Physicochemical and environmental characterization of pistachio shells

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

Journal of Fundamentals of Renewable Energy and Applications

OMICS International

Año: 2016 vol. 6

2090-4541

The objective of this work is to characterize a residual biomass material, salted pistachio shells, from both a physico-chemicaland an environmental point of view, in order to analyze its possible valorization. Studies on pyrolysis of pistachio shells forenergy production have been carried out by various authors. It was observed to have low heat capacity when compared to coal whichis traditionally used. Furthermore, the activated carbon manufacturing and adsorption of heavy metals have been studied. Thesewere analyzed using different characterization techniques: Optical Microscopy (OM), Scanning Electron Microscopy (SEM), EnergyDispersive X-ray Spectroscopy (EDS), X-ray diffraction, loss On Ignition (LOI), thermogravimetric and differential thermal analysis(DTA-TGA), ecotoxicity and emission during calcinations, among others. This material has a microscopic structure in the form offibers, with resistant characteristics, and are mainly composed of C and O (98%), containing small percentages of Na, K, Cl, Ca andSi. But when washed Na, K and Cl are not detected by EDS. The DTA-TGA analysis shows combustion-decomposition exothermicreactions in the range 200°C - 470°C that were assigned to hemicellulose, cellulose and lignin. From these assays, a total weight lossof 98.2% of the original sample has been determined. These values have been compared with the test LOI which was performed inthe laboratory, whose results were about 99.5%. The XRD pattern shows four reflexion peaks for 2θvalues of 16.7, 21.7, 34.7 and 44.4,which are assigned to microcrystalline cellulose. According to the obtained results, different new alternatives for recycling this wasteare discussed.