Simultaneous photoreductive removal of copper (II) and selenium (IV) under visible light over spherical binary oxide photocatalyst

• Published in: Journal of hazardous materials 2011-02, Vol.186 (1), p.360-366
• Main Authors: Aman, Noor, Mishra, T., Hait, J., Jana, R.K.
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalysis; CATALYSTS; Catalytic reactions; Chemical engineering; Chemistry; Copper; Copper (II); COPPER (PURE); Copper - isolation & purification; COPPER RESOURCES; COPPER SELENIDE; EDTA; EDTA (chelating agent); Exact sciences and technology; Formic acid; General and physical chemistry; General purification processes; Hydrogen-Ion Concentration; ions; irradiation; Oxidation-Reduction; OXIDES; Oxides - chemistry; Photocatalysis; photocatalyst; Photochemistry; Photoreduction; Pollution; Reactors; Reduction; Scavengers; Selenium; Selenium (IV); Selenium - isolation & purification; surface area; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; TITANIUM DIOXIDE; ultraviolet radiation; Ultraviolet Rays; Visible light; wastewater; Wastewaters; Water treatment and pollution
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2010.11.001

Spherical zirconia mixed titania materials can reduce 100ppm of Cu(II) and Se(VI) mixture within 40min of reaction under visible light. Waste water of copper mines and copper processing plant contains both copper and selenium ions with other contaminants. In this paper simultaneous photoreductive removal of copper (II) and selenium (IV) is studied for the first time using spherical binary oxide photocatalysts under visible light. All the synthesized materials are found to be mesoporous in nature with reasonably high surface area. Among a range of hole scavengers, only EDTA (ethylene diamine tetraacetic acid) and formic acid are found to be the most active for the reduction reaction. A comparative study is carried out using both the hole scavengers varying reaction time, concentration, pH etc. For a single contaminant, EDTA is found to be the best for Cu(II) reduction whereas formic acid is the best for Se(IV) reduction. In a mixed solution both EDTA and formic acid perform very well under visible light irradiation. Highest photocatalytic reduction in a mixed solution is observed at pH 3. Among all the synthesized materials, TiZr-10 performs as the best photocatalyst for both Cu(II) and Se(IV) reduction. However under UV light, Degussa P25 performs slightly better than TiZr-10. Present study shows that 100ppm of mixed solution can be removed under visible light in 40min of reaction using TiZr-10 as catalyst. Photodeposited material is found to be copper selenide rather than pure copper and selenium metal. This indicates that the waste water containing copper and selenium ions can be efficiently treated under visible or solar light.