scholarly journals Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw

2021 ◽  
Author(s):  
Ali Kamel H. Al Jibouri
Keyword(s):  
Enzymatic Hydrolysis ◽  
Water Content ◽  
Wheat Straw ◽  
Initial Water Content ◽  
Optimal Parameters ◽  
Initial Water ◽  
Hydrolysis Yield ◽  
Fiber Size ◽  
Two Stages ◽  
Hydrolysis Of

Wheat straw was pretreated with ozone to increase the enzymatic hydrolysis yield. Ozonolysis pretreatment was performed in two stages with an intermediate washing step with water in between. Part of the delignification products (lignin fragments) were removed by a washing step so ozone was used to oxidize more lignin rather than oxidizing lignin fragments. Three parameters, i.e. Initial Water Content (IWC) in wheat straw, Washing Starting Time (WST), and Washing Contact Time (WCT), were optimized to minimize Acid Insoluble Lignin (AIL) content of ozonated wheat straw. Performing an experiment using optimal parameters' values, i.e. IWC equal to 45 wt. %, WST equal to 20 minutes and WCT equal to 80 seconds, showed a drop in AIL content to 9.35 % with an increase in enzymatic hydrolysis yield to 80 % of the theoretical. Readjusting water content of wheat straw to 45 % before performing the 2nd ozonolysis stage further reduced AIL content to 7.36 % and increased the hydrolysis yield to 90 %. Increasing wheat straw fiber size from < 2 mm to < 6 mm decreased the hydrolysis yield to 72 %. All results were considered significant improvements when compared to untreated wheat straw with AIL content of 20.5 % and hydrolysis yield of 23 %.

scholarly journals Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw

2021 ◽  
Author(s):  
Ali Kamel H. Al Jibouri
Keyword(s):  
Enzymatic Hydrolysis ◽  
Water Content ◽  
Wheat Straw ◽  
Initial Water Content ◽  
Optimal Parameters ◽  
Initial Water ◽  
Hydrolysis Yield ◽  
Fiber Size ◽  
Two Stages ◽  
Hydrolysis Of

Wheat straw was pretreated with ozone to increase the enzymatic hydrolysis yield. Ozonolysis pretreatment was performed in two stages with an intermediate washing step with water in between. Part of the delignification products (lignin fragments) were removed by a washing step so ozone was used to oxidize more lignin rather than oxidizing lignin fragments. Three parameters, i.e. Initial Water Content (IWC) in wheat straw, Washing Starting Time (WST), and Washing Contact Time (WCT), were optimized to minimize Acid Insoluble Lignin (AIL) content of ozonated wheat straw. Performing an experiment using optimal parameters' values, i.e. IWC equal to 45 wt. %, WST equal to 20 minutes and WCT equal to 80 seconds, showed a drop in AIL content to 9.35 % with an increase in enzymatic hydrolysis yield to 80 % of the theoretical. Readjusting water content of wheat straw to 45 % before performing the 2nd ozonolysis stage further reduced AIL content to 7.36 % and increased the hydrolysis yield to 90 %. Increasing wheat straw fiber size from < 2 mm to < 6 mm decreased the hydrolysis yield to 72 %. All results were considered significant improvements when compared to untreated wheat straw with AIL content of 20.5 % and hydrolysis yield of 23 %.

scholarly journals Effects of Dissociation Water Retention on Pore Structure Disintegration in Hydrate Sediments

2020 ◽  
Vol 8 ◽  
Author(s):  
Liu Yang ◽  
Shuo Wang ◽  
Hongfeng Lu ◽  
Ling Liu ◽  
Rina Sa
Keyword(s):  
Pore Structure ◽  
Water Content ◽  
Clay Minerals ◽  
Water Retention ◽  
Initial Water Content ◽  
Initial Water ◽  
Salt Minerals ◽  
Water Field ◽  
Two Stages ◽  
Main Factor

