CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Lv Xi,Xu Xincheng,Peng Yang,Li Bolin,Yang Lie,He Xiaoman
This study introduces a novel modification method for micron-sized zero-valent iron, utilizing Shewanella oneidensis MR-1 to simultaneously colonize its surface, disrupt the passivation layer, and alter the crystal structure of the core. This process yields a composite that retains its reducing activity even in high concentrations of pollutants (500 ppm Cr(VI)) and under neutral to slightly acidic conditions. Our findings indicate that the modified system induces the Kirkendall effect in zero-valent iron, leading to the formation of amorphous zero-valent iron with a non-spherical core structure, in contrast to conventional direct mixing approaches. The modified system achieves complete reduction of 100 ppm Cr(VI) to Cr(III) within 8 h. Notably, within the first 4 h of reaction, the reduction rate is approximately three times higher than that of the conventional direct mixing system. XPS, XRD, SEM, EEM and TEM analyses reveal that the surface passivation layer of the biochemically modified zero-valent iron is disrupted, leading to changes in its crystal structure, the formation of hollow spherical structures, and the development of a biological protective film on its surface. Interestingly, electrochemical and ETSA analyses indicate that the electron transfer rate of the biochemically modified composite is significantly enhanced. This study provides fundamental insights into the removal of Cr(VI) from groundwater using biochemically modified micron-sized zero-valent iron (mZVI).
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
STARCH-STARKE
·
2024
·Vol. 77
·期 2
·2400050
·
IF 2.6
Xuesheng Qin,Chengzheng Wang,Zhe Zhang,Wei Ma
Hexavalent chromium (Cr(VI)) has attracted much attention because it is a harmful pollutant. In this study, acid hydrolyzed hydrothermal double modified starch (AHS) and hydroperoxide oxidized starch (HOS) are prepared from natural starch and used for the reduction of chromium (VI) in aqueous systems. The effects of hydrothermal acidolysis and oxidative modification of starch on the reduction rate of Cr(VI) are discussed, including the changes of solubility, swelling power, particle size, content of straight-chain starch, and carbonyl/carboxylic group content. The results of response surface methodology (RSM) optimization show that the influence of reaction conditions on the reduction rate of Cr(VI) by NS is as follows: reaction time > initial pH of solution > reaction temperature > starch to Cr(VI) mass ratio; and on the reduction rate of Cr(VI) by AHS and HOS is as follows: initial pH of solution > reaction time > starch to Cr(VI) mass ratio > reaction temperature.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2019
·
IF 3.556
Junfeng Xiao,Yuanpeng Cheng,Caixia Guo,Xiangting Liu,Bing Zhang,Siguo Yuan,Jiajia Huang
A novel functional fiber (PAN-CDs) loaded with carbon dots (CDs) with excellent photoreduction and adsorption properties for Cr(VI) was prepared via an amidization reaction between the CDs' carboxyl groups and amine groups on polyacrylonitrile (PAN)-based ion exchange fibers, which could completely preserve the fluorescence properties of the CDs. The photoluminescence (PL), photocatalysis and adsorption properties of PAN-CDs were characterized and analyzed. The PAN-CDs possess high adsorption capacity (297.6 mg/g) and excellent kinetic behavior (attaining adsorption equilibrium in 30 min) for Cr(VI) adsorption. Furthermore, the residual Cr(VI) (approximately 3 mg/L) after adsorption could be removed completely by subsequent photoreduction by the PAN-CDs. The Cr-saturated PAN-CDs could be easily separated by filtering and regenerated, with no observable decay of removal efficiency after five regeneration cycles. In addition, due to the PL quenching action of Cr(VI), the PAN-CDs can also be used as sensor for quantitative detection of trace Cr(VI) in aqueous solution.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
·
2016
·
IF 2.429
Jinwei Zhang,Zhangwei Han,Bo Teng,Wuyong Chen
For getting a clear and detail process of chromium tanned leather biodeteriorated with Penicillium sp. as a reference for future research and providing a cleaner chromium containing leather waste disposal method. The chromium tanned leather (CTL) and chromium tanned hide powder (CTHP) were biodeteriorated with the Penicillium . The CTL was biodeteriorated at first to verify the biodeterioration effect, and then the changes of the CTHP structure and thermal properties after the biodeterioration were analyzed by Scanning Electron Microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), Thermal Gravimetric Analyzer (TG) and Differential Scanning Calorimeter (DSC). The deterioration degree of the CTHP was characterized by the contents of hydroxyproline and total nitrogen in the filtrate, the Penicillium number was counted too during the process. The results showed that the CTL could be biodeteriorated with the Penicillium as shrinkage temperature and mass decreasing even though the biodeterioration degree was not ideal enough. After the process of CTHP biodeteriorated with the Penicillium , the surface morphology and structure of the CTHP were damaged. The thermal resistance and thermal denaturing temperature reduced which showed the detanning effect happened in the biodeterioration process. With the increasing of biodeterioration time, the hydroxyproline and total nitrogen in the filtrate increased. The Penicillium number maximized at 96 h and protease was produced in the process with enzymatic activity reaching to 9.23U mL −1 . These phenomena demonstrated the Penicillium grew through digesting chromium tanned leather and produced metabolites. To sum up, the biodeterioration process of chromium tanned leather with Penicillium was a synergistic effect of chromium detanning and the Penicillium growth.
