CHEMICAL GEOLOGY
·
2017
·
IF 3.347
Yingying Xie,Guining Lu,Han Ye,Chengfang Yang,Di Xia,Xiaoyun Yi,John Reinfelder,Zhi Dang
The cycling of Fe and Cr is intimately linked to the fate of schwertmannite in acid mine drainage (AMD) and acid sulfate soil (ASS) environments. Dissolved organic matter (DOM) can affect the stability of minerals and speciation, mobility and toxicity of heavy metals via redox reactions and complexation. However, knowledge about the fate of Fe and Cr upon reduction and complexation of CrO 4 2 − -substituted schwertmannite by fulvic acid (FA) is poorly understood. In this study, experiments were devised to investigate the interaction between FA and schwertmannite, with major degeneration of the schwertmannite structure as well as the formation of secondary minerals. For CrO 4 2 − -substituted schwertmannite, results indicated that the concentrations of total Fe and Cr in the solution were determined to be the maximum values at 360 h and 96 h, and then decreasing over the reaction time when FA was 10 mg/L at pH of 6.5. The characterization on the solid phase by X-ray diffraction, scanning electron microscopy and X-ray photo electron spectroscopy technologies revealed that goethite was the dominant newly secondary mineral phases which played a vital role in controlling the fate and transport of Fe and Cr. The possible mechanism was proposed to be synergistic effect including ligand-promoted and reduction. This study provides new insights into the understanding of trace element behavior in environments affected by DOM and also has guiding significance for Cr-contaminant remediation.
研究领域:
环境科学
·
土壤学
✓ 已验证
产品关联
DOI
高影响因子
ACS Earth and Space Chemistry
·
2019
·
IF 2.243
Zhipeng Shu,Lihu Liu,Guohong Qiu,Xiong Yang,Mingzhe Zhang,Wenfeng Tan,Chengshuai Liu,Fei Wu
The formation and transformation of schwertmannite affect the migration, conversion, and toxicity of chromium (Cr) in soils and sediments. Schwertmannite could be obtained from the oxidation of Fe(II) by hydroxyl radicals (OH•) and superoxide radicals (O2•–) generated from the photolysis of NO3– under acidic and sulfate-rich conditions. As one of the most abundant components, montmorillonite is widely distributed in soils and sediments. However, the effect of montmorillonite on the photochemical formation process and corresponding Cr adsorption behaviors of schwertmannite remains elusive. This study indicates that schwertmannite could be formed on the montmorillonite surface during the photocatalytic oxidation of dissolved Fe(II). The formation rate, particle size, and crystallinity degree of schwertmannite formed on montmorillonite surface increased with increasing FeSO4 concentration (1.0–5.0 mmol L–1). The presence of montmorillonite led to a decrease in the particle size of schwertmannite. When the initial concentration of Fe(II) was 5.0 mmol L–1, the specific surface area of schwertmannite–montmorillonite aggregates reached 243.3 m2 g–1, which was remarkably larger than that of single-phase schwertmannite (24.6 m2 g–1) and montmorillonite (138.1 m2 g–1). The schwertmannite–montmorillonite aggregates showed a higher adsorption capacity for Cr(VI) (97.4 mg Cr g–1 Fe) than single-phase schwertmannite (72.9 mg Cr g–1 Fe). This work reveals the possible formation pathway and Cr adsorption behavior of schwertmannite on the surface of montmorillonite in waters and soils.
