Synthesis And Cationization Modification Of Cellulose-silk Sericin Complete Degradable Flocculation Materials

With the development of modern industry,the discharge of waste water also increased.At present,flocculation precipitation is the most economical,direct and most effective treatment method.Flocculation is cheaper and easier to operate than other water treatment techniques.There are many kinds of flocculants in the market,and the most widely used is the organic flocculant.And organic flocculant can be divided into natural polymer flocculants flocculating agent and organic synthesis,synthetic organic flocculant has excellent flocculation performance,but there are non-renewable raw materials,refractory or residual monomer is harmful to the environment,etc.As a result,more and more researchers are focusing on natural polymer flocculants that are renewable,biodegradable,and non-toxic.This study adopts the content is the most abundant natural polymer material in nature cellulose?bamboo pulp cellulose?and in the process of cocoon silk extract were industrial waste protein?silk sericin?as raw materials,use of glutaraldehyde crosslinking,synthesized flocculation effect is good and completely biodegradable cellulose flocculant material by one step.The process for the swelling of cellulose in aqueous solution,and then applied one of the five factors four levels orthogonal experiment to get the optimal process of preparing cellulose grafted sericin copolymer:reaction temperature of 35?,reaction pH of 4,the reaction time for9 h,glutaraldehyde dosage was 0.375 g/g,sericin dosage was 1.5 g/g.Through infrared spectroscopy,thermogravimetric analysis,XRD and scanning electron microscopy,the various performances of the products were investigated.The grafting rate of cellulose based flocculation materials was 60.8%by this method;The removal rate of the turbidity of kaolin was preliminarily reached 95.8%.According by biodegradation experiments,the sample in soil extract can degrade 75.4%of its weight and 92.8%of its weight after 90 d,which can be degraded almost completely.The above data showed the good flocculation properties and biodegradability of cellulose grafted flocculants.Then the effects of pH,coagulant dosage,flocculant dosage and stirring time on the flocculation properties of BPC-g-SS flocculant were studied.The optimized flocculation process was developed.In this paper,the coagulation properties of CaCl₂,Al Cl₃ and FeCl₃ were investigated,and the flocculation effect of cellulose based flocculation material on the actual printing and dyeing wastewater was further studied.Then CTA was used to modify the synthesized cellulose based flocculant.Through an orthogonal experiment of four factors three levels,get a preparation of cationic cellulose graft sericin flocculant,the optimal process:reaction temperature is 80?,reaction time is 6 h,2.5%NaOH concentration,stirring speed of 200 r/min.The performance of the product was investigated by infrared spectroscopy and Zeta potential.The research on the capability of the flocculation kaolin suspension in the product has been found,and the product has excellent flocculation properties for the suspension of kaolin in the flocculating solution pH of 4.Finally,it was applied to the treatment of industrial printing and dyeing wastewater without adding the coagulant,and obtained the excellent effect turbidity removal rate of printing and dyeing wastewater was 93.8%and COD_Cr removal rate of 96.4%.