Preparation of modified ZnO nanoparticles for photocatalytic degradation of chlorobenzene

Pallavi Nagaraju,Kitirote Wantala,Shivaraju Harikaranahalli Puttaiah,Behzad Shahmoradi

doi:10.1007/s13201-020-01228-w

Abstract

Volatile organic compounds (VOCs) are one of the major pollutants present in the petrochemical industrial effluents. These VOCs have high vapor pressure, which makes it to be dispersed into the atmosphere easily. Chlorobenzene is one such VOC, which has an ability to cause adverse impacts on human health by damaging the central nervous systems. The available treatment methods are unable to effectively treat such VOCs in environment. Photocatalytic degradation is the effective and economical methods, which are being used for the treatment of such pollutants. ZnO is one of the widely accepted photocatalyst, but it has a limitation of wide band-gap energy utilization. This paper mainly investigates the preparation of metal-doped ZnO nanoparticles using solgel technique and its application for the degradation of chlorobenzene in an aqueous media under different light sources. Among the modified ZnO nanoparticles prepared (Ag/ZnO, Cd/ZnO and Pb/ZnO), Pb/ZnO was found to be very effective in the degradation of chlorobenzene and achieved up to 100% within a short duration (< 120 min). The Pb/ZnO was also used as a photocatalyst in a vertical continuous photoreactor for the photodegradation of chlorobenzene using LED light.

Highlights

Volatile organic compounds (VOCs) are the organic compounds, which have high vapor pressure at room temperature, and they are characterized by low water solubility (Goldstein Allen 2007; Guo et al 2009)
The results obtained clearly indicated that photocatalytic degradation rate of chlorobenzene in an aqueous media using pure zinc oxide (ZnO) and modified ZnO (Ag/ZnO, Cd-doped ZnO (Cd/ZnO) and Pb-doped ZnO (Pb/ZnO)) nanoparticles found to be highest under tungsten (90%) and light-emitting diodes (LEDs) (96%, 91% and 100%) light sources, respectively
The solgel preparation of modified ZnO nanoparticles was found to be effective in the degradation of chlorobenzene

Summary

Introduction

Volatile organic compounds (VOCs) are the organic compounds, which have high vapor pressure at room temperature, and they are characterized by low water solubility (Goldstein Allen 2007; Guo et al 2009). The scope of the present research is to investigate the photocatalytic degradation of chlorobenzene using modified ZnO nanoparticles in a batch reactor under different light sources and to find an economical way to treat volatile organic compound. ZnO has great beneficial properties for photodegradation of various organic contaminants, visible light-based photocatalysis attributed to the wide band-gap energy (3.37 eV) and large free-excitation binding energy (60 meV) (Malik et al 2013; Meena and Chouhan 2015; Rangkooy et al 2012) Properties such as physicochemical stability, high thermal conductivity, high electron mobility, nontoxicity and large binding energy have make it as a novel semiconductor in the field of photocatalytic applications (Brintha and Ajitha 2015; Chen and Mao 2007; Hasnidawani et al 2016; Khan et al 2014). Initial and final concentration of chlorobenzene in aqueous media was measured by dynamic liquid phase microextraction method (Castellote and Bengtsson 2011) using QP5000 GC–MS instrument (Shimadzu, Tokyo, Japan) equipped with fused-silica capillary column (30 m × 0.32 mm x 0.25 μm) coated with bonded film of DB-1/5MS

Results and discussions

BET surface area

Conclusions

Compliance with ethical standards