Evaluation of the degradation of 3,5-Dinitrosalicylic acid by photochemical advanced oxidation processes

• Grant number: 13/10439-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2013
• End date: January 31, 2014
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Laura Tiemi Okano
• Grantee: Fabio Nery de Assis
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The goal of this project is to evaluate the degradation of 3,5-dinitrosalicylic acid (DNS) by homogeneous photochemical Advanced Oxidation Processes (AOP). The DNS method is regularly used to determine the concentration of reducing sugars in biomass hydrolysates. This method is largely employed in the research laboratories and undergraduate biochemistry courses of the Department of Chemistry of the University of Sao Paulo. However, due to its toxicity, it is not recommended its direct disposal into the sewer, transforming it in a potential wastewater residue. Every semester, the Department of Chemistry generates ca. of 20 L of this residue which it kept in storage rooms. For this reason, we propose the homogeneous AOP such as UV photolysis of hydrogen peroxide and the photo-Fenton processes for the photochemical degradation of the DNS. The degradation will be evaluated by measurements of the UV/visible absorption spectra and total organic carbon (TOC) values. The reactive intermediates will be identified by liquid chromatography coupled with mass spectrometry (LC/MS). We plan to study the photochemical degradation of the DNS, the components of the DNS method for determination of the reducing sugar (DNS and potassium and sodium tartrate), the 3-amine-5-salicylic acid (the resulting compound, after the reaction of DNS with the reducing sugar), and the stocked residues existing in the Department of Chemistry. These studies will be the foundation for the preparation of small-scale wastewater treatment units with solar radiation.(AU)