| In this study,gelatin molecules is successfully introduced onto the PP nonwoven substrate surface,which is realized by two different strategies and through electrostatic self-assembly technique,UV irradiation and diazo coupling reaction.Two kinds of active adsorbent material are then prepared.Preparation,characterization and adsorption behaviors of the adsorbent material are studied as four parts in this thesis.Firstly,-SO3H functional groups are successfully introduced onto the PP fiber surface through Chlorosulphonylation,based on this technology,active aromatic amine is introduced onto the surface of modified PP using electrostatic self-assembly,and then gelatin molecules are anchored on the PP nonwoven substrate surface by diazo coupling reaction,the adsorbent material is finally prepared.Preparation conditions are optimized,the optimal conditions are as follows:(1)Chlorosulphonylation reaction conditions:0.1 mL of HSO3Cl,10 mL of 1,2-C2H4C12,reaction temperature is 50?,and round-trip oscillation for lh in the frequency of 100r/min;(2)electrostatic self-assembly reaction conditions:15 mL of 2mol/L HCl,lOmL of 1mol/L NaNO2,0.4 mol/L electrostatic self-assembly solution is configured by additional adding 1.08g phenylenediamine into the above HCl and NaNO2 solution,which is stirred for 3h without light and the sample is then taken out and irradiated under 15 W UV light for 15min/side on the condition of double-sided irradiation and the irradiation distance is 5cm.(3)diazo-coupling gelatin experiment condition:10 mL of 1mol/L HCl,stirred under ice cooling for 15min,and lOmL of lmol/L NaNO2 is added and being dark-stirred for extra 2 hours,the gelatin concentration is 150g/L,the irradiation intensity of ultraviolet light is 15W,25min/side on the condition of double-sided irradiation from 5cm.After adsorption in 200mg/L(25mL)tannins solution for 4h,the Qt reaches 197.06 mg/g.Its adsorption equilibrium and adsorption kinetics for tannins are also studied and the result shows that its adsorption behavior is in line with Tempkin adsorption equilibrium model and pseudo-second-order kinetic adsorption kinetics.Secondly,a novel sandwich-UV irradiation technology is used for oxidation modification of PP nonwoven substrate,-SO4-anion is then successfully introduced onto the surface of PP fibers,and the subsequent experimental steps for preparing a new adsorbent material is as same as the first part.The optimized conditions are as follows:(1)Ammonium persulfate oxidizing conditions:the concentration of(NH4)2S2O8 solution is 30%(w/w),the intensity of ultraviolet light is 500W,irradiation distance is 15cm for lOmin;(2)electrostatic self-assembly conditions:15mL of 2mol/L HCI,10mL of 1mol/L NaNO2,0.4 mol/L electrostatic self-assembly solution is configured by additional adding 1.08g phenylenediamine into the above HCl and NaNO2 solution,which is stirred for 3h without light and the sample is then taken out and irradiated under 500W UV light for 5min/side on the condition of double-sided irradiation and the irradiation distance is 25cm;(3)diazo-coupling gelatin experiment condition:lOmL of lmol/L HCl,stirred under ice cooling for 15min,and lOmL of lmol/L NaNO2 is added and being dark-stirred for extra 2h,the gelatin concentration is 150g/L,the irradiation intensity of ultraviolet light is 15W,25min/side on the condition of double-sided irradiation from 5cm.After adsorption in 200mg/L(25mL)tannins solution for 4h,the Qt reaches 189.72 mg/g.its adsorption behavior is in line with Tempkin adsorption equilibrium model and pseudo-second-order kinetic adsorption kinetics.Thirdly,the tannins adsorption behavior in model wine solution is discussed in this portion.The adsorption performance influenced by ethanol concentration,pH value and the concentration of potassium hydrogen tartrate are separately studied.The result shows that the two kinds of adsorbent materials possess high adsorption capacity for tannins in model wine,of which PP-CA-PPD-G possesses better adsorption.The adsorption is greatly affected by the pH value,and the better adsorption performance can be obtained when the pH is 3.7.Lastly,tannins adsorption is studied in the case of adding ?-cyclodextrin.and it's found that the ?-cyclodextrin possesses serious impact on the adsorption,with the increase of ?-cyclodextrin the decreases.Then,adsorption behaviors for caffeines by the two kinds of adsorbent materials are also studied.The adsorption isotherm for PP-CA-PPD-G is more in line with Freundlich isotherm model,which shows heterogeneity of its surface properties.While the adsorption isotherm for PP-SO4-PPD-G is more in line with Freundlich isotherm model,which shows heterogeneity of its surface but on different surface,the binding energy for caffeine is similar.Two adsorption materials are both more in line with pseudo-second-kinetic models,indicating that the reaction rate is mainly influenced by the chemical reaction.Water static contact angle measurements,FT-IR and XPS are employed to analyze the surface properties,composition and structure of adsorption materials,confirm the successful introduction of target molecules and adsorption for tannins. |
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