Physicochemical and environmental characterization of pistachio shells

JOSE VALENTINI; MIGUEL UNSEN; MAXIMILIANO DELFINO; MARTA CALIGARIS, ; ADRIÁN CRISTÓBAL; NANCY QUARANTAL

Journal of Fundamentals of Renewable Energy and Applications

OMICS Internatiomnal

Año: 2017 vol. 07

Numerous residual biomasses have been studied in a variety of uses, including biomass-energy processes, as adsorbentof heavy metals contained in liquid effluents, as source of chemicals with higher added value, as raw materials inconstruction industry, etc. In this work, a very common and abundant residual biomass, which is found in the area of fruitproduction in Argentina, peach stones, is studied. This material has been characterized in relation to its possible use as poreformer in ceramic matrices, with the following techniques: scanning electron microscopy with semi quantitative chemicalanalysis (SEM-EDS), differential thermal and thermogravimetric analysis (DTA-TGA), X ray diffraction (XRD), loss weighton ignition (LOI), among others. Figure 1 shows the microscopic appearance of the stones by SEM. A fibrous structure on theouter surface and granular on the inside are observed. The semi-quantitative chemical analysis by EDS shows, in addition tolarge quantities of C and O, the presence of elements such as Na, K, Mg, Al, Si and Fe. DTA-TGA results show some exothermicpeaks corresponding to the combustion of hemicellulose, cellulose and lignin phases. From these curves, it is possible toestimate the composition of this material in relation to the content of adsorbed gases and water, biopolymers and inorganicfraction (ash formation). As the structure of the biopolymers (hemicellulose, cellulose and lignin) becomes more complex, thecombustion temperatures are higher. The DTA-TGA analysis shows that this organic material is burned in a wide temperaturerange, between 300°C and 550°C. This is important to ensure that when this material is incorporated into clay mixtures as poreformer, the sintering process takes place without crack formation in the brick. This test further indicates that after the heattreatment, the residual material that will eventually be incorporated into the bricks (ashes) is less than 2%. XRD analysis revealsthe presence of some peaks corresponding to semi crystalline cellulose.