Synthesis Of Humic Acid/Chitosan/Magnetic/Rectorite Composite For The Removal Of Heavy Metal Ions From Water

The adsorption method is a very good water purification technology because of its low cost,high flexibility,simple operation,and insensitivity to toxic pollutants.The purpose of this paper is to synthesize a new type of magnetic composite adsorbent for the adsorption of heavy metal ions in water and for effective recovery.This has important practical significance for reducing costs and avoiding secondary pollution.The HA/CTS/Fe₃O₄/REC-CTAB was prepared with HA and CTS loaded on the surface of Fe₃O₄/REC-CTAB through sol-gel method,after organic modification of Rectorite with CTAB and the Fe₃O₄/REC-CTABwas fabricated by introducing Fe₃O₄ onto the layers of rectorite-CTAB?REC-CTAB?.The structure and magnetic properties of composites were characterized using SEM,TEM,XRD,VSM and FTIR.The specific surface area,pore size distribution and pore volume of the composites were determined by N₂-BET.The adsorption isotherms were measured by the adsorption of Cu²⁺?Cd²⁺and Pb²⁺in water,and investigate the adsorption kinetics and the regeneration of the adsorbents.The results show that the composite is a mesoporous material with high specific surface area and the maximum adsorption capacities for Cu²⁺?Cd²⁺and Pb²⁺could reach 134.77 mg/g,111.98mg/g and 279.33mg/g,respectively?T=308 K?.The adsorption isotherm was well described by the Langmuir and Freundlich model,and the adsorption followed the pseudo-second order kinetics.The composite material exhibited superparamagnetic behavior with small coercivity in the applied magnetic fields,and could be separated from aqueous solution with a strong magnet.Moreover,the heavy metals absorbed on HA/CTS/Fe₃O₄/REC-CTAB could be easily regenerated with by HCl solutionand and remained a good adsorption capacity.A magnetic humic acid chitosan composite?M-HA/CTS?was prepared by loading chitosan on the surface with magnetic humic acid as a carrier.The structure of composites were characterized using SEM,TEM,XRD,VSM and FTIR,the maximum adsorption capacities for Cu²⁺?Cd²⁺and Pb²⁺could reach 53.48 mg/g,53.45 mg/g and 95.6 mg/g,respectively?T=308 K?.The result showed that the optimal preparation conditions of M-HA/CTS were:M-HA:CTS=8:2,reaction temperature 70°C and reaction time 24 h.The adsorption capacity of M-HA/CTS increases with the increase of pH,and the adsorption of metal ions is monolayer adsorption.The adsorption isotherms can be well fitted by Langmuir and Freundlich models.The adsorption process follows pseudo-second kinetics and chemical adsorption is the main control step for the sorption rate.In addition,the complex can be regenerated by HCl and can be easily separated from the aqueous solution by a magnetic field.