SEPARATION AND PURIFICATION TECHNOLOGY
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2025
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IF 9
Bing Li,Qian Zuo,Zhiyi Deng,Jianhua Cheng,Ping Li,Jinhua Wu
Surface passivation caused by Fe-Cr precipitates limits the application of milli-sized zero-valent iron (mFe 0 ) in filter tanks for Cr(VI) removal. A mFe 0 -based column was established using sand as dispersing media, coupled with a micro-electric field (MEF, 1.2 mA/cm 2 ), to accelerate iron corrosion and enhance Cr(VI) sequestration. A control column without MEF was employed for comparison. Surface analysis verified that the MEF induced mFe 0 particles into three-electrodes with bipolar charges and facilitated electron transfer from iron-core to surrounding O 2 /H 2 O. Ferrous ions from iron corrosion afterwards reduced Cr(VI) and precipitated into secondary minerals (e.g., magnetite, lepidocrocite, and green rust). These minerals effectively sequestered Cr(VI) in their matrices through adsorption-reduction/precipitation on Fe 0 and sand surfaces. Compared to the mFe 0 column, the MEF-mediated mFe 0 (MEF-mFe 0 ) column demonstrated a 2.5-fold increase in kinetic rate constant and a 10-fold decrease in Cr(VI) migration rate, leading to a 9.5-fold augment in Cr(VI) sequestration capacity and a 3.7-fold extension in longevity. Under different hydraulic retention times and influent concentrations, the MEF-mFe 0 column outperformed the mFe 0 column with 6.0 to 9.6-fold higher Cr(VI) sequestration and 3.5 to 5.7-fold longer lifespan. Our study revealed that MEF-assistance represented a promising approach to enhance mFe 0 activation for subsequent Cr(VI) sequestration from water.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Qian Guo,Dongmei Yu,Jing Yang,Ting Zhao,Dan Yu,Lei Li,Duanjie Wang
The distribution characteristics of Cr(VI) species in contaminated soil is crucial for soil remediation; however, there is currently a lack of methods for analysing anionic Cr(VI) species in soil. This study has developed a novel sequential extraction method for speciation of Cr(VI) and Cr(III). Besides extraction experiments, simulated chromium species were prepared to verify the presence of proposed chromium species. The results show that Cr(VI) species in soil can be categorized into water-soluble Cr(VI), electrostatically adsorbed Cr(VI), Cr(VI) specifically adsorbed by minerals containing exchangeable Ca 2+ , Cr(VI) specifically adsorbed by hydrous metal oxides, calcium chromate Cr(VI) and stable complexed adsorption Cr(VI). These Cr(VI) species can be selectively extracted by specific solutions through ion exchange or weak acid dissolution. The most stable Cr(VI) species is Cr(VI) complexed by hydrous iron oxides through bidentate ligand binding; only by dissolution of hydrous iron oxides can this Cr(VI) species be leached. The distribution of Cr(VI) species is closely linked to particular soil compositions including exchangeable Ca 2+ and hydrous iron oxides which determinate the Cr(VI) adsorption in soil. Cr(III) species comprise Fe-Cr coprecipitate hydroxides Cr(III), Fe-Mn oxide-bound Cr(III), organic matter-bound Cr(III) and residual Cr(III). Their distribution depends on the types of reductants present in the soil.
研究领域:
环境科学
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土壤化学
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DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 11
·10808-10819
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IF 2.8
Peng Zhongya,Zhao Hang,Lyu Honghong,Wang Lan,Huang Hua,Nan Qiong,Tang Jingchun
This study was conducted to understand the effects of ultraviolet (UV) irradiation on the physicochemical properties and the hexavalent chromium (Cr(VI)) removal ability of biochar. Structural and morphological analysis showed that UV irradiation increased the specific surface area of biochar and added a large amount of oxygen-containing functional groups (e.g., carboxyl, lactonic, and hydroxyl) to biochar’s surface. Batch sorption experimental results showed that UV-modified biochar (UVBC) produced at the pyrolysis temperature of 300 °C, the irradiated time of 24 h, and the irradiation distance of 40 mm exhibited excellent Cr(VI) removal ability (from 1.11 mg/g for BC to 20.04 mg/g for UVBC, a 18.1-fold increase). The adsorption kinetics and adsorption isotherm data agreed well with the pseudo-second-order model and Freundlich model, respectively. Experimental and modeling results suggest that the oxygen-containing functional groups and specific surface areas of biochars were notably increased by UV irradiation, which enhanced Cr(VI) adsorption by surface complexation. X-ray photoelectron spectroscopy (XPS) analysis of UVBC before and after reaction with Cr(VI) showed that reduction occurred during Cr(VI) adsorption. The energy consumption of UV modification is 2.7 MJ per gram of UVBC produced, which is comparable to that in activated carbon. The results showed that the method of UV modification of biochar is a very novel and effective method for the adsorption of Cr(VI) in solution.
