Removal of Naphthalene, Fluorene and Phenanthrene by Recyclable Oil Palm Leaves’ Waste Activated Carbon Supported Nano Zerovalent Iron (N-OPLAC) Composite in Wastewater

Abstract

Despite keen interest in the development of efficient materials for the removal of polycyclic aromatic hydrocarbons (PAHs) in wastewater, the application of advanced composite materials is still unexplored and needs attention. Therefore, this study focused on the synthesis of the composite of oil palm leaves’ waste activated-carbon (OPLAC) and nano zerovalent iron (NZVI) at Fe:OPLAC = 1:1 (N-OPLAC-1) and 1:2 (N-OPLAC-2). The composite with enhanced surface properties was applied for removal of three PAHs including naphthalene (NAP), fluorene (FLU) and phenanthrene (PHE) in wastewater at various pH, dosages, contact time and initial concentration in batch testing. The PAHs’ removal parameters were optimized using design expert software. The PAHs’ removal efficiency was evaluated in produced water at optimized parameters. The results showed that the N-OPLAC-2 had superior surface properties compared to N-OPLAC-1. The removal of NAP, FLU and PHE was heterogenous, favorable and involved chemisorption proved by Freundlich isotherm and pseudo-second-order kinetic models using N-OPLAC-2. The optimum parameters were as follows: pH of 3, dosage and contact time of 122 mg/L and 49 min, respectively. The application of N-OPLAC-2 in produced water was favorable for removal of NAP, FLU and PHE and showed up to 90% removal efficiency, and higher stability up to 3 cycles. It can be concluded that the NZVI-OPLAC composite was successfully synthesized in this study and the materials showed good removal efficiency for three PAHs (NAP, FLU and PHE) in wastewater.