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The coupling of sand with ZVI/oxidants achieved proportional and highly efficient removal of arsenic

Sana Ullah, Xuejun Guo, Xiaoyan Luo, Xiangyuan Zhang, Yameng Li, Ziyu Liang

《环境科学与工程前沿（英文）》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1273-6

摘要： Abstract • Simply doping sands with ZVI achieved an even activation of ZVI by oxidants. • Sand doping facilitated proportional As trapping along the ZVI/oxidants column. • ZVI/sand/oxidants are highly efficient for arsenic removal. • ZVI/sand/oxidants reduced significantly the Fe2+ leaching and effluent turbidity. • More than 54% of arsenic was reduced to As(III) in ZVI/sand/oxidants system. The coupling of zero-valent iron (ZVI) with common oxidants has recently achieved very rapid and highly efficient removal of Heavy metals from wastewater. However, the uniform activation of ZVI throughout the column and the proportional removal of target contaminants are urgently required for the prevention of premature filter clogging and the extension of the effective column operational time. In this study, we successfully achieved this objective by simply doping granular sand with ZVI at appropriate weight ratios. When pure ZVI packed column was spiked with oxidants, the majority of As trapping occurred between the column inlet and the first sampling point. In a packed column with a 1:20 mixture of ZVI and sand, the average As removal efficiency was 36 (1st), 13.1 (2nd), 18.5 (3rd), 19.2 (4th) and 5.9% (5th outlet). The overall arsenic removal performance of the composite filling system of ZVI/sand was equally as efficient as that of the previous pure ZVI-packed system. Moreover, the leaching of Fe was significantly reduced with an increased sand ratio, resulting in clearer water with less turbidity. The results of X-ray photoelectron spectroscopy (XPS) demonstrated that more than 54% of the arsenic was reduced to As(III). X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the extensive corrosion of the ZVI surface, which resulted in various species of iron oxyhydroxides responsible for the highly efficient sequester of arsenic through reduction, adsorption, and coprecipitation.

关键词： Arsenic     ZVI     Sand     Oxidants     Fixed-bed Column     Removal    

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Zero-valent manganese nanoparticles coupled with different strong oxidants for thallium removal from

Keke Li, Huosheng Li, Tangfu Xiao, Gaosheng Zhang, Aiping Liang, Ping Zhang, Lianhua Lin, Zexin Chen, Xinyu Cao, Jianyou Long

《环境科学与工程前沿（英文）》 2020年 第14卷 第2期 doi: 10.1007/s11783-019-1213-5

摘要： • Nano zero-valent manganese (nZVMn, Mn0) is synthesized via borohydrides reduction. • Mn0 combined with persulfate/hypochlorite is effective for Tl removal at pH 6-12. • Mn0 can activate persulfate to form hydroxyl and sulfate radicals. • Oxidation-induced precipitation and surface complexation contribute to Tl removal. • Combined Mn0-oxidants process is promising in the environmental field. Nano zero-valent manganese (nZVMn, Mn0) was prepared through a borohydride reduction method and coupled with different oxidants (persulfate (S2O82−), hypochlorite (ClO−), or hydrogen peroxide (H2O2)) to remove thallium (Tl) from wastewater. The surface of Mn0 was readily oxidized to form a core-shell composite (MnOx@Mn0), which consists of Mn0 as the inner core and MnOx (MnO, Mn2O3, and Mn3O4) as the outer layer. When Mn0 was added alone, effective Tl(I) removal was achieved at high pH levels (>12). The Mn0-H2O2 system was only effective in Tl(I) removal at high pH (>12), while the Mn0-S2O82− or Mn0-ClO− system had excellent Tl(I) removal (>96%) over a broad pH range (4–12). The Mn0-S2O82− oxidation system provided the best resistance to interference from an external organic matrix. The isotherm of Tl(I) removal through the Mn0-S2O82− system followed the Freundlich model. The Mn0 nanomaterials can activate persulfate to produce sulfate radicals and hydroxyl radicals. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggested that oxidation-induced precipitation, surface adsorption, and electrostatic attraction are the main mechanisms for Tl(I) removal resulting from the combination of Mn0 and oxidants. Mn0 coupled with S2O82−/ClO− is a novel and effective technique for Tl(I) removal, and its application in other fields is worthy of further investigation.

