Synthesis and characterization of magnetic poly(acrylic acid) hydrogel fabricated with cobalt nanoparticles for adsorption and catalytic applications
Synthesis and characterization of magnetic poly(acrylic acid) hydrogel fabricated with cobalt nanoparticles for adsorption and catalytic applications
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DOI：
10.1007/s13738-019-01738-8
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发表时间：
2019-12-01
影响因子：
2.4
通讯作者：
Farooqi, Zahoor H.
中科院分区：
文献类型：
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作者：
Ansari, Tariq Mahmood;Ajmal, Muhammad;Farooqi, Zahoor H.
本研究旨在合成嵌有磁性钴纳米粒子的聚丙烯酸水凝胶，并考察其吸附和催化性能。通过自由基聚合反应制备水凝胶，并通过使用NaBH 4作为还原剂还原Co（II）离子在水凝胶内制备Co纳米颗粒。水凝胶体系中的钴纳米粒子赋予了所得复合凝胶的磁性，也增加了吸附容量。通过重量分析法对水凝胶的溶胀进行了研究。通过傅立叶变换红外光谱和透射电子显微镜分析确定了不同的官能团，以研究Co纳米粒子在水凝胶中的分散性。将裸水凝胶沿着负载Co纳米颗粒的凝胶作为从水溶液中去除阳离子染料（亚甲基蓝）的吸附剂系统进行测试。亚甲基蓝的去除率达到95%，最高吸附容量为836.5 mg/g吸附剂。著名的吸附等温线被用来评估吸附数据。结果表明，该过程符合Freundlich等温模型，R-2值为0.95。该水凝胶还用于催化还原有毒污染物，即，4-硝基苯酚对硝基苯酚还原反应符合准一级动力学模型。计算出反应的活化能和表观速率常数分别为9.24 kJ/mol和0.24 min（-1）。用钴纳米颗粒制造的磁性聚（丙烯酸）水凝胶的再循环进行了四个连续的循环，没有观察到催化活性的显著损失。
The present study aimed to synthesize poly(acrylic acid) hydrogel embedded with magnetic cobalt (Co) nanoparticles and to investigate their potential in adsorption and catalysis. The hydrogel was prepared by facile free radical polymerization reaction and Co nanoparticles were fabricated within hydrogel by reducing Co (II) ions using NaBH4 as reducing agent. Co nanoparticles within hydrogel system imparted magnetic properties to the resulting composite gel and also increased the adsorption capacity. The swelling study of hydrogel was carried out by gravimetric analysis. Different functional groups were identified by Fourier Transform Infrared Spectroscopy and Transmission Electron Microscopy analysis was done to investigate dispersion of Co nanoparticles in hydrogel. The bare hydrogel along with Co nanoparticles loaded gel were tested as adsorbent systems for the removal of a cationic dye (methylene blue) from aqueous solution. 95% removal of methylene blue was achieved with a highest adsorption capacity of 836.5 mg/g of adsorbent. The famous adsorption isotherms were used to evaluate adsorption data. Results showed that Freundlich isotherm model was followed with R-2 value of 0.95. The hydrogel was also used for catalytic reduction in a toxic pollutant, i.e., 4-nitrophenol. Experimental data for 4-nitrophenol reduction followed pseudo first order kinetics model. Activation energy and apparent rate constant were calculated as 9.24 kJ/mol and 0.24 min(-1), respectively. Recycling of the magnetic poly(acrylic acid) hydrogel fabricated with Cobalt nanoparticles was carried out for four consecutive cycles and no significant loss in catalytic activity was observed.