Application of PVDF micro-filtration membrane to processing of natural catechu dye

In order to improve the purity of the dye liquid extracted from catechu and its dyeing properties,polyvinylidene fluoride(PVDF) hollow fiber membrane was used to separate the impurity in natural dye catechu liquid.The catechu liquids processed with and without the membrane separation technology were respectively measured by turbidity tester and were respectively used to dye wool and cotton fabrics.The color characteristics of the wool and cotton fabrics dyed with different catechu dye liquids were compared.The relationships between the permeate flux and filtration time,between concentration of coloring matter and filtration time during the membrane filtration were also investigated.It shows that the application of the micro-filtration membrane can decrease the turbidity values of the permeated catechu dye liquids and improve the dyeing properties of catechu dye on wool,cotton fabrics.The catechu permeate flux and concentration of coloring matter are both decreased after the membrane separate system has been run for 1 hour.Then,the membrane system need to be washed.It is better that NaOH solution is used as detergent.Ultrasonic cleaning can be used to improve membrane flux when the membrane is seriously polluted.