CHEMOSPHERE
·
2021
·
IF 7.086
Fenglei Liu,Shan Hua,Chao Wang,Baowei Hu
Herein, using dialdehyde waste paper (DAWP) as a cross-linking agent to immobilize persimmon tannin (PT) was first used to remove the U(VI) and Cr(VI) via the “waste control by waste” concept. The microscopic and macroscopic surface properties of the as-prepared adsorbent was characterized by the advanced characterization techniques. Factors that affected the elimination process such as variable pH, coexistence ions and equilibrium time were investigated by batch techniques. The results showed that the maximal removal capacities of U(VI) and Cr(VI) on DAWP-PT were 242.3 mg/g (pH = 6.0) and 178.7 mg/g (pH = 2.0) at 298 K, which exhibited competitiveness with most of the reported solid materials. Meanwhile, adsorption data were fitted perfectly to the Langmuir and Pseudo-second-order equations, which indicated that the monolayer and homogenous chemisorption dominated the removal process. The SEM-EDX, DFT and XPS analysis conformed that adsorption of U(VI) was mainly via surface complexation, while the elimination of Cr(VI) was a redox reaction process, and about 65.33% of Cr(III) and 34.67% of Cr(VI) co-existed onto the surface of DAWP-PT. Thus, this study would provide a high-efficiency and low-cost adsorbent for radionuclide and heavy metal treatment.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Xiaojie Zhang,Kangrui Ma,Hong Peng,Yuefa Gong,Yanjun Huang
Simultaneous removal of chromium(VI) oxyanions and heavy metal cations from contaminated water body is of great significance. In this work, a novel and bifunctional sorbent, imidazolium functionalized polysulfone/DTPA-chitosan composite bead (IMPSF/DACS) was successfully constructed by phase inversion method and applied for co-removal of Cr(VI) and Cu(II) from aqueous solutions. The maximum adsorption capacities for Cr(VI) and Cu(II) on IMPSF/DACS in single system at pH 5 were 56.72 and 43.05 mg g −1 , respectively. In binary system, the removal of Cr(VI) could be further enhanced by the presence of Cu(II) due to the electrostatic shielding effect, while Cu(II) sorption was not significantly affected by the coexistence of Cr(VI). Moreover, IMPSF/DACS could simultaneously reduce low concentrations of Cu(II) and Cr(VI) in simulated contaminated lake water below the limit, while also showing good reusability in co-removal of Cr(VI) and Cu(II). The order of inhibitory effect of competing anions on Cr(VI) removal was as follows: H 2 PO 4 − < Cl − < NO 3 − < SO 4 2− , while the competing hardness cations had a little effects on the adsorption of Cu(II), implying that the Cr(VI) removal was mainly depended on the electrostatic attraction between Cr(VI) and imidazolium ions modified on IMPSF/DACS, and Cu(II) uptake was associated with chelation of DACS encapsulated in IMPSF/DACS beads. These assumptions were confirmed by XPS, FTIR and EDS-mapping techniques.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Peng Cheng,Zhiyang Wei,Yara Arbid,Tengfei Fu,Xiaowei Liu,Olivier Monfort
The primary aim of this work is to test a novel adsorbent prepared by cross-linking of tetrafluoroterephthalonitrile with chitosan (CS-TFT) for the removal of Cr(VI) and U(VI). The CS-TFT is stable until 250 °C and possesses amino functional groups due to the presence of CS that remain intact even after the cross-linking reaction, thus being a benefit for adsorption properties; while the TFT brought roughness to CS-TFT that keeps its high porosity. The adsorption efficiency of CS-TFT is evaluated in the batch experiment of Cr(VI) and U(VI) adsorption along with the effect of different experimental parameters (pH, time, temperature, initial concentrations, and co-existing inorganic cations). The maximum adsorption capacity of CS-TFT for adsorption of Cr(VI) and U(VI) was 265.96 mg·g -1 at pH = 3 and 346.06 mg·g -1 at pH = 5, respectively, at 298 K and the corresponding partition coefficients were 12,454 and 6181 mg g -1 mM -1 , respectively. The kinetics of the adsorption process is identified as a pseudo-second-order model and the Langmuir isotherm model is considered. The CS-TFT shows satisfactory reusability since it can be used after 6 cycles of regeneration with a removal efficiency of Cr(VI) and U(VI) higher than 90 %. The adsorption mechanism is also proposed based on investigation of CS-TFT by FTIR, XPS and SEM-EDS before and after adsorption. The results show that hydroxy (–OH) and amino (–NH 2 ) groups play a key role in the chemical adsorption . All these findings suggest that CS-TFT could be a promising adsorbent for wastewaters treatment .
