Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Jieling Ren,Yuanzhe Peng,Aibin Zhu,Chunli Zheng,Chi He,Mudi Ma
Kaolinite-loaded amorphous zero-valent iron composite (K@AZVI) is a promising material for cadmium-contaminated soil remediation. Still, the impact of iron (Fe) oxides on the surface of K@AZVI on the immobilization of cadmium (Cd) in soils caused by varying water management remains unclear. Hence, this study investigated the transformation of Fe oxides in K@AZVI and their effects on Cd morphology under varying soil water management (drying, wetting, and flooding). The results indicated that under K@AZVI treatment, the pe + pH (pe = Eh (oxidation-reduction potential, mV) / 59.2) values decreased from 11.59 to 9.83 and 5.61 with increased soil water management. Meanwhile, the content of crystalline Fe oxides (Fe c ) decreased significantly by 34.02%-72.76%, while the content of amorphous Fe oxides (Fe o ) increased by 29.01%-55.20%. This transformation from crystalline to amorphous Fe oxides significantly enhanced the immobilization of Cd, resulting in a 30.30%-64.59% reduction in the available Cd content compared to the control. In addition, the proportion of low active Cd was enhanced from 32.94% to 56.10%, further indicating that K@AZVI exhibited superior immobilization in flooded soil. Characterization and calculations showed that water management significantly improved the immobilization of Cd by K@AZVI by regulating the crystallinity of Fe oxides and enhancing their electron transfer rate and adsorption capacity. Therefore, investigating the morphological transformation of Fe under varying water management will help us to understand the mechanism of Fe redox-mediated Cd transport and transformation in the soil system.
研究领域:
环境科学
·
土壤学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Maolin Wang,Canyang Hu,Jiahui Xu,Xudong Jing,Hafeez Ur Rahim,Xiyun Cai
Cadmium (Cd) is one of the most toxic substances released in the environment. Cd-contaminated soils usually have a large pool of bioavailable Cd species and lead to excessive Cd accumulation in planted cereal crops. Treatment methods for stable immobilization of Cd in soils are desirable. Here we reported that facile combinations of thiosulfate (STS) and zerovalent iron (ZVI) reinforced Cd immobilization in soils and reduced Cd accumulation in wheat. STS mildly activated Cd in soils through the formation of soluble Cd(S 2 O 3 ) x complexes, whereas intermediates of STS (e.g., sulfate and sulfides) and ZVI synergically facilitated immobilization of Cd in soils. The synergy was ascribed to the facilitated formation of FeOOH with high Cd-binding affinity and formation of stable sulfate-Cd-FeOOH complexes and poorly available CdS x . STS-ZVI treatments increased residual Cd in soils by 101–123% and decreased Cd accumulation in wheat shoots by 13–68%, depending on chemical compositions and doses of binary reagents. Field applications of STS and ZVI (0.06–0.11 kg/m 2 ) demonstrated 24–39% reductions of grain Cd.
研究领域:
环境科学
·
农业科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Gongting Wang,Zedong Teng,Ziyi Wei,Xin Zhao,Wenqing Luo,Yuxin Cheng,Yali Guo,Xiaonan Ji,Wei Hu,Min Li
The serious contamination of cadmium (Cd) in sediments has become an urgent environmental problem. Quinones mediated dissimilatory iron and manganese reduction widely occurs in sediments, this process may enhance Cd immobilization by promoting production of secondary minerals. Nevertheless, the enhancing effect of Cd immobilization is still poorly understood. Here, 9,10-anthraquinone-2,6-disulfonic acid (AQDS) was used to facilitate the microbial reduction of iron and manganese oxides by Geobacter metallireducens GS-15, and its effects on Cd species was investigated. Compared to goethite (FeOOH), microorganisms preferentially reduced birnessite (MnO 2 ) due to more dramatic interfacial electron transfer between birnessite and AQDS. AQDS thus significantly enhanced microbial reduction of iron and manganese coexisted minerals as well as Cd 2+ immobilization. After 80 days, an impressive 83% of reducible-Cd appeared in the FeOOH–MnO 2 -AQDS group, demonstrating the most effective Cd immobilization. Furthermore, XANES results suggested that AQDS promoted the increase of vivianite-Cd in secondary minerals in MnO 2 -AQDS and FeOOH–MnO 2 -AQDS groups. Based on the structural equation model, HCl-extracted Fe(II) indirectly affected the increase of reducible-Cd mainly through vivianite-Cd. The AQDS enhancement on microbial reduction of iron and manganese oxides promotes the recrystallization of secondary minerals and the immobilization of Cd, offering a promising strategy for the remediation of Cd-contaminated sediments.
