固载纳米银的聚酰亚胺混合基质膜的制备及其渗透汽化分离苯的性能

Preparation of Polyimide Mixed Matrix Membrane Immobilized with Nano-silver and Its Performance for Pervaporation Separation of Benzene

以AgNO3为前驱体,利用浸渍吸附-热还原过程合成纳米Ag粒子-氧化石墨烯复合物,将该复合物通过共混法掺杂到聚酰亚胺高分子中,制备固载纳米银的聚酰亚胺混合基质膜,探索该膜在不同条件下对苯/环己烷混合物的渗透汽化分离性能。结果发现,热还原后得到的复合物中存在单质Ag,且Ag粒子良好地分散在氧化石墨烯表面。混合基质膜中Ag含量在15 wt%以内时,Ag粒子在膜中的分散性非常好,膜中没有出现明显的Ag粒子团聚物;当Ag含量超过20 wt%时,膜中出现了较为明显的Ag粒子团聚的形貌。在不同比例的苯/环己烷料液中,混合基质膜对料液渗透通量和分离因子的影响趋势总体相同。随着料液中苯质量分数的增加,膜的渗透通量也增加,分离因子则相反;随着温度的升高,膜的渗透通量也增高,分离因子则反之。

Using AgNO3 as the precursor,the nano-Ag particle-graphene oxide composite was synthesized by the process of immersion adsorption and thermal reduction.Then,the composite was doped into polyimide polymer by a blending method to prepare a polyimide mixed matrix membrane immobilized with nano-silver.The performance for pervaporation separation of benzene/cyclohexane mixture by the membrane under different conditions was explored.As a result,it was found that elemental Ag was present in the composite after thermal reduction,and Ag particles were well dispersed on the surface of graphene oxide.When the Ag content in the mixed matrix membrane is within 15 wt%,the dispersion of Ag particles in the membrane is very good,and there are no obvious Ag particle agglomerates in the membrane.When the Ag content exceeds 20 wt%,the Ag particle agglomeration morphology is obvious in the membrane.In different ratios of benzene/cyclohexane feed liquid,the overall trend of the permeation flux and separation factor of the mixed matrix membrane to the feed liquid is the same.The permeation flux of the membrane increases with the increase of the mass fraction of benzene,while the separation factor is opposite.The permeation flux of the membrane increases with the increase of temperature,while the separation factor is reversed.