Fabrication of carboxymethyl-functionalized porous ramie microspheres as effective adsorbents for the removal of cadmium ions
Fabrication of carboxymethyl-functionalized porous ramie microspheres as effective adsorbents for the removal of cadmium ions
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DOI：
10.1007/s10570-018-1656-z
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发表时间：
2018-01
期刊：
影响因子：
5.7
通讯作者：
Xiongyi Peng;Siwei Su;Minggui Xia;Kankan Lou;Feng Yang;Shuai Peng;Yingjie Cai
中科院分区：
文献类型：
--
作者：
Xiongyi Peng;Siwei Su;Minggui Xia;Kankan Lou;Feng Yang;Shuai Peng;Yingjie Cai
苎麻纤维作为一种最古老、最坚固的天然纤维，对水中重金属离子的吸附受到了广泛的关注，但由于苎麻纤维对重金属离子的响应率低、吸附能力差，其对水中重金属离子的吸附受到了很大的限制。采用乳化蒸发法和羧甲基化反应相结合的方法制备了一种新型羧甲基功能化多孔苎麻微球（CPRM），以有效去除水中镉（II）。XPS和FTIR表征证实羧基被引入到CPRM上。CPRM的直径主要在8 ~ 12 μm范围内，其BET表面积为47.6 m2/g。SEM图像证实CPRM表面存在多孔结构。在303 K下，CPRM对Cd（II）的吸附量高达173.1 mg/g，高于大多数传统吸附剂。吸附等温线和动力学符合Langmuir等温线模型和拟二级动力学模型。这个过程是吸热的，也是自发的。CPRM还能以不同的效率去除废水中的Cd（II）、Pb（II）、Ni（II）和Zn（II）。通过HCl和NaOH处理，可成功再生负载Cd（II）的CPRM。CPRM具有良好的污水净化潜力。
Ramie fiber, one of the strongest and oldest natural fibers, has gained much interest in adsorption of heavy metal ions in water, however, it is severely limited due to the low response rates and low adsorption capability to heavy metal ions. A novel type of carboxymethyl-functionalized porous ramie microspheres (CPRM) were prepared with a combined emulsification-evaporation method and a carboxymethylation reaction, in order to effectively remove Cd(II) in water. XPS and FTIR characterizations confirmed that the carboxyl groups were introduced onto the CPRM. The diameters of the CPRM mainly lied within the range of 8–12 μm, and the BET surface area of the CPRM was 47.6 m2/g. SEM images confirmed a porous structure was present on the CPRM surface. The CPRM obtained a high adsorption capacity of Cd(II) (173.1 mg/g) at 303 K, which was higher than most reported conventional adsorbents. The adsorption isotherms and the kinetics were in agreement with the Langmuir isotherm model and the pseudo-second-order kinetic model. The process was both endothermic and spontaneous. The CPRM could also remove Cd(II), Pb(II), Ni(II), and Zn(II) from wastewater with various efficiencies. The Cd(II)-loading CPRM could be successfully regenerated by the HCl and NaOH treatment. The CPRM show good potential for purifying wastewater.