Hussein Hamad

Functionalization of SBA-15 materials for the adsorption of phenols from aqueous solution

Water pollution by toxic organic compounds is a problem and demand for efficient adsorbents for the removal of toxic compounds is increasing. In the present work, we studied the functionalization of SBA-15 materials via the co-condensation between an alkoxysilane and an organoalkoxysilane in the presence of P123 as structuring agent. Several types of ligands were used: 3-mercaptopropylmethyldimethoxysilane, N-[3-(trimethoxysilyl) propyl] aniline; aminopropyltrimethoxysilane; [aminoethylamino]-propyltrimethoxysilanes and [(2-aminoethylamino) ethylamino] propyltrimethoxysilanes. These materials exhibit BET surface area of 275–776 m2/g and total pore volume of 0.29–1 cm3/g, depending on the ligand types and contents. Elementary analysis results confirm the incorporation of both thiol and amine group in the materials. Batch adsorption studies shows that the adsorption capacity of phenol drifts on the amine and thiol functionalized SBA-15 is greater than that on pure SBA-15. A linear relationship was observed between the adsorption capacity and N/SiO2 ratio. It was shown that the presence of amine promotes interactions with water molecules, on the other hand, these results can also be explained by the basic behavior of N-functionalized materials.

Synthesis and Characterization of MSU Molecular Sieve Catalysts Obtained by Direct Incorporation of Platinum and 12-tungstophosphoric Acid H3PW12O40

Direct incorporation of platinum (Pt) and 12-tungstophosphoric acid H3PW12O40 (HPW) into mesoporous MSU-type silica was achieved by using a mixture of cationic and non-ionic surfactants, such as cetyltrimethylamonium and Triton (TX-100). Various amounts of Pt (0.3–7 wt%) and HPW (9–49 wt%) were incorporated, and the obtained materials were characterized by X-ray diffraction, chemical and thermal analyses, electron microscopy, N2 adsorption–desorption measurements and solid-state 31P nuclear magnetic resonance spectroscopy. © Koninklijke Brill NV, Leiden and Society of Powder Technology, Japan, 2008

NOx Reduction Over MSU Molecular Sieve Catalysts Obtained by Direct Incorporation of Platinum and 12-Tungstophosphoric Acid H3PW12O40: deNOx Catalysis

The catalytic activity of silica-based mesoporous molecular sieves containing tungstophosphoric acid (HPW), platinum (Pt) and Pt/HPW, which were directly incorporated during the synthesis of MSU-type materials, was investigated in the NOx reduction with propene in the presence of O2. The NOx reduction reaction over these catalysts was studied for various Pt and HPW loadings, and oxygen concentrations (0–10 vol.%), and at different temperatures (170–350°C). The reduction of NOx was found to occur for various amounts of O2 in given temperature domains. In the presence of HPW alone, the NOx conversion levels remain low (20%); in contrast, over the Pt-containing catalysts, the NOx conversion is high (around 90%), but it is limited to a narrow O2-poor domain (0.5–1 vol.%). Samples which contain small amounts of Pt and moderate loadings of HPW are the most active (up to 97% at 250° and for 1 vol.% O2). However, whatever the O2 concentration, when the HPW loading increases, the NOx conversion decreases.

Bioadsorption of Pb2+ and Cu2+ on Eucalyptus Camaldulensis Leaves

Herein, the efficiency of Eucalyptus camaldulensis leaves as biosorbent for lead and copper was investigated. The particle size distribution was determined by Granulometric analysis and the functional groups were identified by FT-IR spectroscopy. The effects of contact time, pH and initial metal ions concentration were investigated. The experimental kinetic data were well fitted by the pseudo-second order kinetic model and Langmuir isotherm with a maximum adsorption capacity up to 71 mg g-1 and 37 mg g-1 for Cu2+ and Pb2+ respectively. The selectivity was examined in a binary ions solution where the adsorbent showed preference for lead over copper.