title: Microscale scavenging of pentachlorophenol in water using amine and tripolyphosphate-grafted SBA-15 silica: batch and modeling studies.
abstract: Mesoporous silica SBA-15 meets most criteria for selection of water treatment adsorbents such as high specific surface area, large pore-size, chemical inertness, repertory of surface functional groups, good thermal stability, selectivity, regenerability, and low cost of manufacture. However, its use for water treatment is still largely unexplored. SBA-15 and its functionalized derivatives of aminopropyltriethoxysilane (SA) and tripolyphosphate (ST) were synthesized, characterized, and used to investigate pentachlorophenol (PCP) removal from aqueous solutions. Functionalization improved SBA-15 capacity for PCP removal from solution in accordance with the trend SBA-15 < ST < SA. Sorption rate experiments data fit the Lagergren pseudo-second order kinetics model. Intra-particle diffusion indicated that the sorption is controlled by two mechanisms: intra-particle and equilibrium diffusion. Adsorptive pore-filling and electrostatic interactions were implicated in the removal of PCP from solution. Electrostatic interaction led to ≥75% increase in sorption upon functionalization. The equilibrium sorption data of the PCP on these mesoporous materials fits the Freundlich isotherm. Desorption hysteresis was low for the pristine SBA-15, but the functionalized SBA-15 materials showed higher hysteresis. The results imply that functionalized SBA-15 sorbents are promising materials for microscale scavenging of PCP in solution.
authors.affiliation: Department of Chemistry, University of Ibadan, Ibadan, Nigeria; National Center for Nanoscience and Technology, Beijing 100190, China. Electronic address: pauldn2@yahoo.com.
authors.forename: Paul N
authors.initials: PN
authors.lastname: Diagboya
authors.affiliation: Department of Chemistry, University of Ibadan, Ibadan, Nigeria.
authors.forename: Bamidele I
authors.initials: BI
authors.lastname: Olu-Owolabi
authors.affiliation: Department of Chemistry, University of Ibadan, Ibadan, Nigeria.
authors.forename: Kayode O
authors.initials: KO
authors.lastname: Adebowale
mesh_terms: D000327:Adsorption; D000588:Amines / Q000737:chemistry; D006801:Humans; D010416:Pentachlorophenol / Q000737:chemistry*; D011122:Polyphosphates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D000588:Amines; D011122:Polyphosphates; C509969:SBA-15; D014874:Water Pollutants, Chemical; D012822:Silicon Dioxide; D010416:Pentachlorophenol; C005692:triphosphoric acid
keywords: Adsorption; Functionalization; Mesoporous silica SBA-15; Pentachlorophenol; Tripolyphosphate