Journal of Hazardous Materials, Vol.193, 209-215, 2011
Facile, green encapsulation of cobalt tetrasulfophthalocyanine monomers in mesoporous silicas for the degradative hydrogen peroxide oxidation of azo dyes
A facile and green approach that improves the catalytic lifetime of cobalt tetrasulfophthalocyanine (CoT-SPc) for the degradation of dyes is presented. Structurally ordered mesoporous silicas (MCM-41, MCM-48 and SBA-15), microporous aluminosilicates (ZSM-5) and macroporous alumina (gamma-Al2O3) with different pore sizes were selected for the immobilization of CoTSPc, and a wide range of pH conditions (pH values from 4 to 12) were tested with the CoTSPc immobilization procedure. In the catalytic oxidation study, CoTSPc that was immobilized to MCM-41 silica (CoTSPc@MCM-41) prepared at a pH of 12 showed the longest catalytic lifetime. The TOC removal and discoloration of C. I. Acid Red 73 was approximately 60% and 82%, respectively, in the presence of CoTSPc@MCM-41 with H2O2 after 3 h. These results indicate that MCM-41, which has a matching size between its mesopores (30 angstrom) and CoTSPc molecules (25 A), can prevent CoTSPc molecules from aggregating and improve its catalytic lifetime. In addition, the ability of CoTSPc@MCM-41 to degrade other dyes, and the reuse studies, demonstrated that CoTSPc@MCM-41 could be reused for the degradation of most common dyes. (C) 2011 Elsevier B.V. All rights reserved.