Efficient degradation of orange G dye using the quartz-sand@polythiophene composite for peroxymonosulfate activation: a sustainable approach for advanced oxidation processes

Abstract

In this work, a composite material, QS@PTh, comprising quartz-sand (QS) and polythiophene (PTh) was used for the activation of peroxymonosulfate (PMS) to degrade Orange G dye (OG). The QS@PTh composite was synthesized through a polymerization process that resulted in the attachment of polythiophene onto the quartz-sand surface. The formation of QS@PTh was demonstrated using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), and Fourier-transform infrared (FTIR) spectroscopy. The activation of PMS by the QS@PTh composite was evaluated through degradation experiments using Orange G dye as a model pollutant. The results demonstrated the efficient degradation of Orange G dye by the QS@PTh/PMS system, achieving a degradation efficiency of 99.5% and a COD removal of 79.4% within 60 min. The mechanism of PMS activation for OG degradation was suggested, highlighting the role of electron transfer from the polythiophene component to PMS, leading to the production of highly reactive species such as hydroxyl radicals (˙OH), sulfate radicals (SO₄˙⁻), and singlet oxygen (¹O₂). Furthermore, the system exhibited remarkable efficacy in degrading other organic pollutants and real water samples, confirming its feasibility for decontaminating various pollutants. These promising results position QS@PTh/PMS as a versatile solution with potential application in the industrial sector. Additionally, the QS@PTh composite's catalytic activity remained robust even after five cycles, indicating its potential for repeated use. These outcomes collectively underscore the utility of QS@PTh as a performant catalyst for PMS activation in the degradation of organic contaminants, showcasing its potential for environmental remediation applications.