Life Cycle Assessment of Valorizing Waste Polyethylene and Coconut Shells Into Activated Carbon Polymer Flakes

Polyethylene (PE) accounts for approximately 40% of total global plastic production, yet PE waste remains an underutilized feedstock. Meanwhile, activated carbon (AC) derived primarily from coconut shells (CS), the most popular source, is usually produced as powder, posing challenges in handling and recovery. This study explores the synergistic valorization of these two waste streams to produce value-added AC polymer flakes (ACPF) through (a) chemical activation and pyrolysis of the CS, (b) dissolution of PE and dispersion of activated CS in a common solvent, and (c) heat treatment to form flakes. Life cycle assessment (LCA) results indicate an energy net (EN) consumption of 55 MJ for the NaOH route and 56 MJ for the KOH route, with corresponding climate change (CC) impacts of 2.11 kg CO₂ eq. and 2.17 kg CO₂ eq., respectively. Performance testing of ACPF using rhodamine B and methylene blue dyes demonstrated maximum adsorption capacities of 892 and 389 g/kg, respectively. Besides, replacing the commercial AC with ACPF led to approximately a 56% reduction in both CC impact and EN consumption. The integration of CS and PE waste leads to more sustainable AC production and promotes the utilization of waste for environmental purposes.