title: Cadmium(II) adsorption using functional mesoporous silica and activated carbon.
abstract: The role of surface functionality on silica and carbonaceous materials for adsorption of cadmium(II) was examined using various mesoporous silica and activated carbon. Silica surfaces were principally functionalized by mono-amino- and mercapto-groups, while carboxylic group was introduced to the activated carbons by oxidation. Functional groups on silica surface were formed using grafting and co-condensation techniques in their preparation. Mono-amino group was found more effective than di- and tri-amino groups for cadmium(II) adsorption on the grafted silica. Mono-amino groups prepared by co-condensation adsorbed cadmium(II) as much as 0.25mmol/g compared to mercapto- and carboxyl-groups which adsorbed around 0.12mmol/g, whereas Langmuir adsorption affinities were as strong as 50-60L/mmol for all of the three functions. The working pH range was wider for mercapto- and carboxyl-functions than for amino-group. Basic site could be an adsorption center for amino-functional groups while ion exchange sites were found to work for the mercapto- and carboxyl-functions to adsorb cadmium(II) from aqueous phase. Based on the experimental results, surface functional groups rather than structure of silica and carbon seemed to play a decisive role for cadmium(II) adsorption.
authors.affiliation: Department of Chemistry and Biochemistry, Faulty of Science and Engineering, Laurentian University, Sudbury, Ontario P3E 2C6, Canada.
authors.forename: Motoi
authors.initials: M
authors.lastname: Machida
authors.forename: Babak
authors.initials: B
authors.lastname: Fotoohi
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Amamo
authors.forename: Tomonori
authors.initials: T
authors.lastname: Ohba
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kanoh
authors.forename: Louis
authors.initials: L
authors.lastname: Mercier
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D056951:Photoelectron Spectroscopy
chemical_list: D002104:Cadmium; D002244:Carbon