scholarly journals Counter-Current Suspension Extraction Process of Lignocellulose in Biorefineries to Reach Low Water Consumption, High Extraction Yields, and Extract Concentrations

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1585
Author(s):  
Marc Conrad ◽  
Irina Smirnova
Keyword(s):  
Water Consumption ◽  
Potential Method ◽  
Extraction Process ◽  
High Yield ◽  
Process Window ◽  
Equilibration Time ◽  
High Concentration ◽  
Wastewater Disposal ◽  
Pretreated Wheat Straw ◽  
Counter Current

The processing of large quantities of water in biorefining processes can lead to immense costs for heating, evaporation, and wastewater disposal. These costs may prohibit the exploitation of alternative products, e.g., xylooligosaccharides from straw, which are regarded as too costly. A new counter-current extractions method is proposed that aims at low solvent (water) consumption, as well as high yields and extract concentrations. This process was evaluated with suspension extraction experiments with steam pretreated wheat straw and the process window analysis based on a mass balance for a washing and a leaching scenario. The latter was conducted with two other suspension extraction processes as a comparison. The equilibration time was found to be well below 10 min. While the suspension extraction with and without recycling need to be designed to achieve a high yield or a high concentration and low solvent consumption, the proposed extraction method can reach all three simultaneously. Thus, this new process is evaluated as a potential method to spare water and downstream costs and allow new processing pathways in second-generation biorefineries.

scholarly journals Extraction Equilibrium of Ni(II) in the Ni2+-SO42--Ac-(Na+, H+) - Cyanex 272 (H2A2)-kerosene-3%(v/v) Octan-1-ol System

2011 ◽  
Vol 4 (1) ◽  
pp. 83 ◽  
Author(s):  
R. K. Biswas ◽  
A. K. Karmakar ◽  
M. S. Rahman
Keyword(s):  
Distribution Ratio ◽  
Extraction Process ◽  
Equilibration Time ◽  
High Concentration ◽  
Concentration Region ◽  
Extraction Equilibrium ◽  
Cyanex 272 ◽  
Maximum Loading ◽  
Constant Ph ◽  
Title System

The title system has been studied elaborately. 3% (v/v) octan-1-ol is added as de-emulsifier. Equilibration time is < 2 min. Distribution ratio (D) at constant pH(eq) and [H2A2] is independent of [Ni(II)](aq). The pH dependency is always found to be 2; whilst the extractant dependence is found to vary from 1 (at lower concentration region, lcr) to 3 (at high concentration region, hcr). Moreover, the distribution ratio is found to be inversely proportional to (1+6.92 [SO42-]) and [Ac-]. Based on these results, the extraction equilibrium reactions have been proposed at various parametric conditions. The extraction process is endothermic (?H = 54.66 kJ/mol). The Kex values at 303 K are evaluated to be 10-11.086 and 10-11.56 at lcr and hcr of extractant, respectively. The maximum loading capacity is 21.28 g Ni(II) per 100 g extractant indicating the formation of NiAcA at maximum loading. The stripping ability of various inorganic acids towards loaded nickel, as well as, the possibilities of separation of Ni(II) from its binary mixtures with other ions of 3d-block elements have also been investigated.Keywords:  Extraction equilibrium; Ni(II) extraction; Cyanex 272; Sulphate-acetato medium; Kerosene-octanol.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i1.8007J. Sci. Res. 4 (1), 83-97 (2012) 

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

Efficient trace-scale extraction method of reactor produced 199Au adequate for nuclear medicine applications

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed F. Attallah ◽  
Ahmed M. Shahr El-Din ◽  
Mohamed A. Gizawy ◽  
Amal M. I. Ali
Keyword(s):  
Aqueous Media ◽  
Selective Extraction ◽  
Extraction Process ◽  
High Yield ◽  
High Recovery ◽  
Rapid Separation ◽  
Efficient Separation ◽  
Liquid Liquid Extraction ◽  
Cyanex 302 ◽  
Cyanex 923

