The process of de-colorization and recovery/reuse of ionic liquids can be precisely divided into the following several steps: 

1. Ion liquid decolorization 

The principle of ion liquid nanofiltration decolorization: 

The separation of ionic liquids and pigment-like substances by nanofiltration membranes mainly relies on membrane pore size sieving effect, ionic interaction effect, etc. Due to the small pore size of nanofiltration membranes, polysaccharides and oligosaccharides, pigments, etc., which have relatively larger molecular weights than ionic liquids, cannot pass through the membrane and are retained; ionic liquids and water have relatively smaller molecular weights and are not retained but pass through. Under pressure drive, the raw liquid to be decolorized passes through the nanofiltration membrane, and the ionic liquids and pigment impurities gradually separate, ultimately obtaining a yellowish or basically colorless ionic liquid product of qualified quality. 

II. Ion Liquid Recovery and Reuse 

Recycling method: 

The methods for recovering ionic liquids mainly include distillation, crystallization, extraction, and membrane separation. These methods can be selected and optimized based on the properties of ionic liquids and the specific application scenarios. 

For example, the distillation method separates substances by taking advantage of the vapor pressure difference between the gas phases of ionic liquids and other solvents, and is suitable for the recovery of ionic liquids with high purity requirements. The crystallization method adjusts the solubility of ionic liquids through the solvent, and then uses crystallization. 

The separation method is used for recovery. 

Recycling and Reuse Process: 

After de-colorization or other chemical reactions, ionic liquids can be separated and purified through the aforementioned recovery methods. The recovered ionic liquids can be reused in processes such as de-colorization, catalysis, and reaction separation, achieving recycling. 

In the ion liquid waste oil regeneration method, the ion liquid reacts with the waste oil to remove impurities and harmful substances, thereby regenerating and reusing the waste oil. The recovered ion liquid can be reused after the reaction, reducing production costs. 

And environmental pollution. 

Environmental protection and economic benefits: 

The recovery and reuse of ionic liquids not only helps to reduce environmental pollution and waste of resources, but also can lower production costs and enhance economic benefits. By optimizing the recovery methods and processes, efficient utilization of ionic liquids can be achieved. 

Recycling. 

Ion liquid decolorization and recycling are a complex process involving multiple steps and technologies. By choosing the appropriate ion liquids, decolorization methods, and recycling techniques, efficient, environmentally friendly, and economically viable utilization of ion liquids can be achieved. 

For many years, Wuhan Bona has been dedicated to the application process development of membrane separation technology. By integrating processes, membranes and equipment, it has accumulated rich experience in product purification and engineering-scale expansion. It not only solves manufacturing challenges but also improves product quality, and together with customers, it enhances the technical level of the industry.