Study On Preparation And Adsorption Mechanism Of SiO₂ And Magnetic Composite Adsorbents

At present,with the development of industry,a large number of industrial wastewater without being treated is discharged into rivers or lakes.it will lead to serious risk to us,even the future generations.In sewage disposal,especially removal of heavy metal ions from water,non-toxic and harmless inorganic non-metallic materials SiO2 has become increasing research interests due to its unique physical and chemical performance.Based on the study of adsorption properties of nano-SiO2 by using carbonate decomposition method from sodium silicate as raw materials,in this paper,adsorption performance of nano silica produced from fly ash were studied as well.This research gave the propobility to the utilization of secondary resource like fly ash in a new way like Furthermore,taking advantages of magnetic materials recycling easily,silicon dioxide magnetic composite adsorbent was synthesized.The magnetic composite adsorbents combined the adsorbing material of silica and magnetic cores to solve the recycling difficult problem in the practical application.Firstly,nano-SiO2 was prepared from sodium silicate by carbonate decomposition method.It could get strong adsorption ability through the concentration adjustments of sodium silicate.And the adsorption thermodynamics and kinetics of the adsorbent were studied.Secondly,SiO2 adsorbents were prepared with fly ash as raw material using alkali roasting-carbonate decomposition method.And the adsorption thermodynamics and kinetics of the adsorbent were studied.Finally,magnetic composite adsorbents were prepared by SiO2 deposited magnetic nano cores.At first,the suitable magnetic cores were prepared usinghydrothermal method by controlling reaction time.And then the magnetic composite adsorbents with good adsorption ability were obtained by adjusting the concentration ratio of nickel iron particles to sodium silicate and sodium silicate solution concentration.the composite adsorbents were characterized by XRD,SEM,VSM.The adsorption kinetics and thermodynamics of adsorbent were studied.The results show the nano SiO2 that can be produced from either pure sodium silicate or fly ash.The result offers a new approach to reuse secondary resources.The composite adsorbents composed of magnetic particles and SiO2 have the same adsorption ability too.this work provides the feasibility of recycling.