Removal of direct yellow 12 from aqueous solution by adsorption onto spirulina algae as a high-efficiency adsorbent

Abstract

In this research, the adsorption of direct yellow 12 (DY12) on the algae as an eco-friendly adsorbent in the batch system was studied. After preparation of spirulina algae, it was characterized using FTIR, BET and AFM. This nano-size and mesoporous material was then used to study the DY12 removal from aqueous solution by investigating the effect of adsorbent dosage, pH, and initial concentration of solution and contact time. Furthermore, kinetic study was carried out using well-known models, and the results indicated that the DY12 adsorption by spirulina followed the pseudo-second order model. Moreover, because of the examination of adsorption mechanism, intra-particle diffusion model was investigated. Isotherm study by using equilibrium data revealed that this process is favorable, and its maximum adsorption capacity, 714 mg g-1, is the highest amount among previous works; these results confirm that spirulina is one of the most promising material in eliminating DY12 and other anionic dyes.