Electrochemical-assisted photodegradation of dye on TiO2 thin films: Investigation on the effect of operational parameters

Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
Journal of Hazardous Materials (Impact Factor: 4.53). 03/2005; 118(1-3):197-203. DOI: 10.1016/j.jhazmat.2004.11.009
Source: PubMed

ABSTRACT Electrochemical-assisted photodegradation of methyl orange has been investigated using TiO2 thin films. The films were prepared by sol-gel dip-coating method. Several operational parameters to achieve optimum efficiency of this electrochemical-assisted photodegradation system have been tested. Photoelectrochemical degradation was studied using different light sources and light intensity. The light sources chosen ranged from ultraviolet to visible light. The effect of agitation of the solution at different speeds has also been studied. Slight improvement of photodegradation rate was observed by applying higher agitation speed. Investigation on the electrode after repeated usages show the electrode can be reused up to 20 times with percentage of deficiency less than 15%. The study on the effect of solution temperature indicated that the activation energy of the methyl orange degradation is 18.63 kJ mol(-1).

Download full-text


Available from: Mohd Zobir Hussein, Sep 25, 2015
432 Reads
  • Source
    • "Therefore, the efficiency of PEC degradation of pollutants could be enhanced. Most of the previous publications on the degradation of organic compounds have mainly focused on the optimization of photoreaction conditions and the examination of the primary process by monitoring decolorization [30] [31]. Less attention has been devoted to investigations on the degradation pathway of organic compounds . "
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel dual-tank photoelectrochemical catalytic reactor was designed to investigate the degradation pathway of malachite green. A thermally formed TiO2/Ti thin film electrode was used as photoanode, graphite was used as cathode, and a saturated calomel electrode was employed as the reference electrode in the reactor. In the reactor, the anode and cathode tanks were connected by a cation exchange membrane. Results showed that the decolorization ratio of malachite green in the anode and cathode was 98.5 and 96.5% after 120min, respectively. Malachite green in the two anode and cathode tanks was oxidized, achieving the bipolar double effect. Malachite green in both the anode and cathode tanks exhibited similar catalytic degradation pathways. The double bond of the malachite green molecule was attacked by strong oxidative hydroxyl radicals, after which the organic compound was degraded by the two pathways into 4,4-bis(dimethylamino) benzophenone, 4-(dimethylamino) benzophenone, 4-(dimethylamino) phenol, and other intermediate products. Eventually, malachite green was degraded into oxalic acid as a small molecular organic acid, which was degraded by processes such as demethylation, deamination, nitration, substitution, addition, and other reactions.
    Journal of hazardous materials 06/2013; 260C:585-592. DOI:10.1016/j.jhazmat.2013.05.037 · 4.53 Impact Factor
  • Source
    • "Along with the evaporation of the solvent, wedge shaped film is formed on the surface of substrate. A lot of researchers have used sol-gel dip-coating method to study the application of the photocatalytic TiO 2 (Dongare et al., 2003; Lee et al., 2004; Zainal et al., 2005). "
    Orthodontics - Basic Aspects and Clinical Considerations, 03/2012; , ISBN: 978-953-51-0143-7
  • Source
    • "In the past decades, photocatalytic technique has been shown to be one of the most promising processes for the wastewater treatment due to its advantages over the traditional techniques, such as quick oxidation, no formation of polycyclic products, oxidation of pollutants in the ppb range, etc (Zainal et al., 2005; Zhang et al., 2005a,b; Chen and Liu, 2007; Dillert et al., 2007). The photocatalytic treatment of wastes containing dyes has also been widely reported in the literature (Qaradawi and Salman, 2002; Kyung et al., 2005; Liu et al., 2005; Yang et al., 2005; Zhang et al., 2005a,b; Monteagudo and Durán, 2006; Pedroza et al., 2007). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The photodegradation of methyl orange (MO) was investigated in aqueous suspension containing titania nanoparticles with mesostructures (m-TiO(2)) under UV irradiation. The experimental results show that 98% MO can be mineralized in the 1.0 g l(-1) m-TiO(2) suspension (pH 2.0) after 45 min illumination. Particular attention was devoted to the identification and the transformation of the fragments retaining the chromophoric group. The photodegradation mechanism of the quinonoid MO mainly involves three intermedial processes: demethylation, methylation and hydroxylation. Among those processes, demethylation is more favorable than the hydroxylation, but the hydroxylation results in the largest number of intermediates. The degradation pathway of quinonoid MO under the optimal conditions is also proposed.
    Chemosphere 12/2007; 69(9):1361-7. DOI:10.1016/j.chemosphere.2007.05.021 · 3.34 Impact Factor
Show more