研究领域:
环境科学
·
地球化学
·
土壤学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 35
·21638-21648
·
IF 3.108
Xiaoqing Meng,Su Yan,Wenzhu Wu,Guanyu Zheng,Lixiang Zhou
Heterogeneous Fenton-like degradation of phenanthrene in aqueous solution was investigated using schwertmannite biosynthesized by Acidithiobacillus ferrooxidans LX5 as a catalyst. The effects of different reaction parameters including catalyst loading, H2O2 concentration, initial solution pH and inorganic anions on the Fenton-like degradation of phenanthrene were studied. Results showed that the biosynthesized schwertmannite had an effective catalytic ability on phenanthrene degradation. The degradation efficiency of phenanthrene was 99.0% within 3–5 h reaction under conditions of H2O2 200 mg L−1, schwertmannite 1 g L−1, phenanthrene 1 mg L−1 and pH 3.0–4.5. The degradation was mainly via a surface mechanism, in which phenanthrene was readily adsorbed on the surface of schwertmannite and then oxidized by ˙OH produced from H2O2 decomposition. The XPS results of schwertmannite before and after Fenton-like degradation of phenanthrene revealed the change of Fe2+/Fe3+ species on the surface of schwertmannite. Moreover, phthalates, octadecanoic acid and 9,10-phenanthraquinone were identified by GC-MS analyses as the main intermediate compounds during phenanthrene degradation, and all the intermediates were finally mineralized. The repeated use of biosynthesized schwertmannite for phenanthrene degradation illustrated its stability and reusability as a Fenton-like catalyst. Therefore, schwertmannite biosynthesized using A. ferrooxidans is an excellent catalyst for the degradation of phenanthrene in heterogeneous Fenton-like reactions.
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
JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Xiang Li,Yongkui Zhang,Yi Xie,Yu Zeng,Panyu Li,Tonghui Xie,Yabo Wang
Schwertmannite (Sch) was synthesized by Acidithiobacillus ferrooxidans and used as Fenton-like catalyst for bisphenol A (BPA) degradation combining with ultrasonic technology (US). Physicochemical characterizations showed that the bio-synthesized Sch particles had a pompon-like morphology with high BET surface area of 92.92 m 2 /g. The degradation reaction showed a two-stage pseudo-first-order kinetic process consisting of an induction period and a followed rapid degradation period. A synergistic effect existed between US and Sch on activating H 2 O 2 and the synergy factor was calculated to be 2.32. The catalytic efficiency of the system was mainly affected by pH, Sch dosage and temperature, but less relevant to H 2 O 2 concentration. Free OH radicals in the bulk solution were identified to be the dominant oxidant, which were produced by both heterogeneous and homogeneous processes. The promotional effect of US on Fenton-like degradation of BPA can be ascribed to the reasons of (1) increasing the radical generation by ultrasonic cavitation; (2) reducing the apparent activation energies of degradation reaction; (3) accelerating the dissolution of iron and (4) keeping the high surface area of catalyst by continuous surface cleaning. Ecotoxicity tests indicated lower toxicities of intermediates than BPA. In addition, Sch exhibited high reusability in the recycle study.
研究领域:
环境科学
·
生物化学
✓ 已验证
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Su Yan,Lingling Zhan,Xiaoqing Meng,Dianzhan Wang,Xiaomeng Wang,Guanyu Zheng,Junhe Lu,Lixiang Zhou
Ultraviolet (UV)/peroxydisulfate (PDS) system has been employed for degrading organic pollutants in water, but the insufficient production of reactive species in the system limits the mineralization of organic pollutants. This study evaluated for the first time the effectiveness of integrating iron hydroxysulfates, including schwertmannite (Sch) and jarosite (Jar), with UV/PDS system for sulfamethoxazole (SMX) degradation in water. The optimal conditions identified for 40 μM SMX degradation were PDS 2 mM, photocatalysts 1 g L -1 and pH 3 in both of Sch/UV/PDS and Jar/UV/PDS systems. A synergetic effect between UV/PDS and Sch/UV processes was found in Sch/UV/PDS system with synergistic factor of 1.15, which drastically enhanced the production of reactive species ( OH and SO 4 •- ) and consequently improved SMX degradation and TOC mineralization. Additionally, schwertmannite exhibited higher photocatalytic activity than jarosite in UV/PDS system for both SMX degradation and TOC mineralization. In Sch/UV/PDS system, ≡Fe(OH) 2+ on schwertmannite can be efficiently photolyzed to ≡Fe 2+ and OH under UV irradiation with O 2 – generation, in which the produced reactive species contributed to a relatively small fraction of SMX degradation. More importantly, the regeneration of ≡Fe 2+ accelerated PDS activation to SO 4 •- / OH, which was responsible for the degradation of most SMX. However, the photoreduction of ≡Fe 3+ to ≡Fe 2+ on jarosite by UV irradiation was insignificant, thus leading to the poor PDS activation to SO 4 •- / OH and a lower SMX degradation rate. The degradation pathways of SMX in Sch/UV/PDS system were further proposed based on the identified degradation intermediates of SMX. Besides, schwertmannite exhibited a good adaptability in wide pH (2–9) range, good stability, and recyclability for catalyzing SMX degradation in UV/PDS system. Therefore, integrating schwertmannite with UV/PDS system is an attractive method for efficiently removing organic pollutants in water.