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2020
·
IF 4.302
Kai Liu,Fangbai Li,Qingwen Tian,Chengrong Nie,Yibing Ma,Zhenlong Zhu,Liping Fang,Yuanying Huang,Siwen Liu
Paddy soil and irrigation water are commonly contaminated with hexavalent chromium [Cr(VI)] near urban industrial areas, thereby threatening the safety of agricultural products and human health. In this study, we develop a porous and high specific area bone char (BC) to support nanoscale zero-valent iron (nZVI) and apply it to remediate Cr(VI) pollution in water and paddy soil under anaerobic conditions. The batch experiments reveal that BC/nZVI exhibits a higher removal capacity of 516.7 mg/(g•nZVI) for Cr(VI) than nZVI when normalized to the actual nZVI content, which is 2.8 times that of nZVI; moreover, the highest nZVI utilization is the nZVI loading of 15% (BC/nZVI15). The Cr(VI) removal efficiency of BC/nZVI15 decreases with increasing pH (4 – 10). Coexisting ions (phosphate and carbonate) and humic acid can inhibit the removal of Cr(VI) with BC/nZVI15. Additionally, BC exhibits a strong advantage in promoting Cr(VI) removal by nZVI compared to the widely used biochar and activated carbon. Our results demonstrate that reduction and coprecipitation are the dominant Cr(VI) removal mechanisms. Furthermore, BC/nZVI15 shows a significantly higher reduction and removal efficiency as well as a strong anti-interference ability for Cr(VI) in paddy soil, as compared to nZVI. These findings provide a new effective material for remediating Cr(VI) pollution from water and soil.
研究领域:
环境科学
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土壤学
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产品关联
DOI
PubMed
高影响因子
ACS Applied Nano Materials
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2021
·
IF 5.097
Bin Zuo,Qinyue Deng,Han Shao,Bingbing Cao,Yunhui Fan,Wanfang Li,Mingxian Huang
In this work, we designed the Fe3O4@mesoporous-SiO2@chitosan@polyaniline core–shell nanoparticles (Fe3O4@mSiO2@CS@PANI, hence abbr. FSCP), which can be used to capture Cr(VI) in wastewater. Rapid adsorption behavior and high removal capability (249.6 mg Cr(VI) per gram of FSCP) were exhibited by this material. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that Cr(VI) was adsorbed and in situ reduced on FSCP at pH 2. Adsorption was facilitated by the electrostatic attraction of HCrO4– and −N+═C–/–N+H–, while the active −NH–/–N+H– sparked the reduction of Cr(VI) to Cr(III). Moreover, the coordination of the resulting Cr(III) with the amino group promoted adsorption, thus achieving detoxification of Cr(VI) in wastewater. After eight recycling experiments, the Cr(VI) removal efficiency of this material is still more than 90%, indicating that this material has excellent stability and good application potential. Therefore, this magnetic adsorbent offers a potential solution for the successful handling of chromium-containing wastewater.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 42
·35332-35339
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IF 3.289
Dan Chen,Xuelian Xiao,Kai Yang
In this work, a novel adsorbent derived from waste eggshell (ES) was used for phosphate and hexavalent chromium adsorption. EDS, XRD, and FTIR analyses demonstrated that α-FeOOH was successfully loaded onto the eggshell, thus increasing the available sorption sites and facilitating the adsorption abilities of phosphate and hexavalent chromium. The maximum phosphate and hexavalent chromium adsorption capacities on α-FeOOH modified eggshell (F-ES) were 248.73 and 41.57 mg g−1, which were much greater than that of the original eggshell 89.74 and 11.81 mg g−1, indicating that the modification process significantly improved the phosphate and hexavalent chromium removal abilities. Besides, the kinetics data were both well fitted with pseudo-first-order, pseudo-second-order, and Richie kinetics models, which proved that the adsorption process onto the eggshell was controlled by multiple mechanisms. In addition, the removal rates of phosphate and hexavalent chromium increased with increasing adsorbent dosage. However, the removal rates showed downward trends with pH increased from 3 to 9 and ionic strength increased from 0 to 0.1 M.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2017
