纳米钴复合凝胶的制备及催化降解对硝基苯酚的应用

Preparation of Co Nanoparticles Gel and its Application in Catalytic Degradation of Nitro Phenol

本文采用自由基聚合法,以水为反应介质,丙烯酸(AA)为单体,N.N’-亚甲基双丙烯酰胺(BIS)为交联剂,过硫酸铵(APS)为引发剂,合成了高溶胀比的聚丙烯酸水凝胶。该凝胶吸附金属Co2+离子后,用硼氢化钠还原剂通过原位还原得到纳米钴复合凝胶。用红外光谱仪(FT-IR)、XRD对所得产品进行表征,证明金属钴以纳米粒子的形态分散在凝胶网络中。将纳米钴复合水凝胶作为催化剂,在水中催化过量硼氢化钠还原对硝基苯酚(4-NP),并在不同条件下研究了催化活性,结果表明,该反应符合一级动力学方程,表观活化能约为21.11 k J·mol-1。单体浓度为15%、交联度为1%时活性较好,增大反应温度和复合凝胶的投入量均可以加快催化反应速率。

In this paper, polyacrylic acid hydrogel with the high swelling ratio was prepared by free radical polymerization of AAcsolution in the presence of crosslinker and initiator. These pAAc hydrogel networks were utilized for in situ cobalt nanoparticlesynthesis by reduction of metal ions absorbed into the hydrogel network with a reducing agent NaBH4.FT-IR and XRD wasconfirmed that Co particles was dispersed as nanoparticles in the hydrogels. The hydrogel network with embedded Co nanoparticleswas utilized as a catalyst in the reduction of 4-nitrophenol （4-NP） in aqueous media in the presence of an excess amount of NaBH4.The kinetics of the reduction reaction under different reaction conditions was investigated to determine the activation parameters.The results showed that the reduction reactions comply with first order reaction kinetics. Activation energy was 21.11kJ/mol. Thecatalytic activity was better when the monomer concentration was 15% and the cross-linking degree was 1%. The reduction ratecould enhanced by increased the catalyst amount or raised the temperature.