Estudo da produção e caracterização de Biochar oriundo da pirólise do resíduo de Maçã e suas aplicações

Abstract

The apple is one of the most consumed fruits in the world and widely used for the production of juices, jellies and other products. Apple juice has been gaining space in the market as a beverage additive due to its physicochemical properties and nutritional content, with the high demand for juice production, apple pomace production also is increased, an agro-industrial residue from fruit processing. Technologies for the reuse or treatment of agro-industrial waste have been growing as a way to offer renewable raw materials, decrease costs and provide a “cleaner” and environmentally friendly production. Biochar is an example of a product that can be produced from agro-industrial waste, it is a solid product from the pyrolysis reaction and a material rich in carbon that can act in the most diverse areas such as catalysis, adsorption, effluent treatment, soil conditioner, among others. In this work, an attempt was made to produce a biochar from apple pomace, for this purpose an experimental design was carried out for the pyrolysis reaction of the residue with time (minutes) and temperature (ºC) as independent variables and the fixed carbon content (%) as dependent variable. As result of the planning, the optimized time and temperature of 85 minutes and 350 ºC respectively were obtained. The apple residue and the biochar produced at optimized time and temperature were characterized by thermal analysis (TGA), spectroscopy in the infrared region, textural analysis (scanning electron microscopy), immediate analysis and evaluated as potential soil conditioners through water retention capacity (WRC) and cation exchange capacity (CEC). The results showed that it was possible to produce a biochar with a fixed carbon content of 61.75%, eight times greater than the apple residue. Biochar had a high content of potassium (11,149 mg/kg) and phosphorus (794.06 mg/kg), two important elements for plant growth. They presented CEC and WRC of 490.3 mmolc/kg and 1.49 g/g for the apple residue and 208.4 mmolc/kg and 1.31 g/g for the biochar determining that both have characteristics to be used as soil conditioners according to MAPA IN 35, which requires at least 200 mmolc/kg CEC and 0.6 g/g WRC for commercial conditioners. The leaching test showed that both apple residue and biochar acted on the nutrient leaching dynamics, but the biochar is more advantageous because it has a higher nutrient content and because the recalcitrant structure, it acts for a longer time in the soil without being decomposed.