Characterization of Modified Pinus sylvetris Bark Activated Carbon for Adsorptive Capacity on Dye and Drug Industrial Wastewater

Abstract

Water is an essential natural resources needed by all living nature but access to clean water has been a serious global problem courtesy industrial revolutions and developments involving generation of large amount of wastewaters containing toxic pollutants which find their ways into the various water sources and cause serious health and environmental challenges. In quest to proffer a solution, we prepared an alkaline modified Pinus sylvetris bark activated carbon (MPSBAC) to remove Congo red (CR) dye and tetracycline (TC) from aqueous solutions. MPSBAC was characterized by FESEM, FTIR and EDAX and the results revealed an irregular-scattered, porous and coarse morphology with the presence of several functional moieties and ionizable elements that are possibly responsible for removal of CR and TC from aqueous solutions through surface interactions. Adsorption capacity of the MPSBAC for removal of CR-dye and TC was also studied under different experimental conditions including pH, adsorbent dosage, contact time, temperature and initial concentration. The results showed optimal pH 2.0 and 8.0 for maximum adsorption of CR and TC respectively. Equilibrium adsorption capacity (q_e) decreased from 2038.45- 5.58 mg/g and 797.92- 0.25 mg/g for CR and TC respectively as adsorbent dosage increased from 1.00- 200.00 mg. The study of initial CR and TC concentrations showed increased adsorption capacities as the initial concentrations increased from 5 to 200 mg/L at 298 K, 308 K and 328 K. For CR and TC at 298 K, 313 K and 328 K, q_e increased from 18.07- 989.06 mg/L, 0.42- 671.04 mg/L; 19.84- 777.06 mg/L, 8.15-769.02 mg/L and 18.59- 988.02 mg/L, 14.87- 823.98 mg/L respectively. Contact time studies of adsorption of CR-dye and TC onto MPSBAC revealed that uptake of the dye and TC increased from 54.01- 99.22 % (135.05- 244.95 mg/kg) and 96.45- 97.63 % (482.23- 487.98 mg/g) respectively as agitation time increased until equilibrium is reached after 180 minutes. The present study is of the opinion that MPSBAC could be a promising cheap adsorbent for the removal of dye and pharmaceutical products from aqueous solutions. It is therefore recommended that kinetics and thermodynamics studies should be carried out on the adsorbent to corroborate these findings.