Quick adsorption followed by lengthy photodegradation using FeNi3@SiO2@ZnO: A promising method for complete removal of penicillin G from wastewater

Abstract

In this study, FeNi3@SiO2@ZnO nanoparticles were prepared via coprecipitation and sol-gel methods and were used as both PNG adsorbent and photodegradation catalyst. Thereafter, an aqueous solution containing penicillin G (PNG) was subjected to adsorption for 20 min followed by photodegradation for 200 min. To optimize the treatment method, the PNG removal efficiencies of the adsorption and photodegradation processes were measured under different experimental conditions, and it was determined that the increase in FeNi3@SiO2@ZnO nanoparticle concentration from 0.005 to 1 g/L favored adsorption but hindered photodegradation, as PNG removal efficiency noticeably decreased after increasing the catalyst concentration beyond 0.01 g/L. The results revealed that a PNG removal efficiency of 100 could be achieved after 220 min of successive adsorption and photodegradation at a pH of 5, FeNi3@SiO2@ZnO concentration of 0.01 g/L, PNG concentration of 10 mg/L, and H2O2 concentration of 150 mg/L. Analysis of the PNG photodegradation mechanism demonstrated that the superoxide anion radicals generated during photodegradation played a major role in PNG degradation. FeNi3@SiO2@ZnO is a sustainable adsorbent/catalyst because it can be reused for six consecutive treatment cycles with minor losses in efficiency (<3 ) and quantity (<1 ). Our results indicated that the prepared FeNi3@SiO2@ZnO nanoparticles were highly effective treatment agents and presented great practical application potential for the treatment of PNG-laden wastewater using adsorption-photodegradation.