CTAB modified large surface area nanoporous geopolymer with high adsorption capacity for copper ion removal

• Published in: Applied clay science Vol. 150; pp. 106 - 114
• Main Authors: Singhal, Aditi, Gangwar, Bhanu P., Gayathry, J.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2017
• Subjects: Adsorption; Geopolymer; Kinetics; Nanoporous; Geopolymer; Kinetics; Adsorption; Nanoporous
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2017.09.013

Nanoporous geopolymer was synthesized with and without using Cetyl trimethylammonium bromide (CTAB) by condensing the mixture of metakaolin and alkali solution at a fixed ratio at room temperature. The surface area of CTAB-geopolymer was found to be more (216m2/g) as compared to without CTAB added geopolymer (137m2/g). The experimental results verified that the geopolymer could adsorb copper ions completely at lower concentrations and partially at higher concentrations. Pseudo second order model fits well at all the concentration from 55 to 1700ppm as the values of the correlation coefficient lies between 0.96 and 0.99. Intraparticle diffusion model at the concentration 55ppm explains that there is only boundary layer diffusion (instantaneous) and after this step, all the Cu ions are exchanged by the nanoporous geopolymer. At 120ppm, intraparticle diffusion model shows multilinearity. Different adsorption models - Langmuir, Freundlich and Tempkin were also tested to evaluate the most appropriate model and it was found that adsorption follows Langmuir model. The adsorption capacity and pseudo second order rate constant is estimated to be 1.65meq/g which is significantly higher than the fly ash based nonporous geopolymer. •High surface area geopolymer using CTAB•Surface area and pore volume is 216m2/g and 0.22cm3/g.•High adsorption capacity; 1.65meq/g