| Nowadays, how to get sustainable clear drink water and industrial&agriculturalproductin water become one of the biggest challenges that human being facing. Papermaking industry need lot of water and also discharge lot of wastewater. With thedeveloping of paper making industry, the methods to deal with the wastewater must bea solution to sustainable development, and the membrane treatment technology has thepotential to become the key technology to paper making wastewater deep treatmentand reuse, it has the theoretical and practical application significance to the recycle ofpaper making wastewater and water saving.This paper studied the acetate fibermodification, the preparation membrane and membrane separation technique in wastewater treatment of paper making.Firsty, Cationic modification the cellulose acetate, then discuss the effect of thereact condition to the degree of substitution of the modified products. The results showthat when the mass ratio of CA and catalyst is15:3, the mass ratio of CA andetherifying agent is15:3and the reaction temperature is60℃,the degree ofsubstitution can be0.06, then grafting the cellulose acetate by use hard monomeracrylamide, and we can confirm success though the infrared spectra.Secondly, this paper using cationic cellulose ether acetate as membrane materialsto make membrane, and discuss the effects of the condition of make membranes to theperformance of membranes. The experiment results show that the ratio of acetone andDMAc is7:2, the concentration of Casting membrane solution is15%, the additivecontent is5%and the evaporation time is3minutes, the tensile strength of themembrane is12.0N, the breaking length is1.136Km,the pure water flux is5.97L/ （m2·h）and the desalination rate is78.4%. Then this paper using cellulose acetategrafted products as membrane materials to make membrane, and discuss the effects ofthe condition of make membranes to the performance of membranes. The experimentresults show that the ratio of acetone and DMAc is7:2, the concentration of Castingmembrane solution is5%, the additive content is17%and the evaporation time is3minutes, the tensile strength of the membrane is5.7N, the breaking length is0.858Kmand the porosity of membrane is12.60%. This also discuss the performance ofcommodity membrane, the experiment results show that when the BW30andX-20wasunder the operating pressure which is0.020MPa, the pure water flux of the membraneswere1.99L/（m2·h）and1.36L/（m2·h）each, and the single desalination rate of themembranes to the NaCl solution which is1000mg/L were17.3%and15.2%, then dealwith the solution of different ionic radius, the results show that the bigger of the ionicradius, the better of the desalination rate. Under the operating pressure as0.15Mpa, thepure water flux of the low pressure Reverse osmosis membranes of TS-40and TS-80were1.72L/(m2·h) and1.99L/(m2·h) each, and the single desalination rate of themembranes to the MgSO4solution which is1000mg/L were47.2%and45.6%.Finally, this paper make surface SEM pictures of the CA cationic modifiedmembrane, the CA grafting modified membrane, the reverse osmosis membrane ofBW30and X-20and the low pressure reverse osmosis membrane of TS-40and TS-80respectively. Then deal with these pictures by using MATLAB, when set the thresholdvalues as0.2,0.58,0.384,0.27,0.2and0.27respectively, it can calculate the porosityof these membranes, the results are5.84%,13.86%,13.28%,10.01%,10.40%,12.53%.To deal with the wastewater of paper making by using the self-made CA cationicmodified membrane, the CA grafting modified membrane, the reverse osmosismembrane of BW30and X-20and the low pressure reverse osmosis membrane ofTS-40and TS-8, this paper measure the COD of these membranes, the results showthat the COD of wastewater descend from141.5mg/L to82mg/L,120mg/L,38mg/L,41mg/L,61mg/L,59mg/L respectively, and the self-made CA cationic modifiedmembrane have good removal effect. Lastly, detecting the conductivity of thesemembrane, and the results show that the conductivity of wastewater descend from1673μS/cm to350μS/cm,1458μS/cm,63μS/cm,67μS/cm,115μS/cm,108μS/cm, theself-made CA cationic modified membrane have good removal effect, but the self-made grafting modification membrane’s performance still needs improved. |
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