Research On Dyeing Wastewater Recycling Of Reactive Dyes For Cotton

In this paper,the mid-temperature reactive dyes were selected,the influence of different influence factors on the flocculation process was discussed,the effect of salt,alkali on the oxidation process was studied;through the utility evaluation of various separation methods,the separation method of different dyeing scale was ensured;the knitted cotton fabric was dyed with the fresh water as dyeing medium,the dyeing wastewater was treated by the means of flocculation,oxidation,centrifugal,filtering,etc.then the reused water was got.Wastewater was reused in the orginal process after combination with the water planning principles,The dyeing parameters were adjusted according to content of inorganic salt in reused water,and dyeing was carried out using reused water as the dyeing medium.Then comparison between dyed fabrics and fabric dyed in fresh water was made.The quality of reused water and the dyeing effect were evaluated.The results indicated that:1.The flocculation ability for reactive dyeing wastewater was studied using cationic organic flocculant,the results shows that the quantity of flocculant E,the quantity of coagulant aid CP,contentration of salt,soda and pH value have great effect to the flocculation ability,under the optimum flocculation condition,the dye removal rate of actual dyeing wastewater reached more than 98%.2.The reactive dyeing wastewater was decolored by oxidation process,shows that decolorization effect was obvious,the chromaticity and turbidity could be dropped to zero after oxidation process;with the increase of number of back to dye,the dyeing wastewater contains salt,soda ash had no impact to oxidation process.the dyeing wastewater contains generation of alkali and the substitution alkali had larger influence on oxidation process.3.The reactive dyes separation effect was studied using membrane separation and centrifugal separation method.It is determine that the LG 10-2.4 electric centrifuge and 022μm polypropylene microporous membrane filter for filtering method,as a processing under the condition of dye bath volume is 900mL of dyeing wastewater separation method;GQF75 type tubular centrifuges and tertiary membrane filtration device for processing under the condition of dye bath volume of 12L dyeing wastewater separation method.4.Dual water supply and regeneration recycling is feasible in the reactive dyeing wastewater.Compared with conventional dyeing process,it can save the 73.3%of fresh water under the different dye bath condition.5.Wastewater was reused in the original process after flocculation and oxidation treatment,and the results show that it is feasible.After oxidation treatment,the colour fastness of dyeing cloth is 4～5,After flocculation treatment,the colour fastness of dyeing cloth is 3～4.The dyeing effect of reused wastewater,oxidation process is higher than the flocculation process.With the enlargement of the dye bath volume,the fastness of dyeing cloth that treated by each process increases gradually,the dyeing effect of reused wastewater is getting better.