Ceramic matrices for immobilization of heavy metals adsorbed on rice husk

Abstract

Numerous studies have been conducted about the removal of heavy metal ions from aqueous solutions using lignocellulosic materials, which are capable of adsorbing various contaminants present even at low concentrations. Rice husk constitutes biomass waste that has found multiple applications in diferent felds, such as the removal of heavy metals by adsorption. After this process, a biomass-contaminant waste is generated, which currently does not have viable and low-cost alternatives for its fnal disposal. Thus, the objective of this work is to evaluate the possibility of incorporating rice husk contaminated with Cu–Ni–Cd and Pb–Zn into ceramic matrices, to immobilize these hazardous metals. Ceramic pieces from mixtures of commercial clay and rice husk with adsorbed metal, added by 10% in volume were obtained. The raw materials were characterized by diferent techniques, such as SEM-EDS, XRD, DTA-TGA, particle size distribution, ecotoxicity, etc., while in ceramic products were analysed porosity, permanent volumetric variation, weight loss of ignition, ecotoxicity, among others. From the overall results, it is possible to conclude that the obtained ceramic pieces have immobilized within their structure, the heavy metals present on rice husk. The bricks have excellent physical and mechanical properties that make possible their use in civil construction.