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针铁矿及其前体吸附亚砷酸根离子的反应及预处理方法的影响 总被引:5,自引:1,他引:5
观察了针铁矿及其前体对溶液中亚砷酸根离子的吸附过程和吸附性能。3种吸附剂分别为氢氧化铁凝胶、经微波真空干燥的凝胶和80℃烘干的凝胶,它们均转变成了针铁矿。氢氧化铁凝胶与亚砷酸钠溶液混和后,溶液的pH值在6min内从9.71上升到10.36,原因是亚砷酸根离子置换了针铁矿和氢氧化铁中的氢氧根;40min后开始持续下降,和亚砷酸根离子与吸附剂之间的缩合反应有关。pH值的转折点并不意味着吸附反应的结束,但代表了反应类型的转变。这两种类型的反应受温度和气体溶解组分的影响不大。吸附剂经超声波处理后,改善了其在介质中的分散性,吸附效率因此普遍提高,但也造成了固体微粒难以分离的问题。经真空微波处理的凝胶对砷阴离子的吸附率优于另外两种吸附剂,去除率分别提高了53.18%和17.22%。其主要原因可能是凝胶中的水分子在微波辐射场作用下的高频振动,使其内部在干燥脱水过程中保持了较高的孔隙度;此外,吸附剂的表面活性在微波处理过程中亦有可能得到了改善。 相似文献
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Zhanjun YANG Yuegang TANG Xiao ZHENG Juanjuan LI Weilong HAN Shuting YANG 《中国地球化学学报》2006,25(B08):50-50
Since 1976 high arsenic coal in Xingren County, Guizhou Province, has attracted more and more attention because of coal-burning-type arsenic poisoning, There are many studies on enrichment of arsenic in high-arsenic coal and they come from difference materials: organic matter, authigenic pyrite, epigenetic pyrite, authigenic clay mineral and epigenetic clay mineral. In this paper, fourteen samples were examined by proximate analysis. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the trace element contents of thirty-six samples in high-arsenic coal, As was determined by instrumental neutron activation analysis (INAA) and atomic fluorescence spectrometry (AFS). SEM-EDX was used to analyze the contents of As, Sb, Tl and Se in sample XR-8 from Xingren, Guizhou, and we analyzed the petrographic compositions of the same sample. 相似文献
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Chaoyang WEI 《中国地球化学学报》2006,25(B08):83-83
Municipal solid waste incinerator (MSWI) fly ash is world-widely defined as hazardous waste because of its high concentration of heavy metals and high toxic equivalents of dioxin-like compounds. Therefore, if not properly disposed, it would pose a risk of being released into the environment including soil and groundwater. Heavy metals in the MSWI fly ash are considered as the most dangerous component owing to their leaching characteristics and migration capability. To get a better knowledge of their releasing behavior, it is important to assess the potential environmental mobility of heavy metals in MSWI fly ash and to investigate the factors affecting their leaching characteristics. Fly ashes from four MSW incinerators were characterized and leaching of heavy metals according to both Chinese HVEP and USA TCLP were performed. A geochemical modeling computer program, PHREEQC (version 2) was used to calculate the equilibrium concentration, the speciation and possible precipitation of heavy metals in the leaching systems. In the modeling, the heavy metals, Cd, Cr, Cu, Ni, Pb, Zn, were input as master aqueous species in solutions, while the major and accessory components, Ca, Na, K, Cl, S, etc., were defined as finite solids. The agreement between the experimental results and the modeling ones varies for different metals as well as for different fly ashes. In general, the fitness of the modeling for different heavy metals is: Pb〉Zn〉Cd〉Cu. The modeling is excellent for fly ashes with low calcium but high chloride content, or with high concentration of heavy metals, which favor the implicit postulation of component input in the modeling, i.e., high availability of heavy metals. 相似文献