PANI膜电聚合过程及电控分离苯酚的EQCM研究

EQCM Studies of Electropolymerization and Electrochemically Controlled Phenol Separation of Polyaniline Film

通过电沉积方法在镀铂石英晶片上制备了导电聚苯胺(PANI)膜,采用电化学石英晶体微天平(EQCM)技术探讨了苯胺聚合机制及在苯酚溶液中的氧化还原特性.在0.5 mol/L硫酸溶液中结合循环伏安法考察了PANI膜在完全还原态(L)-半氧化态(E)-完全氧化态(P)之间的电活性和稳定性;在不同浓度的苯酚溶液中结合恒电压阶跃法和傅里叶红外光谱(FTIR)考察了PANI薄膜电控分离苯酚的性能.结果表明,苯胺在聚合过程中随着膜厚增加,伴随有离子的掺杂/脱掺杂并导致有规律的质量突变;PANI薄膜在完全还原态-半氧化态之间具有良好的电活性和循环稳定性;薄膜处于半氧化态时溶液中的苯酚置入膜中,处于还原态时膜中的苯酚又可逆地释放到溶液中.通过控制PANI薄膜的电位可以方便地控制苯酚的置入与释放,从而达到分离溶液中苯酚的目的.

Electroactive polyaniline（PANI） thin films were synthesized on platinum substrates by electrochemical polymerization,the electrochemical quartz crystal microbalance（EQCM） technique was adopted to investigate the polymerization process of the PANI film and its redox behavior in phenol solution.Combined with cyclic voltammetry（CV）,electroactivity and stability of the PANI film cycled between the reduced,leucoemeraldine（L） state and the half-oxidized,emeraldine（E） state or between L and the fully oxidized,pemigraniline（P） state were investigated in 0.5 mol/L H2SO4 solution.In mixed solutions of phenol and H2SO4,chronocoulometry and FTIR were also used to investigate the electrochemically controlled phenol separation property of PANI film.Experimental results indicate that the abrupt changes of the film mass exist during the redox switching of PANI with the ion ejection/injection,especially with the increase of the films thickness;and PANI films have good electroactivity and stability when films are controlled between L and E during cycling process.Phenol in electrolyte will enter into the film when PANI is controlled as E,while release from the film into electrolyte again when PANI is modulated to L.Phenol enter or release from film can controlled freely by modulating the potential of PANI films,this characteristic can be used to separate the phenol from the solution.