关键词： Nano zero-valent manganese     Thallium     Adsorption     Oxidation     Sulfate radical     Hydroxyl radical    

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Rapid and long-effective removal of broad-spectrum pollutants from aqueous system by ZVI/oxidants

Sana Ullah, Xuejun Guo, Xiaoyan Luo, Xiangyuan Zhang, Siwen Leng, Na Ma, Palwasha Faiz

《环境科学与工程前沿（英文）》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1268-3

摘要： Abstract • The coupling of oxidants with ZVI overcome the impedance of ZVI passive layer. • ZVI/oxidants system achieved fast and long-effective removal of contaminants. • Multiple mechanisms are involved in contaminants removal by ZVI/oxidant system. • ZVI/Oxidants did not change the reducing property of ORP in the fixed-bed system. Zero-valent iron (ZVI) technology has recently gained significant interest in the efficient sequestration of a wide variety of contaminants. However, surface passivation of ZVI because of its intrinsic passive layer would lead to the inferior reactivity of ZVI and its lower efficacy in contaminant removal. Therefore, to activate the ZVI surface cheaply, continuously, and efficiently is an important challenge that ZVI technology must overcome before its wide-scale application. To date, several physical and chemical approaches have been extensively applied to increase the reactivity of the ZVI surface toward the elimination of broad-spectrum pollutants. Nevertheless, these techniques have several limitations such as low efficacy, narrow working pH, eco-toxicity, and high installation cost. The objective of this mini-review paper is to identify the critical role of oxygen in determining the reactivity of ZVI toward contaminant removal. Subsequently, the effect of three typical oxidants (H2O2, KMnO4, and NaClO) on broad-spectrum contaminants removal by ZVI has been documented and discussed. The reaction mechanism and sequestration efficacies of the ZVI/oxidant system were evaluated and reviewed. The technical basis of the ZVI/oxidant approach is based on the half-reaction of the cathodic reduction of the oxidants. The oxidants commonly used in the water treatment industry, i.e., NaClO, O3, and H2O2, can be served as an ideal coupling electron receptor. With the combination of these oxidants, the surface corrosion of ZVI can be continuously driven. The ZVI/oxidants technology has been compared with other conventional technologies and conclusions have been drawn.

关键词： Zero-Valent Iron (ZVI)     Oxidants     Heavy Metals (HMs)     Metalloids     Nitrate     Phosphate    

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Rapid control of black and odorous substances from heavily-polluted sediment by oxidation: Efficiency and effects

Kun Li, Min Yang, Jianfeng Peng, Ruiping Liu, Tista Prasai Joshi, Yaohui Bai, Huijuan Liu

《环境科学与工程前沿（英文）》 2019年 第13卷 第6期 doi: 10.1007/s11783-019-1171-y

摘要： Oxidants were proposed to rapidly control black and odorous substances in sediments. NaClO and KMnO4 had excellent efficiency to remove black and odorous substances. NaClO dramatically accelerated the release of organics, NH4+-N, P, and heavy-metals. Moderate oxidation had a limited effect on microbial communities. NaClO of 0.2 mmol/g was viewed to be the optimum option. The control of black and odorous substances in sediments is of crucial importance to improve the urban ecological landscape and to restore water environments accordingly. In this study, chemical oxidation by the oxidants NaClO, H2O2, and KMnO4 was proposed to achieve rapid control of black and odorous substances in heavily-polluted sediments. Results indicate that NaClO and KMnO4 are effective at removing Fe(II) and acid volatile sulfides. The removal efficiencies of Fe(II) and AVS were determined to be 45.2%, 94.1%, and 93.7%, 89.5% after 24-h exposure to NaClO and KMnO4 at 0.2 mmol/g, respectively. Additionally, rapid oxidation might accelerate the release of pollutants from sediment. The release of organic matters and phosphorus with the maximum ratios of 22.1% and 51.2% was observed upon NaClO oxidation at 0.4 mmol/g. Moreover, the introduction of oxidants contributed to changes in the microbial community composition in sediment. After oxidation by NaClO and KMnO4 at 0.4 mmol/g, the Shannon index decreased from 6.72 to 5.19 and 4.95, whereas the OTU numbers decreased from 2904 to 1677 and 1553, respectively. Comparatively, H2O2 showed a lower effect on the removal of black and odorous substances, pollutant release, and changes in sediment microorganisms. This study illustrates the effects of oxidant addition on the characteristics of heavily polluted sediments and shows that chemical oxidants may be an option to achieve rapid control of black and odorous substances prior to remediation of water environments.

关键词： Oxidants     Heavily polluted sediment     Black and odorous substances     Release behaviors     Microorganism    

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标题 作者 时间 类型 操作

The coupling of sand with ZVI/oxidants achieved proportional and highly efficient removal of arsenic

Sana Ullah, Xuejun Guo, Xiaoyan Luo, Xiangyuan Zhang, Yameng Li, Ziyu Liang

期刊论文

Zero-valent manganese nanoparticles coupled with different strong oxidants for thallium removal from

Keke Li, Huosheng Li, Tangfu Xiao, Gaosheng Zhang, Aiping Liang, Ping Zhang, Lianhua Lin, Zexin Chen, Xinyu Cao, Jianyou Long

期刊论文

Rapid and long-effective removal of broad-spectrum pollutants from aqueous system by ZVI/oxidants

Sana Ullah, Xuejun Guo, Xiaoyan Luo, Xiangyuan Zhang, Siwen Leng, Na Ma, Palwasha Faiz

期刊论文

Rapid control of black and odorous substances from heavily-polluted sediment by oxidation: Efficiency and effects

Kun Li, Min Yang, Jianfeng Peng, Ruiping Liu, Tista Prasai Joshi, Yaohui Bai, Huijuan Liu

期刊论文