Tratamento do efluente contendo hexametilfosforamida oriundo do processo de produção de feromônios

Abstract

With the population increase, the need to produce food more efficiently per hectare planted grew. To this end, several agricultural pesticides were developed, with the aim of preventing and combating pests that harm crop production. But the indiscriminate use of these products has caused damage to the environment, either by contaminating the soil and groundwater, or by damaging human health, both the agricultural worker and the person who consumes the contaminated food. With the intention of obtaining a sustainable agricultural production, several researches appeared aiming at the reduction of the application of pesticides. One of these lines of research was the identification, isolation and use of pest pheromones, aiming at their control and reducing the application of toxic substances in plantations. After identifying these pheromones, it is necessary to develop a synthesis method for large-scale production. Unfortunately, many of these processes use highly toxic substances as raw materials, such as hexamethylphosphoramide (HMPA), which are persistent and are found in the final effluent of the production process. Within this context, this work aimed to evaluate the efficiency of treatments: chemical with sodium hypochlorite and electrochemical using Dimensionally Stable Anodes (ADE), both in the degradation of a synthetic effluent and a real effluent containing HMPA. The chemical process proved to be inefficient in treating the effluent, with a large amount of the pollutant (HMPA) being observed at the end of the treatment, and the formation of some HMPA degradation products even after 96 hours of reaction with concentrated hypochlorite. In the electrochemical process of the synthetic HMPA effluent using NaCl as electrolyte, the total degradation of the pollutant and the formation of some products was obtained after only 2 hours of reaction. For the real effluent, after 2 hours of electrochemical reaction, the presence of the initial pollutant was still observed, and after 6 hours of reaction, a reduction of approximately 90% of the pollutant was obtained. The results indicate that the electrochemical process is a promising technology for the degradation of the contaminant, originating from the synthesis process of pheromones containing HPMA, only needing to optimize the experimental conditions, such as reaction time, to reach the total degradation of the pollutant and the formed by-products.