Improved Extraction Procedures for Coal Products Based on the Soxtec Apparatus

Giner, Luis Membrado; Rodrigo, Jesús Vela; Navarro, and Ana Cristina Ferrando; Burillo, Vicente Luis Cebolla

doi:10.1021/ef960018o

Cited by 18 publications

(7 citation statements)

References 21 publications

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“…Solvent refluxes from the condenser and washes down the free compounds on the coal surface, improving the recovery of extracts in the cup. Membrado Giner et al (1996) showed that a combination of 1 minute boiling and 30 minutes rinsing produced the equivalent yield to 24 hours of Soxhlet extraction.…”

Section: Coal Extractionmentioning

confidence: 99%

Characterisation of bioavailability of Surat Basin Walloon coals for biogenic methane production using environmental microbial consortia

Chen

Zheng

Hamilton

et al. 2017

International Journal of Coal Geology

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The study sets out to characterize the bioavailability of six Surat Basin Walloon coals from different stratigraphic layers in a single borehole to environmental methanogenic consortia. Factors that control bioavailability have also been investigated on grounds of coal petrographic composition and the organic composition of solvent-extractable matter. Finely crushed coal core samples were inoculated with digested sludge culture from domestic wastewater treatment in serum bottles kept anoxically before incubation at mesophilic temperature over 30 days for biomethane production. Degradation of coal compounds was demonstrated via GC-MS characterization of methanol and dichloromethane (DCM) extracts, in combination with aqueous volatile fatty acids and alcohols and TOC (total organic carbon) analysis on fresh and microbially-digested coal samples. The resulting methane yields ranged from 14 to 33 μmol/g, with an average of 21 μmol/g (0.515 m 3 /tonne), comparable to those previously reported for subbituminous coals. Organic solvent-extractable materials that accounted for 3.8 to 12% of coal weight were generally dominated by aliphatic compounds, composed of mainly medium-long-chain n-alkanes, n-alcohols and esters. Aromatics were detected up to three fused rings, and are rich in dibenzofuran, alkyl benzene, diphenyls and alkyl PAH (polymeric aromatic hydrocarbon). The abundance of solvent-extractable matter was found to be positively associated with liptinite content, particularly suberinite, sporinite and liptodetrinite. Preservation of these compounds was thought to rely on vitrinite, such as telinite and collotelinite that are rich in micropores, serving as storage for the hydrocarbons. Environmental factors, such as microbe-carrying groundwater might compromise coal extractability by converting coal hydrocarbons to biogas. Bioavailability of coal was shown to be controlled by three factors: 1) Water solubility-Bioassay eliminated an average 98% of aqueous compounds (based on TOC), which were dominated by volatile fatty acids and alcohols, and to a lesser degree, medium-chain (primarily C 10 to C 20) n-alcohols, esters and aliphatic amine; 2) Solvent extractability-34.5% of solvent-extractable compounds were shown to be biodegraded (based on peak intensity in GC-MS), with methanol extracts being more bioavailable than DCM's; 3) Heterogeneous moieties, particularly aliphatic hydroxyl group, ester bond, ether bond and C-N bond in aliphatic amine-These functional groups present heteroatoms that can lower the activation energy of nearby bonds, making them vulnerable for microbial cleavage. Compound degradation in bioassays was shown to be clearly associated with methane yield, but only a small proportion degraded was converted to methane. Further improvement may be achieved via proper adaptation of the current microbial community.

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Section: Coal Extractionmentioning

confidence: 99%

Characterisation of bioavailability of Surat Basin Walloon coals for biogenic methane production using environmental microbial consortia

Chen

Zheng

Hamilton

et al. 2017

International Journal of Coal Geology

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“…In most cases, the amount of lipids extracted by the Soxtec method exceeded those extracted using the reflux method; however, differences in lipid yields were only significant for the ground and DDGS forms indicating that the method of extraction does not affect lipid yields of whole kernels. Membrado et al [23] attributed the higher performance of the Soxtec method, compared to the reflux method, to favored mass transfer due to the two steps involved in the operation of this method. After the boiling step, where the sample was submerged in the solvent, the Soxtec method included a rinsing step, where ''clean'' solvent condensed over the sample.…”

Section: Lipidsmentioning

confidence: 99%

Plant Sterol and Policosanol Characterization of Hexane Extracts from Grain Sorghum, Corn and their DDGS

Leguizamón

Weller

Schlegel

et al. 2009

J Americ Oil Chem Soc

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Plant sterols (PS) and policosanols (PC) have been attributed with plasma cholesterol-lowering properties in humans. Hexane extracts from grain sorghum, corn and their distillers dried grain with solubles (DDGS), an important co-product of ethanol production, contain these health promoting compounds, which could be used to develop health promoting dietary products. However, limited information is currently available regarding optimal methods of extraction and their influence on plant sterol or PC levels and compositions. Therefore, the objective of this study was to quantify lipids, particularly PS and PC extracted from grain sorghum and its DDGS using reflux and Soxtec methods. Corn and its DDGS were also extracted to compare lipid yields and PS/PC compositional profiles in these two related cereals. Intact grains were extracted either as whole or ground kernels. Lipid yields from all the corn sources were typically greater than those obtained from grain sorghum. Lipid yields from DDGS were the highest among all the forms of the grains used whereas corn/sorghum DDGS contained the highest levels of PS and PC, respectively. Additional study demonstrated that hydrolysis (acidic and alkaline) of ground sorghum or sorghum DDGS increased the levels of total extractable plant sterols. Overall, the Soxtec method extracted higher amounts of lipids than the reflux method.

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“…Solvent extraction of coal was carried out in a Tecator Soxtec system HT2 1045, a method adapted from Soxhlet with improved efficiency (Membrado Giner et al, 1996). Extraction used a mixture of AR grade dichloromethane and HPLC grade of methanol (2:1 by volume) in order to efficiently recover both polar and non-polar compounds.…”

Section: Coal Extractionmentioning

confidence: 99%

Improving coal bioavailability for biogenic methane production via hydrogen peroxide oxidation

Chen

Rodrigues

Golding

et al. 2018

International Journal of Coal Geology

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Improved Extraction Procedures for Coal Products Based on the Soxtec Apparatus

Cited by 18 publications

References 21 publications

Characterisation of bioavailability of Surat Basin Walloon coals for biogenic methane production using environmental microbial consortia

Characterisation of bioavailability of Surat Basin Walloon coals for biogenic methane production using environmental microbial consortia

Plant Sterol and Policosanol Characterization of Hexane Extracts from Grain Sorghum, Corn and their DDGS

Improving coal bioavailability for biogenic methane production via hydrogen peroxide oxidation

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