Mudar Abou Asi

Mesoporous zinc ferrite: Synthesis, characterization, and photocatalytic activity with H2O2/visible light

Mesoporous ZnFe(2)O(4) (meso-ZnFe(2)O(4)) was synthesized by a hydrothermal process in which cetyltrimethylammonium bromide (CTAB) participates in the reaction to produce nanocrystals. Synthesized ZnFe(2)O(4) was characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectra (DRS). The meso-ZnFe(2)O(4) was resulted from the agglomeration of nanoparticles with size of 5-10nm. The photocatalytic activity of ZnFe(2)O(4) under visible light (λ>400 nm) was evaluated by the degradation of Acid Orange II (AOII) at different sintering temperatures, the amount of ZnFe(2)O(4), and the concentration of H(2)O(2). The photocatalytic degradation of AOII was almost complete within 2h in H(2)O(2)/visible light system. The high efficiency for AOII degradation was attributed to the strong absorption of ZnFe(2)O(4) in visible-light region and the generation of reactive OH by H(2)O(2) in the system. The involvement of OH in oxidizing AOII was examined by determining the photocurrent of ZnFe(2)O(4), [OH], and degradation rates using different scavengers. Organic compounds as intermediates of the degradation process were identified by LC/MS. Moreover, ZnFe(2)O(4) retained their degradation efficiencies for a series of repetitive batch runs, indicating the true photocatalytic process.

Photoelectrocatalytic degradation of organic pollutants in aqueous solution using a Pt-TiO2 film.

A series of Pt- films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt- films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt- films was evaluated in the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of formic acid in aqueous solution. Compared with a film, the efficiency of formic acid degradation using the Pt- films was significantly higher in both the PC and PEC processes. The enhancement is attributed to the action of Pt deposits on the surface, which play a key role by attracting conduction band photoelectrons. In the PEC process, the anodic bias externally applied on the illuminated Pt- films can further drive away the accumulated photoelectrons from the metal deposits and promote a process of interfacial charge transfer.

A novel wet-scrubbing process using Fe(VI) for simultaneous removal of SO2 and NO

The objective of this work was to develop a novel wet-scrubbing process using Fe(VI) for the simultaneous removal of gaseous NO and SO(2). The oxidation of SO(2) and NO with Fe(VI) was studied in aqueous solution at alkaline pH (9.0-11.0). A stoichiometric molar ratio for NO and SO(2) oxidation with Fe(VI) was determined to be nearly 3.0. Sulfate and nitrate was identified as final products by ion chromatography from the reaction at pH 9.0-11.0. The feasibility of simultaneous removal of multiple gas pollutants with the continuous feeding of ferrate in lab-scale was investigated from the view of industrial application. It was found that the removal efficiency of NO and SO(2) was enhanced with the increase of Fe(VI) concentration, more than 90% NO removal efficiency and 100% SO(2) removal efficiency were achieved by wet-scrubbing process using Fe(VI) at room temperature and ambient atmosphere. The results demonstrate that Fe(VI) could be an effective wet-scrubbing agent for the simultaneous removal of NO and SO(2).

Preparation of novel layered AgBr-based inorganic/organic nanosheets by pulsed laser ablation in aqueous media

A novel layered AgBr-based inorganic/organic nanocomposite was prepared by pulsed laser ablation (PLA) of Ag in aqueous media in the presence of cetyltrimethylammonium bromide (CTAB). The obtained AgBr-based inorganic/organic nanocomposite possesses well-defined 2D shape. X-ray diffraction (XRD) pattern was composed of a series of peaks that could be indexed to (00l) reflections of a layered structure, and the basal spacing of 20.0 Å indicated that the surfactant was included between the AgBr interlayers in an interdigitated bilayer arrangement.