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 Environmental Sciences
·
2023
·
IF 6.9
Hanbing Meng,Shiwen Hu,Zebin Hong,Wenting Chi,Guojun Chen,Kuan Cheng,Qi Wang,Tongxu Liu,Fangbai Li,Kexue Liu,Yang Yang
Zero-valent iron (ZVI) is a promising material for the remediation of Cd-contaminated paddy soils. However, the effects of ZVI added during flooding or drainage processes on cadmium (Cd) retention remain unclear. Herein, Cd-contaminated paddy soil was incubated for 40 days of flooding and then for 15 days of drainage, and the underlying mechanisms of Cd immobilization coupled with Fe/S/N redox processes were investigated. The addition of ZVI to the flooding process was more conducive to Cd immobilization. Less potential available Cd was detected by adding ZVI before flooding, which may be due to the increase in paddy soil pH and newly formed secondary Fe minerals. Moreover, the reductive dissolution of Fe minerals promoted the release of soil colloids, thereby increasing significantly the surface sites and causing Cd immobilization. Additionally, the addition of ZVI before flooding played a vital role in Cd retention after soil drainage. In contrast, the addition of ZVI in the drainage phase was not conducive to Cd retention, which might be due to the rapid decrease in soil pH that inhibited Cd adsorption and further immobilization on soil surfaces. The findings of this study demonstrated that Cd availability in paddy soil was largely reduced by adding ZVI during the flooding period and provide a novel insight into the mechanisms of ZVI remediation in Cd-contaminated paddy soils.
研究领域:
土壤科学
·
环境修复
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL MANAGEMENT
·
2020
·Vol. 65
·期 6
·818-828
·
IF 2.561
Zhou Changrui,Yuan Haiyan,Ning Chuanchuan,Li Shuailin,Xia Zhuqing,Zhu Mengmeng,Ma Qiang,Yu Wantai
Using amendments is a cost-effective method to soil cadmium (Cd) remediation, whereas knowledge about how different amendments and rates affect remediation efficiency remains limited. This study aimed to evaluate the impacts of different types and amounts of amendments on soil Cd immobilization and its uptake by plants. Biochar (BC), zeolite (ZE), humic acid (HA), superphosphate (SP), lime (L), and sodium sulfide (SS) were applied at three rates (low, medium, and high) ranging from 0.5 to 5%. The concentration of CaCl 2 -extractable Cd was considerably affected by the amendments, except HA, and the high doses achieved better immobilization effects than the low doses did. The addition of amendments decreased weak acid soluble Cd by 4.1–44.0% but slightly increased the fractions of oxidizable and residual Cd. These amendments (except BC and HA dose of 1%) decreased Cd accumulation in grains by 1.3–68.8% and (except SP) in roots by 16.3–65.5% compared with the control. The SP efficiently immobilized Cd but posed a potential soil acidification risk. Moreover, SS treatment increased the soil electrical conductivity (EC) value and restricted the growth of wheat, possibly due to high-salt stress. BC, ZE, and L exerted significant effects on the reduction in available Cd as the application rate increased. These amendments enhanced Cd immobilization mainly by changing Cd availability in soil and influencing its redistribution in different fractions in soil and root uptake by plants. This study concluded that BC-5%, ZE-1%, and L-0.5% can be used for Cd immobilization in acidic or neutral soils.
研究领域:
环境科学
·
农业科学
✓ 已验证
DOI
PubMed
高影响因子
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