Removal of Brilliant Green Cationic Dye Using Bioadsorbent Material from Oyster Shells

Abstract

This study explored the potential of coral rock, specifically coquina derived from oyster shells, as a bioadsorbent for the removal of dyes from wastewater generated by the textile industry. The investigation included an examination of particle size fractions (300 µm and less than 300 µm) and thermal treatment; the investigation involved drying at 120 °C and calcination at temperatures ranging from 200 °C to 800 °C. The material was subjected to a comprehensive analysis through various characterization techniques. Laboratory-scale experiments were conducted to evaluate the removal capacity and adsorption kinetics of the bioadsorbent utilizing brilliant green dye. The experiments involved varying dye concentrations (25, 50, and 75 mg L−1), pH levels (2 to 12), and different doses of biosorbent material (0.2 to 0.6 g L−1), with constant agitation. Various kinetic models were applied to fit the experimental data, with the pseudo-second-order model demonstrating the best fit. The findings reveal that coquina rock, characterized by a temperature of 120 °C and a particle size of greater than 300 µm, exhibits remarkable effectiveness. It achieved a removal efficiency of 90% within 15 to 20 min at pH 7.8. This study concludes that coquina rock not only stands out as demonstrating remarkable efficacy in dye removal but also underscores a sustainable approach, leveraging readily available and environmentally friendly materials for wastewater treatment.