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2015
·
IF 4.529
Jian Rong Zhang,Ai Lian Zeng,Hong Qun Luo,Nian Bing Li
In this work, a simple and sensitive Cr(VI) sensor is proposed based on fluorescent polyethyleneimine-stabilized Ag nanoclusters, which allows the determination over a wide concentration range of 0.1 nM–3.0 μM and with a detection limit as low as 0.04 nΜ and a good selectivity. The quenching mechanism was discussed in terms of the absorption and fluorescence spectra, suggesting that Cr(VI) is connected to Ag nanoclusters by hydrogen bond between the oxygen atom at the vertex of tetrahedron structure of Cr(VI) and the amino nitrogen of polyethyleneimine that surrounded Ag nanoclusters and electron transfer from Ag nanoclusters to highly electron-deficient Cr(VI) results in fluorescence quenching. Despite the failure to quench the fluorescence efficiently, Cr(III) can also be measured using the proposed Ag nanoclusters by being oxidized to Cr(VI) in alkaline solution (pH ∼9) containing H 2 O 2 . Therefore, our approach could be used to detect Cr(VI), Cr(III) and the total chromium level in aqueous solution. In addition, Cr(VI) analysis in real water samples were satisfactory, indicating this method could be practically promising for chromium measurements.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Xiaoyu Lin,Xi He,Ling Lei,Yufeng Zhao,Longzhe Cui,Guiping Wu
Cr(VI)-contaminated water poses a serious threat to the environment. In this study, capsule-type biosorbent Aliquat-336-filled chitosan capsules (AFCCs) were prepared by a simple and gentle method for more efficient and eco-friendly removal of Cr(VI). The experimental results show that the uptake of Cr(VI) by AFCCs increased with increasing Aliquat-336 content. The AFCCs show excellent stability under acidic conditions, and the maximum adsorption capacity was reached at a pH of 2. The maximum adsorption capacity of AFCCs for Cr(VI) was 110.94 ± 5.07 mg/g at 20 °C, which was calculated based on the Langmuir model. The kinetic results show that the adsorption rate control process changed from liquid film diffusion to a chemical reaction with increasing shaking rate. In addition, the AFCCs and adsorption-reduction mechanism of Cr(VI) were characterized by digital photography, electron microscope , zeta potential , Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results indicated that the electrostatic attraction between quaternary amine groups in Aliquat-336 and Cr(VI) anions plays a major role in the removal of Cr(VI). Subsequently, the adsorbed Cr(VI) obtained electrons from C C/C H and NH 3 + / NH 2 + were reduced to Cr(III), while C C/C H and NH 3 + / NH 2 + were oxidized to C O, C O, =NH + , =N and N O, respectively.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Xiaoqi Liu,Yanyun Zhang,Yan Liu,Ting'an Zhang
In this paper, a novel grafted zeolite/Fe 3 O 4 /chitosan (ZMC-MAH-TEPA) adsorbent was greenly synthesized and evaluated for the removal of Cr(VI) and Ag(I) in single and bi-component solutions. The characterization data of XRF , XRD, FT-IR, VSM, TGA , BET and SEM showed the successful fabrication of the adsorbent with abundant -NH 2 and -NH- as well as great recovery properties (11.70 emu/g). The effects of experimental parameters, including pH value, initial concentration, temperature, time, and coexisting ions on single and bi-component