Optimization on Methylene Blue and Congo Red Dye Adsorption onto Cassava Leaf using Response Surface Methodology

Abstract

In this work, the operating parameters for removal of Methylene blue (MB) and Congo red (CR) dye via adsorption onto Cassava leaf (CL) powder was optimized using Response Surface Methodology (RSM). The range of study for contact time was between 20 to 120 minutes while the adsorbent dosage range was 0.2 to 1.0 g. As for the pH, the range was from pH 2.0-11.0. Lastly, the temperature of the solution was set from 25 ËšC to 75 ËšC. The trend of the dye removal was found to be best fitted into quadratic model. It was found that pH played a significant role in the MB and CR dye removal. Alkaline condition was more favourable for MB dye removal while CR dye can be adsorbed better on CL in acidic solution. Optimum MB removal at 99.9% could be obtained at minimum contact time of 20 min and room temperature under neutral pH and 0.83 g of CL powder. Meanwhile, 93.24% of CR dye removal could be achieved under optimized condition of 0.86 g of CL powder and acidic condition of pH 2.0 at minimum contact time of 20 min as well as room temperature. This indicates that CL powder has the potential for dye removal under mild condition of room temperature and within short period of time.