ABSTRACT
Rapid population growth, industrial expansion, and increased water consumption have led to pollution issues in many areas. Consequently, the contamination of water by both organic and inorganic chemicals has become a significant environmental concern. Phenol, in particular, poses a serious threat even at low concentrations, and its presence in water can result in adverse health effects such as protein degeneration, vomiting, discolored urine, and central nervous system paralysis if not removed from industrial effluents before entering water streams. The objective of this study is to evaluate the efficacy of activated carbon derived from orange peel in adsorbing phenol from aqueous solutions, using phosphoric acid as the activating agent. The orange peel underwent a drying process in an oven for three hours, followed by carbonization in a closed furnace at 400°C for one hour. The carbonized orange peel was then crushed and activated using 25% phosphoric acid for 15 hours. Various parameters, including pH, concentration, contact time, and adsorbent dose, were examined to determine the percentage removal of phenol from the aqueous solution. A spectrophotometer was utilized to measure the absorbance of the aqueous solution, enabling the determination of the percentage removal of phenol. The Box-Behnken design (BBD) of Design Expert 9.0.6 was employed to assess the effects and interactions of the adsorbent dose, pH, contact time, and concentration on the removal efficiency. Optimal conditions were determined for each variable, resulting in an adsorbent dose of 2g, a pH of 4.985, a concentration of 10μg/L, and a contact time of 150 minutes, achieving a phenol removal rate of 96.94%. This was significantly higher compared to the lowest phenol removal rate of 59.77%. These findings demonstrate the suitability of the response surface methodology approach for optimizing the adsorption of phenol removal from aqueous solutions.