During the depressurization process, natural gas hydrates (NGHs) decompose and release methane gas and water. Field experience shows that only 1% of the dissociation water is recovered, hindering the continuous pressure decline and further NGHs decomposition. The retention effect of the dissociation water on the pore structure is still unclear in NGHs sediments. In this paper, the hydrate sediment samples were tested for porosity, permeability, pore structure and clay minerals content, etc. The ions concentration change of solution was continuously measured using a conductivity meter to evaluate the disintegration mechanism of sediments. The results show that the pore structure of sediments tend to disintegrate under the action of dissociation water, leading to an increase in the ions concentration of dissociation water. According to the ions concentration curve, the sediment disintegration is divided into two stages. The rapid disintegration stage is mainly related to clay minerals. The slow disintegration stage is mainly related to the dissolution of soluble salt minerals. The initial water content is the main factor affecting the disintegration of the sediment skeleton. Under the condition of low initial water content, the sediment skeleton disintegrates instantaneously in dissociation water. When the initial water content exceeds 30.6–37.9%, the pore structure of sediments tends to be stable in dissociation water. Studying the effect of dissociation water on the sediment pore structure is helpful to understand the mechanism of low water production and to optimize the exploitation regime of gas hydrate.

scholarly journals study on sedimentation characteristics of soft clay

2021 ◽  
Vol 236 ◽  
pp. 02039
Author(s):  
Wang Xuekui ◽  
Wang Qingqing
Keyword(s):  
Water Content ◽  
Soil Property ◽  
Raw Materials ◽  
Soft Clay ◽  
Initial Water Content ◽  
Initial Water ◽  
Hydraulic Fill ◽  
Two Stages ◽  
Short Time ◽  
Property Index

There are large areas of soft clay distributed in coastal areas of China, which are often used as raw materials for hydraulic fill engineering in recent years, and its sedimentation characteristics have attracted more and more attention. In this paper, the influence of initial water content on the sedimentation characteristics of soft clay is studied through the experiment. The results show that: (1) the sedimentation process of soft clay can be divided into two stages: sedimentation stage and self weight consolidation stage. The sedimentation stage has a short time, and the soil property index tends to be stable quickly; the self weight consolidation stage is very slow, and the soil property index almost has no change; (2) the larger the initial water content of soft clay, the greater the sedimentation rate and the faster the sedimentation; (3) the higher the initial water content, the faster the sedimentation, the higher the water content and the void ratio, the smaller the density.

Influence of initial water content and strain rate on remolded yield stress in marine clay

2021 ◽  
pp. 1-8
Author(s):  
Xiaobing Li ◽  
Jianpeng Chen ◽  
Xiuqing Hu ◽  
Hongtao Fu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Water Content ◽  
Yield Stress ◽  
Initial Water Content ◽  
Marine Clay ◽  
Initial Water

scholarly journals Application of the Calorimetric Methods to the Characteristics of Seeds from Olives

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 90
Author(s):  
Andrzej Bryś ◽  
Joanna Bryś ◽  
Marko Obranović ◽  
Dubravka Škevin ◽  
Szymon Głowacki ◽  
...  
Keyword(s):  
Olive Oil ◽  
Water Content ◽  
Cooling System ◽  
Waste Product ◽  
Normal Pressure ◽  
Ash Content ◽  
Initial Water Content ◽  
Scanning Calorimetry ◽  
Initial Water

The olive oil industry represents an important productive sector in the Mediterranean basin countries. Olive stone is an essential by-product generated in the olive oil extraction industries and it represents roughly 10% by weight of the olive fruit. The seeds of pickled olives are also a significant waste product. In the present study, we have investigated the possibility of the use of differential scanning calorimetry for the thermal characterization of seeds from green and black pickled olives from Croatia. The differential scanning calorimeter (DSC) with a normal pressure cell equipped with a cooling system was used to determine the thermal properties of seeds from olives. The following analyses were also performed: the determination of calorific values in a pressure bomb calorimeter, the determination of initial water content, the determination of changes of water content during drying at the temperatures of 30 °C, 50 °C and 80 °C, the determination of a percentage content of seeds mass to the mass of the whole olives, and the determination of ash content. Seeds from olives are characterized by very good parameters as a biomass. The analyzed olive seeds were characterized by low water content, low ash content, and a relatively high caloric value.

scholarly journals Effects of Initial Water Content on Microstructure and Mechanical Properties of Lean Clay Soil Stabilized by Compound Calcium-Based Stabilizer

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1933 ◽  
Author(s):  
Chenglong Yin ◽  
Wei Zhang ◽  
Xunli Jiang ◽  
Zhiyi Huang
Keyword(s):  
Water Content ◽  
Soil Stabilization ◽  
Clay Soil ◽  
Soil Aggregates ◽  
Optical Microscope ◽  
Initial Water Content ◽  
Reaction Products ◽  
Unconfined Compression Test ◽  
Initial Water ◽  
X Ray

