Anthraquinone dyes represent the largest class of textile dyes in industrial use. These reactive anthraquinone dyes are not easily amenable by conventional treatment methods due to their stability and non-biodegradable nature. Heterogeneous solar nano photocatalysis has been found to be the most promising treatment process for the degradation of various dyes. In the present work alizarin red S is used as model compound for the nanophotocatalytic degradation. The effects of operational variables such as catalyst dose, pH, H₂O₂/COD ratio are investigated. The complete color removal is achieved at optimum conditions of catalyst dose of 7 mg/500 mL, pH= 7 and contact time 95 min for dye sample. This is the first attempt made to analyse the degradation pathway of the dye by the thermo acoustical studies of solar nanophotocatalytic degradation of alizarin red S. Based on the data obtained, various acoustical parameters like adiabatic compressibility, intermolecular free length, acoustic impedance, relative association, solvation number, vander Waal’s constant, Rao’s constant and relative association have been calculated. From the data of acoustical parameters, the intermolecular interactions between the selected dye, H₂O₂ and the nano photocatalyst have been discussed and the mechanism of nanophotocatalytic degradation of alizarin red S is proposed.

Keywords: Nanophotocatalytic; Thermoacoustical Parameters; Intermolecular Interactions;