Enhanced transport of K-nZVI by bentonite suspensions in porous media
Due to high reactivity and relatively low cost,nano zero-valent iron(nZVI)has become an alternative material for in-situ remediation of contaminated sites.However,factors such as short transport distance and easy deposition in porous media also seriously restrict its injection remediation effect.The optimum ratio of bentonite and kaolin supported nano zero-valent iron(K-nZVI)in the remediation agent was determined by sedimentation and rheological tests.The transport characteristics of deionized water and bentonite suspensions carrying K-nZVI in porous media under different injection pressures were investigated using simulating column tests.The results show that bentonite suspensions could significantly improve the stability and dispersibility of K-nZVI.The proportion of bentonite and K-nZVI are 5%and 0.4%,respectively,which is the best ratio of the remediation agent.The transport capability of K-nZVI carried by deionized water increases with the increase of injection pressure,while there is a critical injection pressure for bentonite suspensions carrying K-nZVI remediation agent.The numerical simulation results show that the diffusion radius of K-nZVI is positively correlated with the injection pressure and negatively correlated with the viscosity of the remediation agent.The results provide theoretical guidance for the remediation project of heavy metal pollution in non-ferrous smelting sites.
heavy metal contaminationbentonite suspensionkaolin-supported nano zero-valent irondiffusion radiusenhanced transport
魏贺、贺勇、江钧、宋相志、娄伟、张召、张可能
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Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,Changsha 410083,China
School of Geosciences and Info-Physics,Central South University,Changsha 410083,China
School of Metallurgy and Environment,Central South University,Changsha 410083,China
School of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China
国家重点研发计划国家自然科学基金国家自然科学基金国家自然科学基金国家自然科学基金Central South University Innovationdriven Research Program,ChinaResearch Foundation of the Department of Natural Resources of Hunan Province,China