Mechanisms of Alizarin Red S and Methylene blue biosorption onto olive stone by-product: Isotherm study in single and binary systems.
The biosorption process of anionic dye Alizarin Red S (ARS) and cationic dye methylene blue (MB) as a function of contact time, initial concentration and solution pH onto olive stone (OS) biomass has been investigated. Equilibrium biosorption isotherms in single and binary systems and kinetics in batch mode were also examined. The kinetic data of the two dyes were better described by the pseudo second-order model. At low concentration, ARS dye appeared to follow a two-step diffusion process, while MB dye followed a three-step diffusion process. The biosorption experimental data for ARS and MB dyes were well suited to the Redlich-Peterson isotherm. The maximum biosorption of ARS dye, qmax = 16.10 mg/g, was obtained at pH 3.28 and the maximum biosorption of MB dye, qmax = 13.20 mg/g, was observed at basic pH values. In the binary system, it was indicated that the MB dye diffuses firstly inside the biosorbent particle and occupies the biosorption sites forming a monodentate complex and then the ARS dye enters and can only bind to untaken sites; forms a tridentate complex with OS active sites.
Department of Chemical and Environmental Sciences, Materials & Surface Science Institute, University of Limerick, Ireland; School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, Northern Ireland, UK. Electronic address: Ahmad.B.Albadarin@ul.ie.
Ahmad B
AB
Albadarin
School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, Northern Ireland, UK.
Chirangano
C
Mangwandi
D000327:Adsorption; D000880:Anthraquinones / Q000737:chemistry*; D018533:Biomass; D004396:Coloring Agents / Q000737:chemistry; D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008751:Methylene Blue / Q000737:chemistry*; D031658:Olea; D014866:Waste Products; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D000880:Anthraquinones; D004396:Coloring Agents; D014866:Waste Products; D014874:Water Pollutants, Chemical; C004468:Alizarin Red S; D008751:Methylene Blue
Alizarin Red S; Anionic dye; Biosorption; Cationic dye; Methylene blue; Olive stone