Treatment of laboratory wastes by heterogeneous photocatalysis with TiO2

Abstract

Environmental pollution caused by hazardous waste is a growing and globalized problem. Such waste, once emitted, can remain in the environment for hundreds of years. Chemical substances are handled and several operations are carried out in dif-ferent university laboratories, which generates waste that in most cases is dangerous to human health and the environment. Some of these residues include those produced during Gram staining procedures. This paper presents an alternative for treating residues of Gram staining by Hetero-geneous Photocatalysis (HP). Evonik® TiO2 P-25 was used, and the radiation source was a germicidal lamp. In addition, UV-Vis spectroscopy together with COD measure-ments were used as analytical techniques. In view of the nature of these residues, it was decided to treat them in concentra-tions lower than real ones (diluted to 10 %), with TiO2 dosages according to the litera-ture on dying processes. Within 2 hours, a degradation of around 70 % and a reduction of 40 % of the COD were achieved, which shows the feasibility of the implementation of this process to eliminate said wastes.

Keywords

• Gram staining
• Heterogeneous Photocatalysis
• Hazardous waste
• titanium dioxide