Removal of Sr2+ from radioactive wastewater by the composite MnO2/MCM-41

MnO2/MCM-41 composite was prepared by one-pot method to investigate its removal of Sr2+ from radioactive wastewater. The prepared composite were characterized by SEM，BET，FT-IR. The effects of parameters such as mass ratio，pH，adsorption time and competing ion effect of MnO2 and MCM-41 on the adsorption test were investigated. The results showed that the composite adsorbent could rapidly adsorb Sr2+ in water and reached the adsorption equilibrium in 120 min with the maximum adsorption capacity of 85.46 mg/g. The composite adsorbent had the highest adsorption capacity when the mass ratio of MnO2 and MCM-41 was 4∶1 ，and the composite adsorbent had high adsorption performance in the range of pH 4-9. In addition，the composite adsorbent maintained good adsorption capacity in the presence of Na+，K+，Mg2+ and Ca2+，and the inhibited adsorption capacity followed the order of Na+< K+< Mg2+< Ca2+. The adsorption kinetic data analysis of the pseudo-secondary model fit the adsorption data better than the pseudo-first-order model，indicating that chemisorption dominated the adsorption process. The novel MnO2/MCM-41 composite prepared for the removal of Sr2+ from radioactive wastewater had the advantages of rapid adsorption，high adsorption capacity，selectivity，and the ability to be prepared on a large scale，which made it promising to play an important role in the field of Sr2+ containing radioactive wastewater removal.