title: Synthesis of highly phosphonic acid functionalized benzene-bridged periodic mesoporous organosilicas for use as efficient dye adsorbents.
abstract: Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved π-π stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles.
authors.affiliation: Department of Chemistry, National Central University, Chung-Li 32054, Taiwan, ROC.
authors.forename: Juti Rani
authors.initials: JR
authors.lastname: Deka
authors.affiliation: Department of Chemistry, National Central University, Chung-Li 32054, Taiwan, ROC.
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Liu
authors.affiliation: Department of Chemistry, National Central University, Chung-Li 32054, Taiwan, ROC.
authors.forename: Tzu-Hua
authors.initials: TH
authors.lastname: Wang
authors.affiliation: Department of Chemistry, National Central University, Chung-Li 32054, Taiwan, ROC.
authors.forename: Wei-Chieh
authors.initials: WC
authors.lastname: Chang
authors.affiliation: Department of Chemistry, National Central University, Chung-Li 32054, Taiwan, ROC. Electronic address: hmkao@cc.ncu.edu.tw.
authors.forename: Hsien-Ming
authors.initials: HM
authors.lastname: Kao
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry; D001555:Benzene Derivatives / Q000737:chemistry*; D001557:Benzenesulfonates / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D017646:Organosilicon Compounds / Q000737:chemistry*; D010619:Phenazines / Q000737:chemistry; D010757:Phosphorous Acids / Q000737:chemistry*; D016062:Porosity; D012235:Rhodamines / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D001555:Benzene Derivatives; D001557:Benzenesulfonates; D004396:Coloring Agents; D017646:Organosilicon Compounds; D010619:Phenazines; D010757:Phosphorous Acids; D012235:Rhodamines; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C011977:phenosafranine; C029773:rhodamine B; C014722:2-naphthol orange; D008751:Methylene Blue
keywords: Adsorption; Dyes; Periodic mesoporous organosilicas; Phosphonic acid