| In this study,the renewable biomass material cellulose(microcrystalline cellulose,flax noil)as raw materials,two kinds of molecular chain structure of quaternary ammonium salt as the modified agents,to be modified in the heterogeneity and homogeneous state,respectively.The modified cellulose was used as adsorbent for the removal of dye and antibiotic from aqueous solution.As well as was used as antibacterial agent applied to the preparation of antibacterial packaging composite films.In order to analysis the molecular structure,element composition,crystal structure change,thermodynamic properties and the microstructure of samples.The samples were characterized by a 1H nuclear magnetic resonance spectrometer(1H NMR),a solid-state CP/MAS spectrum(13C NMR),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),elemental analysis,X-ray diffraction(XRD),thermogravimetric analysis(TGA),scanning electron microscopy(SEM).1)Microcrystalline cellulose and flax noil as raw materials,quaternized cellulose(FMCC,QCFN)were heterogeneously prepared by modified with N,N-dimethyl-1-dodecylamine.After modification,the 13C NMR,FTIR and XPS results indicated that the quaternary amine group was successfully grated onto the cellulose.The nitrogen content of EMCC and QCFN was 2.1%and 2.2%,and more the average degree of substitution was 0.26 and 0.28.respectively.The XRD analysis results showed that after modified with quaternary ammonium.the crystal structure of the cellulose and arrange order was disrupted.The SEM analysis showed that original microstructure of cellulose was changed,the surface of FMCC and QCFN was transformed to be more coarse.It is conductive to the adsorption of dye wastewater and antibiotic wastewater.2)The batch adsorption experiments were carried out to investigate the removal of dye(Congo Red,C.I.Reactive Blue)and antibiotic(Amoxicillin,Ciprofloxacin)from aqueous solution using quaterized cellulose(FMCC,QCFN)as adsorbents,respectively.The effects of various parameters such as adsorbent dose,contact time,pH,and temperature on the adsorption performance were investigated.The linear and nonlinear models of kinetics and isotherms were used in predicting the adsorption process of dye onto FMCC and antibiotic onto QCFN,respectively.Thermodynamic parameters and data processing were used to get the further analysis on the adsorption behavior.FMCC and QCFN adsorption of dye and antibiotic respectively reached adsorption equilibrium state at 3 h and 2 h.The various pH values seriously affect the adsorption capacity.The FMCC purification data on dye wastewater treatment fit well with pseudo-second-order kinetic model,intra-particle diffusion model,as well as the Langmuir isotherm model.The FMCC for the removal of Congo Red and C.I.Reactive Blue exhibited the highest Langmuir adsorption capacity of 312.50 mg g-1,408.90 mg g-1,respectively.The QCFN purification data on simulated antibiotic wastewater treatment fit well with the pseudo-second-order kinetic model,intra-particle diffusion model,as well as the Langmuir isotherm model.The QCFN for the removal of amoxicillin and ciprofloxacin exhibited the highest Langmuir adsorption capacity of 183.14 mg g-1,247.41 mg g-1,respectively.FMCC and QCFN have been shown to be the promising and efficient adsorbent for the removal of dyes and antibiotics from an aqueous solution.3)Quaternized cellulose(CM,YM)was homogeneously synthesized by with microcrystalline cellulose(MCC)as raw material,3-chloro-2-hydroxypropyl trimethyl ammonium chloride,N,N-dimethyl-l-dodecylamine and epoxy chloropropane synthesis of 3-chloro-2-hydroxypropyldodecyltrimethyl ammonium chloride as the modifying agent.The effects of different cellulose solvent(7%NaOH/12%urea/81%water aqueous solution,6%NaOH/5%thiourea/89%water aqueous solution),different quaternary ammonium salt/cellulose anhydrous glucose unit mole ratio(3:1,4.5:1.6:1,9:1,12:1)on the modification extent and degree of substitution(DS)were studied.1H NMR analysis results show that 3-chloro-2-hydroxypropyldodecyltrimethyl ammonium chloride was successfully synthesized in the experiment.The elemental analysis results show that the substitution degree of quaternary ammonium group did not appear to be much difference under two different solvent.N content and the DS value of the modified cellulose increased with the increase of the molar ratio.When the mole ratio was greater than 6:1,the increase of N content and substitution degree value of modified cellulose was not obvious.In the comprehensive consideration,this study choosed 7%NaOH/12%urea/81%water aqueous solution as the cellulose solvent,and more,the molar ratio of quaternary ammonium salt and cellulose anhydrous glucose units will be suitable of 6:1.4)Using microcrystalline cellulose as raw materials,7%NaOH/12%urea/81%water aqueous solution as solvent,3-chloro-2-hydroxypropyltrimethyl ammonium chloride and 3-chloro-2-hydroxypropyldodecyltrimethyl ammonium chloride as modified agent,and molar ratio of quaternary ammonium salt/cellulose anhydrous glucose unit as 6:1 to prepare the quaternized cellulose solution(CM,YM).The modified cellulose(CM,YM)was blended in a polyvinyl alcohol(PVA)matrix to produce binary composite films(CMP.YMP)via co-regeration from the alkaline solution.The FTIR and XRD analysis results show that the quaternized cellulose could interact with PVA by strong hydrogen bonding.SEM analysis showed that quaternized cellulose could be miscible with polyvinyl alcohol,and can fom a smooth,dense homogeneous composite film.Composite film(CMP,YMP)had good tensile strength,high oxygen and water vapor harrier property,higher antibacterial activity against Staphylococcus aureus(S.aurea)and Escherichia coli(E.coli).The structure of chitosan with amino group is similar with cellulose.So this study using the quaterized chitosan(antibacterial agent)/polyvinyl alcohol composite film as contrast group confirmed that the quaternized cellulose can effectively kill bacteria and its composite film has good performance and promising application. |
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