Financial support from the Spanish Government (CTQ2009-
13699, CTQ2009-13459-C05-03/PPQ, RIRRAF RETICS), and
the Generalitat Valenciana (Prometeo Program) is gratefully
acknowledged. Dedicated to Prof. Avelino Corma on the occasion of his 60th birthday.

Organic photocatalysts for the oxidation of pollutants and model compounds.

Ultrasound enhanced heterogeneous activation of peroxydisulfate by magnetite catalyst for the degradation of tetracycline in water

Blue solution of copper(II) acetylacetonate complex, [Cu(acac)2] in dichloromethane (DCM) and an aqueous alkaline solution of thioacetamide (TAA) constitute a biphasic system. The system in a screw cap test tube under a modified hydrothermal (MHT) reaction condition produces a greenish black solid at the liquid−liquid interface. It has been characterized that the solid mass is an assembly of hexagonal copper sulfide (CuS) nanoplates representing a hierarchical structure. The as-synthesized CuS nanoplates are well characterized by several physical techniques. An ethanolic dispersion of CuS presents a high band gap energy (2.2 eV) which assists visible light photocatalytic mineralization of different dye molecules. Thus a cleanup measure of dye contaminated water body even under indoor light comes true.

Evolution of Hierarchical Hexagonal Stacked Plates of CuS from Liquid−Liquid Interface and its Photocatalytic Application for Oxidative Degradation of Different Dyes under Indoor Lighting

Molecular imprinting for removing highly toxic organic pollutants

Hydrothermal growth of CuS nanostructures and its photocatalytic properties

Reactive oxygen species (ROS), namely superoxide anion (O2*-, singlet oxygen (1O2), are potentially important substances for the mineralization of toxic organic molecules. The utility of hematoporphyrindihydrochloride (HPDHC) as a photosensitizer to generate ROS and their subsequent role in the destruction of magenta (MaG) in aqueous media is the main concern. The light irradiation of oxygenated aqueous solution of HPDHC and 1.5 x 10(-5) mol dm(-3) MaG at pH 3 yielded micromolar levels of NO3(-) ions. A higher rate of photodegradation (1.02 mol dm(-3) min(-1)) at pH 3 was observed compared to that of at pH 6 (0.68 mol dm(-3) min(-1)). Experiments were carried out in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as singlet oxygen (1O2) quencher and bezoquinone (BQ) as superoxide anion (O2*-) quencher. Only BQ was able to stop photodegradation suggesting that the photooxidation of MaG is mainly caused by O2*-, which is generated by an electron transfer from the excited HPDHC to ground-state oxygen. The presence of iron(II) at pH 3.0, compared to that without iron(II), showed a higher rate of photodegradation due to the formation of extremely reactive hydroxyl radicals (HO*) upon dismutation of O2*- anion through H2O2 intermediate. The formation of O2*-, H2O2, and HO* is therefore evident, which may act as active sites for subsequent photodegradation of MaG.

Anura Wicramasinghe

Papers

Photodegradation of triphenylamino methane (magenta) by photosensitizer in oxygenated solutions.

Electrochemical investigation of superoxide anion scavenging ability of 1,2,3-triketohydrindene hydrate in aprotic solvents