| Ion exchange resins were applied to wastewater treatment field and organic catalytic reactions due to the advantage of large ion exchange capacity and good thermal stability.The iron-supported D72 resins were prepared for the phenol hydroxylation.The supported resins' catalytic performance were studied.The whole work were divided into two parts.Firstly,adsorption behavior for Fe?II?and Fe?III?with D72 resin were studied in batches.The parameters influencing the adsorption properties such as pH,initial solution concentration,adsorption time,temperature,rotating speed and the particle radium were explored.The controlling steps and adsorption isothermal process were studied by fitting the relatied theories with the experimental data.SEM?FTIR?XPS and ICP characterization were used to explore morphostructure changes of adsorbent after adsorption and reaction mechanism.The results illustrated that the optimized adsorption occured when the pH value was 3.0 for Fe?II?and 1.7 for Fe?III?.The time getting the adsorption process equilibrium is 120 min.The temperature is determined as 40 ?.The rotating speed was 180 rpm and the particle radius was 0.6-0.45 mm.Under the operation condition above,the maximum adsorption capacity of Fe?III?is 113.8 mg·g-1,which was higher than the value of Fe?II?(98.8 mg·g-1).The results demonstrated that Langmuir adsorption model was more favorable to fit the experimental data when compared with the Freundlich model.The intra-particle diffusion was the controlling step in the whole adsorption process with the liquid film diffusion controlling at the initial stage by the HPDM and SPM model fitting.Lagergren pseudo-second-order models showed better fitting results.Several characterization methods showed that iron ions successfully take the ion exchange process with sodium ions in the adsorption process.Stable adsorption performance were kept by the complex force between the metal ions with sulfonic acid functional groups.Iron supported on the ion exchange resin was prepared as Fe-D72 catalyst and applied to the phenol hydroxylation with H2O2 as oxidant.The effects of different reaction conditions such as the iron capacity of catalyst,reaction temperature,water volume were investigated.The orthogonal experiment was carried out to obtain the better optimized operating conditions.The catalytic performance were improved through the preparation of Fe-Cu-D72 resins.Under the conditions of iron capacity as 95.4 mg·g-1,catalyst dosage as 0.05 g,molar ratio of hydrogen peroxide to phenol as 1:1,water volume as 40 ml,40%-42% phenol conversion was obtained with the selectivities to catechol and hydroquinone being 92%-94%,dihydroxybenzenes yield being 37%-39%.Fe-Cu-D72 resins were prepared by keeping the initial solution concentration as 1 mol·L-1 copper chloride and ferric chloride solution with other operating condition unchanged,the phenol conversion was increased to 45% and the benzodiazepines selectivities could be up to 95%.The reusability of prepared catalyst illustrated that it could be recovered and reused without notable loss of activity.SEM characterization showed that uniform channel distribution were advantageous for the reactant taking part in the reaction.The comprehensive force between D72 resin and loaded metals kept the stable iron supporting and catalytic performance. |
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