adsorption, were investigated. The results demonstrated that the adsorption capacities increased with the enhanced shaking time and concentration until equilibrium was reached. The optimum pH value was 3 for Cr(VI) adsorption and 5 for Ag(I) adsorption. The maximum adsorption capacities for Cr(VI) and Ag(I) ions, obtained by the Langmuir model, were 50.75 and 70.12 mg·g −1 in single metal solutions and 45.45 and 58.94 mg·g −1 in bi-component metal solutions (Cr(VI)/Ag(I) = 1:1), respectively. Additionally, the adsorption mechanism of Cr(VI) and Ag(I) was explained in terms of electrostatic interaction and hydrogen bonding between metal ions and -NH 2 and -NH- in ZMC-MAH-TEPA. Taken together, this study provides a clean approach to synthesizing chitosan-based adsorbents for the efficient removal of Cr(VI) and Ag(I) ions.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2017
·
IF 5.651
Yuanji Shi,Tao Zhang,Hongqiang Ren,Andrea Kruse,Ruofan Cui
An adsorbent hydrochar was synthesized from corn cobs and modified with polyethylene imine (PEI). The hydrochars before and after modification were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis. FTIR and XPS revealed that the PEI was grafted onto the hydrochar via ether and imine bonds formed with glutaraldehyde. The maximum adsorption capacities for Cr(VI) (33.663 mg/g) and Ni(II) (29.059 mg/g) on the modified hydrochars were 365% and 43.7% higher, respectively, than those on the unmodified hydrochar. A pseudo-second-order model described the adsorption of Ni(II) and Cr(VI) on all the adsorbents. The adsorption of Cr(VI) was endothermic, spontaneous, increased disorder, and obeyed the Langmuir model. By contrast, the adsorption of Ni(II) was exothermic, spontaneous, decreased disorder, and obeyed the Freundlich model. XPS confirmed that the adsorption sites and mechanisms for Ni(II) and Cr(VI) on the modified hydrochars were different.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS ES&T Engineering
·
2022
·
IF 0
Dazhong Yang,Zheting Chu,Xuezhen Feng,Qiuyue Ge,Ranhao Wang,Juan Zhang,Shangying Li,Renji Zheng,Wenfei Wei,Shuping Yi,Hong Chen
Both alkaline heavy metal (HM) contaminated red mud (RM) recycling and Cr(VI) polluted soil remediation are severe hazardous environmental problems. Herein, we developed a novel integrated approach to neutralize and stabilize the hazardous RM via the introduction of Ca2+ and Cl– dual ions. When 3% CaCl2·2H2O is added, the pH of RM is reduced from 11.0 to 8.9, and the Pb, Cr, Zn, Cu, and As leaching concentrations from RM are suppressed lower than the environmental standards of China and the World Health Organization (Pb, Cr, Zn, Cu < 0.50 mg/L; As < 10 μg/L). Detailed mechanism studies reveal that the pH neutralization is attributed to the novel OH– flocculation effect ascribing to Ca2+ charge neutralization and Cl– promoted proton neutralization. Furthermore, as the pH decreases, the HM adsorption capacity of RM is enhanced, achieving stable HM immobilization. The treated RM can be further employed to remediate Cr(VI) contaminated soil (Cr concentration 570 ppm; treated RM weight percentage in soil 5.0%), which can suppress 56.0% Cr mobility in soil and 68.4% bioaccumulated Cr in the harvested vegetables. Overall, this work demonstrates an ecofriendly “waste-to-soil remediation” strategy to solve both the solid waste and soil pollution problems.
