Static and Dynamic Leaching Experiments of Heavy Metals from Fly Ash-Based Geopolymers
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2013年第5期
论文作者：郭晓潞 施惠生 XU Mingfeng
文章页码：938 - 943
摘 要：The feasibility of high calcium fly ash（CFA）-based geopolymers to fix heavy metals were studied.The CFA-based geopolymers were prepared from CFA,flue gas desulfurization gypsum（FGDG）,and water treatment residual（WTR）.The static leaching showed that heavy metals concentrations from CFAbased geopolymers were lower than their maximum concentration limits according to the U.S.environmental protection law.And the encapsulated and fixed ratios of heavy metals by the CFA-based geopolymers were 96.02%-99.88%.The dynamic real-time leaching experiment showed that concentration of Pb（II） was less than 1.1 μg / L,Cr（VI） less than 3.25 mg / L,while Hg（II） less than 4.0 μg / L.Additionally,dynamic accumulated leaching concentrations were increased at the beginning of leaching process then kept stable.During the dynamic leaching process,heavy metals migrated and accumulated in an area near to the solid-solution interface.When small part of heavy metals in "the accumulated area" breached through the threshold value of physical encapsulation and chemical fixation they migrated into solution.The dynamic leaching ratios and effective diffusion coefficients of heavy metals from CFA-based geopolymer were very low and the long-term security of heavy metals in CFA-based geopolymer was safe.
郭晓潞1,2，施惠生1,2，XU Mingfeng2
1. Key Laboratory of Advanced Civil Engineering Materials,Ministry of Education(Tongji University)2. Environmental Materials Institute,Tongji University
摘 要：The feasibility of high calcium fly ash（CFA）-based geopolymers to fix heavy metals were studied.The CFA-based geopolymers were prepared from CFA,flue gas desulfurization gypsum（FGDG）,and water treatment residual（WTR）.The static leaching showed that heavy metals concentrations from CFAbased geopolymers were lower than their maximum concentration limits according to the U.S.environmental protection law.And the encapsulated and fixed ratios of heavy metals by the CFA-based geopolymers were 96.02%-99.88%.The dynamic real-time leaching experiment showed that concentration of Pb（II） was less than 1.1 μg / L,Cr（VI） less than 3.25 mg / L,while Hg（II） less than 4.0 μg / L.Additionally,dynamic accumulated leaching concentrations were increased at the beginning of leaching process then kept stable.During the dynamic leaching process,heavy metals migrated and accumulated in an area near to the solid-solution interface.When small part of heavy metals in "the accumulated area" breached through the threshold value of physical encapsulation and chemical fixation they migrated into solution.The dynamic leaching ratios and effective diffusion coefficients of heavy metals from CFA-based geopolymer were very low and the long-term security of heavy metals in CFA-based geopolymer was safe.
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