,Zhang Lin
A facile pyrolysis-quenching-reroasting process was developed to prepare a sludge-based biochar adsorbent, and its adsorption performance for Cr(VI) ions was investigated. The unquenched biochar (U-BC) and quenched biochar (Q-BC) were systematically compared and characterized. Fourier transform infrared spectroscopy (FTIR) results showed that more carbon and oxygen functional groups such as –COOH and –OH were formed on the surface of Q-BC. These functional groups could be used as active sites during the adsorption process and help to improve the adsorption performance of the material. The results of Brunauer-Emmett-Teller (BET) analysis showed that the specific surface area of U-BC biochar was 523.36 m 2 /g, while the specific surface area of Q-BC biochar after quenching treatment increased to 785.3 m 2 /g. The adsorption performance of Q-BC biochar was studied, and the effects of pH, contact time and temperature on the adsorption performance of the material were explored. The pseudo-second-order model and Langmuir isotherm model indicated that the removal of Cr(VI) by Q-BC biochar material was a chemical adsorption-based adsorption process. At a temperature of 298 K and a pH of 1, the maximum Cr(VI) adsorption capacity of the quenched Q-BC biochar is as high as 291.54 mg/g, which was much higher than the maximum adsorption capacity of U-BC biochar (91.46 mg/g). This pyrolysis-quenching-reroasting process to prepare modified biochar provides a new, economical and effective way for the preparation of high-performance adsorption materials from municipal sludge .
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高影响因子
NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 44
·期 18
·7611-7620
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IF 3.288
Phung Nhat Minh,Van-Tuan Hoang,Ngo Xuan Dinh,Ong Van Hoang,Nguyen Van Cuong,Dang Thi Bich Hop,Tran Quoc Tuan,Nguyen Tien Khi,Tran Quang Huy,Anh-Tuan Le
Reduced graphene oxide-wrapped silver nanoparticles (Ag@rGO) were synthesized by a simple photochemical process with the GO nanosheets as both a stabilizing and reducing agent. The synthesized Ag@rGO nanohybrids were used as a localized surface plasmon resonance (LSPR) colorimetric sensor for the detection of chromium(VI) and carbaryl. For chromium(VI), the result showed a color change from yellow to colorless and linear-dependence of the absorption intensity on the concentration of Cr(VI) in the range 0.1–25 μM. For carbaryl, the calibration curve presented a high level of linearity in the range of 0.1–50 μM corresponding to color changes from yellow to purple. The limits of detection (LODs) for Cr(VI) and carbaryl were found to be 31 nM and 42 nM, respectively. The novel Ag@rGO nanohybrids will become an excellent platform for colorimetric probes in the detection of Cr(VI) ions and carbaryl or other heavy metal ions/pesticides.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Yiming Zhang,Xiaoyan Yang,Yonglin Wang,Peng Zhang,Dan Liu,Yongwei Li,Zhouzheng Jin,Bhekie B. Mamba,Alex T. Kuvarega,Jianzhou Gui
For obtaining ultra-fine Cu 2 S nanoparticles with reduced recombination of their photogenerated electron/hole pairs, in-situ growth of Cu 2 S nanoparticles on exfoliated MoS 2 nanosheets was achieved in this study. We have exhaustively studied l -cysteine in-situ conjugation with sulfur defects on the surface of MoS 2 nanosheets, which makes particle-level superlattice structured Cu 2 S nanoparticles (average 6.2 nm) well disperse on MoS 2 nanosheets. Further, XPS and Raman analysis confirm that the intense interfacial effects are formed between Cu 2 S and MoS 2 for the 2-Cu 2 S-MoS 2 composite, which significantly promote separation of photogenerated electron-hole pairs and prolong their lifetime, as shown by PL and TRPL. As a result, 2-Cu 2 S-MoS 2 exhibits the fastest photoreduction rate of Cr(VI) (0.0058 min −1 ) under visible light irradiations, which are almost 8.3 times and 2.9 times higher than that of MoS 2 nanosheets (0.0007 min −1 ) and pure Cu 2 S (0.002 min −1 ), respectively. Meanwhile, 2-Cu 2 S-MoS 2 also possesses an optimal composite proportion between Cu 2 S and MoS 2 , which presents outstanding photocatalytic activity among series of x-Cu 2 S-MoS 2 composites. The photoreduction mechanism of Cr(VI) is investigated in detail. As a matter of fact, l -cysteinecoupled with sulfur defects on MoS 2 nanosheets could produce the coordination inner heterojunction interface of 2-Cu 2 S-MoS 2 samples, which greatly improves migration efficiency of photoinduced carriers and ultimately endows it outstanding photoreduction activities. Furthermore, the strategy was extended to fabricate CdS-MoS 2 and ZnS-MoS 2 heterojunctions, implying that this strategy is of promising potentials for designing more active metal sulfides heterojunction photocatalysts.
