OPTIMIZATION OF CONGO RED (CR) DYE ADSORPTION FROM AQUEOUS SOLUTION ONTO RICE HUSK (RH) BIOSORBENT USING RESPONSE SURFACE METHODOLOGY (RSM)

In this study, Rice husk (RH) a renewable agricultural by product was utilized as biosorbent for the removal of Congo Red (CR) dye from aqueous solution. Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis were used to characterized the adsorbent. Batch Adsorption experiments were designed and conducted with the aid of Statistical Box-Benkhen Design (BBD) in other to investigate the effects of contact time, adsorbent dosage and pH on Congo Red (CR) removal. Adsorption of Congo Red (CR) dye onto RH was best described by a quadratic model equation, and analysis of variance revealed the significance of the model equation. Response surface methodology (RSM) was used to optimize the conditions of Congo Red (CR) dye adsorption onto RH biosorbent. The predicted optimum values of the process variables for Congo red (CR) removal were found to be at pH of 2.0, contact time of 10 minutes and adsorbent dosage of 0.539 g. The experimental percentage adsorption of Congo Red (CR) obtained under the predicted optimum conditions was 98.97 %, which is very close to the predicted value of 100 % and thus validates the developed model. Adsorption capacity of the biosorbent (RH) was found to be 3.95 mg/g. The research generally revealed that Rice husk (RH), a renewable agricultural by product could be utilized as a promising adsorbent in the removal of the Congo Red (CR) dye from aqueous solution