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PDF of thesis T13566 PDF of thesis T13566 - (13 M)
Title Removal of VOCs and H₂CO from air by nanoparticulate silica adsorbents or TiO₂ photocatalysts / Abdunaser Mabruk S Ewlad-Ahmed.
Name Ewlad-Ahmed, Abdunaser Mabruk S. .
Abstract Constant concentrations of selected VOCs (toluene, ethylbenzene, cumene and dichlorobenzene) and formaldehyde (H₂CO) were successfully generated in separated sampling chambers. A commercially available sorbent (Tenax TA) and silica C₁₈ cartridges impregnated with trapping solution were used to determine experimental masses "references masses" of VOCs and H₂CO, respectively, using selected sampling conditions. Mesoporous silica samples (MCM-41, MWD-MCM-41 and SBA-15) were synthesised under harsh conditions by traditional sol-gel methods. Extraction efficiencies of these adsorbents were compared to Tenax TA, and showed similar performances (64 to 69 %) for VOCs extraction. However, SBA-15 had slightly higher dynamic capacity due to its bimodal pore structure which includes microporores. Novel silica green nanomaterials (GNs) were synthesised using a bioinspired route; under mild conditions of natural pH and ambient temperature, rapid synthesis (15 min) and in all aqueous s olutions. However produced GN materials have significantly lower surface areas (58 - 355 m² g-¹) compared to MCM-41 (1014 m² g-¹), they had similar or better extraction efficiencies (60 - 80 %) of MCM-41 due to their unique porosity including micropores. In addition they had comparable capacities per unit surface area with MCM-41. A novel synthesis route "green" was applied to produce mesoporous silica (USG) with high surface area (up to 1100 m² g-¹), pore size of 2.6 nm and large pore volume (1.00 cm³ g-¹) which are similar to MCM-41 properties. The new produced USG demonstrated a similar performance (60 %) and adsorption capacity for VOCs extraction compared with MCM-41. Furthermore all silica adsorbents were successfully functionalised with organic amine groups in order to examine their performance for H₂CO extraction.
Abstract Results demonstrated that H₂CO was removed from air permanently by chemisorption on functionalized adsorbents. Finally, porous TiO₂ coated onto glass beads were used for VOCs degradation as the first time. The results indicated that the best performance of VOCs degradation (up to 80 %) was achieved by using smaller glass beads, at lower flow rate or an increase of coating number (thickness of films).
Publication date 2013
Name University of Strathclyde. Dept. of Pure and Applied Chemistry.
Thesis note Thesis PhD University of Strathclyde 2013 T13566
System Number 000003288

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