摘要
以聚乙烯吡咯烷酮(polyvinyl pyrrolidone,PVP)包覆纳米Fe_(3)O_(4)(以Fe_(3)O_(4)@PVP表示,下同)作为U(Ⅵ)吸附剂,开展了pH值、初始铀浓度、吸附温度、离子强度、吸附时间等因素对吸附U(Ⅵ)的影响研究,同时进行了吸附等温线、吸附动力学、吸附热力学与循环利用研究。结果表明,在pH=6.00、温度为20~40℃时,Fe_(3)O_(4)@PVP吸附U(Ⅵ)达到平衡的时间为5~60 min,单次铀吸附率均大于75%。该吸附过程符合准二级吸附动力学模型,温度为20~40℃时,准二级吸附速率常数为0.000646~0.012500 g/(mg·min);该过程符合Redlich-Peterson与Langmuir等温线模型,根据Langmuir等温线预估20~40℃时Fe_(3)O_(4)@PVP吸附U(Ⅵ)的饱和吸附容量为185.8~291.0 mg/g。此吸附过程是一个吸热过程(标准吸附焓变ΔH>0),且为自发吸附过程(标准吉布斯自由能ΔG<0)。
The nano-Fe_(3)O_(4)coated by polyvinyl pyrrolidone was systematically conducted this research as U(Ⅵ)adsorbent about the effect of pH value,initial U(Ⅵ)concentration,temperature,ion strength and adsorption time on U(Ⅵ)adsorption,meanwhile study the adsorption isotherm models,kinetics,thermodynamics and adsorption recycles.Results show that the adsorption equilibrium time is from 5 to 60 minutes when the pH value is 6.00 at 20-40℃,and the removal rate of U(Ⅵ)is more than 75%.The kinetic of U(Ⅵ)adsorption onto Fe_(3)O_(4)@PVP is nearly to pseudo-secondary adsorption kinetics and obeys Redlich-Peterson and Langmuir models.The adsorption rate constant of U(Ⅵ)adsorption onto Fe_(3)O_(4)@PVP is 0.000646-0.012500 g/(mg·min)at 20-40℃,and the corresponding maximum adsorption capacity of Langmuir isotherm models is 185.8-291.0 mg/g.Thermodynamicstudies reveal that the adsorption process of U(Ⅵ)onto Fe_(3)O_(4)@PVP is endothermic and spontaneous(ΔH>0,ΔG<0).
作者
谢汶级
李佳
王辛龙
任萌
周显明
XIE Wen-ji;LI Jia;WANG Xin-long;REN Meng;ZHOU Xian-ming(State Key Laboratory of Nuclear Fuel and Materials,Nuclear Power Institute of China,Chengdu 610041,China;School of Chemical Engineering,Sichuan University,Chengdu 610065,China)
出处
《核化学与放射化学》
CAS
CSCD
北大核心
2022年第3期377-385,I0008,共10页
Journal of Nuclear and Radiochemistry
