| In this study,CS/?-CD/Nano-Zn O composite porous membrane were synthesized by sol-gel method and polymer assisted phase inversion method,which the organic polymer including chitosan(CS)and beta-cyclodextrin(?-CD),inorganic nanomaterials nanometer zinc oxide(Nano-Zn O)acted as raw materials,polyethylene glycol(PEG)acted as porogen,JH-V151 acted as crosslinking agent.Meanwhile,the optimum preparation conditions,the surface topography and adsorption properties and mechanism of CS/?-CD/Nano-Zn O were studied.Single factor and Box-Behnken test were used to design response surface methodology,which JH-V151(A),?-CD(B)and Nano-Zn O(C)were selected as the test objects,while the adsorption capacity Q as the response value.Then,the 3 factor and 3 level response surface test were carried out.The optimum preparation conditions of CS/?-CD/Nano-Zn O membrane were determine that the volume fraction of JH-V151 alcohol solution was 11%,the ratio of CS to ?-CD was 1:5.35,and the ratio of Nano-Zn O's mass to solution's volume was 0.36%.Different characterization methods including Field-emission scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction,UV-Vis spectrophotometer,Universal material testing machine,and had been used to prove the appearance,crystallinity,and functional groups,swelling degree,transmittance,tensile property.The CS/?-CD/Nano-Zn O membrane was used for the adsorption of Copper Ion(Cu2+),and the optimum experiments conditions were as follows: The maximum adsorbing capacity reached 49.20 mg.g-1,removal rate reached 98.40% with contact time 3 h,initial concentration 25 mg.L-1,temperature 55?,p H 6,adsorbent dose 0.5 g.L-1.The adsorption kinetics could be well described by pseudo-second-order(R2=0.9987,25 mg.L-1).The adsorption isotherm parameters were applied to Langmuir adsorption isotherm(R2=0.9924),and the theoretical saturated adsorption capacity was 140.06 mg.g-1.The values ?G were-7.59,-8.30,and-10.02 k J.mol-1 at 298,308,318 K temperatures,respectively.20<?H=28.62<80 k J.mol-1,indicating that it is endothermic and spontaneous in nature,and the adsorption process has both physical and chemical adsorption,but more on chemical adsorption.?S value was 0.12 k J.mol-1.K-1,indicating the disorder of substance on the solid-liquid interface increases when adsorbed.With 100 m Lof 0.05 mol.L-1 EDTA disodium solution desorbed and adsorbed circularly,the adsorption capacity of the membrane can still reach more than 87%.The CS/?-CD/Nano-Zn O membrane was used for the adsorption of Congo Red(CR)dye waste-water,and the optimum experiments conditions were as follows: The experimental parameters were 4 h,50 mg.L-1,7.0,55.0?,0.5 g.L-1 as contact time,initial concentration,p H,temperature,and adsorbent dose.The maximum adsorption capacity on CR reached 96.33 mg.g-1.The batch experimental data were best described by pseudo-second-order kinetics model(R2=0.9965,chemisorption)and Langmuir isotherm model(R2=0.9965,theoretical saturated adsorption capacity 147.28 mg.g-1).The values ?G were-2.09,-4.73 and-7.37 k J.mol-1 at 298,308,318 K temperatures,respectively.20 <?H=76.68 <80 k J.mol-1,indicating that it is endothermic and spontaneous in nature,and the adsorption process has both physical and chemical adsorption,but more on chemical adsorption.?S value was 0.26 k J.mol-1.K-1,indicating the disorder of substance on the solid-liquid interface increases when adsorbed.The adsorption capacity decreased only 5.8% after six recycling runs,indicating the reusability of the membrane.Therefore,CS/?-CD/Nano-Zn O membrane is a promising and novel functionalized adsorbent for waste-water treatment. |
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