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铁硅复合材料固定砷的酸释放特征
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作者 鞠琳 郭湘 +2 位作者 姚爱军 仇荣亮 汤叶涛 《中国环境科学》 EI CAS CSCD 北大核心 2021年第5期2329-2335,共7页
为评估酸化条件下铁硅复合材料(IS)对砷(As)钝化的环境稳定性,以酸滴定法结合X射线衍射分析技术(XRD)对铁硅复合材料固持态砷(IS-As)的酸释放特征开展研究.结果表明,IS具有较强的应对环境酸化的酸缓冲能力;IS-As对酸最为敏感的pH值区间... 为评估酸化条件下铁硅复合材料(IS)对砷(As)钝化的环境稳定性,以酸滴定法结合X射线衍射分析技术(XRD)对铁硅复合材料固持态砷(IS-As)的酸释放特征开展研究.结果表明,IS具有较强的应对环境酸化的酸缓冲能力;IS-As对酸最为敏感的pH值区间介于7.68~11.48,在该区间内随酸的加入,AsO_(4)^(3-)快速溶出,该非酸稳态砷占总As的37.5%;而在pH值7.68~4.10区间,As溶出速率相对缓慢,该弱酸稳态As约占总As的7%.酸化条件下稳定存在、释放微弱的As为酸稳态,该部份约占总As的55.5%.XRD结果表明,在加入H^(+)过程中,铁硅材料主要固砷矿物随pH值由高到低溶解的顺序依次为Ca_(3)(AsO_(4))_(2)>AlAsO_(4)>As_(2)O_(3)>Ca_(4)SiAs_(4)>FeAs_(3)O_(9)·4H_(2)O>Mn_(2)As_(2)O_(7)/SiAs_(2).酸化条件下IS-As元素溶出率依次为S(94.8%)>Na(93.0%)>Ca(78.8%)>As(44.5%)>Mg(41.7%)>Al(37.6%)>Mn(37.5%)>Fe(5.5%).IS-As中主要含砷矿物pH值稳定区间与伴生元素酸溶解特征结果表明,非酸稳态砷主要为钙结合态砷,弱酸稳性As主要为镁、锰、铁弱结合态,酸稳态As主要为铁锰硅强结合态.研究结果为铁硅复合材料修复土壤砷的安全利用风险评估及揭示其修复稳定机理提供了依据,并为土壤砷修复材料选择及形态研究方法方面提供新的参考. 展开更多
关键词 铁硅复合材料 酸稳定性 土壤
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Fabrication of Z-type barium ferrite/silica composites with enhanced microwave absorption
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作者 SHEN JunHai CHEN KeYu +3 位作者 LI LiangChao DING Yan LI JuanBi KONG WeiQiu 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第9期1858-1864,共7页
The Z-type barium ferrite/silica composites(Z-BCF/SiO2)were fabricated by in situ chemical synthesis method.The composition,structure,morphology and magnetic behavior of the composites were characterized by chemical a... The Z-type barium ferrite/silica composites(Z-BCF/SiO2)were fabricated by in situ chemical synthesis method.The composition,structure,morphology and magnetic behavior of the composites were characterized by chemical analysis,IR,XRD,SEM,TEM and VSM.The results indicated that there were some interactions between two components in the Z-BCF/SiO2 composites due to the coating of SiO2 on the Z-BCF particles.The magnetic properties of the Z-BCF/SiO2 composites were evidently less than that of the Z-BCF,owing to the small volume fraction of magnetic components in the samples.Due to the good transmission and loss properties on electromagnetic waves,the composites were better at microwave absorption than the parent component.Therefore,this research laid a foundation for the fabrication of highly efficient microwave absorbing material with enhanced wave impedance matching. 展开更多
关键词 barium ferrite SILICA COMPOSITES microwave absorption performance
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