Next-Generation Biodegradable Ternary BiOI/TiO₂/PPy Heterojunction Hydrogel for Efficient Photocatalytic Tetracycline Degradation

Abstract

This study investigates the photocatalytic degradation of tetracycline (TC) using BiOI/TiO2/PPy (BTPY) hydrogels, highlighting their efficiency and applicability for wastewater treatment. BTPY was synthesized via hydrothermal method followed by polymeric interaction with carboxymethyl cellulose and crosslinked with FeCl3 to enhance stability and reusability. The photocatalytic performance was evaluated under visible light, achieving up to 91% degradation efficiency under optimized conditions. The process involved the activation of peroxymonosulfate (PMS), which facilitated the generation of reactive oxygen species (ROS) such as sulfate (SO₄•⁻) and hydroxyl (•OH) radicals, identified as key contributors to TC degradation. Experimental parameters, including BTPY dosage, PMS concentration, pH, and water matrix composition, were systematically analyzed to optimize degradation efficiency. Scavenger studies confirmed the predominance of sulfate and hydroxyl radicals in the degradation pathway, with sulfate radicals having the most significant impact. While BTPY showed high efficiency in distilled and drinking water, its performance was reduced in complex matrices like lake water due to natural organic matter interference. These findings underscore the potential of BTPY hydrogels as cost-effective photocatalysts for environmental remediation. Future work should explore scalability, application in diverse water matrices, and integration into solar-assisted systems to advance sustainable water purification technologies.