Kinetic, thermodynamic and equilibrium studies on removal of hexavalent chromium from aqueous solutions using agro-waste biomaterials, casuarina equisetifolia L. and sorghum bicolor

• Published in: The Korean journal of chemical engineering 2016, 33(8), 197, pp.2374-2383
• Main Authors: Prasanthi, Mokkapati Ramya, Jayasravanthi, Mokkapati, Nadh, Ratnakaram Venkata
• Format: Article
• Language: English
• Subjects: Biotechnology; Catalysis; Chemistry; Chemistry and Materials Science; Environmental Engineering; Industrial Chemistry/Chemical Engineering; Materials Science; 화학공학
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-016-0078-6

Removal of Cr(VI) by biosorption on two agro waste materials, casuarinas fruit powder (CFP) and sorghum stem powder (SSP), has been investigated. The prepared adsorbent materials were characterized by SEM, EDX, FTIR and BET. These biomaterials effectively removed Cr(VI) with a maximum removal of 93.35% and 63.75% using 15 gL −1 and 5 gL −1 of CFP and SSP, respectively, at 60 °C with 20mgL −1 initial Cr(VI) concentration in solution. In both cases of adsorbents, kinetic data of adsorption fitted well in pseudo-second-order in terms of correlation coefficient (R 2 ). This helps in proposing the process of adsorption as chemical coordination, which is correlated with the thermodynamic study results conducted at different values of temperature. Langmuir, Freundlich and D-R models were evaluated for description of metal sorption isotherms. Values of coefficients of intra-particle diffusion and mass transfer have also been determined at different values of temperature.