Eparation Of Compound Modified Nano-Montmorillonite And Its Application To Cr(?) Adsorption In Water

Montmorillonite is a kind of silica-aluminate mineral,which has layered-porous stereomorphic structure.Specific surface area,high cation exchange capacity,in the treatment of containing Cr???has the unique superiority of industrial wastewater.Nano-montmorillonite was prepared by sol-gel method with tetrabutyl titanate?TBT?and EDTA.To simulate a Cr???removal rate in wastewater as adsorbent performance evaluation index,for the preparation of modified montmorillonite adsorption performance comparison.The adsorbents were characterized by XRD,FT-IR,BET,SEM and TEM.The preparation and process conditions of the adsorbent were optimized,and the adsorption properties of the adsorbent on different heavy metal ions were studied.Langmuir and Freundlic adsorption isotherm equations and three kinetic models of quasi-first order,quasi-second order and particle diffusion were established to explore adsorption isotherm and adsorption kinetics.The TBT modified montmorillonite showed that the nano-sheet structure of the modified montmorillonite was not destroyed.TBT pillared agent concentration as the tendency of 15 g,ultrasonic power 80 W,ultrasonic temperature 25?,solid liquid ratio is 1.0%,TBT-MT-Q absorption effect is best.TBT on Cr-MT-Q???removal rate was 81.02%,the adsorption unit is 12.18 mg/g.The composite modified montmorillonite was modified by EDTA and TBT.Two modifier to join at the same time,the mole ratio of 1:2 preparation of samples for Cr???removal rate reached 97%,adsorption unit is 14.20 mg/g.Research on process conditions found in reaction temperature 25?,30 mg/L Cr???initial concentration,simulated wastewater pH=6.0,adding the amount of 0.2 g/100 ml samples to Cr???removal rate was 99.012%,adsorption unit is 14.851 mg/g.Be regenerated through regeneration study found:first removal rate was 96.680%,continuing"adsorption regeneration-"test,the removal rate of Cr???decreased.When the number of regeneration reached four,almost no adsorption effect.Sample ETAM-1:2 in addition is adsorption capacity for Cr???on the Fe???,Pb???,Cu???,Cd???has good capability of adsorption and removal order for:Cr???>Fe???>Pb???>Cu???>Cd???.Finally,the modified montmorillonite were studied adsorption Cr???adsorption isotherm equation and the adsorption dynamics.Langmuir isothermal equation can better describe the process by fitting.By particle diffusion model,quasi level 1,level 2 dynamic adsorption Cr combined???is proposed to calculate:quasi secondary dynamics equation is more in line with the adsorption of Cr???process,the whole adsorption process in addition to physical adsorption and chemical adsorption.By particle diffusion model fitting found within the whole Cr???adsorption process is divided into"fast adsorption stage"and"not saturated adsorption phase"two adsorption phase,after fitting drawing quick adsorption rate is greater than the not saturated adsorption phase rate(k_d1>k_d2).