Solar photocatalytic oxidation and disinfection of municipal wastewater using advanced oxidation processes based on pH, catalyst dose, and oxidant

Abstract

There are great interests in photocatalytic oxidation of contaminants using advanced oxidation processes (AOP) based on photocatalytic oxidation in recent years. The main aim of the paper is to develop a method which takes care of energy and water conservation together. The study was performed on photocatalytic disinfection of total coliform (TC) bacteria as water microbial pollution and reducing the chemical oxygen demand (COD) as organic pollution index using catalytic and oxidant in present of sun light. The municipal wastewater was monitored for TC and in then was irradiated with solar light, solar light/TiO 2 , and solar light/TiO 2 /H 2 O 2 . Various parameters such as contact time, pH, and different concentration of TiO 2 and H 2 O 2 were studied for their effect on reaction process. The result showed that in presence of solar light, catalyst, and oxidant, very effective disinfection and reduction of TC and COD took place. 95.2% and 97% of TC and COD were reduced by irradiation for 240-300 min. Based on the results of various AOP combinations, Solar photolytic, solar/TiO 2 , Solar/TiO 2 /H 2 O 2 , the rate of COD, and TC removal was in the order of TiO 2 /H 2 O 2 > TiO 2 > Solar photolytic. It can be suggested as an effective treatment method for wastewater containing microbial and organic contamination.

A biochar-promoted V2O5/g-C3N4 Z-Scheme heterostructure for enhanced simulated solar light-driven photocatalytic activity

“…Semiconductor photocatalysis is an efficient and promising green technology that can utilize solar light energy to degrade organic or inorganic pollutants in wastewater treatment. 1,2 A number of traditional photocatalysts, such as titanium dioxide (TiO 2 ) and zinc oxide (ZnO) are only active in ultraviolet light, due to their large intrinsic band gap (3.0-3.2 eV). This results in an inefficient use of solar light or visible light (<5% of the solar spectrum) and, thus restricts their practical application.…”

Visible light induced photocatalytic reduction of metals (Cr, Cu, Ni, and Zn) and its synergism with different pH, TiO2, and H2O2 doses in simulated wastewater

“…The schematic diagram of the photocatalytic system used in our study is reported. 18 It maintains the turbulent conditions and there is no mass transfer limitation. It is a nearly closed system no vaporization of volatile compounds takes place.…”

Kinetic Behavior of Some Azo Dyes Decolorization by Variation of Zinc Oxide and Titanium Dioxide Concentrations

“…9 The optimization of the photocatalytic process for several organic contaminants degradation has been carried out, varying the semiconductor concentration, pH, oxidants addition such as peroxides, persulfates, among others. [10][11][12][13][14] In general, the degradation rate constant of the contaminants increases with TiO 2 concentration in heterogeneous photocatalysis. So, it has been considered that the larger the number of active sites to dye adsorption, as well the interaction with electron-hole pairs, the larger the degradation efficiency will be.…”