Green synthesis of palm carbon composite derived of oil palm empty fruit bunches with metal organic frameworks comprising Cu(II)-benzene dicarboxylate for heavy metals remediation

Oil Palm Empty Fruit Bunches (OPEFB) are the primary solid waste generated by the palm oil industry. They are produced in large quantities and remain underutilized, despite their significant potential as carbon precursors for environmental applications. This study aims to develop OPEFB Activated Carbon or Palm Carbon (PC), then compose with Metal–Organic Frameworks (MOFs) consist of Cu(II) and benzene dicarboxylate (BDC) as Cu(BDC) 2 through a green synthesis approach of chemical activation, produced PC-Cu(BDC) 2 composite or refer to PC-CB-1. The XRD characterization revealed a structural transformation from the monoclinic system of pure MOFs Cu(BDC) 2 to a semi-amorphous triclinic system in the PC–CB-1 composite, with crystallinity increasing from 4.6% in Palm Carbon (PC) to 32.8% in the PC–CB-1 composite. BET analysis confirmed the formation of a hierarchical pore structure with a higher surface area of PC–CB-1 compared to PC. Adsorption studies of PC–CB-1 exhibited the highest Fe(II) adsorption capacity of 16.04 mg/g, significantly higher than PC (3.77 mg/g). The Fe(II) adsorption isotherm on PC–CB-1 followed the Langmuir model, indicating monolayer adsorption on relatively homogeneous active sites. Kinetic studies showed that Fe(II) adsorption on PC–CB-1 was better described by the pseudo-first-order model, whereas Cu(II) and Zn(II) adsorption followed the pseudo-second-order model. These findings suggest the involvement of both diffusion and chemisorption mechanisms. These results indicate a combination of diffusion and chemisorption adsorption mechanisms. OPEFB-based carbon–MOFs composites show high potential as environmentally friendly adsorbents for heavy metal remediation in wastewater.