Experimental Research On Treating Wastewater Containing Azo Dye By Lignite

Lignite was used for adsorbing and flocculating three dye wastewater: reactive brilliantred X-3B, acid red3R and acid red B. Respectively, time, pH value, lignite dosage, ionicstrength and dye concentration and other parameters were studied. The strcture of the adsorbentwas characterized by Scanning Electron Microscope and infrared spectroscopy, the results showthat:1. The adsorption processes of the three dye sorption conformed to the second-order rateexpression, the isothermal data of dye adsorption coincided with the Freundlich models, andbelonged to multilayer adsorption.2. In the course of three dyes adsorption，three dyes all reached balance in24h; in bindingand adsorption process, reactive brilliant red X-3B and acid red3R absorption reached balance in15min, while acid red B absorption in2h.3. The Azo Dye wastewater could be adsorbed effectively at pH1, while they could beflocculated at pH12in binding stage, at pH1in adsorption stage; as the sorbent dosageincreased, the removal rate of dye increased too; as the Nacl dosage increased, the removal rateof three dye increased obviously, the existence of salinity has certain stimulation effect toadsorption and flocculation. The removal rate appeared best when dye concentration was at5mg/L.4. Lignite has developed micropore structure, the lignite surface is covered with dyemolecules; after adsorption, adsorption spectra have little change than before, O-H，C=C, C-Oinvolved in the reaction.Lignite with high dye removal capacity is a locally available, low cost and untried botanicmaterial in China. It could reduce the operating cost to lignite for absorbing dye from wastewater.Therefore, as a kind of new treatment method for dye wastewater, this experiment is worth doingfurther research and popularization.