Chemically modified vermiculite clay: a means to remove emerging contaminant from polluted water system in developing nation

The performance of chemically modified vermiculite clay (VCM) and unmodified vermiculite clay (VCL) was evaluated for the removal of 4-aminoantipyrine from aqueous solution. The chemical modification of VCL was achieved using cellulose nanocrystals and nitrilotriacetic acid via facile dispersion and intercalation. After the modification, the BET surface area of VCL increased from 4 to 96 m(2) g(-1) in VCM. The removal of 4-aminoantipyrine was pH dependent which followed pseudo-second-order kinetics. Langmuir isotherm model provided the best fit for the sorption data while a percentage removal of 4-aminoantipyrine unto VCM of up to 98.410% was attained. Quantum chemical computational analysis was also used to describe the sorption process in molecular terms. The lowest unoccupied molecular orbital and highest occupied molecular orbital are distributed over the molecule of 4-aminoantipyrine, and interaction between the surfaces of VCL/VCM and 4-aminoantipyrine may have occurred via donor-acceptor interactions. A regeneration capacity of 76% was obtained for VCM while that of VCL was 60%. The study has revealed that the property of vermiculite clay can be improved via facile dispersion and intercalation with the potential of removing pharmaceutical pollutants from water system.