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Journal of Environmental Chemical Engineering
·
2020
·
IF 4.3
Rui Shan,Yueyue Shi,Jing Gu,Jingwang Bi,Haoran Yuan,Bo Luo,Yong Chen
A series of mangosteen-derived biochars were produced by several modifiers (HCl, KOH and ZnCl 2 ), in different preparation conditions (i.e. pyrolysis temperature, pyrolysis process and impregnation ratio). It indicated that the Z2PT350-700 presented excellent ability for Cr(VI) removal. The physical/chemical properties of the prepared biochar are reflected by the electrostatic interaction, surface complexation, ion exchange occupied primary position in the process of adsorbing Cr(VI). Besides, the effects of reaction time, pH, adsorbent dosage and initial adsorbate concentration on Cr(VI) removal were evaluated. The sorption process of Cr(VI) could be described by the pseudo-second order (PSO) kinetic model and Sips isotherm model. In optimal reaction condition, the surface of Zn2MB350-700 was composed of homogeneous and heterogeneous adsorption and the chemical adsorption dominated in the adsorption process . Therefore, the results suggested that Zn2MB350-700 could be used as an inexpensive and highly efficient adsorbent for Cr removal from water environment.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2020
·
IF 7.864
Shishu Zhu,Xiaochen Huang,Xiaobao Yang,Peng Peng,Zhipeng Li,Chao Jin
Redox processes mediated by biochar(BC) enhanced the transformation of Cr(VI), which is largely dependent on the presence of PFRs as electron donors. Natural or artificial dopants in BC’s could regulate inherent carbon configuration and PFRs. Until recently, the modulation of PFRs and transformation of Cr(VI) in BC by nonmetal-heterocyclic dopants was barely studied. In this study, changes in PFRs introduced by various nitrogen-dopants within BC are presented and the capacity for Cr(VI) transformation without light was investigated. It was found N-dopants were effectively embedded in carbon lattices through activated-Maillard reaction thus altering their charge and PFRs. Transformation of Cr(VI) in N doped biochar relied on mediated direct reduction by surface modulatory PFRs. The kinetic rate of transformation of Cr(VI) was increased 1.4–5 fold in N-BCs compared to nondoped BCs. Theortical calculation suggested a deficiency in surface electrons induced Lewis acid–base bonding which could acted as a bridge for electron transfer. Results of PCA and orbital energy indicated a colinear relationship between PFRs and pyrrolic N, as well as its dual-mode transformation of Cr(VI). This study provides an improved understanding of how N-doped BC contributes to the evolution of PFRs and their corresponding impacts on the transformation of Cr(VI) in environments.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2020
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IF 6.551
Jing Li,Mingjie Fan,Miao Li,Xiang Liu
The excellent potential of nanoscale zero-valent iron (nZVI) makes it a promising remedy for contaminated aquifers. More efficient remediation modes with nZVI have been investigated recently to overcome the inherent drawbacks of materials. In this study, a double surfactant-modified synthesis method is established to make the removal of Cr(VI) more efficiency. A specific focus of the materials status (suspension or powder) is devoted to explore the best application condition, especially for groundwater remediation . A non-ionic surfactant, polyvinylpyrrolidone (PVP), and an anionic surfactant, sodium oleate (NaOA), were selected to modify nZVI simultaneously. The kinetics and isotherm experiments, reactions at different pHs, initial concentrations, gas conditions, and coexisting ion conditions were conducted to analyse the removal mechanism. The characterizations before and after the reaction were used to further explain the results. From the batch experiments, a synergistic effect could be recognized in Cr(VI) elimination when PVP and NaOA were both used for nZVI modification. The materials in suspension (without drying process) exhibited higher removal efficiency in comparison with powder ones. These reactions happened in acidic condition demonstrated higher reactivity. The anaerobic condition facilitated the reaction, which showed prospect application in groundwater. Equilibrium could be reached within 2 min using the suspension sample with a removal efficiency above 99.5% and a maximum removal amount of 231.75 mg g −1 . The reaction process was well-fitted with pseudo-second-order kinetics and the Langmuir model. Cr(VI) was fully transformed into Cr(III), a safer status. These results show this is a promising in-situ method to eliminate Cr(VI) pollution in groundwater.
