Purification Of Seawater And Its Application On Textile Reactive Dyeing Technology

As a big country of textile dyeing and finishing,how to improve the utilization ratio of water resources and save water resources has become the main issue of our country.Facing the severe situation of freshwater resources,people began to try new sources of water,such as seawater purification and the reuse of wastewater and so on.Seawater utilization has a broad prospect.This paper aims at conducting a series of processing towards seawater,selectively removing some kinds of ion,and trying to use the processed seawater in the process of dyeing and finishing.This paper mainly consists of three parts,seawater treatment,adsorption properties of 732 cation exchange resin towards calcium and magnesium ions and the application of treated seawater.The part of seawater processing includes flocculating sedimentation,chemical precipitation of seawater softening,ion exchange of seawater purification,etc.It's found that the flocculant of aluminum chloride polymerization can obviously increase the sediment rate of soil in seawater.When the flocculant of aluminum chloride polymerization amount is 80mg/L,seawater turbidity can be dropped to 30NTU after quietly placed for 1h,which can meet the requirements of water turbidity in dyeing and finishing.Chemical precipitation can remarkable reduce seawater hardness.Lime(3.1?3.3g/L)and soda ash(6g/L)combined method and caustic soda(3.3?3.4g/L)soda ash(0.5-0.8g/L)method all can make the hardness descend to 150ppm below,which can meet the requirements of water hardness in dyeing and finishing.After the treatments above,seawater's then exchanged by 732 cation exchange resin,during which sodium ion concentration of seawater rise and magnesium,potassium and calcium ion concentration drops.Through the method of static adsorption experiment the adsorption perfonnance of 732 cation exchange resin towards calcium and magnesium ions was studied.The adsorption type,adsorption rate and thermodynamic parameters of resin for the two ions were investigated.The results showed that the adsorption properties of resin for the two ions were similar.The adsorption type was the type of Langmuir,and the adsorption was both a heat adsorbing and entropy increase process.Discussed the utilization of treated seawater in the process of dyeing,pretreatment of cotton fabric and rinsing.Then compare these samples with that processed with freshwater under the same condition.The results showed that the dyeing data of the two mediums were similar in percentage of exhaustion,percentage of dye fixing,rub fastness,soap fastness.The color difference between them was below 0.8,which could meet the requirements for dyed product quality and color difference in practical production.Treated seawater is partial alkaline,so under the same condition,samples treated by seawater are higher than that treated by tap water in whiteness,capillary effect and strength loss.After soap boiling,samples rinsed with different proportions of seawater are similar to that rinsed with freshwater in rubbing fastness,soap fastness,K/S value and the color difference between them is below 0.6 as well.