Photodegradation of soluble and emulsive cutting fluids using TiO2 as catalyst

Abstract

Este artigo descreve os resultados da fotodegradação de três tipos de fluidos de corte solúveis e emulsionavéis em meio aquoso, usando TiO 2 como catalisador em suspensão e radiação UV. O TiO 2 mostrou ser um catalisador efetivo na degradação dos fluidos de corte investigados. A velocidade de degradação depende do pH e da natureza dos fluidos. O melhor desempenho do catalisador foi observado em pH = 8,0 para todos os fluidos, quando mais de 70% da carga orgânica foi decomposta. This paper describes results of the photo-degradation of three types of soluble and emulsive cutting fluids in an aqueous medium, using TiO 2 as catalyst in suspension and UV radiation. The TiO 2 proved to be an effective catalyst for the degradation of the cutting fluids investigated. The degradation rate depends on pH and nature of the fluids. The best performance of catalyst was observed at pH 8.0 for all the fluids when most of 70% of the organic load was decomposed.

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Photocatalytic Degradation of Nitrobenzene Using Nanocrystalline TiO2 Photocatalyst Doped with Zn Ions

“…An important parameter in photocatalytic reactions is the pH of the solution since it dictates the surface charge of the photocatalyst, the size of the particle aggregates formed; the chemical nature of the pollutant and therefore its adsorption behavior [31,32]. The interpretation of the pH effects on the degradation process is difficult as it includes various factors such as electrostatic interactions between the catalyst surface and reaction of charged radicals such as superoxide, hydroxyl radicals, etc.…”

In situ treatment of metalworking wastewater by chemical addition-dissolved air flotation coupled with UV, H2O2 & ZnO

“…Since the each of biological treatment approaches needs a strong concentration of organic substances along poor low molecular weight and BOD to COD proportion more than 0.4 (a standard rate), the toxicity of these fluids is a downside for applying these processes as a pretreatment or even single treatment [8,9,10]. The Ozone-based advanced oxidation processes (AOPs) [29], heterogeneous photo-catalysis by applying semiconductors as TiO 2 [30], ZnO as well as homogenous processes such as Fenton reaction have advantage of the fast oxidation of pollutants to harmless end products especially when is motivated by ultraviolet (UV) radiation [9,16,25]. Recently, combining processes as hybrid techniques for MWF wastewater treatment has been investigated by many researchers such as incorporating biodegradation and advanced oxidation process [13], hybrid biological, electron beam and zero-valent Nano iron [28], the DAF followed with the photo-Fenton process and other DAF-based hybrid approaches [8,22,31].…”