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

Abstract

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

Isotherm and kinetic studies of acid yellow 11 dye adsorption from wastewater using Pisum Sativum peels microporous activated carbon

“…This study's outcomes show that PPAC successfully removes the AY11 dye from the aqueous solution; as a result, PPAC can be used repeatedly without experiencing considerable loss in effectiveness.Anxieties about water shortage continue to grow in some parts of the world with ongoing pollution of present rivers in diverse locations. Chemical materials that place a heavy load on the aquatic environment can be listed as pesticides 1-3 , drugs 4,5 , dyes 6-10 , hydrocarbons 11,12 , and heavy metals [13][14][15][16][17] . These chemicals are introduced into the environment through home sewage or sewage from industrial and hospital facilities 18,19 .…”

Synthesis of Plant-Mediated Iron Oxide Nanoparticles and Optimization of Chemically Modified Activated Carbon Adsorbents for Removal of As, Pb, and Cd Ions from Wastewater

“…It is easier to adsorb a cation on a negatively charged surface. However, some other interactions may also be stronger than electrostatic forces . It is clear from the results that optimum pH on, which high adsorption, was recorded was beyond the pH pzc i.e.…”

Production of Activated Carbons from Food/Storage Waste

“…Dhahri et al proved that this material is able to adsorb 2527 mg of iodine per g of adsorbent [ 34 ]. Slightly larger capacities were also obtained for the activated carbons prepared by steam activation of walnut shells (1450 mg/g) [ 35 ] and the activation of shea butter husk with potassium chloride (1244 mg/g) [ 36 ]. However, it should be emphasized that the activated carbons obtained from expired or broken food products perform better than adsorbents obtained from such precursors as spinach leaves, citrus fruit skins, olive stones, and the commercial products obtained from the non-renewable precursors, such as peat and bituminous coal [ 38 , 39 , 40 ].…”