Integrative Disposal Of Dyeing Wastewater By Mixture Of Surfactant And Bentonite

Dyeing wastewater,due to its high chroma and high toxicity,is difficult to biodegrade, resulting in a severely impair on the aquatic ecological environment.Bentonite mineral with a special 2:1 crystal structure is an inexpensive material available easily,showing an excellent adsorption property for pollutants.The surfactant-modified organobentonite,treating dyeing wastewater effectively,has broad applications in the field of sewage treatment.However, there are some problems in the separation of solid-liquid,and some surfactants are desorbed easily when used to deal with wastewater.On the other hand,the surfactants are expensive. These drawbacks inhibit their applications in the actual wastewater treatments.Mixing the cationic surfactant(CTMAB or CPC)directly with bentonite to treat dyeing wastewater was investigated in this paper.The results showed that the cationic surfactant interacting with bentonite in aqueous solution greatly increased decolourization rate as compared with the traditional sorption method of organobentonite.of all surfactants, CTMAB-bentonite showed the highest removal rate of 99%for 100 mg·L^-1isatin.The process was little influenced by pH change and contact time,showing a distinct synergistic effect of adsorption,flocculation and decolourization.The result from treating actual dyeing wastewater with CTMAB+Bentonite showed its effectiveness,fast decolourization,less sludge production and easy operation.The different dyeing wastewater treatments depend on the different mixture ratios of CTMAB and bentonite.When the combination of 0.8 g·L^-1CTMAB and 0.3 g·L^-1bentonite was used to treat the dyeing wastewater from a print works in Nanning,both decolourization rate and NTU removal rate of 98%achieved,while the COD removal rate reached to 85%.After further biological treatment,the wastewater meeting the discharge standards could be obtained.The sludge could be regenerated after decolorization and calcinations.