Abstract Production of no carrier-added (NCA) 199Au through natPt(n, γ) reaction and subsequent purification using liquid-liquid extraction from other radioisotopes is studied in the context of theranostic application. Comparative separation of NCA 199Au after dissolution of activated Pt target using three Cyanex compounds (Cyanex-272, Cyanex-302 and Cyanex-923) is evaluated. The extraction process is optimized in terms of the type of extractant, the concentration of extractant, extraction time and aqueous media (HNO3, NH4OH). Among these extractants, the Cynaex-923 is efficient and promising for rapid separation and production of NCA 199Au from HNO3 by high extraction %. Selective extraction of 199Au from other Pt and Ir radioisotopes is observed. High recovery of 199Au was obtained in the case of Cyanex-923 using 0.05 M thiourea dissolved in HCl or 2 M NaOH. Our results find the Cyanex-923 as a promising extractant for efficient separation of 199Au from irradiated Pt target with high yield (99%).

scholarly journals Production of Cellulosic Ethanol from Enzymatically Hydrolysed Wheat Straws

2020 ◽  
Vol 10 (21) ◽  
pp. 7638
Author(s):  
Vasile-Florin Ursachi ◽  
Gheorghe Gutt
Keyword(s):  
Enzymatic Hydrolysis ◽  
Wheat Straw ◽  
Cellulosic Ethanol ◽  
Raw Material ◽  
High Yield ◽  
Liquid Ratio ◽  
Hydrolysis Process ◽  
Pretreatment Conditions ◽  
Pretreated Wheat Straw ◽  
First Time

The aim of this study is to find the optimal pretreatment conditions and hydrolysis in order to obtain a high yield of bioethanol from wheat straw. The pretreatments were performed with different concentrations of sulphuric acid 1, 2 and 3% (v/v), and were followed by an enzymatic hydrolysis that was performed by varying the solid-to-liquid ratio (1/20, 1/25 and 1/30 g/mL) and the enzyme dose (30/30 µL/g, 60/60 µL/g and 90/90 µL/g Viscozyme® L/Celluclast® 1.5 L). This mix of enzymes was used for the first time in the hydrolysis process of wheat straws which was previously pretreated with dilute sulfuric acid. Scanning electron microscopy indicated significant differences in the structural composition of the samples because of the pretreatment with H2SO4 at different concentrations, and ATR-FTIR analysis highlighted the changes in the chemical composition in the pretreated wheat straw as compared to the untreated one. HPLC-RID was used to identify and quantify the carbohydrates content resulted from enzymatic hydrolysis to evaluate the potential of using wheat straws as a raw material for production of cellulosic ethanol in Romania. The highest degradation of lignocellulosic material was obtained in the case of pretreatment with 3% H2SO4 (v/v), a solid-to-liquid ratio of 1/30 and an enzyme dose of 90/90 µL/g. Simultaneous saccharification and fermentation were performed using Saccharomyces cerevisiae yeast, and for monitoring the fermentation process a BlueSens equipment was used provided with ethanol, O2 and CO2 cap sensors mounted on the fermentation flasks. The highest concentration of bioethanol was obtained after 48 h of fermentation and it reached 1.20% (v/v).

scholarly journals The Effect of Operating Conditions on Curcumin Extracted from Turmeric by Hydrothermal Extraction

2019 ◽  
Vol 125 ◽  
pp. 19001
Author(s):  
Mohamad Endy Yulianto ◽  
Rizka Amalia ◽  
Vita Paramita ◽  
Indah Hartati ◽  
Nissa Ayu Maulinda ◽  
...  
Keyword(s):  
High Efficiency ◽  
Economic Value ◽  
Bioactive Compound ◽  
Extraction Process ◽  
Operating Conditions ◽  
Extraction Temperature ◽  
Liquid Ratio ◽  
High Concentration ◽  
Solid Liquid ◽  
Hydrothermal Extraction

