Desenvolvimento de reagente remediador a base de biocarvão e ferro zero valente

Abstract

Brazil is a country with a strong influence of the agribusiness sector on the Gross Domestic Product - GDP, with crops distributed in the five regions of the country. It stands out among world agricultural production rankings, such as rice production, in which it ranks ninth, with 1.5% of total production. The country is still rich in biomass, generated in the production and processing processes of agribusiness. On the other hand, contamination of groundwater has been generated due to anthropic actions, in particular, by industrial activity. One of the problems is that the contaminating compounds are difficult to degrade, and another is that there is a shortage of specific remedial products in the country. It is in this context, in which the present work sought to develop a national remedial reagent to recover groundwater, contaminated by organochlorines, organic compounds that are difficult to degrade. The work also aimed to promote the valorization of biomass and residues from the agricultural and cutlery industry. The reagent developed has as its main composition carbon and metallic iron. The carbon source used is biochar, obtained from rice husks in natura by the thermochemical process of slow pyrolysis, and the source of metallic iron is waste from cutting cutlery blades. The experimental program was divided into stages: characterization of a commercial remedial reagent, production of the reducing reagent from industrial waste (agribusiness and metalworking) and its characterization. It was considered that potential effluents generated during the research were treatable and a brief study was carried out on the feasibility of producing a national innovative commercial product. The efficiency of the remedial reagent produced was evaluated through a bench treatability test, lasting 42 days. The results of the treatability test identified a degradation potential of the remedial reagent, developed on a laboratory scale, above 90%, of the organochlorines present in the studied water samples. The results obtained in the chemical and physical analyzes of the remedial reagent produced, presented some characteristics similar to the studied commercial reagent: iron content of 27.54% and the commercial reagent 28.56; adsorption content of 92% and the commercial reagent 90%; specific mass of 2.0023 g cm-3 and that of the commercial reagent 1.9444 g cm-3; zero charge point between pH 7 and 7.5 and commercial reagent pH 7. As for the inorganic elemental chemical composition of the remedial reagent produced, the combination of iron and silicon elements was identified, which suggests that both are acting together in aqueous environment, supporting a greater degradation or decontamination of contaminants. By evaluating the results obtained, it was possible to conclude that the remedial reagent produced has a high innovative potential for future production on an industrial scale.