A novel combination of non-thermal plasma process and a heterogenous nanophotocatalyst-sorbent comprising zinc sulfide, graphene oxide and polyaniline as an efficient strategy for treatment of organic-contaminated water

Abstract

A dielectric barrier discharge (DBD) reactor was designed in the present study to generate non-thermal atmospheric pressure Ar plasma. A heterogeneous p-n-p visible-driven photocatalyst comprising ZnS, Graphene oxide, and Polyaniline (ZGP) was also synthesized via chemical polymerization. A novel combination of photocatalyst and plasma treatment was then developed for the synergetic removal of organic pollutants from aqueous solutions. The addition of the p-n-p photocatalyst (5 mg) to the dye solution (malachite green, 50 mL, 20 mg/L) under plasma radiation resulted in a 97 % removal rate in 12 min. Scavenging studies confirmed a decline in the effectiveness of the reactive species in the following order: OH• > e־ > O2־• > h+. The changes in surface chemistry of the recovered photocatalyst were probed by XPS, and possible involved reactions were suggested. The synergetic factor of 1.53 in this system was a remarkable achievement comparable with the records of air or oxygen plasma reactors. The absence of hazardous by-products was confirmed by GC–MS and AAS techniques. The treated aqueous solution was utilized to evaluate its effect on lentil seed growth and trout blood factors, which led to promising results with several advantages but no negative effects.