Development of a Solid Catalyst Based on Pt Supported on Heterostructure (NaNbO3/NaNb3O8/NiO) Applied to the Photodegradation of Phenol in Seawater

Abstract

Phenol and its derivatives are present in effluents from several industrial processes, such as petroleum refining (produced water) and the pharmaceutical industry, and they are highly toxic. The present work elaborated a new catalyst for the removal of phenol and its derivatives. The photocatalyst was prepared by a simple method from the ammonium oxalate of niobium and nickel nitrate, resulting in heterostructures (principally NaNbO3/NaNb3O8 and a lesser amount of NiO) named NiNb. Platinum was deposited on this catalyst (NiNb/Pt catalyst), and its photocatalytic activity was tested on the degradation of phenol in seawater and distilled water, in the presence and absence of UV-C light (germicidal, λ = 254 nm), and with varying concentrations of platinum and varying pH of the solution. The catalyst was characterized by different techniques (SEM, EDS, DRS, XRD, TXRF, SBET,). The results of the study showed that the NiNb/Pt catalyst achieved 65% phenol removal in seawater and about 57% removal in distilled water. The reuse of the catalyst was also studied, and the photocatalytic mechanism was investigated by tests with scavenger agents and terephthalic acid.