A robust bio-source mediated CeO2 – SnS2 quantum dots @Oryza sativa var. biochar, photo-adsorbent for removal of Baszol Violet 57L dye from aqueous discharge: Development, materialistic analyses, and its application

• Published in: Journal of water process engineering Vol. 60; p. 105159
• Main Authors: Gupta, Shaswat Vikram, Kulkarni, V.V., Ahmaruzzaman, Md
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-04-2024
• Subjects: Baszol Violet 57L dye; CeO2 – SnS2 quantum dots; Green synthesis; Integrated photocatalytic-adsorption process; Oryza sativa var., biochar; Osmium Tenuiflorum leaves extract; Baszol Violet 57L dye; Integrated photocatalytic-adsorption process; Green synthesis; CeO2 – SnS2 quantum dots; Osmium Tenuiflorum leaves extract; Oryza sativa var., biochar
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.105159

This research aims to develop an entirely novel kind of photocatalytic adsorbent, known as integrated photocatalytic adsorbent, using a hydrothermal process that is environmentally friendly. This method utilizes an extract derived from Tulsi (Osmium Tenuiflorum) leaves as a stabilizing and capping agent. The purpose of the synthesized material is to effectively remove Baszol Violet 57L (BV57L) dye from wastewater. CeO2, was combined with a semiconductor photocatalyst, SnS2, to create a composite photocatalyst. This choice was made based on the exceptional photocatalytic activity of the catalyst when supported on rice straw (Oryza sativa var.) biochar, specifically for the adsorption of selected pollutants. The study investigated the integrated photocatalytic and adsorption (IPA) characteristics of the fabricated material, using BV57L dye as a representative emerging pollutant commonly found in wastewater. From the Tauc's plots of final nanohybrid (CSB) it was calculated that the energy band gap of CSB was around ∼2.7 eV. The novelty of the current study lies in its examination of the synergistic adsorption and photocatalytic properties under diverse reaction conditions that replicate real-world wastewater conditions. The inclusion of biochar in the CeO2-SnS2 nanocomposite yielded a discernible decline in the rate of charge recombination, thereby causing a notable enhancement in the photocatalytic efficiency of the nanocomposite.
The adsorption data confirmed with the Langmuir isotherm model with maximum adsorption capacity of 333.58 mg g−1 at BV57L concentration of 350 mg L−1 under optimal conditions, suggesting the occurrence of monolayer chemosorption and following pseudo-second-order rate kinetics with rate constant of 1.59 × 10−5 g mg−1 min−1. The process of photodegradation exhibits kinetics that can be approximated as pseudo-first-order, with the BV57L dye displaying a significant constant of 0.0731 min−1. A simultaneously processed adsorption and photodegradation model was found to achieve an overall BV57L removal efficiency of 97.26 % within a 90-min timeframe. Additionally, impact of pH, reusability-stability of catalyst, and a photodegradation mechanism for the BV57L removal is also clearly presented. The combination of visible light-induced photodegradation activity in CeO2-SnS2 nanocomposite and the adsorption capability of biochar leads to the highly effective removal of pollutants from the liquid phase.
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•Successfully biosynthesized a novel nanocatalyst of CeO2 – SnS2 @ Oryza sativa var. biochar surface (CSB)•Quantum Dots of CeO2 – SnS2 exist in final nanocomposite of CSB•CSB exhibits superior integrated adsorption-photocatalytic (IAP) efficiency toward Baszol Violet 57L dye (BV57L) dye up to 97.26% within 90 minutes•Adsorption process of BV57L via CSB explained by Pseudo second order rate kinetics and Langmuir isotherm model•CSB showed fairly consistent efficiency for removal of BV57L dye up to fifth run after catalyst recovery