A New Synergetic Nanocomposite for Dye Degradation in Dark and Light

Abstract

Environmental hazard caused due to the release of dyes in effluents is a concern in many countries. Among the various methods to combat this problem, Advanced Oxidation Process, in which semiconductor photocatalysts are used, is considered the most effective one. These materials release Reactive Oxygen Species (ROS) such as hydroxyl radical and superoxide in suspension that degrade the dyes into non-toxic minerals. However, this process requires visible or UV light for activation. Hence, there is a need to develop materials that release ROS, both in the absence and in the presence of light, so that the efficiency of dye removal is enhanced. Towards this objective, we have designed and synthesized a new nanocomposite ZnO2/polypyrrole which releases ROS even in the dark. The ROS released in the dark and in light were estimated by standard methods. It is to be noted that ZnO2 degrades the dye only under UV light but not in dark or in the presence of visible light. We propose the mechanism of dye degradation in dark and light. The synergically coupled nanocomposite of ZnO2/ppy is the first example that degrades dyes in the dark, through advanced oxidation process without employing additional reagents.

Photocatalytic degradation of dyes in water by analytical reagent grades ZnO, TiO<sub>2</sub> and SnO<sub>2</sub>: a comparative study

“…Lattice parameters were calculated for all three metal oxides by using XRD data and are listed in Table 1. The lattice parameters were consistent with reported values (Pawar et al, 2016;Cheng et al, 2011;Li et al, 2014Li et al, , 2013. Crystallite sizes were calculated using the intense peaks in XRD by the Debay-Sherrer formula; they were 103, 36, and 66 nm for ZnO, TiO 2 , and SnO 2 , respectively.…”

Facile and scalable production of heterostructured ZnS-ZnO/Graphene nano-photocatalysts for environmental remediation

“…For better understanding of the photocatalytic mechanism, it is important to investigate the active species formed during photocatalytic process. In general, photocatalytic degradation of dyes and phenols primarily comprises several active radical species which includes hole (h + ), electrons (e − ) superoxide anion radical ( ● O 2 − ), and hydroxyl radicals ( ● OH) 50 . Hence, to distinguish the role of the reactive species, scavenging analysis were performed using series of scavengers during the photodegradation process of MB.…”

Photocatalytic degradation of Dyes in Water by Analytical Reagent Grade Photocatalysts – A comparative study

“…In this mechanism, the dye molecules adsorbed on the surface of catalyst absorb visible radiations and undergoes electronic excitation from highest occupied molecular orbitals (HOMO) to lowest unoccupied molecular orbitals (LUMO). Then excited electron from LUMO of the dye molecule is injected to conduction band (CB) of the photocatalyst and the dye is converted into cationic dye radical (Lakshmi Prasanna and Rajagopalan, 2016). This dye radical undergoes degradation to produce mineralized products (Li et.…”