Influence of Chemical Surface Characteristics of Ammonium-Modified Chilean Zeolite on Oak Catalytic Pyrolysis

Abstract

The influence of chemical surface characteristics of Chilean natural and modified zeolites on Chilean Oak catalytic pyrolysis was investigated in this study. Chilean zeolite samples were characterised by nitrogen absorption at 77 K, X-ray powder diffraction (XRD), and X-ray fluorescence (XRF). The nature and strength of zeolite acid sites were studied by diffuse reflectance infrared Fourier transform (DRIFT), using pyridine as a probe molecule. Experimental pyrolysis was conducted in a quartz cylindrical reactor and bio-oils were obtained by condensation of vapours in a closed container. Chemical species in bio-oil samples were identified by a gas chromatography/mass spectrophotometry (GC/MS) analytical procedure. Results indicate that after the ionic exchange treatment, an increase of the Brønsted acid site density and strength was observed in ammonium-modified zeolites. Brønsted acids sites were associated with an increment of the composition of ketones, aldehydes, and hydrocarbons and to a decrease in the composition of the following families (esters; ethers; and acids) in obtained bio-oil samples. The Brønsted acid sites on ammonium-modified zeolite samples are responsible for the upgraded bio-oil and value-added chemicals, obtained in this research. Bio-oil chemical composition was modified when the pyrolysis-derived compounds were upgraded over a 2NHZ zeolite sample, leading to a lower quantity of oxygenated compounds and a higher composition of value-added chemicals.

Synergistic Effects and Mechanistic Insights into the Co-Hydropyrolysis of Chilean Oak and Polyethylene: Unlocking the Potential of Biomass–Plastic Valorisation

“…Cellulose and hemicellulose are thermally degraded to anhydrosugars, aldehydes, ketones, alcohols, acids, furans and pyrans, and other oxygenated compounds by decarbonylation, decarboxylation, and dehydration reactions. Likewise, lignin degradation has been identified as the primary source of phenolic compounds [ 41 , 42 , 43 ].…”

Upcycling agro-industrial blueberry waste into platform chemicals and structured materials for application in marine environments

“…This result is highly relevant since bio-oils with low acid content are relatively stable and can be used as fuels without further treatment. 37 A detailed report on the chemical composition of the solid fraction (BPw, CRSF, and LRSF) vapors from pyrolysis is available as supplementary data (Table S1 † ). The primary compounds for each fraction and their relative abundance (eqn (S1) † ) were as follows: CRSF: 27% acids (15.5% acetic acid), 14% ketones (3.2% 1-hydroxy-2-propanone), and 13 % aldehydes (4.4% methylglyoxal, 3.9% furfural, and 1.8% hydroxy-acetaldehyde).…”

Efficient and Stable Rice Husk Bioderived Silica Supported Cu2S-FeS for One Pot Esterification and Transesterification of a Malaysian Palm Fatty Acid Distillate

“…A change in acidity to 402.3206 µmol/g and 4133.29 µmol/g was noted following the addition of Cu and Fe, respectively, to the catalyst support. The acid quantity and density were also enhanced following the use of sulphur to modify the supported catalyst; this was a result of the electron engagement between the sulphur atom and the element at the active site [37]. In temperatures greater than 600 • C, a de novo desorption zenith was evident for the bimetallic catalyst; this was indicative of the high acidity and acid density of the sites, i.e., 4133.29 µmol/g.…”