1. Preparation of the Prawn Waste Adsorbent
The prawn shell was obtained from an aquaculture farm in Nagapattinaum (Tamil Nadu). It was air-dried and powdered in a grinder. The dry biomass was crushed into granules, sieved to different particle sizes, and then preserved in desiccators for use (RPR). Airdried and powdered prawn waste was soaked in concentrated HSO for 12 h and washed thoroughly with 24 distilled water until it attained neutral pH and soaked in 2% NaHCO overnight in order to remove any ex3 cess acid present. Then the material was washed with distilled water until it attained neutral pH and dried at 110 ± 2 °C. The dry biomass was crushed into granules, sieved to different particle sizes, and then preserved in desiccators for use (APR).
2. Preparation of Cationic Dye Solution
MB, in commercial purity, was purchased from S.D. Fine Chemicals, Mumbai, India, and used without further purification. The dye stock solutions were prepared by dissolving dyes in distilled water to 500 mg -1L . The experimental solutions were obtained by diluting the dye stock solutions in proportions to different initial concentrations.