Evaluation of rice husk ash in adsorption of Remazol Red dye from aqueous media

Abstract

Abstract: The rice husk ash (RHA) extracted from the rice husk (RH) was measured on the removal of the Remazol Red dye. Adsorption variables such as solution pH, dye concentration, adsorbent amount, contact time, and reuse of the RHA were measured. The adsorption equilibrium was achieving in approximately 30 min, due to the rapid electrostatic attraction between the OH2+ groups of the RHA surface and the sulfonic groups of the dye, which occurred mainly at a pH = 2 value. The removal efficiency of the RHA decreased when the initial dye concentrations were higher, due to pore-filling within of the RHA structure with the migration dye molecules. However, the removal percentage increased with increasing adsorbent amount. The adsorption data were suitable with the Freundlich isotherm and pseudo-second order models. Graphical abstract: [Figure not available: see fulltext.]