研究领域:
环境科学
·
水处理技术
✓ 已验证
DOI
高影响因子
Journal of Industrial Textiles
·
2022
·
IF 2.926
Jing Han,Hai-Tao Ren,Ting-Ting Li,Bing-Chiuan Shiu,Yong-Gui Li,Jia-Horng Lin,Ching-Wen Lou
Visible light response PAN@Ag-Ag2O/Sch (PAN@AS, schwertmannite and polyacrylonitrile abbreviated as Sch and PAN) nanofibers with different mass ratios were synthesized by electrospinning technology and pH-induced precipitation reaction. X-Ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy analysis showed that the formation of Ag-Ag2O/Sch heterojunction and Ag-Ag2O nanoparticles were evenly distributed on the surface of Sch. The prepared nanofibers have high oxidative removal performance for As(III) under visible light. In the PAN@AS0.10 system, the total As removal percent can reach 90.96% after 120 min irradiation at pH 4.0. The scavenger experiments confirmed that the main active substances of the PAN@AS0.10 system were h+ and •OH. The high oxidation and removal performance of the PAN@AS0.10 composite for As(III) was attributed to the effective separation of photogenerated electron-hole pairs and high adsorption capacity of Sch for As under acidic conditions. This research provides a new material for the oxidation and removal of pollutants in water [such as As(III)] and also provides a research basis for the preparation of recyclable photocatalysts.
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
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Yingying Xie,Han Ye,Zhen Wen,Zhi Dang,Guining Lu
The cycling of Fe/S is often related to the formation and fate of schwertmannite which is particularly suitable as a scavenger for heavy metals and metalloids in acid mine drainage (AMD). However, the interactions between reactivity of S(-II) and schwertmannite with structurally incorporated Cr(VI) remain elusive. This work evaluated dissolution experiments in combination with XRD, SEM, FTIR, TEM, and XPS characterization to provide detailed information regarding the transformation of schwertmannite induced by S(-II) following changes in pH, Cr loading, and S(-II) concentration. Our results found that the presence of sulfide significantly decreased the stabilization of schwertmannite under acidic conditions. The reactivity of the three schwertmannite samples depended on the contents of Cr(VI) that were structurally incorporated and followed the order Sch > 0.13Cr-Sch > 0.17Cr-Sch. High S(-II) concentrations and low Cr doping favored the release of Fe and SO 4 2− from schwertmannite. Attenuation of Cr mobility occurred via elevating the S(-II) concentrations and pH values resulting in Cr concentrations spanning ∼1.39 to ∼0.10 mg L −1 and ∼1.58 to ∼0.12 mg L −1 for 0.13Cr-Sch and 0.17Cr-Sch, respectively. Combining the results of characterization, goethite was the dominant end product constituted secondary phase together with sulfide minerals (FeS, FeS 2 ), iron oxides (Fe 3 O 4 , Fe 2 O 3 ), and Cr Fe minerals on the bulk mineral surface. The substituted Cr significantly inhibited the reductive transformation of schwertmannite by sulfide and led to the formation of lepidocrocite. Thus, we concluded that a three-stage transformation mechanistic pathway governed partial conversion of schwertmannite to goethite. This finding provides new understanding of the biogeochemical processes of iron minerals affected by reducing substances that control the transport and fate of immobilizing contaminants in an AMD-polluted area.
