Microwave-assisted activated carbon from cocoa shell as adsorbent for removal of sodium diclofenac and nimesulide from aqueous effluents

• Published in: Journal of hazardous materials Vol. 289; pp. 18 - 27
• Main Authors: Saucier, Caroline, Adebayo, Matthew A., Lima, Eder C., Cataluña, Renato, Thue, Pascal S., Prola, Lizie D.T., Puchana-Rosero, M.J., Machado, Fernando M., Pavan, Flavio A., Dotto, G.L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30-05-2015
• Subjects: Activated carbon; Adsorbents; Adsorption; Anti-inflammatory; Anti-Inflammatory Agents, Non-Steroidal - isolation & purification; Cacao - chemistry; Carbon - chemistry; Charcoal - chemistry; Cocoa; Diclofenac; Diclofenac - isolation & purification; Drug Residues; Effluents; Hydrogen-Ion Concentration; Indicators and Reagents; Kinetics; Mathematical models; Medical Waste - analysis; Medical Waste Disposal - methods; Microwave-assisted activation; Microwaves; Sodium; Sulfonamides - isolation & purification; Thermodynamics; Microwave-assisted activation; Anti-inflammatory; Activated carbon; Effluents
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2015.02.026

•Microwave-assisted cocoa shell activated carbon was prepared and characterized.•The anti-inflammatories, diclofenac and nimesulide, were adsorbed onto MWCS-1.0.•Adsorption maximum values are 63.47 (diclofenac) and 74.81mgg−1 (nimesulide).•General order kinetic model suitably explained the adsorption process.•MWCS-1.0 was effectively used for treatment of simulated hospital effluents.
Microwave-induced chemical activation process was used to prepare an activated carbon from cocoa shell for efficient removal of two anti-inflammatories, sodium diclofenac (DFC) and nimesulide (NM), from aqueous solutions. A paste was obtained from a mixture of cocoa shell and inorganic components; with a ratio of inorganic: organic of 1 (CSC-1.0). The mixture was pyrolyzed in a microwave oven in less than 10min. The CSC-1.0 was acidified with a 6molL−1 HCl under reflux to produce MWCS-1.0. The CSC-1.0 and MWCS-1.0 were characterized using FTIR, SEM, N2 adsorption/desorption curves, X-ray diffraction, and point of zero charge (pHpzc). Experimental variables such as initial pH of the adsorbate solutions and contact time were optimized for adsorptive characteristics of MWCS-1.0. The optimum pH for removal of anti-inflammatories ranged between 7.0 and 8.0. The kinetic of adsorption was investigated using general order, pseudo first-order and pseu do-second order kinetic models. The maximum amounts of DCF and NM adsorbed onto MWCS-1.0 at 25°C are 63.47 and 74.81mgg−1, respectively. The adsorbent was tested on two simulated hospital effluents. MWCS-1.0 is capable of efficient removal of DCF and NM from a medium that contains high sugar and salt concentrations.