Research On Decolorizing Of Dye Wastewater By Mineral Adsorption Composites

Industrial wastewater, especially the dye wastewater is harming more and moreseriously to the natural environment. The dyes were difficult degraded because of itwere so many properties such as a strong resistance photolysis, anti-oxidation,thermal stability, and anti biodegradable etal. The dye wastewater treated is notquantity huge but also extreme difficult. Dye wastewater treated is becoming moreand more important in a round world.These natural minerals were used widely wastewater treatment due to large surfacearea, poriness, rich source and lower price.In this paper, adsorption material which isan excellent adsorption performance was preparated with single mineral or compositegranulating into lower dissipation rate. Static adsorption study has been done with thetypical dyes example for azo (Methyl Orange), thiophene oxazine (Methylene Blue)and triphenylmethane dyes (Malachite Green).Then, the effects of the differentadsorption dose, initial concentration, adsorption time and pH on the decolorizationwere studied, furthermore, the thermodynamics and dynamics were also investigated,the results demonstrated as follows:1．The optimum adsorption conditions of Methyl Orange are as follows: under thecondition of room temperature and raw water pH value, at the best dosage of5g/Ladsorbent, the decolorization rate was44.18%after adsorption for1h, and theadsorption quantity is26.08mg/g, when the initial concentration is300mg/L ofMethyl Orange dye solution. The decolorizing effect has no obvious enhancementwith enhancive time, which shows that composite materials can adsorb MethylOrange dye quickly. In addition, the maximum absorption peak shift occurs underacidic conditions (pH value is less than2). According to the effect of pH value on thedecoloring rate of Methyl Orange, the best initial pH value is4. The adsorptionisotherm and adsorption dynamics analysis of Methyl Orange show that it is morelikely to be fit the Freundlich adsorption model, and the secondary dynamic model.2．The optimum adsorption conditions of Methylene Blue are as follows: under thecondition of room temperature and raw water pH value, at the best dosage of7.5g/Ladsorbent, the decolorization rate and adsorption capacity is91.72%and36.24mg/gfor200mg/L Methylene Blue solution at6h. According to the effect of pH value onthe decoloring rate of Methylene Blue, the raw water’s pH is the best initial pH valueThe adsorption isotherm and adsorption dynamics analysis of Methylene Blue show that it’s the same of Methyl Orange.3． The optimum adsorption conditions of Malachite Green are as follows: Thecomposite materials can adsorb Malachite Green dye quickly even in the highconcentration solution. Its decolorization rate and adsorption capacity is72.37%and71.98mg/g, with the best dosage of the adsorbent for5g/L, for500mg/L MalachiteGreen dye at1h. By the study of adsorption, the optimum adsorption conditions ofMalachite Green are as follow: the best initial concentration of Malachite Green is300mg/L, and is adsorbed6h with5g/L adsorbent. At this point, the reaction reachedequilibrium. The decolorization rate is95.2%, and the adsorption capacity is56.27mg/g. The best pH value is less than2, so a little of acid was added to the wastewaterin practical application. The adsorption isotherm and adsorption dynamics analysis ofMalachite Green shows that it is more likely to fit the Langmuir adsorption model,and the secondary dynamic model.