Utilizing Cement Kiln Dust as an Efficient Adsorbent for Heavy Metal Removal in Wastewater Treatment

Abstract

Cement kiln dust (CKD), a by-product of cement manufacturing, has been largely underutilized despite its potential as an eco-friendly adsorbent for wastewater treatment. This study addresses the knowledge gap regarding CKD’s effectiveness in removing heavy metals from wastewater residuals. A comprehensive experimental program was conducted to optimize key parameters such as the pH (6–9), contact time, sorbent dosage, and initial heavy metal concentrations using a batch equilibrium technique. The results demonstrated that CKD can effectively remove heavy metals, achieving removal efficiencies of 98% for Pb, 94% for Zn, 92% for Cu, and 90% for Cd within just 4 h of treatment. Importantly, CKD not only provided high adsorption efficiency but also resulted in a significant reduction in the formation of hazardous solid sludge, a major concern in traditional wastewater treatment methods. The adsorption data closely matched the Langmuir isotherm model, further validating CKD’s potential as a sustainable, cost-effective solution for reducing heavy metal contamination in wastewater while minimizing the environmental impact.