Prepartion And Application Of Two Cationic Adsorbents Based On Large Pore Alumina

Dye wastewater is an important source of water pollution.Adsorption is a simple and efficient method for treating dye wastewater.Activated alumina and activated carbon are the two most commonly used adsorbents.Activated alumina has good mechanical strength and large pore size but small specific surface area.In addition,activated alumina usually has a positive charge on the surface and has a small adsorption capacity for cationic dyes.Activated carbon has the characteristics of large specific surface area,but the pores are usually dominated by micropores and the pore size is small.How to prepare high-efficiency adsorbents for cationic organic dyes with large specific surface area and macropores is one of the current research focuses of cationic dye adsorbents.The boehmite with large pore size was prepared by hydrothermal method,and the activated alumina with large pore size was obtained after calcination.On this basis,based on the purpose of adsorbing cationic dyes,two adsorbents were designed and prepared,and their adsorption properties for the cationic dye Malachite Green were verified.The polyacrylamide(PAM)was added by in-situ polymerization in the pores of activated alumina with large pore by in-situ polymerization,and dithiocarbamate(DTCs)groups were grafted.Inorganic-organic composites Al-PAM-DTCs were prepared.Its specific surface area is244.9 m~2/g,the pore volume is 1.39 cm~3/g,and the most probable pore size is 20.8 nm.The saturated adsorption capacity for cationic dye MG is as high as 3284.2 mg/g.Using activated alumina with large pore size as hard template and polypyrrole as carbon source,mesoporous carbon materials were prepared by KOH activation method.The preparation conditions were systematically studied.The maximum specific surface area of the prepared mesoporous carbon material was 3123.1 m~2/g,the pore volume was 1.70 cm~3/g.And the pore diameter was a bimodal distribution,with peaks at 2.37 nm and 46.62 nm,respectively.The cationic dye MG solution was statically adsorbed,and the adsorption capacity was up to8679.4 mg/g.The adsorption process conformed to pseudo-second-order kinetics,and the adsorption model was close to the Langmuir isotherm adsorption model.