Ecology & Safety, Volume 11, 2017

Abstract: Formaldehyde (HCHO) is regarded as one of the most versatile basic chemicals in various industries but it is hazardous for environment and living organisms. Therefore, it is imperative to remove it from wastewater which is directed to natural water. Heterogeneous catalytic oxidation of toxic substances in water with the participation of oxides of transition metals is an efficient approach for abatement these pollutants. In this study, nanostructured NiOx was synthesized by ultrasound assisted precipitation-oxidation method and its catalytic properties for low-temperature complete oxidation of 50 mg/l HCHO with NaOCl in aqueous solutions were explored. The catalyst was characterized by XRD, FTIR spectroscopy, TEM, thermal and chemical analyses. The catalytic activity of NiOx was evaluated through both the rate constant (k, min-1) and the degree of HCHO conversion (, %). The effect of several parameters on the HCHO degradation efficiency such as catalyst loading, temperature, and oxidant concentration was explored. By applying the method of the planned experiment the optimal conditions for achieving complete conversion of HCHO were determined (catalyst loading 1.5 g/l temperature 30oC, and NaOCl concentration 15 ml/l).