Grafting Bulrush with Acrylic Acid using Fenton’s Redox Initiator for the Removal of Methylene Blue Dye from an Aqueous Solution

Methylene blue dye in wastewater poses significant environmental and health risks due to its toxicity and resistance to conventional treatments. It disrupts aquatic ecosystems by reducing light penetration and harming photosynthetic organisms. A study was conducted on grafting Bulrush with acrylic acid using an innovative approach based on the Fenton redox initiator to enhance its adsorption capacity for methylene dye. Poly (acrylic acid) grafted Bulrush demonstrated a much higher adsorption capacity of 75 mg/g. The grafting procedure was improved, and the optimal conditions were determined to be an acid concentration of 0.9 mol/L and a monomer ratio of 8:10. The grafted Bulrush was characterised using FTIR and SEM/EDX. These analyses revealed that grafting with polyacrylic acid (PAA) introduced carboxyl (- COOH) and ester (- COOR) functional groups onto the surface of the material. The adsorption capacity was assessed through batch experiments, identifying the optimal conditions as an adsorbent dose of 2 g, a pH of 8, an initial methylene blue dye concentration of 100 mg/L, and a temperature of 60 °C. The Langmuir model best described the adsorption mechanism, with a high R2 value of 0.9970. The pseudo-second-order model, which demonstrated an excellent fit to the adsorption data, provided compelling evidence that chemisorption was the dominant mechanism in the adsorption of methylene blue dye onto PAA-grafted Bulrush. The reusability of the adsorbent was tested, with NaOH being the most effective desorbing agent, followed by water. This approach offers a sustainable and efficient method for removing methylene blue dye from wastewater, contributing to environmental protection and public health.