Degradação eletroquímica do herbicida metano arseniato ácido monossódico

Abstract

Several tons of pesticide products having the chemical element arsenic as active ingredient, are used every year in various types of crops and cultures, producing a huge amount of waste that will contaminate the soil and water. This contamination is mainly due to use outside of technical standards, without the guidance and supervision of licensed professional and is common to use the concentrations much higher than the recommended pesticides. The methane arsenate monosodium acid, known by the acronym MSMA, belongs to this group of pesticides being used mainly in the planting of sugarcane and cotton crops. This herbicide has the chemical element arsenic in its formula, which is the main responsible for the effects of the herbicide on the weeds and on the environment. The study of this compound degradation methods is important to avoid cases of contamination that could lead to the death of animals and even entire biomes. This research was the basic objective of the degradation of MSMA herbicide through the production of free radicals with high oxidizing power in metallic titanium electrodes and titanium and ruthenium oxides in the electrolyte solution of sodium chloride, UV radiation presence, employing dimensionally stable anodes (DSA®), thus characterizing the oxidative process Advanced (POA). The tests were divided into two groups, the first being performed only with electrochemical treatment of samples and the second group underwent electrochemical photo assisted treatment. Behavioral testing of solutions containing the commercial herbicide and the active principle, capable of determining the chemical oxygen demand and the concentration of arsenic present in the solutions were measured before and after each treatment and the result obtained was the complete elimination of organic carbon in solutions, regardless of the treatment used, and a removal percentage of soluble arsenic 99.85% and 99.89% in the solution of the commercial herbicide and 99.71 and 99.82 in the active principle. Even with the small percentage difference observed between the electrochemical treatment and electrochemical treatment photo assisted becomes clear more effective treatment with the use of UV radiation.