Preparation of nanophotocatalysts for color removal from wastewater and determination of photocatalytic performance using spectrophotometer

The use of low-cost and readily available species as catalyst plays a significant role for cost-effective chemical processes. Metallophthalocyanines (MPcs) are very attractive due to their thermal stability, easily accessible and cost-effective. Most importantly, the ability of some of these phthalocyanines is to produce efficiently reactive singlet oxygen from the ground state molecular oxygen in the presence of light that is of much interest since singlet oxygen is a good candidate for oxidative processes. MPcs are immobilized on a solid support to achieve recoverable and recyclable photocatalysts. The covalent immobilization of catalysts on inorganic supports not only gives good catalyst with recycling results but also shows minimal influence of the support by the catalytic site. In this study, tetraperiferal phthalocyanines contain both bulky esteric groups (-COOCH3) and functional -SH groupson -positions is synthesized in the presence of corresponding metal salts (MgCl2, Zn(Ac)2 and GaCl3). After characterization novel phthalocyanines which have the high singlet oxygen production is chosen by measuring the photophysical and photochemical properties. On the other hand, initially silica microparticles used for the solid support is modified to bear the -NH2 functional groups, then the surface of the same size silica microparticles are coated with gold (Au) or silver (Ag) nanoshell and are characterized. Next, the esteric groups of phthalocyanines having the high amount of singlet oxygen production (ZnPc) are bond to amine functional groups (-NH2) on the silica microparticle. In addition, the same phthalocyanine derivatives are bound covalently to the nanometal coated silica microparticles with -SH functional groups and the contribution of the nanometal coated silica on the singlet oxygen production amount of the phthalocyanines are examined. A cartridge is prepared by selecting composites (SiO2-Pc) producing high amounts of singlet oxygen and used for the apparatus designed by our group is used for the removal of organic pollutants in water for the first time. In this study, 4-chlorophenol methyl orange and orange G chemicals are used as examples for organic pollutants for the photocatalytic measurements.