Effects of Acid and Heat Treatments on the Structure of Sepiolite and its Adsorption of Tannin

Abstract

In this paper, it was investigated the changes of structure of sepiolites under different conditions of acid treatments and heat treatments using fourier transform infrared spectroscopy(FTIR). At the same time, through the tannin adsorption experiments, it was studied the changes adsorption properties of sepiolites by acid treatments and heat treatments. The H2SO4 treatment was found to be more effective for the removal of tannin than HCl and HNO3 treatments. With increasing the acid concentration and acid treatment time of H2SO4, the removal rates and adsorption capacity of tannin by sepiolites were first increased and then decreased. The removal rates and adsorption capacity were 61.0% and 23.7mg/g when the acid concentration was 4.0mol/l. And the removal rates and adsorption capacity were 62.5% and 24.3mg/g when the acid treatment time was 16 hours. The calcinations treatment exhibited significant effects on the adsorption of tannin. The removal rates and adsorption capacity were 77.9% and 30.8mg/g when the calcined temperature was 400°C. However, when the calcined temperature was 700°C, the removal rates and adsorption capacity were only 54.1% and 20.8mg/g.