Preparation of raw Oyster Shell as adsorbent for removal of Congo Red in aqueous solution

Low-cost raw oyster shell was successfully prepared as adsorbent for removal of Congo Red dye from aqueous solution. Therefore, different parameters were carried out in which the effect of adsorbent size, dose of adsorbent, initial dye concentration, contact time and pH were investigated. Based on the adsorption method, the optimum condition for adsorption of Congo Red dye were obtained under following condition; adsorbent size of 150 µm, 3.0 g of adsorbent dose, 50 mg/L of initial dye concentration with contact time at 7 hours and pH value at 3. Next, the adsorption isotherm which made up of Langmuir and Freundlich isotherm were also studied and generally, the result showed the best fit values nearer to 1 was Langmuir isotherms, R2= 0.989 for adsorbent size. The efficiency of removal for Congo Red dye were found out to be 92.69% in which this result indicates the raw oyster shell have a big potential as biosorbent in removal of Congo Red dye in aqueous solution and can be applied in industrial wastewater treatment.