Preparation Of Microcrystalline Cellulose-based Quaternary Ammonium Flocculant In NaOH/Urea Uniform System And Application

With the rapid development of industrial production,a large amount of wastewater isgenerated along with various processes.Most of them contain large amounts of fine suspended solids;this increases the turbidity of the water and poses a significant hazard to microorganisms and aquatic ecosystems.Every year,a large number of dyes are used in industry,including textiles,food,plastics,pulp and paper,cosmetics and printing.These dyes enter the wastewater stream causing many environmental problems.For example,many studies have demonstrated that dyes in water are toxic to aquatic organisms and inhibit photosynthesis of aquatic plants.Flocculation is an effective method to promote the solid-liquid separation of colloidal suspensions.At the same time,compared with other wastewater treatment processes,it has the advantages of low cost,low energy consumption and easy operation.In this paper,microcrystalline cellulose was used as raw material,and a large amount of free radicals were generated by grafting polymerization of acrylic acid and methacryloyloxyethyltrimethylammonium chloride(DMC)by using an initiator in a homogeneous system.The quaternary quaternary amine flocculant,the finally obtained flocculant is applied to the removal of turbidity in kaolin solution and the removal of anionic dye wastewater in water.Firstly,the microcrystalline cellulose was dissolved in NaOH/Urea solution with potassium persulfate and ammonium cerium nitrate as activators,and grafted acrylic acid and methacryloyloxyethyltrimethylammonium chloride successfully prepared cellulose-based season.The flocculant was characterized by Fourier transform infrared spectroscopy,XPS spectroscopy,environmental scanning electron microscopy and Zeta potential analysis.Through the orthogonal experiment of L16(4)~4,it is concluded that the most suitable synthesis condition for the treatment of turbidity wastewater by cellulose-based quaternary amine flocculant is the reaction temperature is 40°C,the molar ratio is 1:4 for MCC and AA,MCC and DMC.The molar ratio was 1:11 and the reaction time was 4 h.Then,the flocculation performance of cellulose-based quaternary amine flocculant on kaolin solution was studied.The effect of flocculant addition on the flocculation performance of kaolin solution with different concentrations and the flocculation performance of kaolin under different pH conditions were discussed.As a result,it was found that MCC(pAA-co-pDMC)treated the high-turbidity wastewater simulated by the black middle-stage wastewater and the kaolin suspension from the pulp and paper industry by flocculation experiments.MCC(pAA-co-pDMC)has good flocculation ability for high turbidity kaolin suspension.When the initial concentrations are 5g/L,7g/L and 10g/L,the turbidity removal rates are 98.7%,99.8%and 99.8%.The residual turbidity was about 20 NTU under the optimum conditions for all test samples.In the real industrial wastewater treatment process,ozone and MCC(pAA-co-pDMC)are combined to treat the black mid-stage wastewater in the pulp and paper industry,achieving perfect results.The COD,turbidity and color of the main black mid-stage wastewater were removed by flocculation of MCC(pAA-co-pDMC).Finally,the flocculation performance of cellulose-based quaternary amine flocculant on simulated dye wastewater was studied.The optimum pH and water ion of flocculant for flocculating two dyes were discussed by acid black dyeing dye wastewater and direct peach red simulated dye wastewater.The effect of different initial concentrations of dyes on the flocculation effect.The results show that:MCC(pAA-co-pDMC)flocculation acid tender black simulated dye wastewater optimal pH=2,flocculation direct peach red simulated dye wastewater optimal pH=3;MCC(pAA-co-pDMC)flocculation two simulated dyes The optimum dosage of wastewater is 0.05g;in tap water,the removal rate of both dye wastewater by flocculant is higher than that in deionized water because of the metal ion and MCC(pAA-co-pDMC)in tap water.“Chelism”improves the removal rate of dye wastewater by flocculant;in the experiment of exploring the effect of flocculant performance at different initial concentrations of dye,the initial concentration of acid black dye dye wastewater and direct peach dye wastewater increased continuously,and the decolorization rate The decrease after nearly 100%is because the cation provided by MCC(pAA-co-pDMC)cannot completely neutralize the anion in the wastewater,and a part of the dye molecules remain in the wastewater,resulting in a decrease in the removal rate.In summary,the cellulose-based quaternary amine flocculant prepared in the NaOH/Urea homogeneous system is environmentally friendly,and the product substitution degree is improved by the optimization scheme,and the flocculation performance is also improved,and the theory is provided for the development of the field.Foundation and application foundation.