Papermaking is one of the the Four Great Inventions in China's traditional culture,which has had a profound impact on the world.Paper making mainly uses fiber raw materials such as wood,rice straw,and reeds to be chemically processed into pulp,which is then further processed into paper.Modern papermaking technology has become more automated and mature,and can produce paper with different hardness,thickness,and color according to different processing techniques.Paper making is one of the key polluting industries.In order to reduce the harm to the environment,new paper making technologies such as oxygen alkali method,whole cellulose method,closed loop water method,and synthesis method are being developed and popularized.

In order to solve the pollution problem of papermaking wastewater,China has adopted various treatment methods.Currently,the main method is the combination of"physicochemical+biochemical",which separates lignin,mud,fibers,ions,organic matter and other substances in papermaking wastewater through sedimentation filtration,chemical reaction treatment,and biological action.In addition to these methods,the hollow fiber ultrafiltration membrane being promoted can also provide excellent treatment effects for papermaking wastewater.It is a small pore membrane separation technology that utilizes the screening and permeation characteristics of the filter membrane under the pressure of the solution itself to achieve the separation of low molecular solutes and water in the solution.

In the treatment of papermaking wastewater,the main functions and advantages of hollow fiber ultrafiltration membranes are:

1.The pore size is small,the membrane pores are tightly arranged,and the ion interception effect is good.It can fully intercept a large amount of suspended solids,BOD,COD,methanol,rosin acid,unsaturated fatty acids and other toxic substances in papermaking wastewater;

2.It has good anti pollution ability and adopts the form of"cross flow filtration"to reduce the risk of pollutant blockage;

3.The process flow is simple,relying solely on pressure to drive the filtration process,without the need for thermal energy,chemical additives,or catalysts.The process flow is short,the operation is simple,and separation without phase change is achieved,making secondary pollution less likely to occur;

4.Small footprint,high degree of automation,low operating energy consumption,convenient and fast cleaning and maintenance work,and low investment cost.