Modification of spent grains to improve acid turquoise blue A adsorption from wastewater

In order to adsorb acid turquoise blue A from wastewater, HCl、NaOH、AlCl₃ and CH₃COONH₄ were used as modifiers for spent grains modification. The results show that spent grains modified by 0.8 mg/L AlCl₃ 12 h at 30 ℃ have the best adsorption for acid turquoise blue A whose solution pH is 3, with eff iciency of 98.9% and capacity of 19.78 mg/g. The mechanism of spent grains modification was studied through Fourier Transform Infrared Spectroscopy (FTIR) and kinetics study. The study indicates that the newly added active function groups such as N-Cl and C-Cl after AlCl₃ modification increase the adsorption capacity, and its adsorption process conforms to the pseudo-second-order kinetics model.