研究领域:
环境科学
·
地球化学
✓ 已验证
DOI
PubMed
高影响因子
Processes
·
2026
·Vol. 14
·期 8
·1258
·
IF 3.4
Guiping Liao,Hongmei Tang,Jiayan Wu,Quanyun Ye,Yihao Li,Zhongbo Shang,Leiye Sun,Pingxiao Wu
Schwertmannite (Sch) is a widespread iron oxyhydroxysulfate mineral in acid mine drainage (AMD) systems, and its transformation strongly influences the environmental fate of chromium (Cr). However, the role of Ca(II), which is commonly introduced during alkaline neutralization of AMD, in regulating the transformation of Cr(VI)-adsorbed schwertmannite (Cr-Sch) and subsequent Cr redistribution remains insufficiently understood. In this study, transformation experiments were conducted under various pH conditions (3.0, 7.0, and 10.0) to investigate the effects of Ca(II) speciation on mineral transformation and Cr behavior. The results demonstrated that the transformation of Cr-Sch was predominantly pH-dependent. Under acidic conditions, Cr-Sch transformed into goethite via dissolution–recrystallization, resulting in transient Cr release followed by partial refixation. The presence of Ca(II) exerted only a minor influence due to weak interactions between Ca2+and positively charged mineral surfaces. Under alkaline conditions, Cr-Sch preferentially transformed into hematite through dehydroxylation and cation rearrangement, leading to the sustained release of adsorbed Cr(VI). In contrast, Ca(II) predominantly precipitated as CaCO3precipitate (calcite, aragonite, and vaterite) under alkaline conditions, which coated mineral surfaces and inhibited phase transformation and Cr release. These findings reveal that Ca(II) regulates Cr redistribution primarily through pH-dependent speciation and mineral–surface interactions, highlighting coupled geochemical processes governing iron mineral transformation and contaminant mobility in AMD environments. This study provides mechanistic insights for predicting Cr behavior and optimizing alkaline remediation strategies in mining-impacted systems.
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2020
·
IF 4.302
Ting Li,Jianru Liang,Lixiang Zhou
Here we reported an effective method to solve the rate-limiting steps, such as the reduction of Fe 3+ to Fe 2+ and an invalid decomposition of H 2 O 2 in a conventional Fenton-like reaction. A magnetic heterogeneous photocatalyst, Fe 3 O 4 -schwertmannite (Fe 3 O 4 -sch) was successfully developed by adding Fe 3 O 4 in the formation process of schwertmannite . Fe 3 O 4 -sch shows excellent electrons transfer ability and high utilization efficiency of H 2 O 2 (98.5%). The catalytic activity of Fe 3 O 4 -sch was studied through the degradation of phenol in the heterogeneous photo-Fenton process. Phenol degradation at a wide pH (3 - 9) was up to 98% within 6 min under visible light illumination with the Fe 3 O 4 -sch as heterogeneous Fenton catalyst, which was higher than that using pure schwertmannite or Fe 3 O 4 . The excellent photocatalytic performance of Fe 3 O 4 -sch is ascribed to the effective recycling between Fe 3+ and Fe 2+ by the photo-generated electron, and also profit from the formation of the “Z-Scheme” system. According to the relevant data, photocatalytic mechanism of Fe 3 O 4 -sch for degrading phenol was proposed. This study not only provides an efficient way of enhancing heterogeneous Fenton reaction , but also gives potential application for iron oxyhydroxysulfate mineral.
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 MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Qian Li,Zhen Zeng,Lei Huang,Sijie Zhao,Jia Yan,Xiaoyu Zhao,Zhenxin Chen,Hongguo Zhang
Due to fluoride pollution in the global water, the development of economical and efficient adsorption materials is urgent. In this study, schwertmannite were successfully synthesized by a low-cost chemical method, and the complex mechanism of fluoride adsorption process was analyzed in depth by combining experiments and theoretical calculations. The fluffy cauliflower-like morphology contributed to increasing the specific surface area of adsorbent (193.4 m 2 /g) and exposing active sites. The effect of pH on the adsorption process was discussed in conjunction with density functional theory. The experiment found that higher temperature improved fluoride removal, best performance at 318 K with 40.5 mg/g. In addition, fitting results showed that the Langmuir and pseudo-second-order models could better describe the adsorption behavior. Coexisting anions and adsorption regeneration experiments demonstrated the high selectivity and reusability of schwertmannite. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to determine the mechanism of adsorption and fluoride removal. Combined with theoretical calculations, three adsorption configurations and the corresponding binding energies were obtained. The stability of different adsorption modes specifically showed OH-F > SO 4 -HF > OH-HF. Density of states analysis revealed the formation of resonance peaks and stable bonding interactions, further confirming the chemical adsorption mechanism. It provides the foundation for future industrial applications by using schwertmannite to deal with fluoride.
