Insights into chemically modified cocoa pods for enhanced removal of an anti-malaria drug

Abstract

Cocoa pod activated carbon prepared by ortho-phosphoric acid activation and used for the sequestration of Lumefantrine, an antimalarial drug from solution. EDX, FTIR and SEM characterization methods were used to elucidate the textural characteristics and morphological features of the adsorbent surface. Results from these characterization methods show that the CPHAC contains a high percentage of carbon, basic functional groups such as the hydroxyl groups and well-developed cylindrical pores on the surface. Batch adsorption studies were conducted to show the influence of agitation time, initial LUMF concentration and solution temperature on the adsorption process. At 303 K, maximum percentage removal of 90.9% was obtained at 20 mg/L initial LUMF concentration. Four models of isotherm were used to test experimental data, out of which the Langmuir isotherm model gave the best fit with an R2 value of 0.9934 at 303 K. The nature of adsorption was physical in nature as mean free energy of the d-R isotherm model was 0.745 kJ/mol. Maximum monolayer sorption capacity of 79.365 mg/g was recorded at 303 K and the pseudo-second-order kinetic model best explains the kinetics of adsorption. Thermodynamic studies reveal that the adsorption process was spontaneous, feasible and endothermic in nature. CPHAC proved to be very efficient in sequestering Lumefantrine drug from solution.