Enhanced photocatalytic decomposition of 4-nonylphenol by surface-organografted TiO_2:a combination of molecular selective adsorption and photocatalysis

摘要

n-Octyl-grafted TiO_2(C8-TiO_2)was prepared as a model of aphotocatalyst with high molecular adsorption selectivity,and its photocatalytic activity for the decomposition of dilute 4-nonylphenol(an endocrine disrupter,ca.2 ppm)in water was investigated.The catalyst was highly active in the presence of concentrated phenol(lOOOppm),and the 4-nonylphenol was decomposed in 180min,while pristine TiO2(P-25)under the same conditions showed much lower activity.The high C8-TiO_2 activity was ascribed to the molecular selective adsorption of the organic molecules on the alkyl-grafted hydrophobia surface.Infrared spectra showed that the grafted alkyl groups were gradually decomposed under photoirradiation.The model catalyst demonstrated that molecular selective adsorption is important for removal of low-concentration contaminants in the presence of other,more concentrated compounds.