Abstract
The increasing contamination of water streams with heavy metals has continuously posed significant environmental and health concerns, highlighting the need for sustainable and cost-effective methods. This study aimed to synthesize biomass derived activated carbon (AC) from pinecone and avocado seed for the recovery of heavy metals in wastewater. Activated carbons were successfully synthesized from using a chemical activation method with potassium hydroxide (KOH) as an activating agent. The activation process was done under varying conditions such as temperature, time, and KOH concentration. The structural and functional properties of the prepared activated carbons were analysed using Fourier-transform infrared spectroscopy (FTIR) Raman spectroscopy, scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) surface area analysis. FTIR analysis of avocado seed-derived activated carbon (ASAC) and pinecone-derived activated carbon (PCAC) revealed the presence of characteristic functional groups such as hydroxyl (–OH), carbonyl (C=O), and carboxyl (–COOH) associated with activated carbon. while SEM micrographs confirmed the progressive pore development in PCAC and ASAC
The optimum synthesis parameters for PCAC were 600 °C, 0.7M KOH, and 1 hour of activation time, yielding a porous structure with interconnected pores and a surface area of 1 680.81m2/g. For ASAC, the optimal conditions were 700 °C, 0.3 M KOH, and 1 hour, resulting in a surface area of 1 343.61m2/g. The ACs were further immobilized with ionic liquid 1-butyl-3-methylimidazolium bromide ([Bmim][Br]) to enhance adsorption capacity. The modified composites were evaluated for their ability to remove Pb, Cu, Ni, and Pt from aqueous solutions
The PCAC-IL composites achieved maximum removal efficiencies of 79% for Pb, 23% for Cu, 13% Ni and 16 % for Pt, while ASAC-IL composites achieved maximum removals of 98% for Pb, 62% for Cu, 19% Ni and 42% for Pt. A significant decrease in metals adsorption was observed as IL loading increased. The findings demonstrate that biomass-derived activated carbon served as an effective and sustainable adsorbent for heavy metal removal, with potential application in wastewater treatment and metal recovery industries.