Exhaustive Photocatalytic Lindane Degradation by Combined Simulated Solar Light-Activated Nanocrystalline TiO2 and Inorganic Oxidants

Abstract

Organochlorine compounds (OCs) are very toxic, highly persistent, and ubiquitous contaminants in the environment. Degradation of lindane, a selected OC, by simulated solar light-activated TiO2 (SSLA-TiO2) photocatalysis was investigated. The film types of the TiO2 photocatalyst were prepared using a dip-coating method. The physical properties of the films were investigated using X-ray diffraction, transmission electron microscopy, and environmental scanning electron microscopy. The SSLA-TiO2 photocatalysis led to a lindane removal of 23% in 6 h, with 0.042 h−1 of an observed pseudo first-order rate constant (kobs). The SSLA-TiO2 photocatalysis efficiency was greatly enhanced by adding hydrogen peroxide (H2O2), persulfate (S2O82−), or both combined, corresponding to a 64%, 89%, and 99% lindane removal in the presence of 200 µM of H2O2, S2O82−, or equimolar H2O2-S2O82−, respectively. The hydroxyl and sulfate radicals mainly participated in lindane degradation, proven by the results of a radical scavenger study. The degradation kinetics were hindered in the presence of the water constituents, indicated by a 61%, 35%, 50%, 70%, 88%, and 91% degradation of lindane in 6 h, using a SSLA-TiO2/S2O82−/H2O2 photocatalysis system containing 1.0 mg L−1 humic acid (HA), or 1 mM of CO32−, HCO3−, NO3−, SO42−, and Cl−, respectively. The TiO2 film demonstrated high reusability during four runs of lindane decomposition experiments. The SSLA-TiO2/S2O82−/H2O2 photocatalysis is very effective for the elimination of a persistent OC, lindane, from a water environment.

Green Synthesis of Flower-Shaped Copper Oxide and Nickel Oxide Nanoparticles via Capparis decidua Leaf Extract for Synergic Adsorption-Photocatalytic Degradation of Pesticides

“…The decrease in the percentage of removal attained when increasing the concentration of target pollutant is associated with the fact that a higher number of molecules should react with the same number of oxidants that were generated by the identical number of catalytic sites. Furthermore, the presence of organic compounds that may absorb radiation can hinder photon transport and decrease at the same time as the generation rate of oxidants [84][85][86].…”

Determination of lindane in surface water samples and its degradation by hydrogen peroxide and persulfate assisted TiO2-based photocatalysis

“…For better comparison, the results of solar/TiO 2 , solar/H 2 O 2 /TiO 2 and solar/PS/TiO 2 photocatalytic degradation of lindane in distilled water (DW) – performed in our previous study 29 – has been provided in Table 4 . Compared to DW results, the RW sample (Amangarh) showed lower removal efficiency of lindane by solar/TiO 2 photocatalysis, attributed to the matrix effects, as indicated from the physico-chemical characteristics of the RW samples (Table S1, ESI † ).…”

Adsorptive removal of organochloride pesticide in water using surfactant modified aluminum hydroxide nanoparticles

“…The DDT residual in water is still a serious concern due to its very low biodegradation. Recently, various techniques were developed for removal of DDT and OCPs including biodegradation [3], photocatalysis [4], coagulation/ flocculation [5] and adsorption [1,6,7]. Among them, adsorption is an effective, simple and lowcost technique for OCPs removal [1,8] when using the natural or waste adsorbents.…”