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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
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2017
·Vol. 93
·期 4
·1147-1158
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IF 3.135
Chongzhuo Bao,Chen Mingxin,Guangrong Liu,Xin Jin,Qiang Huang
BACKGROUND Uniform and well-dispersed hollow microspheres of oligoaniline were synthesized by a facile and template-free method in alkaline medium. The morphology of oligoanilines was controlled from hollow to hard microspheres, by simply changing the volumes of alkaline medium. SEM, TEM, XRD, FTIR and physical adsorption of nitrogen were used to characterize the products. Hexavalent chromium ion uptake experiments were run with these aniline oligomers. RESULTS Adsorption experiments showed that the removal of chromium ions was strongly dependent on the initial pH of the solution. The pseudo-second-order kinetic and Langmuir isotherm models were well correlated with the experimental data. The adsorption of Cr(VI) and synergistic reduction to Cr(III) were confirmed by analyzing remnant chromium in the liquid and XPS detection of the exhausted adsorbent. A redox/pseudo-protonation process was suggested as the mechanism to explain the Cr(VI) removal. The adsorbed chromium ions could be desorbed by NaOH solution. The higher desorption efficiency of 96.2% was achieved by using 1.0 mol L -1 NaOH as the desorption agent. CONCLUSIONS It was observed that the hollow microsphere were the most effective adsorbent of the three adsorbents and its removal efficiency reached 99% to remove 60 mg L -1 Cr(VI). The facile fabrication, efficient removal of Cr(VI) and simple regeneration offered an option to remove Cr(VI) contamination from natural water and industrial wastewater. © 2017 Society of Chemical Industry
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Environmental Science-Nano
·
2021
·Vol. 8
·期 11
·3331-3342
·
IF 8.131
Dingyuan Zheng,Wenrui Yao,Ce Sun,Xiaojian Chen,Jiyuan Zhou,Baiwang Wang,Haiyan Tan,Yanhua Zhang,Yonggui Wang
Chromium (Cr(VI)) pollution poses a serious threat to the ecological environment and biological health; therefore, there is an urgent need to develop advanced technologies for Cr(VI) detection and removal. Here, a novel fluorescent wood sponge (citric acid modified wood sponge decorated with carbon dots, CA/WS-CDs) was constructed combining hierarchical porous wood sponge (WS) and carbon dots (CDs) via chemical bonding, which could simultaneously detect and remove hexavalent Cr(VI) in an aqueous medium. The chemical and physical structure of the fluorescent wood sponge was characterized, and its detection and adsorption performances for Cr(VI) were studied. The results demonstrated that the CA/WS-CDs showed excellent performance for Cr(VI) detection and removal. After being immersed in a Cr(VI) solution (50 mL, 50 mg L−1) at 25 °C for 24 h, the strong blue fluorescence of CA/WS-CDs-3 under 365 nm light weakened and fluorescence quenching started to occur, which makes the fluorescent wood sponge a detector of Cr(VI). Moreover, this novel fluorescent wood sponge had a higher adsorption ability for Cr(VI) (maximum adsorption capacity, 450.5 mg g−1), and its sorption performance met Langmuir and pseudo-second-order models. Furthermore, FTIR and XPS analysis confirmed that the hierarchical structure of the fluorescent wood sponge provided many effective sorption sites and ion transport channels, thereby guaranteeing the selective detection and efficient adsorption properties for Cr(VI). Such intriguing Cr(VI) warning and sorption performance make the proposed CA/WS-CDs hold huge prospects for practical environmental remediation.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 21
·3788
·
IF 4.329
Hua Zeng,Zhiyuan Hu,Chang Peng,Lei Deng,Suchun Liu
