ABSTRACT
High cost of commercially available activated carbon increases the cost of effluent treatment, thus it is necessary to explore the utilization of low-cost, agricultural waste as adsorbents. Hence, the aim of this study was to investigate the efficiency and capacity of palm Kernel Shell derived activated carbon as an adsorbent in the removal of heavy metals in a binary competitive adsorption system from synthetic waste water.
The palm kernel shell activated carbon (PKSAC) was characterized to determine its physical properties using Fourier Transform Infrared Spectroscopy (FTIR); and Scanning Electron Microscope(SEM). The Central composite design (CCD) was used to study the effect of initial adsorbate concentration, contact time and adsorbent dosage on the adsorption process. Statistical models were developed for the process that fit the experimental data using Python Jupyter Notebook. Multi-objective optimization of statistical models for removal efficiency of the two metals were optimized using genetic algorithm in the MATLAB software environment.
Results showed that the pH of the adsorbent obtained was 6.8,moisture content was19.6%, ash content was 23.1%; had a bulk density of 0.7615 g/cm3 and a relatively high iodine number of 577.86.Infrared spectroscopy revealed strong thiocyanate and isothiocyanate class of compounds (S-C≡N stretching, N=C=S stretching group). Findings indicated that the adsorption process was influenced by the operational variables: contact time, initial metal concentration, and concentration of adsorbent. The optimal values for initial concentration, contact time and adsorbent dosage was : 38.595(mg/l); 260.4104 mins, and 0.8175 g respectively. The maximum removal efficiency was 82.06% for copper and 99.99% for Lead. Lead was competitively adsorbed more in comparison to copper which may be due to the sulphor-based groups on the adsorbent having higher affinity for lead ions. It is concluded that Palm Kernel shell activated carbon is cheap, renewable and effective in the treatment of Heavy metals: Lead and Copper from waste water.