研究领域:
微生物学
·
环境科学
·
皮革化学
✓ 已验证
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 9
·2224
·
IF 3.623
Xinzhe Sun,Peng Guo,Yuanyuan Sun,Yuqian Cui
Lanthanun oxide (La2O3) is a lanthanum chemical compound incorporates a sensible anionic complexing ability; however, it lacks stability at a low pH scale. Biochar fibers will give the benefit of their massive space and plethoric uses on the surface to support a metal chemical compound. Herein, wet spinning technology was used to load La3+onto sodium alginate fiber, and to convert La3+into La2O3through carbonization. The La2O3-modified biochar (La-BC) fiber was characterized by SEM, XRD and XPS, etc. An adsorption experiment proved that La-BC showed an excellent adsorption capacity for chromates, and its saturation adsorption capacity was about 104.9 mg/g. The information suggested that the adsorption was in step with both the Langmuir and Freundlich models, following pseudo-second-order surface assimilation mechanics, which showed that the Cr (VI) adsorption was characterized by single-phase and polyphase adsorption, mainly chemical adsorption. The thermodynamic parameters proved that the adsorption process was spontaneous and endothermic. The mechanistic investigation revealed that the mechanism of the adsorption of Cr (VI) by La-BC may include electrostatic interaction, ligand exchange, or complexation. Moreover, the co-existing anions and regeneration experiments proved that the La-BC is recyclable and has good prospects in the field of chrome-containing wastewater removal.Keywords:wet spinning;lanthanum oxide;biochar;chromate;adsorption
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
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
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2020
·
IF 5.647
Bing Li,Li Zhang,Weizhao Yin,Sihao Lv,Ping Li,Xiangyu Zheng,Jinhua Wu
In this study, nano α-FeOOH (nFeOOH, 100–500 nm) was coated onto activated carbon (nFeOOH@AC) through a dipping means for enhanced Cr(VI) immobilization from drinking water . The nFeOOH@AC significantly improved the Cr(VI) removal from 19.9% (AC control) to 93.4%. XPS spectra and chromium speciation demonstrated that about 90% of adsorbed Cr(VI) was converted to Cr(III) by the nFeOOH@AC, accompanying with a reduction-oxidation of Fe 3+ /Fe 2+ in the nFeOOH matrix due to electrons delivering between AC and surface-bound Cr(VI). The resultant Cr(III) subsequently reacted with Fe(III) to generate stable (Cr χ Fe 1-χ )(OH) 3 precipitates, leading to a much lower Cr(III) release of 7.5% back to solution by the nFeOOH@AC as compared to the AC control of 33.8%, indicating that the nFeOOH@AC had a prospective potential for Cr(VI) immobilization and decreased Cr residue in treated drinking water. Results from column experiment also showed that the nFeOOH@AC afforded a 3.5 times higher capacity for Cr(VI) immobilization and a 3.4 times longer life-span than the pristine AC. Besides, Cr(VI) immobilization by the nFeOOH@AC was a pH-dependent process and the adsorbed Cr on the nFeOOH@AC could be readily desorbed with acetic acid. The disabled nFeOOH@AC could be refreshed by recoating nFeOOH particles with the above dipping method after stripping all the iron oxides with hydrochloric acid . This study demonstrated that nFeOOH coating is an efficient approach to enhance Cr(VI) elimination by AC during drinking water treatments.
