DOI: https://doi.org/10.55373/mjchem.v25i2.117

Keywords: Charcoal; black carbon; biochar; activated carbon; lead

Abstract

A cost-effective treatment for lead (Pb)-contaminated wastewater has been a challenge due to the high consumption of costly chemicals. Palm kernel shell (PKS) has been used as a solid fuel for boilers. An incomplete combustion produces a by-product called PKS biochar that can be used as a sorbent for the removal of Pb from wastewater. The objectives of this study are to determine the optimized sorption parameters and to study the Pb sorption mechanism of PKS biochar using non-linear kinetics and isotherm models. The maximum Pb removal was achieved at a PKS biochar dosage of 1.25 g/L, and pH 5. The sorption data were best described by the Langmuir isotherm model (R2: 0.9478) and the pseudo-second order model (R2: 0.9317). The Langmuir maximum Pb sorption capacity of PKS biochar was 7.48 mg/g. The decrease of CEC and intensity of the -OH band in FTIR spectra indicate a net loss of negative-charge oxygen functional groups via decarboxylation and decarbonylation. The slightly increased iodine number and BET surface area corroborated with proximate analysis, showing that pyrolysis at 500 C did not eliminate volatile matter from the pore of PKS biochar, The sorption process may have involved the formation of the Pb monolayer on the surface of PKS biochar, and indicate the rate-limiting step of the Pb sorption process is the formation of strong chemical bonds.