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高影响因子
CATALYSIS LETTERS
·
2020
·Vol. 150
·期 9
·2497-2509
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IF 2.482
Yang Qiang,Liu Jiali,Yan Dejian,Liu Jikai,Luo He’an
Abstract Boron-rich alloy boron suboxide (B 6 O) as a novel metal-free photocatalyst was recently explored for photocatalytic CO 2 reduction and water splitting. However, to broaden the potential applications of B 6 O in the field, further improving its activity and understanding its fundamental chemical properties are essential. Herein, transition metal doping (Cr or Co) is designed to engineer the band structure of B 6 O via a solid state reaction. The valence band edge of Cr or Co doped B 6 O is proposed to be more positive than that of pristine B 6 O while the original conduction band of B 6 O is not much influenced by doping, contributing to the better light harvesting ability and lower charge recombination rate of doped B 6 O. The photocatalytic and photoelectrochemical (PEC) performances of doped B 6 O were therefore remarkably enhanced. The apparent quantum yields (AQY) of 20 wt% Cr or Co doped B 6 O are much higher than that of pristine B 6 O. In addition, the 20 wt% Cr doped B 6 O exhibits the best electrical conductivity and photocatalytic performance compared with the Co doped B 6 O and pristine B 6 O. The present work demonstrates a facile and effective strategy to engineer the band structure and reduce the charge migration resistance of B 6 O. Graphic Abstract
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
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IF 3.99
Xu Yang,Yuhong Zhou,Zhaojie Sun,Chunhui Yang,Dongyan Tang
ZIF-8@ZIF-8/PAN nanofibers were fabricated by the incorporation of zeolitic imidazolate frameworks (ZIFs) with electrospun polyacrylonitrile (PAN) nanofibers, and following by the in-situ growth of ZIFs onto the surface of the nanofibers. The abundant micropores and active sites of ZIFs supplied the effective adsorption and reduction to heavy metal ions of Cr(VI). The obtained novel nanofibers overcome the crystal agglomeration of ZIF-8 effectively and maintained the porous structures by the nanofibrous morphology of PAN and the evenly distributed ZIF-8, and thus exhibited relative higher surface area (871.0 m 2 g −1 ) and excellent loading efficiency of ZIF-8 (82.9 %). As target adsorbate, Cr(VI) could be removed from aqueous media effectively with the maximum adsorption capacity ( q max ) of 39.68 mg g −1 , and with better recyclability. Significantly, guided with the proposed feasible adsorption-reduction mechanism of Cr(VI), toxic Cr(VI) ions could be further reduced partially to the relative harmless Cr(III). Potentially, the present stable and advantageous approach to loading and growing metal organic frameworks (MOFs) onto electrospun nanofibers could be extended to other water-stable MOFs and to remove various heavy metal ions.
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CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Jianting Liu,Yicong Chen,Shuyu Jiang,Jianhui Huang,Yuancai Lv,Yifan Liu,Minghua Liu
A cellulose-g-poly-(acrylamide-co-sulfonic acid) polymeric bio-adsorbent (CASA) was prepared by grafting copolymerization, and used to adsorb Cr(III) from leather wastewater. The SEM, XRD, FTIR , and XPS results showed that CASA contains many spherical particles and functional groups such as NH 2 , C O, and HSO 3 . The adsorption experiments revealed that CASA presented excellent adsorption performance for Cr(III) (274.69 mg/g of max adsorption capacity) from high-salinity wastewater, which was much better than other reported adsorbents with different structures. Meanwhile, adsorption equilibrium could be reached within 10 min due to the introduction of abundant sulfonic acid groups on its surface. In addition, the adsorption process followed the Langmuir adsorption isotherm , and the experimental data conformed to the pseudo-second-order kinetics model . Moreover, the main adsorption mechanisms include chelation, electrostatic interactions , and cation exchange , which provide an important theoretical basis for the removal of toxic inorganic pollutants from leather wastewater.
