A COMPARATIVE STUDY TO ENHANCE THE PHOTOCATALYTIC ACTIVITY OF PICKERING EMULSIONS STABILIZED WITH DIFFERENT SURFACE-MODIFIED TITANIUM DIOXIDES VIA MEMBRANE EMULSIFICATION WAY

Abstract: This study is based on the application of surface-modified TiO2 to stabilize Pickering emulsions (PE) and then to be used in photocatalytic system for degradation of indigo carmine dye. Number of the reactive sites on the TiO2 surface plays an important role on the performance of photocatalytic degradation. Due to this theory, the aim must be to increase the amount of TiO2 nanoparticles adsorbed on the water/oil interface thereby creating stabilization of PE. In this regard, TiO2 were modified using various types of organic acids such as salicylic, benzoic, and citric acids to investigate their effects on photocatalytic reaction efficiency and kinetics. Instead of conventional emulsification technologies, membrane emulsification method was used to prepare PE which enables the homogeneous particle size distrubition. The bonding structure and surface properties of the particles along with the degradation efficiency of indigo carmine dye were investigated to assess the effect of the surface modification of TiO2 on the photocatalytic activity of the PE-based system in terms of types of oil phase and organic acid. Additionally, the efficiencies of PE and bare surface-modified TiO2 were compared to understand the advantage of PE. Characterization of surface modified TiO2 was performed using TGA, BET, DSC, FTIR, XRD, and SEM analyses. It is found that surface modified particles help to achieve better degradation percentages rather than bare TiO2. According to the results, olive oil based composite particles stabilized with salicylic acid-TiO2 having a content of 6.23 mg-TiO2 /g-particles provided the best promising result as a 86% dye removal.