The paper industry extensively uses paper additives. Among them, strength additives are used to enhance the strength of paper, reduce the number of breaks, and increase productivity. Polyamide epoxy chloride propylene (PAE) has been widely used as a wet strength agent for paper, to improve the wet strength of paper. The unreacted epoxy chloride propylene hydrocarbons during the production of wet strength agent PAE will undergo hydrolysis or acidolysis, generating toxic by-products such as chloropropanols. 

Chloropropanol compounds are internationally recognized as food contaminants, including 3-chloro-1,2-propanediol (3-MCPD), 2-chloro-1,3-propanediol (2-MCPD), and 1,3-dichloro-2-propanol with double chlorine substitution (1,3-DCP) and 2,3-dichloro-1-propanol (2,3-DCP). 1,3-DCP and 3-MCPD have high toxicity, and 3-MCPD is classified as a 2B carcinogen by the World Health Organization. With the widespread use of toilet paper and paper products for daily use, as well as food-contact paper, to ensure product safety and protect consumers' health, it is urgent to control the residual of chloropropanol in wet strength agents from the source and manufacture environmentally friendly wet strength agents. 

The wet strength agent PAE is a water-soluble macromolecular compound with a concentration of 10-15%, and it is a pale yellow transparent viscous liquid. Chloropropanol is a small molecule compound that is easily soluble in water and can be miscible with the wet strength agent. The removal of chloropropanol from PAE can be achieved using solvent extraction or membrane filtration methods. Among these, membrane filtration has the advantages of no phase change, low energy consumption, no introduction of external substances, continuous operation, and linear industrialization scalability, and thus has significant advantages. Shandong Bonan Group has adopted membrane filtration technology to remove chloropropanol from the wet strength agent PAE. The content of chloropropanol in the raw material solution was reduced from the initial 10,000 mg/kg to less than 10 mg/kg. By optimizing the pretreatment of the raw material solution and the selection of equipment, low pressure, high throughput, and high recovery rate production was achieved. Combined with membrane concentration technology, the chloropropanol wastewater was concentrated and reused water was returned, greatly reducing the amount of wastewater treatment, alleviating environmental pressure, and lowering production costs. 

With its rich engineering experience and separation purification expertise, Wuhan Bona is adept at overcoming technical challenges. It not only provides customers with high-quality equipment solutions but also offers excellent process solutions to alleviate their concerns and jointly promote industrial development.