Improved phenol sequestration from aqueous solution using silver nanoparticle modified Palm Kernel Shell Activated Carbon
Mujidat O. Aremu, A. O. Arinkoola, Idayat A. Olowonyo, K. K. Salam
Abstract
Modified Palm Kernel Shell Activated Carbon (PKSAC) using silver nanoparticle (Ag-NPs-PKSAC) was investigated on phenol uptake from aqueous solution. Effects of temperature (500-700 °C), time (90-120 min), and alkaline concentration (0.1-0.5 M) were studied on the yield and methylene blue numbers for the synthesis. Effects of initial concentration (100-200 mg/L), agitation (150-250 rpm), contact time (30-120 min), and adsorbent dosage (0.15-0.25 g) were studied in a batch experiment on percentage removal of phenol. The PKS, char, PKSAC and Ag-NPs-PKSAC were characterized using BET, FTIR, SEM, and proximate analyses. The synthesis of PKSAC was optimum at 608 °C, 0.5 M KOH, and carbonization holding time of 60 min. The optimum phenol uptake was 85.64, 90.29 and 91.70% for PKSAC, Ag-NPs-PKSAC, and commercial adsorbent, respectively. The adsorption mechanism of phenol followed the Langmuir isotherm and best described as physio-sorption with pseudo-second-order kinetics. Phenol exhibits high affinity (ΔS° = 0.0079 kJ/mol K) for Ag-NPs-PKSAC with favorable adsorption (ΔG° = -1.551 kJ/mol) at high temperature due to endothermic (ΔH° = 1.072 kJ/mol) nature of the system. The result obtained in this study compared favorably with the literature.