In situ formation of Ca(OH)(2) coating shell to extend the longevity of zero-valent iron biochar composite derived from Fe-rich sludge for aqueous phosphorus removal

文献类型: 外文期刊

第一作者: Zhang, Qi

作者: Zhang, Qi;Li, Jun;Zhang, Qi;Chen, De;Xiao, Wendan;Zhao, Shouping;Ye, Xuezhu;Zhang, Qi;Chen, De;Xiao, Wendan;Zhao, Shouping;Ye, Xuezhu;Zhang, Qi;Chen, De;Xiao, Wendan;Zhao, Shouping;Ye, Xuezhu;Li, Hui;Li, Hui

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关键词: Zero valent iron biochar composite; Fe/C micro-electrolysis; Ca(OH)(2) coating shell; phosphorus removal; longevity

期刊名称:SCIENCE OF THE TOTAL ENVIRONMENT ( 影响因子:10.753; 五年影响因子:10.237 )

ISSN: 0048-9697

年卷期: 2023 年 854 卷

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收录情况: SCI

摘要: Despite being an effective and attractive functional strategy for aqueous phosphorus (P) removal, the use of zero valent iron (ZVI) biochar composites has been severely impeded by rapid self-erosion. We describe a new approach for extending the lifespan of Fe-rich sludge-derived ZVI biochar composites via CaCl2 modification. Preliminary results showed that composites obtained at 900 degrees C without modification (MBC900) and at 900 degrees C with 100 g Cl/kg addition (MBC900(100)) had the highest P removal efficiency. In subsequent batch experiments, MBC900(100) exhibited more stable P adsorption capacities than MBC900 over a wide pH range (4-10) and at various dosages, which was enhanced by the presence of HCO3-. The theoretical maximum P adsorption capacities of MBC900 and MBC900(100) were 227.14 and 224.15 mg g(-1), respectively. Kinetic analysis indicated that chemisorption dominated the removal process. Continuous experimental data using the Yoon-Nelson model indicated that MBC900(100) had a considerably longer half-penetration time. The primary mechanism of P removal by MBC900 was Fe/C micro-electrolysis. As the embedded CaO formed a dissolvable Ca(OH)(2) shell in situ on the surface of MBC900(100), the phosphate formed a precipitate with free Ca2+ before being removed via micro-electrolysis. Overall, CaCl2 modification successfully enhanced the longevity of the ZVI biochar composites.

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