Chemical Industry
More than 3,000 organic solvents are widely used in industries such as paints, pharmaceuticals, papermaking, chemicals, petrochemicals, printing, and textiles, and the consumption of organic solvents in industrial production is often substantial. Common organic solvents include toluene, alcohols (methanol, ethanol, isopropanol), esters, ketones (acetone, cyclohexanone, methyl ethyl ketone, N-methylpyrrolidone), acetonitrile, ethyl acetate, dimethylformamide, aromatic hydrocarbons, halogenated hydrocarbons, etc. Most of these solvents are toxic, and many have been proven to be strongly carcinogenic. Therefore, how to recycle organic solvents more effectively is particularly important.
Current traditional separation and purification processes used in organic solvent systems, such as centrifugation, conventional dead-end filtration, and evaporation, not only easily cause solvent volatilization and air pollution but are also difficult to automate. Operators frequently come into contact with solvents, which can easily harm their health. After years of experience in membrane technology applications, Guochu Technology (Xiamen) Co., Ltd. has integrated advanced solvent-resistant membrane technology into organic solvent systems, achieving closed control of organic solvents. At the same time, this technology also enables automated control of equipment, effectively reducing direct contact between operators and organic solvents, allowing organic solvents to function better and more safely for industrial production. Membrane technology recovery of homogeneous catalysts is one such application.
A membrane is a selective barrier between two phases. It is a polymer material that selectively separates a feed solution under a pressure difference. The separation process using such membranes is called membrane separation technology. Unlike conventional filters, membranes can perform separation on a molecular scale, and the process is physical, involving no phase change or addition of auxiliary agents. Membrane thickness is generally on the micron scale. Based on pore size, membranes can be classified into microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) membranes. In cross-flow membrane processes, the separation and rejection performance of various membranes is distinguished by pore size and molecular weight cut-off. The figure below briefly illustrates four different membrane separation processes (the reflected arrows indicate that the substance cannot permeate through the membrane and is retained):
Organic solvent passes through the solvent-resistant membrane under operating pressures not exceeding 60 bar to become the permeate, while substances with molecular weights larger than the membrane cut off are retained to become the retentate. One or more solutes can pass through the membrane into the permeate, while others remain in the retentate. Currently, specialty solvent-resistant membranes are available with molecular weight cut offs of 150D, 200D, 300D, 500D, 900D, 20KD, and others. Guochu Technology is currently developing specialty separation membranes with additional molecular weight cut offs.
The main applications of membrane technology in organic solvents are as follows:
Concentration of target products in organic solvent systems
Impurity removal and purification of target products in organic solvent systems
Separation of different components in organic solvent systems
Decolorization in organic solvent systems
Separation of products and recycling of organic solvents in organic solvent systems
Organic solvent recovery
Characteristics of membrane technology in organic solvent applications:
Process advantages:
Solvent-resistant membranes can operate at ambient or low temperatures without affecting the activity of active substances
Solvent-resistant membranes can filter and separate active substances in organic solvents, reducing investment and process steps
Repeated filtration with solvent-resistant membranes can increase product yield
Multi-stage parallel configuration of solvent-resistant membranes can increase production scale
Multi-stage series configuration of solvent-resistant membranes can improve product purity
Reduces the complexity of system integration and improves operational separation reliability
Tolerated solvents include:
Application fields:
In the field of solvent systems, Guochu Technology also has a pervaporation dehydration technology for organic solvents that form azeotropes with water. This technology also utilizes the permselectivity principle of membranes, but the separation is driven by the partial pressure difference of components in the vapor phase, exploiting differences in adsorption diffusion rates and molecular sizes of each component in the pervaporation membrane material to achieve selective separation. An organic solvent vapor (or liquid) is fed on one side of the pervaporation membrane, while a vacuum is applied on the other side to promptly remove water from the solvent, thereby obtaining anhydrous organic solvents to further meet high quality requirements in industrial production.
Pervaporation for dehydration of organic solvents that form azeotropes with water
Characteristics of pervaporation membrane technology in organic solvent dehydration:
Application fields:
Dehydratable solvents include:
Since its establishment, Guochu Technology (Xiamen) Co., Ltd. has focused on membrane separation technology, dedicated to promoting novel separation technologies and continuously exploring new applications of membrane separation in fields such as biopharmaceuticals, microelectronics, metallurgy, chemicals, machinery, food, dairy, beverages, and the environment. The company provides targeted filtration and purification integrated solutions to meet the highly differentiated needs of various customers, improving product quality and satisfying customer requirements.