Initial water content significantly affects the efficiency of soil stabilization. In this study, the effects of initial water content on the compressibility, strength, microstructure, and composition of a lean clay soil stabilized by compound calcium-based stabilizer were investigated by static compaction test, unconfined compression test, optical microscope observations, environment scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The results indicate that as the initial water content increases in the range studied, both the compaction energy and the maximum compaction force decrease linearly and there are less soil aggregates or agglomerations, and a smaller proportion of large pores in the compacted mixture structure. In addition, for specimens cured with or without external water supply and under different compaction degrees, the variation law of the unconfined compressive strength with initial water content is different and the highest strength value is obtained at various initial water contents. With the increase of initial water content, the percentage of the oxygen element tends to increase in the reaction products of the calcium-based stabilizer, whereas the primary mineral composition of the soil-stabilizer mixture did not change notably.

Kinetic model of enzymatic hydrolysis of steam-exploded wheat straw

2012 ◽  
Vol 87 (2) ◽  
pp. 1280-1285 ◽  
Author(s):  
Greta Radeva ◽  
Ivo Valchev ◽  
Stoiko Petrin ◽  
Eva Valcheva ◽  
Petya Tsekova
Keyword(s):  
Enzymatic Hydrolysis ◽  
Kinetic Model ◽  
Wheat Straw ◽  
Hydrolysis Of

scholarly journals Solidification of High Organic Matter Content Sludge by Cement, Lime and Metakaolin

2018 ◽  
Author(s):  
Ke Rui ◽  
Wang Hongxing ◽  
Tan Yunzhi ◽  
Wang Lehua
Keyword(s):  
Organic Matter ◽  
Water Content ◽  
Organic Matter Content ◽  
Microscopic Analysis ◽  
Chemical Components ◽  
Orthogonal Experimental Design ◽  
Initial Water Content ◽  
Initial Water ◽  
Lime Content ◽  
Sheet Structure

Based on orthogonal experimental design, the key solidification controlling technology of Solidified/Stabilized (S/S) sludge with high total organic content (TOC) by cement, lime and metakaolin was explored by macroscopic tests, chemical components measurements and microscopic analysis. The macroscopic tests show that, the permeability coefficient is mainly affected by initial water content and lime content, and the unconfined compression strength is mainly affected by cement content and lime content. The chemical components measurements show that, the solidification effect of S/S sludge with high TOC is controlled by organic matter consumption, and organic matter consumption is determined by the alkaline environment from the cement and lime hydration reactions, which is mainly affect by the initial water content and lime-metakaolin content ratio. The microscopic analysis results show that, lime consumes parts of organic matter while excess lime produces weak Ca(OH)2 crystal fluffy sheet structure, matakaolin produces pozzolanic reactions with cement and lime instead of soil particles, and consumes the weak Ca(OH)2 crystal fluffy sheet structure produced by superfluous lime. The research has confirmed key controlling points of S/S sludge in case of high TOC, which will provide theoretical guidance and technical support for S/S sludge promotion with high TOC.

Determination of the tensile strength of unsaturated tailings using bending tests

2015 ◽  
Vol 52 (11) ◽  
pp. 1874-1885 ◽  
Author(s):  
Bibiana Narvaez ◽  
Michel Aubertin ◽  
Faustin Saleh-Mbemba
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Water Retention ◽  
Water Retention Curve ◽  
Initial Water Content ◽  
Ambient Conditions ◽  
Initial Water ◽  
Bending Tests ◽  
Retention Curve ◽  
Apparent Cohesion

Bending tests were conducted on specimens of unsaturated tailings from three hard rock mines to evaluate their tensile strength. Saturated samples were prepared at an initial water content, w0, of 40% and then naturally dried under ambient conditions to pre-selected degrees of saturation, Sr, which can be related to the corresponding suction using the water retention curve. The basic interpretation of the bending tests results is based on an elastic–brittle behavior. The results show how the tensile strength, σt, of unsaturated tailings varies with water content, w (and Sr). The experimental data are also used to evaluate Young’s modulus in tension, Et, and to estimate the apparent cohesion, capp, as a function of Sr. Predictive equations are also applied to estimate the values of σt of unsaturated tailings using the water retention curve.

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