Upcycling boiler fuel rice-husk waste: a sustainable cellulose–clay nanocomposite for lead remediation

Abstract

A novel approach for the utilization of a boiler fuel rice-husk silica waste-based cellulose–clay nanocomposite (CCN) has been developed for the first time, and it has been assessed as a green adsorbent for the removal of Pb²⁺ from water. The addition of cellulose, which is rich in hydroxyl groups, along with the layered clay, enhanced the surface reactivity, porosity, and structural stability of the resulting composite. The CCN was characterized through a variety of methods, including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), Zetasizer, and UV-vis spectroscopy. Characterization of the CCN confirmed the development of a well-integrated composite featuring numerous active sites. A specially designed dynamic packed column adsorption system showed quick and efficient uptake of Pb²⁺, where the removal effectiveness of the CCN was influenced by several factors such as pH, initial concentration, and contact time. The CCN achieved an impressive adsorption capacity of 195.80 mg g⁻¹ under controlled flow rates, adsorption dosage, and pH conditions. These findings underscore the potential of CCNs as affordable and high-performance materials for the remediation of heavy metals in wastewater treatment.