Investigating the toxicity of acid dyes from textile effluent under UV/ZnO process usingDaphnia magna

Abstract

Some of textile wastewater dyes and their raw materials are carcinogenic for humans due to production of toxic aromatic amines. The toxicity measurement of the textile wastewater was analyzed using zinc oxide nanoparticles under ultraviolet irradiation process (UV/ZnO) and Daphnia magna bioassay was performed. D. magna has been evaluated as indicator to test effluent toxicity in dyes effluent. The impact of effective parameters such as zinc oxide nanoparticles load, pH, and exposure time were well investigated and optimized. It was found that increase in toxicity during the process is possibly due to the production of intermediate toxic compounds, presence of excessive hydrogen peroxide in the solution, presence of excessive ZnO in the solution, or ZnO toxicity or presence of excessive hydrogen peroxide in wastewater and consequent death of D. magna. Obtained experimental results revealed that toxicity increases during the nanophotocatalytic process.