Photocatalytic Oxidation Process (UV/H2O2/ZnO) in the treatment and sterilization of dairy wastewater

Abstract

ABSTRACT. Advanced Oxidation Processes (AOP) have attracted much interest of scientific and industrial communities. Therefore, this process was employed experimentally to determine its efficacy in treating dairy effluents. For this, it was employed an artificial light reactor using photolysis (UV), hydrogen peroxide (H 2 O 2 ) as an oxidant, and zinc oxide (ZnO) as an alternative catalyst. The variables studied in the photocatalysis were: H 2 O 2 , ZnO, under different values of pH, both in relation to the interferences with the reaction rate and with the process efficiency. First order differential equations were applied in determining the degradation rate over the hydraulic retention time (HRT); the F-test and the signal: noise ratio comparison were used to test the significance of variables. The AOP using photolysis UV, H 2 O 2 and ZnO was effective in COD removal with 80% efficiency. As for the sterilization, in terms of total and fecal coliforms the efficiency was 100%, with the most probable number of total and fecal coliforms (MPN 100 mL -1 ) equal to zero. A catalyst/oxidant/pH ratio was observed at 1 g 30 mL Desempenho do Processo Oxidativo Fotocalítico (uv/h 2 o 2 /zno) no tratamento e esterilização de efluentes de laticínio RESUMO. Os Processos Oxidativos Avançados (POA) têm atraído grande interesse tanto da comunidade científica como industrial. Assim, esse processo foi empregado experimentalmente com o objetivo de determinar sua eficiência no tratamento de efluentes de laticínios. Foi utilizado um reator com luz artificial utilizando a fotólise (UV), peróxido de hidrogênio (H 2 O 2 ) como oxidante e, como catalisador alternativo, o óxido de zinco (ZnO). Foram avaliados diferentes concentrações de H 2 O 2 e ZnO em diferentes valores de pH, tanto em relação às interferências na velocidade de reação quanto na eficiência do processo. Nesta pesquisa, equações diferenciais de primeira ordem foram utilizadas na determinação da velocidade de degradação em função do tempo de detenção hidráulica (TDH), análise estatística como o teste F e comparação razão-sinal-ruído na significância das variáveis estudadas. O POA, utilizando fotólise UV, H 2 O 2 e ZnO, demonstrou ser eficaz na remoção de DQO apresentando eficiência de 80%. Quanto à esterilização do efluente, no que tange aos coliformes totais e fecais, a eficiência foi de 100%, com o número mais provável de coliformes totais e fecais (NMP 100 mL -1 ) igual a zero. Observou-se para melhor reação cinético-química, durante 1h de luminosidade, a relação catalizador/oxidante/pH de 1 g 30 mL

Application of response surface methodology in the degradation of Reactive Blue 19 using H2O2/MgO nanoparticles advanced oxidation process

“…Also, the decolorization of RB19 being favorable in the acidic environment is due to the electrostatic attractions between the negatively charged functional groups present on the anionic dye and the positively charged MgO NPs surface. A study that investigated the effect of nanoparticles on the treatment of dairy wastewater resulted in an optimum pH of 4 [41]. The contact time is also important in all experimental processes.…”

Textile Waste Water and the advanced Oxidative Treatment Process, an Overview

“…More commonly, and in a more practical sense though, AOP refers to the treatment processes involving UV light, Ultrasound, Ozone (O 3 ) and hydrogen peroxide (H 2 O 2 ) either singly, serially or in combination with or without catalysts, such as metal ions or semiconductors, [53,56], such as in the equations below . [57]…”

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