Characteristics of Films on the Surface of Sea Sand and Effects on the Dissolution of Chloride

2020 ◽  
Vol 842 ◽  
pp. 326-336
Author(s):  
Fei Long Sun ◽  
Shuai Wu ◽  
Quan Jiang ◽  
Huo Cheng Chen ◽  
Hong Yan Guan

In this study, the effects of the specimen preparation method, temperature, and duration of the extraction step for the determination of the water-soluble chloride content of sea sand were investigated. The results demonstrated that increasing the heating temperature and duration promoted the dissolution of chloride, where the maximum value was obtained at 80°C and 60 min. Hot water extraction (80°C/60 min) could eliminate the effects of different specimen preparation methods on the final test results. Therefore, a new method was developed with drying at a temperature of 110 ± 5°C and hot water extraction at a temperature of 80°C for 60 min. The suitability of the new method for determining the water-soluble chloride content of sea sand was verified by testing the extracted specimens again. The results indicated that the chloride in sea sand dissolved fully with the new method, and thus it is suitable for testing the water-soluble chloride content of sea sand. Finally, the organic and inorganic compositions of the film adsorbed on the surface of sea sand were studied based on thermogravimetric analysis, inductively coupled plasma atomic emission spectrometry, ion chromatography, and total organic carbon measurements. The results indicated that a layer of substance (a multi-substance film) was adsorbed onto the surface of sea sand. This layer comprised inorganic salts (such as Cl–, Na+, Mg2+, SO42–, and Ca2+) and organic compounds, which were related to the composition of sea water. The multi-substance film greatly affected the dissolution and diffusion of chloride in the sea sand. Hot water extraction accelerated the dissolution of the film and increased the test results in terms of the water-soluble chloride contents.

2012 ◽  
Vol 27 (4) ◽  
pp. 680-688 ◽  
Author(s):  
Petri Kilpeläinen ◽  
Kaisu Leppänen ◽  
Peter Spetz ◽  
Veikko Kitunen ◽  
Hannu Ilvesniemi ◽  
...  

Abstract Birch sawdust was extracted using pressurized hot water (PHW), with the ultimate aim of maximizing the yield of large and intact non-cellulosic heteropolysaccharides, i.e. hemicellulose molecules. The extractions were performed using a flow-through vessel. Effects of different extraction temperatures between 140 and 200°C were evaluated. The amount of extracted xylans, as weil as monosaccharides, increased as the temperature rose to 1 90°C, accordingly the degree of polymerization of the xylans decreased. The extracted xylans retained most of the native acetyl groups and were thereby water-soluble after the extraction. The PHW extract contained not only xylan and other hemicellulose-derived oligomers, but fragmented Iignin molecules and some extractives as well. Only trace amounts of furfurals were found in the extract at lower extraction temperatures. An optimal yield of water-soluble, polymeric xylans with the smallest amount of unwanted impurities and degradation products was thus achieved at an extraction temperature of 1 80°C using the flow-through vessel


2011 ◽  
Vol 291-294 ◽  
pp. 1339-1343
Author(s):  
Wen Bo Zhang ◽  
Hong Rui Li ◽  
Jun Tao ◽  
Bing Bing Dong

The research in this paper optimized the extraction technique of lentinan with ultrasonic assistant method on the basis of hot water extraction technique, and investigated the promoting function of ultrasound to polysaccharides extraction. Extraction condition was selected by means of orthogonal experimental design, four factors and three levels L9(34), after key elements were respectively chosen through single factor experiments. Comparison between optimal extraction parameters of two method, hot water extraction technique and ultrasonic assistant extraction technique, showed decreased extraction temperature and significantly shortened extraction time, which existed in the second means, improved the extraction efficiency. Lentinus edodes polysaccharide extracted with ultrasonic assistant technique, the extraction rate and polysaccharide content percentage increased 6.22% and 8.66% respectively, comparative to which extracted with hot water extraction technique.


Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nacera Benouadah ◽  
Andrey Pranovich ◽  
Djamel Aliouche ◽  
Jalel Labidi ◽  
Stefan Willför

AbstractThe effectiveness of pressurized hot-water extraction conditions for obtaining galactoglucomannans (GGMs) from Pinus halepensis suitable for applications like coatings and films packaging was investigated. For this purpose, high molar masses with high yields are required, presenting a serious challenge for hot-water extraction processes. The extraction of GGMs was carried out in an accelerated solvent extractor (ASE) and the isolation was performed by precipitation in ethanol. Three temperatures in the range 160–180 °C and five extraction times 5–90 min were tested in order to optimize extraction parameters of GGMs, avoiding thermal and chemical degradation in hot-water. Total dissolved solids (TDS) were determined gravimetrically after freeze-drying and weight average molar masses (Mw) were determined by high-performance size exclusion chromatography (HPSEC). Total non-cellulosic carbohydrates were determined by gas chromatography (GC) after acid methanolysis. Free monomers were additionally analyzed by GC. Lignin in water extracts was measured by an ultraviolet (UV) method. Acetic acid was determined after alkaline hydrolysis of acetyl groups and analyzed by HPSEC. The main parameters influencing the extraction processes of the GGMs, namely, extraction time and temperature were studied. Optimal extraction parameters of GGMs were identified at 170 °C and 20 min extraction time, with average Mw of extracted fraction of 7 kDa leading to a GGM yield of approximately 56 ${\text{mgg}}_{\text{o}.\text{d}.\text{m}}^{-1}$, corresponding to 6% on dry wood basis.


Fitoterapia ◽  
2018 ◽  
Vol 126 ◽  
pp. 65-68 ◽  
Author(s):  
Bianca J. Deans ◽  
Wesley J. Olivier ◽  
David Girbino ◽  
Alex C. Bissember ◽  
Jason A. Smith

2017 ◽  
Vol 241 ◽  
pp. 120-126 ◽  
Author(s):  
Joanna Wojtasz-Mucha ◽  
Merima Hasani ◽  
Hans Theliander

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