Abstract

MERA BENAVIDES, David Alejandro  and  MERA BENAVIDES, Adriana Consuelo. Photocatalytic treatment of waste water from laboratories with bromocresol green indicator. Rev. Lasallista Investig. [online]. 2011, vol.8, n.1, pp.28-41. ISSN 1794-4449.

Introduction. The advance of heterogeneous photocatalysis as an advanced oxidation process has been used in the treatment of water contaminated with recalcitrant substances, which bring negative impacts to the environment and, in consequence, to human health.Given the urgent necessity of preserving water as a natural resource, heterogeneous photocatalysis was used in this research work to treat effluents generated in chemical and environmental research laboratories. Objetive. To apply heterogeneous photocatalysis by the use of TiO₂ to treat waste water with bromocresol green. Materials and methods. Batch type reactors were used in this process. Titanium dioxide (TiO₂) Degussa P-25 was used as a catalyst and natural UV radiation was taken as the source to activate the photocatalytic method to generate the discoloration and mineralization of the bromocresol green indicator in the liquid effluents. The process was followed up by pH tests; Absorbance by the use of a spectrophotometer (418 nm wave length) and COD by the technique suggested by Standard Methods, every day during a five days period. Results. The comparison of the data obtained shows the feasibility of the technique, especially by the use of a 300 ppm concentration of catalyst, obtaining a 93,94% of degradation and a 72.22% of mineralization. Conclusion. With the results of degradationand mineralization percentages obtained, it is evident that heterogeneous photocatalysis, using sunlight, is an advanced oxidation process useful to treat waste water with bromocresol green indicator.

Keywords : degradation; titanium dioxide; heterogeneous photocatalysis; mineralization; natural UV radiation; bromocresol green.

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