Adsorption And Flocculation Performance Of Modified Chitosan On Printing And Dyeing Wastewater

Printing and dyeing wastewater is a class of intractable industrial waste waterwith deep color&high COD.Chemical flocculation and physical adsorption are the recent treatment of dyeing wastewater which can be both economical andeffective.Therefore,it plays a imperative and crucial role in printing and dyeing wastewater for adsorbent and flocculant,Because of its unique molecular structure of chitosan on the adsorption of various types of wastewater,the flocculation effect is good.For the development of new adsorbents and flocculants,this paper studies the properties of modified chitosan flocculant and adsorbent and then its application in dyeing wastewater.In this paper,physical adsorption and chemical flocculation can be used by the treatment of dyeing wastewater.Adsorbent and the modified chitosan flocculant were obtained by chitosan.Preparation of Chitosan in the process of adsorption and flocculation,both sin-gle factor and orthogonal design experiments to determine the optimum preparation con-ditions.The article also carried out on modified chitosan and coagulant properties of ads-orbent.At the same time,the use of FT-IR,UV-Vis equipment obtained by the modified chitosan-carboxymethyl chitosan were characterized.(1)The preparation of Chitosan adsorbent which is modified is adopted by single factor experiment and orthogonal experiment to study the different factors on the degree of carboxy-methyl substitution(DS).We also studied the modified chitosan on adsorption simulation of methylene blue dye wastewater and studied effects of different factors on the decolorization rate.The best Adsorptiontreatment conditions are:Dosage is 0.10g,PH 8.00,the initial concentration of 5mg/L,the decolorization rate reached 86%-The influences ofadsorption process followed by the adsorption isotherm equation.Adsorption thermodynamics show that:the reaction is exothermic,the adsorption process of basic chemical adsorption.Adsorption kinetics showed that:m-odified chitosan adsorption process followed pseudo second adsorption kinetic rate model.(2)The preparation of modified carboxymethyl chitosan flocculant uses Traditional method and microwave method.Experimental was study of the thermodynamics of carboxymethyl chitosan by the different factors on the degree of DS and also studied the flocculation performance of the product which was modified by microwave method,and studied effects of different factors on COD removal efficiency of dyeing wastewater,decolorization rate and the removal of turbidity.The modified chitosans which were prepared by Microwave and traditional method were compared on the flocculation effect.The result is:Printing and dyeing wastewater COD remove with Microwave Method is 66%,Decolorization efficiency is 84%.Remove efficiency of turbidity is 78%.Printing and dyeing wastewater COD with traditional methods remove with microwave method remove efficiency is 57%.Decolorization efficiency is 72%.Remove efficiency of turbidity is 72%.Compared with the conventional,the microwave method greatly reducing the response time,thereby reducing costs.(3)Samples were characterized by FT-IR,UV-Vis.FT-IR characterization of displ-ay:modified chitosan hydroxyl and amino hydrogen bonds were destroyed,and appeared carboxymethyl absorption peak.with the greater the DS and the higher the degree of deacetylation product,the more absorption of carboxymethyl Acute.With the increased degree of deacetylation of chitosan,in the field 200nm-400nm UV absorption peak within the gradual strength may because of the increase number of NH2.