研究领域:
环境科学
·
土壤学
✓ 已验证
DOI
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.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 106
·104693-104698
·
IF 3.289
Guo Jian-feng,Hou Chang-jun,Yang Mei,Huo Dan-qun,Fa Huan-bao
In this work, we have developed a simple, cost-effective and sensitive fluorescent method for the selective determination of chromium(VI) ions (Cr(VI)) in aqueous solution. In the presence of bromide ions (Br−), the strong oxidization of Cr(VI) enables it to selectively etch the bovine serum albumin-stabled gold nanoclusters (BSA-Au NCs) and formed AuBr2− complexes. Proportional fluorescence quenching of BSA-Au NCs induced by the leaching process was closely connected with concentrations of Cr(VI) and thus provided a new detecting strategy towards Cr(VI). Under optimal conditions, the amount-dependent fluorescent response was linearly correlated with the Cr(VI) concentrations ranging from 1.0 nM to 2.5 μM over 3 orders of magnitude, with a detection limit down to 0.6 nM. The as-developed strategy also performed satisfactory selectivity as well as excellent reproducibility. Moreover, this method had been successfully applied to monitor Cr(VI) with real river water samples which demonstrated the potential for field applications.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2018
·Vol. 5
·期 11
·2570-2578
·
IF 6.087
Xinwen Ou,Xueming Liu,Weizhen Liu,Wencong Rong,Jingyuan Li,Zhang Lin
The surface defects of adsorbents are generally considered to be the active sites for adsorbates, and the adsorption behaviors of a variety of pollutants in wastewater are strongly influenced by the surface defects of the adsorbents. With simple chemical and structural properties, nano-Mg(OH)2 exhibits a high adsorption affinity and selectivity to heavy metals from wastewater. The insight into the surface complex structures of heavy metals on the Mg(OH)2 surface is fundamental for both the mechanism and application of defective adsorbents in wastewater treatment. In this study, the impact of surface defects of Mg(OH)2 nanoplates on the structure, energy, and adsorption amounts of toxic heavy metal oxyanions (HAsO42− and CrO42−) was investigated by combining the first-principles calculations and batch experiments. The first-principles calculations illustrated that the heavy metal oxyanions can be steadily incorporated into the surface defects to form inner-sphere complexes. The incorporated heavy metal oxyanions have strong charge–charge and chemical bonding interactions with the surface defect sites, which are much stronger than the hydrogen bonding interactions with the surface OH sites. Moreover, the adsorption affinity of surface defects towards heavy metal oxyanions is stronger than that towards other oxyanions (e.g. SO42− and NO3−), indicating the high adsorption selectivity of heavy metal oxyanions over other oxyanions. Batch adsorption experiments verified that the adsorption of defect-rich Mg(OH)2 adsorbents towards heavy metal ions, e.g., As(V) and Cr(VI), was favorable even under the condition of low concentration (mg L−1 level). These findings reveal the significance of surface defects of Mg(OH)2 for extracting As(V) and Cr(VI) from low-concentration solutions. The proposed strategy of surface defect-fabrication should provide a useful insight into designing effective adsorbents for the selective extraction of heavy metal oxyanions at low concentration.
研究领域:
环境科学
·
材料科学
·
理论化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Zhipan Wen,Yalei Zhang,Gang Cheng,Yingru Wang,Rong Chen
In this study, nanosized ordered magnetic mesoporous Fe-Ce bimetal oxides (Nanosized-MMIC) with highly well-ordered inner-connected mesostructure were successfully synthesized through the KIT-6 template method. This Nanosized-MMIC displayed excellent adsorption capacities for As(V), Cr(VI) and AO7, and the corresponding calculated maximum adsorption capacities of material were 111.17, 125.28 and 156.52 mg/g, respectively. As(V) and Cr(VI) removal by Nanosized-MMIC were slightly dependent on the ionic strength but highly solution pH-dependent, the coexistent silicate and phosphate ions competed remarkably with both As(V) and Cr(VI) for the adsorption active site. Mechanisms indicated As(V) and Cr(VI) formed inner-sphere complexes on Nanosized-MMIC interface via the electrostatic interaction and surface complexation, while the total organic carbon (TOC) change demonstrated that AO7 could be removed completely and no organic intermediates formed through the adsorption process. In addition, Nanosized-MMIC also possessed superior adsorption performance in As(V)/Cr(VI)-AO7 binary systems, and the reusable and regeneration properties indicated that the obtained nanomaterials could maintain at a comparatively high level after several recycling. Finally, fixed-bed experiments suggested the Nanosized-MMIC was expected to have a promising excellent nano-adsorbent with high application potential for co-existed toxic heavy metals and organic dyes removal in practical wastewater treatment .
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）