Optimization of the Preparation of Activated Carbon from Prickly Pear Seed Cake for the Removal of Lead and Cadmium Ions from Aqueous Solution

In this study, we evaluated the use of prickly pear seed cake, a by-product oil extraction, as new precursor for producing activated carbon by phosphoric acid activation, and obtained carbon’s capacity heavy metal removal from aqueous solution. Response surface methodology based on full factorial design at two levels (24) was developed to reduce number experiments reach optimal preparation conditions cadmium lead ions solutions. Design Expert 11.1.2.0 Trial software used generating statistical experimental analyzing observed data. Factors influencing activation process, such carbonization temperature, time, impregnation ratio, were studied. Responses studied in depth with an analysis variance estimate their significance. Each response outlined first-order regression equation demonstrating satisfactory correspondence between predicted results adjusted coefficients correlation. Based data, best metals solution indicated. The maximum iodine methylene blue index 2527.3 mg g−1 396.5 g−1, respectively, using following conditions: Tc = 500 °C, Ta ratio 2:1 (g H3PO4: g carbon), time hours. adsorption reached 170.2 158.4 Cd2+ Pb2+, 600 400 one hour. characterized Boehm titration, pH point zero charge (pHPZC), Brunauer–Emmett–Teller area (SBET), scanning electron microscopy. Adsorption performed according different parameters: solution, adsorbent dosage, contact initial concentration. Regeneration proved that still had high Pb2+ after five regeneration cycles.