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
ENVIRONMENTAL RESEARCH
·
2023
·
IF 8.3
Yujie Li,Jia Wang,Chao Liu,Long Wang,Peng Zhang,Qianyu Zhao,Zhu Xiong,Gaosheng Zhang,Wei Zhang
Schwertmannite (SCH) is a promising material for adsorbing inorganic arsenic (As). We synthesized SCH nanoparticles (nano-SCH) via a modified chemical oxidation method and investigated the application of nano-SCH for the remediation of As-contaminated soils. The production of nano-SCH was successfully prepared using the persulfate oxidation method with carboxymethyl cellulose stabilization. The spherical structure of the nano-SCH particles had an average hydrodynamic diameter of 296 nm with high specific surface areas (108.9 m 2 /g). Compared with SCH synthesized via the H 2 O 2 oxidation method, the percentage of Fe 3+ precipitation in nano-SCH synthesis increased from 63.2% to 84.1%. The inorganic As adsorption capacity of nano-SCH improved by 2.27 times at solution pH = 6. After remediation of heavily As-contaminated soils by using 5% nano-SCH, the leachability of inorganic As rapidly decreased to 0.01% in 30 d. Correspondingly, the immobilization efficiencies of inorganic As in soil reached >99.9%. The inorganic As fractions in treated soil shifted from specifically and nonspecifically bound forms to amorphous and crystalline hydrous oxide-bound fractions. After treatment with 5% nano-SCH for 60 d, soil pH slightly decreased from 5.47 to 4.94; by contrast, soil organic matter content increased by 20.9%. Simultaneously, dehydrogenase concentration in soil decreased by 22.4%–34.7% during the remediation process. These changes in soil properties and As immobilization jointly decreased microbial activity and initiated the re-establishment of bacterial communities in the soil. In summary, this study presents a novel and high-productivity technology for nano-SCH synthesis and confirms the high As immobilization effectiveness of nano-SCH in the remediation of As-contaminated soils.
研究领域:
环境科学
·
土壤学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Hongmei Tang,Meiqing Chen,Pingxiao Wu,Yihao Li,Tianming Wang,Jiayan Wu,Leiye Sun,Zhongbo Shang
Schwertmannite (Sch) is considered as an effective remover of Chromium (Cr) due to its strong affinity for toxic Cr species. Since the instability of Sch, the environmental fate of Cr deserves attention during the transformation of Sch into a more stable crystalline phase. The ubiquitous manganese(II) (Mn(II)) probably affects the transformation of Sch and thus the environmental fate of Cr. Therefore, this study investigated the impact of Mn(II) on the transformation of Cr-absorbed Sch (Cr-Sch) and the associated behavior of SO 4 2− and Cr. We revealed that the transformation products of Cr-Sch at pH 3.0 and 7.0 were goethite and Sch, respectively. The presence of Mn(II) weakened the crystallinity of the transformation products, and the trend was positively correlated with the concentration of Mn(II). However, Mn(II) changed the transformation products of Cr-Sch from hematite to goethite at pH 10.0. Mn(II) replaced Fe(III) in the mineral structures or formed Mn-O complexes with surface hydroxyl groups (-OH), thereby affecting the transformation pathways of Sch. The presence of Mn(II) enhanced the immobilization of Cr on minerals at pH 3.0 and 7.0. Sch is likely to provide an channel for electron transfer between Mn(II) and Cr(VI), which promotes the reduction of Cr(VI). Meanwhile, Mn(Ⅱ) induced more -OH production on the surface of secondary minerals, which played an important role in increasing the Cr fixation. In addition, part of the Mn(Ⅱ) was oxidized to Mn(Ⅲ)/Mn(Ⅳ) at pH 3.0 and pH 7.0. This study helps to predict the role of Mn(II) in the transformations of Cr-Sch in environments and design remediation strategies for Cr contamination.
研究领域:
环境科学
·
矿物学
✓ 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）