巯基功能化碳纳米管吸附稀土元素研究

Study on the adsorption of rare earth elements by thiol functionalized carbon nanotube

通过硫醇-烯烃点击反应制备了巯基功能化碳纳米管(CNT)薄膜,使其对稀土元素(REEs)具有高回收率、可循环吸附/脱附的能力.研究了巯基化合物功能化薄膜的种类、吸附液的pH值、蠕动泵流速和洗脱液浓度等因素对REEs回收率的影响规律.结果表明:当吸附液的pH为7.0、泵速为0.2 mL·min^(-1)和HNO_(3)洗脱液浓度为1.0 mol·L^(-1)的萃取条件下,六氢均三嗪巯基化合物功能化的CNT薄膜(NCNT-3)对15种REEs具有良好的循环吸附/脱附性能,循环吸附5次后仍然具有较高的回收率.扫描电子显微镜(SEM)、比表面与孔径分布测试仪(BET)和接触角等研究证实了REEs的高回收率源于碳纳米管薄膜上巯基、羟基和羧基的引入提高了表面浸润性和吸附性能.

Thiol functionalized carbon nanotube films were prepared by thiol-ene click reaction and showed high recovery and recyclable adsorption/desorption ability for rare earth elements(REEs).The effects of the different mercaptans functionalized films,pH value of the adsorption solution,flow rate of the peristaltic pump and eluent concentration on the recovery of REEs were investigated.The results indicated that under the extraction conditions of pH of 7.0,pump speed of 0.2 mL·min^(-1) and HNO_(3) eluent concentration of 1.0 mol·L^(-1),the carbon nanotube film(NCNT-3)functionalized by 2,2′,2″-(1,3,5-hexahydro-s-triazine-1,3,5-triyl)benzyl mercaptan had good recyclable adsorption/desorption performance for 15 REEs,and the recovery rate remained high after five cycles of adsorption.Scanning electron microscopy(SEM),specific surface and pore size distribution(BET)and contact angle studies confirmed that the high recovery rate of REEs was due to the introduction of thiol,hydroxyl and carboxyl groups to the carbon nanotube film,such that the surface wettability and adsorption performance were improved.