Synthesis And Performance Of Hyperbranched Cellulose-based Bifunctional Materials Combined With Adsorption And Flocculation

Controlling and treating the waste water of industry and agriculture is an important topic for current green sustainable development of society.Adsorption and flocculation are traditional treatment method for soluble pollutants and insoluble pollutants respectively,and both methods are very efficient and economical.However,just use only adsorbent or flocculants can't achieve the standards of sewage treatment,we need to use flocculation and adsorbents together which resulting complex treatment processes and high cost.Therefore,it's important for us to research and develop an adsorption-flocculation dual functional to deal with the sewage which contain both soluble and insoluble pollutants by one step.It has great scientific significance and practical value.Due to the traditional adsorbent and flocculant can't remove all kinds of pollutants in the wastewater,and the adsorption efficiency is not excellent and so on.So,this paper using cellulose and branched polyethylene imine(hPEI)as raw materials,and then use NaIO4 to oxide cellulose to get dialdehyde cellulose(DAC),hereafter,this paper is based on the chemical structure and formation theory of Schiff base,use DAC and hPEI as raw materials and heat in a water bath to make chemical reaction,and then get the hyperbranched polyethyleneimine-cellulose adsorption-flocculation dual functional materials(hPEI-CE).During the whole experiment process,we studied the effect of oxidation of cellulose and preparation process of hPEI-CE on the property of the material we prepared.We studied the adsorption and flocculation of hPEI-CE bi-functional materials on soluble organic dyes and insoluble kaolin suspension and further explore its industrial machinery wastewater and silk printing and dyeing waste water turbidity removal effect.Results are as follows:(1)The preparation of hPEI-CE: We used cellulose as raw material,then used NaIO4 to oxide cellulose to earn dialdehyde cellulose on non-homogeneous conditions,hereafter,this paper is based on the chemical structure and formation theory of Schiff base,used DAC and hPEI as raw materials and heat in a water bath to make chemical reaction,and then get the hPEI-CE.During the whole experiment process,we studied the effect of oxidation of cellulose and preparation process of hPEI-CE on the property of the material we prepared.We got soluble s-hPEI-CE and insoluble d-hPEI-CE.The amino content of s-hPEI-CE is 4.01 mmol/g and the amino content of d-hPEI-CE is 3.85 mmol/g.The zeta potential of s-hPEI-CE and d-hPEI-CE is in the range of-17 ~ 44 eV and-35 ~ 30.5 eV respectively.(2)Study on the adsorption capacity of d-hPEI-CE: This paper used anionic dye Congo Red(CR)and cationic dyes Basic Yellow 28(BY28)as models and studied the effect of adsorption time,temperature,adsorbents dosage on the adsorption capacity.We found that d-hPEI-CE shows perfect adsorption capacity of the two kinds of dyes,the maximum adsorption capacity for CR and BY28 up to 2100 mg/g and 1860 mg/g respectively.And the dye removal rate reached 99% and 96.6% respectively.In addition,we have studied the dynamics analysis and adsorption isotherm analysis of the adsorption performance.Through the study we found that the adsorption performance of hPEI-CE fit Langmuir's adsorption isotherm and pseudo second-order dynamic equation.On the basis,this paper studied the adsorption capacity for different dyes,d-hPEI-CE has different adsorption capacity on different structure dyes,rendering out good selective adsorption and smart separation capacity.(3)Study on the flocculation effect of s-hPEI-CE: This paper used kaolin suspension as models and studied the effect of flocculation time,flocculation time,flocculant dosage on the flocculation capacity.We found that the zeta potential of whole system close to 0 when we added 3 mL 80 mg/L s-hPEI-CE.The flocculation effect got the best result at this condition.The turbidity of kaolin solution dropped from 490 NTU to 3.6 NTU at this condition.And we selected mechanical wastewater and silk dyeing wasterwater as the actual industrial wastewater,our materials can effectively reduce the COD and turbidity of industrial wastewater.The COD of the actual industrial wastewater have a significant drop when we added s-hPEI-CE,the COD of mechanical wastewater dropped from 45 mg/L to 13 mg/L and the COD of silk dyeing wasterwater dropped from 118 mg/L to 37 mg/L;the turbidity of mechanical wastewater dropped from 4 NTU to 3.2 NTU and the turbidity of silk dyeing wasterwater dropped from 15 NTU to 4.6 NTU.We discovered that the products have good adsorption and flocculation capacity,it will has a very good prospect in wastewater processing.