Coconut Shell Based Activated Carbon for Heavy Metal Removal from Combustion Engine
Abstract:
The production of inexpensive activated carbon (AC) for the removal of heavy metals from spent motor oil was studied through the chemical activation of coconut shell with K2CO3. According to proximate analysis, the fixed carbon content increased from 68.17% to 72.77%, while the volatile matter, moisture, and ash content decreased from 14.98% to 14.01%, 8.43% to 6.10%), and the bulk density decreased from 0.578 to 0.543 g/mL. Additionally, the surface pH changed from 7.3 to approximately 8.0, indicating that the pore development and surface function alization were successful. When applied to used lubricating oil, the AC achieved removal efficiencies of 90.16 % for Cu, 73.64 % for Fe, and 78.51 % for Pb, respectively. Following activation, FTIR spectroscopy showed increased oxygen-containing functional groups (–OH, –COOH, C=O, and C=C), with significant transmittance decreas es around 1700 cm⁻¹, suggesting increased adsorption sites. SEM micrographs showed a highly porous, honey comblike morphology with interconnected macro and mesopores, supporting rapid mass transfer and contaminant capture. These results show that K2CO3 activated coconut shell carbon has favorable structural and chemical properties for effective removal of divalent heavy metals from complex oily matrices. Future research is advised to optimize activation parameters, evaluate regenerability, and handle chromium speciation issues.