Due to its lethal effect on the human body and other creatures, Cr(VI) ions have attained widespread public attention, and an effective adsorbent for removing Cr(VI) ions is vital. Chitosan (CS)/cellulose nanocrystals grafted with carbon dots (CNCD) composite hydrogel with strong sorption ability and sensitive detection ability for Cr(VI) was formed. The cellulose nanocrystals (CN) offered a natural skeleton for assembling 3D porous structures, and then improved the sorption ability for Cr(VI); moreover, carbon dots (CD) acted as a fluorescent probe for Cr(VI) and provided Cr(VI) adsorption sites. With a maximum adsorption capacity of 217.8 mg/g, the CS/CNCD composite hydrogel exhibited efficient adsorption properties. Meanwhile, with a detection limit of 0.04 μg/L, this hydrogel was used for selective and quantitative detection of Cr(VI). The determination of Cr(VI) was based on the inner filter effect (IFE) and static quenching. This hydrogel retained its effective adsorption ability even after four repeated regenerations. Furthermore, the economic feasibility of the CS/CNCD composite hydrogel over activated carbon was confirmed using cost analysis. This study provided one new method for producing low-cost adsorbents with effective sorption and sensitive detection for Cr(VI).Keywords:chitosan;cellulose nanocrystals;carbon dots;adsorption;hexavalent chromium
研究领域:
材料科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2020
·Vol. 10
·期 4
·686
·
IF 4.324
Linlin Du,Peng Gao,Yuanli Liu,Tsuyoshi Minami,Chuanbai Yu
The removal of Cr(VI) in wastewater plays an important role in human health and environment. In this work, polypyrrole/hollow mesoporous silica particle (PPy/HMSNs) adsorbents have been newly synthesized by in-situ polymerization, which prevent the aggregation of pyrrole in the process of polymerization and exhibit highly selective and powerful adsorption ability for Cr(VI). The adsorption process was in good agreement with the quasi-second-order kinetic model and the Langmuir isotherm model. And the maximum adsorption capacity of Cr(VI) was 322 mg/g at 25 °C. Moreover, the removal rate of Cr(VI) by PPy/HMSNs was ~100% in a number of binary systems, such as Cl−/Cr(VI), NO3−/Cr(VI), SO42−/Cr(VI), Zn2+/Cr(VI), Fe3+/Cr(VI), Sn4+/Cr(VI), and Cu2+/Cr(VI). Thus, the PPy/HMSNs adsorbents have great potential for the removal of Cr(VI) in wastewater.Keywords:polypyrrole/hollow mesoporous silica particle;chromium(Cr);adsorption
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
·
2022
·
IF 9.988
Teng Xu,Xiaofeng Jiang,Yuling Tang,Yunhang Zeng,Wenhua Zhang,Bi Shi
Trivalent chromium [Cr(III)] and tannins serve as necessary substances in leather processing and coexist in tannery site, which lead to the chromium contamination in site soil when disposed improperly. However, coexisting tannins are very likely to complex with Cr(III) and affect its properties, ultimately changing the mobility of chromium in soil. In this study, tannic acid (TA) was selected to investigate the complexation with Cr(III) and the influence on the solubility and sorption of Cr(III) in soils. Then, the transport behavior and mechanism of Cr(III)-TA complexes in soil was clarified. Dialysis results showed that the increase of TA concentration and solution pH promoted the formation of complexed Cr(III). The results of UV–Vis absorption spectroscopy , X-ray photoelectron spectroscopy, and density functional theory calculations indicated that the adjacent ionized phenolic hydroxyls in TA functioned as the binding sites with Cr(III) to form the Cr–O bonds and the degree of complexation increased with pH. The Cr(III)-TA complexes had higher solubility than free Cr(III) at pH ≥ 6.0. Batch sorption experiments demonstrated that the sorption capacity of Cr(III)-TA to soils with different pH was always lower than that of free Cr(III). These reasons led to the stronger mobility of Cr(III)-TA in soil columns than Cr(III). Our research reveals that the enhanced mobility of Cr(III) in soils coexisting with TA.
研究领域:
环境科学
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土壤学
✓ 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）