Turmeric has a bioactive compound namely curcuminoid. It has many pharmacology effects such as anticancer, antidiabetic, antioxidant, hypolipidemic, anti-inflammatory, antimicrobial, antifertility, anti-venom, anti-coagulant, anti-HIV hepatoprotective, nephroprotective, and anticoagulant properties. To increase the economic value of turmeric, it is necessary to develop a hydrothermal extraction process of turmeric’s active compound. The advantages of hydrothermal extraction were inexpensive, abundant availability, high purity, non-toxic, and easy to handle. This research aims to study the effect of operating conditions : temperature (130-150oC), time (10-40 minutes) and solid:liquid ratio (1:10 and 1:12) on the bioactive compounds of turmeric extracted from hydrothermal extraction process. Generally, high extraction yield was obtained at higher extraction temperature (140 and 150oC). Under these conditions, with a lower solid : liquid ratio (1:10), high concentration of curcumin is produced. Further, a higher solid : liquid ratio will likely produce the opposite result, except when it operates at low extraction temperature. The high temperature of the pressurized liquid water can reduce the viscosity and surface tension of water so it will increase the diffusion rates and absorption. The higher the solid:liquid ratio, the greater the different concentration between interior and exterior cell, which promote the high efficiency of diffusion process.

Separation, purification and recovery of thorium from monazite leach liquors by counter-current extraction process

2020 ◽  
Vol 324 (1) ◽  
pp. 245-255
Author(s):  
Kyeong Woo Chung ◽  
Ho-Sung Yoon ◽  
Chul-Joo Kim ◽  
Rajesh Kumar Jyothi
Keyword(s):  
Extraction Process ◽  
Counter Current

scholarly journals Production ofN-Acetyl-d-Neuraminic Acid by Use of an Efficient Spore Surface Display System

2011 ◽  
Vol 77 (10) ◽  
pp. 3197-3201 ◽  
Author(s):  
Xiaoman Xu ◽  
Chao Gao ◽  
Xifeng Zhang ◽  
Bin Che ◽  
Cuiqing Ma ◽  
...  
Keyword(s):  
Surface Display ◽  
Value Added ◽  
Neuraminic Acid ◽  
High Yield ◽  
Permeability Barrier ◽  
Chemical Production ◽  
High Concentration ◽  
Suitable Alternative ◽  
Content Type ◽  
Whole Cells

ABSTRACTProduction ofN-acetyl-d-neuraminic acid (Neu5Ac) via biocatalysis is traditionally conducted using isolated enzymes or whole cells. The use of isolated enzymes is restricted by the time-consuming purification process, whereas the application of whole cells is limited by the permeability barrier presented by the microbial cell membrane. In this study, a novel type of biocatalyst, Neu5Ac aldolase presented on the surface ofBacillus subtilisspores, was used for the production of Neu5Ac. Under optimal conditions, Neu5Ac at a high concentration (54.7 g liter−1) and a high yield (90.2%) was obtained under a 5-fold excess of pyruvate overN-acetyl-d-mannosamine. The novel biocatalyst system, which is able to express and immobilize the target enzyme simultaneously on the surface ofB. subtilisspores, represents a suitable alternative for value-added chemical production.

Thermodynamics of Solvent Extraction of Perrhenate with N235 at High Concentration

2010 ◽  
Vol 150-151 ◽  
pp. 890-894
Author(s):  
Ke Xu Jiang ◽  
Da Wei Fang ◽  
Han Wang ◽  
Bao Xin Wang ◽  
Ying Xiong ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Aqueous Phase ◽  
Supporting Electrolyte ◽  
Extraction Process ◽  
Extraction System ◽  
Thermodynamic Quantities ◽  
High Concentration ◽  
Extraction Constants ◽  
Solvent Extraction System

In solvent extraction system of perrhenate with the extractant of N235 at high concentration, the equilibrium molalities of ReO4- were measured at ionic strengths from 0.2 to 2.0 mol.kg-1 in the aqueous phase containing Na2SO4 as the supporting electrolyte from 278.15K to 303.15K. The standard extraction constants K0 at various temperatures were obtained. Thermodynamic quantities for the extraction process were also calculated.

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