Publication: Amoxicillin, chloramphenicol and oxytetracyclines antibiotics adsorption by activated carbon generated from tecoma wood waste
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Date
2023-08-01
Authors
Mohamad Nasran Bin Nasehir Khan
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Abstract
The occurrence of antibiotics in the environment has contributed to negative consequences towards human health and aquatic life. Antibiotics are very difficult to be removed from wastewater using traditional techniques due to their highly soluble nature. This study focuses on synthesizing Tecoma chip based activated carbon (TCAC) to adsorb antibiotics namely amoxicillin (AMOX), chloramphenicol (CAP) and oxytetracyclines (OXY) from aqueous solution. TCAC was prepared by physicochemical activation which includes microwave heating, carbon dioxide (CO2) gasification and potassium hydroxide (KOH) chemical treatment. Response surface methodology (RSM) was used as the optimizing tool in producing TCAC. Optimum preparation conditions were found at 657 watts for radiation power, 20 minutes for radiation time and 0.99 for impregnation ratio (IR), which resulted into 27.68% of TCAC’s yield with 84.06 %, 87.84 % and 82.71 % removal of AMOX, CAP and OXY, respectively. Optimized TCAC shows high BET surface area of 924.85 m2/g and total pore volume of 0.3854 cm3/g. In the equilibrium study, adsorption uptakes increased with adsorbates initial concentration. Isotherm study revealed that AMOX-TCAC and OXY-TCAC adsorption systems followed Langmuir model while CAP-TCAC adsorption system followed Freundlich model. Langmuir monolayer adsorption capacities, Qm of TCAC were found to be 357.14 mg/g, 434.78 mg/g and 344.83 mg/g for adsorbing AMOX, CAP and OXY, respectively. In term of kinetic study, all adsorption systems followed pseudo-second order kinetic model. Adsorption mechanism study found that the rate controlling step were film diffusion based on the Boyd plots. The thermodynamic study revealed that all adsorption systems studied were endothermic, spontaneous in nature and controlled by physisorption. In bed column studies, the adsorbates percentage removals were found to increase with bed height while decrease with adsorbate flowrate and initial concentration. The best model fitted the breakthrough curve for both AMOX-TCAC and CAP-TCAC were Yoon Nelson model while OXY-TCAC was excellent with Thomas model for these studies. TCAC was found to be suitable in removing AMOX, CAP and OXY from an aqueous solution.