Optimization Studies of The Treatment of Laundry Wastewater Using Activated Carbon Derived from HDPE Chars

Abstract

Growing plastic waste and industrial wastewater necessitate sustainable treatment solutions. This study optimized industrial wastewater treatment using activated carbon derived from high-density polyethylene (HDPE) pyrolysis char via thermal activation, eliminating the need for aggressive chemical agents. Characterization via FTIR, BET, and SEM-EDX revealed a micro-mesoporous structure with a BET surface area of 287.3 m²/g, a 90.05 atomic percent carbon content, and dominant pore sizes of 2.1 to 2.6 nm. The adsorbent performance was evaluated against laundry wastewater using a Central Composite Design and Response Surface Methodology. Statistical analysis yielded a robust model (R² = 0.9406, adequate precision = 15.54) to assess the impact of dosage, contact time, and initial concentration. Numerical optimization identified ideal conditions: 8.68 g/L dosage and 15-minute contact time for a 100 mg/L initial concentration. Experimental validation confirmed a 77.99% total dissolved solids (TDS) reduction, aligning closely with the predicted 79.48%. Post-treatment analysis indicated significant quality improvements, with COD and TOC levels decreasing to 35.8 mg/L and 21.6 mg/L, respectively, while dissolved oxygen increased from 0.6 to 4.3 mg/L. This research confirms that HDPE-derived activated carbon offers an effective, sustainable approach for both wastewater remediation and plastic waste valorization. Copyright © 2026 by Authors, Published by Universitas Diponegoro and BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).