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
BIORESOURCE TECHNOLOGY
·
2024
·
IF 9.7
Yuxin Liu,Zhichao Kang,Quanying Wang,Tianye Wang,Ningning Song,Hongwen Yu
Microbial immobilization technology is effective in improving bioremediation efficiency and heavy metal pollution. Herein, Bacillus LD513 with hexavalent chromium (Cr(VI)) tolerance was isolated and immobilized on a novel ferrous disulfide (FeS 2 )/iron nitride (FeN) modified hydrochar (Fe3-SNHC) prepared from waste straws. The prepared Fe3-SNHC-based LD513 (FeLD) significantly improves Cr(VI) adsorption and reduction by 31.4 % and 15.7 %, respectively, compared to LD513 alone. Furthermore, the FeLD composite system demonstrates efficient Cr(VI) removal efficiency and good environmental adaptability under different culture conditions. Microbial metabolism and electrochemical analysis indicate that Fe3-SNHC is an ideal carrier for protecting LD513 activity, promoting extracellular polymer secretion, and reducing oxidative stress . Additionally, the carrier serves as an electron shuttle that accelerates electron transfer and promotes Cr(VI) reduction. Overall, FeLD is an environmentally friendly biocomposite that shows good promise for reducing Cr(VI) contamination in wastewater treatment.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION SCIENCE AND TECHNOLOGY
·
2021
·
IF 2.475
Jiahong Wang,Ruihua Cao,Dengji He,Atif Saleem
Polyethyleneimine modified activated sludge (AS-PEI) was prepared and used for the removal of Cr(VI) in wastewater. Characterized results exhibited that PEI was successfully anchored on the surface of activated sludge. At 25 ºC and pH = 5.0, the maximum adsorption amount of Cr(VI) on AS-PEI was 86.96 mg/g. The adsorption amount of AS-PEI for Cr(VI) decreased as the pH values increased. The existence of Cl-, SO42- and PO43- decreased the Cr(VI) adsorption, and HA enhances the Cr(VI) adsorption. The electrostatic interaction combined reduction was the main mechanism of Cr(VI) adsorption. Cr(VI) loaded adsorbent can be regenerated in alkaline solution and AS-PEI can be reused.
研究领域:
环境科学
·
污水处理
✓ 已验证
产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2013
·Vol. 9
·期 2
·248-255
·
IF 0.797
Jianxian Zeng,Qiannan Guo,Zhenzhong Ou-Yang,Hu Zhou,Huajun Chen
Polyelectrolyte-enhanced ultrafiltration was investigated for the removal of chromium(VI) anion from aqueous solutions with the help of cationic polyquaternium-6 (PQ6). The ultrafiltration behavior of Cr(VI) aqueous solutions was studied at pH 6. Owing to an effect of electrostatic repulsion, the membrane with a molecular weight cutoff (MWCO) of 10 000 Da rejected about 30% of Cr(VI). Then, ultrafiltration of aqueous solutions of a Cr(VI)–PQ6 complex was further studied. Factors affecting Cr(VI) rejection coefficient ( R Cr ) and permeate flux ( J ) such as pH, polymer metal ratio (PMR), the added salts, temperature, operating pressure and MWCO were investigated. The best operating parameters, such as pH 9 and PMR 10, were obtained in order to achieve high R Cr (>0.97). By increasing the concentrations of the added salts (KCl, KNO 3 and K 2 SO 4 ), R Cr was found to decrease significantly. J decreases slightly in the pH range of 2–5. Cl − or SO 4 2− does not affect J , whereas NO 3 − results in the decrease of J . The binding mechanisms of dichromate, chromate and nitrate with PQ6 were proposed. Finally, the concentration experiment was carried out under the optimal conditions. R Cr was close to 1, and J decreases slightly. Chromium was effectively concentrated by the membrane. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL GEOLOGY
·
2019
·
IF 3.618
Jing Liu,Runliang Zhu,Qingze Chen,Huijun Zhou,Xiaoliang Liang,Lingya Ma,Steve C. Parker
