Estudo da pirólise da semente do juá (Ziziphus joazeiro Martius) visando a viabilização do extrato pirolenhoso

Abstract

The juazeiro tree (Ziziphus joazeiro Martius) is a typical tree of the Brazilian semi-arid region, also known as juá, laranjeira-de-vaqueiro, juá-fruta, and juá-espinho. There are various uses for this fruit. The bark and leaves of juá are rich in saponin, used as an antidandruff shampoo and hair tonic (LIMA, 1985). Shavings from the bark serve as soap and toothpaste. The bark is an excellent hair tonic when infused or macerated (BARROS, 1982). Juá water is used to soften and lighten facial skin (BRAGA, 1960). Juazeiro wood is of high quality and resistance, and the fruit powder is used in cosmetics production and as a natural form of organic nutrition (for both humans and animals). Despite the numerous applications of juá, no use was found for its seed. This study aims to pyrolyze the juá seed to obtain pyroligneous extract, identifying the best process conditions. Pyrolysis involves the irreversible degradation of raw material in the absence of oxygen, generating compounds with shorter chains: a volatile fraction, a solid one called biochar, and a liquid one. The liquid product of pyrolysis has two phases, one of which is bio-oil, also called tar, a dense and dark multicomponent mixture with a combustion capacity similar to petroleum diesel. The other phase, called aqueous or pyroligneous extract, comes from various reactions, including dehydration, containing many oxygenated compounds of higher polarity than those in the organic phase, such as phenols, organic acids, ketones, aldehydes, among others (QI, 2007). The vacuum pyrolysis process was carried out in a pilot plant composed of a stainless steel tubular reactor; a tubular furnace model JUNG LT6 2010 with 1 kW power, a temperature controller, and a heating rate controller JUNG J400, model 6.2010 with 2.5 kW; a condensation system consisting of 4 glass condensers connected in series and cooled by a thermostatic bath, model TECNAL TE-18; and a FANEM vacuum pump. Analyses were performed using a Shimadzu GC/MS chromatograph and thermogravimetric analysis on Shimadzu equipment mod. TGA-51H. As a result, it is confirmed that the studied biomass contains compounds with antimicrobial affinity, providing this product with its antifungal potential, and allowing the characterization of pyrolysis for a temperature range between 700ºC~750ºC.