Preparation Of New Modified Bentonite And Investigation Of Its Adsorption Properties

This article focuses on the study of quaternary ammonium cation cetyltrimethylammonium bromide(CTAB)and inorganic polymer coagulant polyaluminum chloride(PAC)composite modified bentonite,particulary the influences of modifiaton conditions on the performances of the bentonite during its modification process.Because bentonite has good ion exchange properties,it can exchange with organic cations,metal ions,etc.on the interlayer structure.Therefore,composite modification can improve the adsorption performance of the original soil,improve acid resistance and heat resistance,etc.Expand the ways and fields of application of bentonite in environmental protection.This study was mainly conducted to make the modification toorganic-inorganic composite on the basis of sodium bentonite.The purpose is to explore a set of optimal modification process and apply the modified bentonite adsorbent to simulated phenol-containing wastewater.The removal effect and adsorption performance of phenol in water were studied in detail.In addition,a preliminary exploration on thedesorption regeneration performance of modified bentonite was conducted,which confirmed that the bentonite adsorbent does have a certain level of regeneration capacity.The main research results are as follows:(1)During the composite modification process,CTAB and PAC molecules can effectively intercalate into the bentonite layer to form an intercalated composite adsorption material,thereby expanding the adsorption gap and space,and improving the adsorption performance of the bentonite;(2)The modification effect of bentonite is affected by many operating factors.The mass ratio of CTAB and PAC is 1:1;pH=7 is neutral;the temperature of the modifier is 60℃,and the hydrothermal reaction is at 200℃ for 3 hours.Composite modified bentonite has the best phenol adsorption performance;modified bentonite has the adsorption performance for phenol-containing wastewater,affected by many factors such as temperature,adsorption time,and adsorbent dosage,and the highest removal rate of phenol can reach about 98.5%;(3)The adsorption kinetics of modified bentonite shows that the adsorption of phenol by modified bentonite belongs to the pseudo-second-order kinetic equation.There are two stages in the adsorption process:the initial stage of the adsorption process is mainly controlled by interface diffusion,and after 30 minutes,it is mainly affected by particle diffusion;the adsorption process of phenol by modified bentonite belongs to the second type of isothermal adsorption model,which is a multi-molecular layer physical adsorption;(4)Modified bentonite has excellent regeneration effect and adsorption performance.After five times of regeneration,the adsorption rate of phenol is still as high as 80%.Finally,based on the experimental data and the theoretical analysis of the adsorption process,the modified bentonite adsorbent was once again proved to have a certain practical value in the adsorption of phenol wastewater,and may be further applied to the treatment of organic mixed wastewater in the future.