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JOURNAL OF MEMBRANE SCIENCE
·
2021
·
IF 8.742
Wen-Han Yu,Zhi-Qiang Gan,Jia-Rong Wang,Yu Zhao,Jun Han,Li-Feng Fang,Xiu-Zhen Wei,Ze-Lin Qiu,Bao-Ku Zhu
Nanofiltration (NF) membrane has an extensive application in the field of water treatment, but weakly negative surface-charge and even charge inversion in acidic environment restrict wide applications of traditional aromatic polyamide (PA) thin film composite (TFC) NF membrane in a broad pH range. In this work, 4, 4′-diaminostilbene-2, 2′-disulfonic acid (DSDA), a novel acidic aqueous monomer , was introduced into interfacial polymerization to fabricate a TFC NF membrane with enhanced negative charge and pH stability. The effects of interfacial polymerization parameters were investigated to improve membrane performance. The optimal membrane exhibits a pure water permeance (PWP) of 10.0 ± 0.5 L m −2 h −1 ·bar −1 and a high Na 2 SO 4 rejection (i.e., ~97.0%). The resultant membrane remains a strongly negative charge when the pH value is changed from 2 to 12. Due to enhanced negative charge, Donnan exclusion plays a significant role in membrane separation process, which results in a huge superiority in removal of Na 2 SO 4 , Na 3 PO 4 and K 2 Cr 2 O 7 in a broad pH range especially in acidic environment. Hence, it is demonstrated that the negative-charged NF membrane prepared in this work has improved and stable separation performance under a broad pH range, which expands application scopes of NF membrane, especially in removing Cr (VI) and phosphate in acidic environments. Besides, this study also provides a feasible route for preparation of suitable TFC NF membrane for working in acidic environment via introducing strongly acidic groups in selective layer.
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JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Yangzi Shangguan,Renji Zheng,Qiuyue Ge,Xuezhen Feng,Ranhao Wang,Yuanhao Zhou,Siyuan Luo,Lele Duan,Jia Lin,Hong Chen
Configuring reactive and stable catalytic interfaces is crucial to design efficient photocatalysts for Cr(VI) reduction. Herein, via the platinum decoration approach based on interfacial engineering , we developed an effective catalytic interface within novel semiconducting chalcopyrite quantum dots (Pt/CuFeS 2 QDs). Benefiting from the catalytic merits of the Pt modulated interfacial structure and electronic structure, Pt/CuFeS 2 QDs show a broader light absorption capability extending to near-infrared radiation (NIR) range with superior carriers separation performance and faster charge transfer efficiency, which delivers a three-folder faster photocatalytic Cr(VI) reduction efficiency comparing to the original CuFeS 2 QDs. Density functional theory (DFT) calculations unravel that Pt atoms prefer to be anchored with the surface S atoms to form a stable interfacial structure with faster electron transfer and Cr(VI) reduction dynamics. This work demonstrates that platinum decoration based on interfacial engineering is an effective strategy to simultaneously modulate the band structure and accelerate the interfacial reaction dynamics for semiconductor photocatalysts, which paves the way for designing highly efficient photocatalysts for light-driven environmental and energy engineering applications.
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JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Yibo Yuan,Xipeng Wei,Hua Yin,Minghan Zhu,Haoyu Luo,Zhi Dang
The effects of organic acids on hexavalent chromium (Cr(VI)) removal by reduced iron-based materials have been extensively studied. Nevertheless, the promotion mechanism from the perspective of the electron transfer process is still unclear. Herein, sulfidated nanoscale zero-valent iron (S-nZVI) and the selected organic acids, citric acid (containing both -OH and −COOH groups) and oxalic acid (containing only −COOH groups), showed significant synergistic promotion effects in Cr(VI) removal. The FeS and FeS 2 on S-nZVI surface could enhance the Cr(VI) reduction as the reductive entity and electron conductor. Furthermore, even though the reactivity of FeS with Cr(VI) is higher than that with FeS 2 , the Cr(VI) removal efficiency by FeS 2 was much higher than that by FeS with organic acids. Under neutral and alkaline conditions (pH 6.0–8.0), organic acids promoted the diffusion, adsorption and complexation of Cr(VI) on S-nZVI surface, thus enhancing the electron selectivity towards Cr(VI). However, when the solution pH changed to acidic conditions (pH 4.0), organic acids facilitated the dissolution of Fe(II) ions from S-nZVI and enhanced the electron utilization towards Cr(VI) via the fast Fe(III) reduction process. This study provided a new insight into the Cr(VI) removal, which was beneficial to understand the application boundaries of S-nZVI for Cr(VI) remediation.
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