Evaluation of Cs+ removal from aqueous solution by adsorption on ethylamine-modified montmorillonite

In this study, the adsorption performance of ethylamine-modified montmorillonite (Ethyl-Mt) and calcium-saturated montmorillonite (Ca-Mt) were evaluated by Cs + adsorption experiments considering the influencing factors (initial solution pH, contact time, initial Cs + concentration, temperature and ionic strength). FTIR, BET, SEM, EDS and Zeta potential analysis were used to characterize the surface properties of Ethyl-Mt and Ca-Mt. Experimental results demonstrated that the equilibrium uptake of Cs + was highly pH-dependent. Pseudo-second-order model fitted well with the adsorption kinetic studies. The adsorption processes were described by Langmuir model with maximum adsorption capacity of 60.03   mg   g −1 and 80.27   mg   g −1 for Ca-Mt and Ethyl-Mt, respectively. Also, the thermodynamic studies showed that the adsorption of Cs + was spontaneous and exothermic in nature. The presence of cations such as Na + , K + , Ca 2+ astricted the adsorption of Cs + . The Cs + removal on Ca-Mt was mainly ion exchange, while that on Ethyl-Mt would also involve coordination and surface complexation. On the basis of our results, Ethyl-Mt with high adsorption capacity and good surface characteristics is beneficial to be used for removal of Cs + .