Naturally occurring semiconducting metal (oxyhydr)oxides (MeO x ) are ubiquitous geosorbents and geocatalysts, regulating the geochemical behaviors of the chemicals in the environment. The interactions between these MeO x and redox-sensitive elements may involve both the photo-catalytic redox reactions and surface adsorption, and the interplay of the two processes, therefore, makes the interactions rather complex and may have unique environmental effects. The complex interactions between Cr (Cr(III) or Cr(VI)) and hematite under simulated sunlight irradiation were systematically studied under different geochemical conditions (pH, light irradiation, beginning Cr species, etc.). The batch experimentals, X-ray photoelectron spectroscopy (XPS), transmitted electron microscopy (TEM), and energy-dispersive spectroscopy (EDS) were used to determine the concentration and distribution of Cr species (Cr(III), Cr(VI), or the sum of the two) in the aqueous and solid phases. Here we found that both the oxidation of Cr(III) and the reduction of Cr(VI) were accelerated by hematite under sunlight irradiation, resulting in the enhanced immobilization of Cr on hematite. The reduction and oxidation efficiencies were pH-dependent and more evident under acidic condition. In the Cr (III) reaction systems, the reactions can be characterized by (1) the adsorption of aqueous Cr(III) (Cr(III) aq ) to hematite surfaces, (2) the oxidation of adsorbed Cr(III) (Cr(III) ad ) to Cr(VI) ad by the photogenerated holes on hematite, i.e., heterogeneous oxidation, (Bargar et al., 1997) the accumulation of Cr(III) ad on hematite enhanced by Cr(VI) ad , and even the formation of Cr-riched precipitation, which was observed by TEM , and (3) the homogeneous oxidation of Cr(III) aq to Cr(VI) aq by the hydroxyl radicals , generating through interaction between O 2 and the photogenerated electrons (more evident under acidic environment, e.g., pH 3). In the Cr(VI) reaction systems, the reduction of Cr(VI) ad by photogenerated electrons from hematite was also noticeable, with the yielded Cr(III) being fixed on the surfaces. Although the reactions in reduction systems were less extensive than those in the oxidation systems, the reduction reactions would reduce the environmental toxicity of Cr species; while in the oxidation systems, inspite of the higher removal efficiency, the oxidation processes actually increased the environmental risk of Cr. Our results clearly show that hematite could either oxidize Cr(III) or reduce Cr(VI), influencing the speciation and immobilization of Cr under sunlight irradiation. In this term, the natural semiconducting MeO x (e.g., hematite) on Earth's surfaces should play a significant role in affecting the environmental behaviors and toxicities of the redox-sensitive elements (e.g., Cr) through adsorption and photo-catalytic redox processes.
研究领域:
环境科学
·
地球化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Qin Liang,Menghan Zhang,Cai Liang,Huichao Chen
The modified red mud was prepared by thermal reduction with coconut shell for Cr(VI) contaminated soil remediation . Significant reduction of Cr(VI) in soil was achieved for the modified red mud with an efficiency up to 100%. The mass ratio of the modified red mud to soil presents the greatest impact on Cr(VI) reduction in soil, followed by pH, and then the soil moisture. Under the conditions of pH = 4%, and 40% water content, the reduction of Cr(VI) in soil reached 99.37%with 10 wt% of the modified red mud (RM1C-T800(1 h)). Based on the X-ray diffraction spectrum, zero valence iron (ZVI) was detected in RM1C-T800(1 h). The characterization analysis showed that the originally tight and porous surface of RM1C-T800(1 h) became loose and flocculation state after the soil remediation . It implied that internal ZVI particles had recombined with Cr and gradually separated from the parent by exposing to the external surface of RM1C-T800(1 h). The decrease of Cr(VI)in soil was probably attributed to the adsorption and reduction of the ZVI in RM1C-T800(1 h) when mixing the Cr(VI) contaminated soil with RM1C-T800(1 h). The work offers an effective strategy for the resource utilization of solid waste and contaminated site remediation.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）