摘要
铷是一种稀贵的碱金属,具有很高的经济价值和广阔应用前景,从卤水中有效提取铷具有重要意义。通过热引发聚合法合成水凝胶基质(聚丙烯酰胺/羧甲基纤维素/氧化石墨烯水凝胶,PCG)固定亚铁氰化铜(KCuFC),制备了一种新型的铷(Rb+)吸附剂(KCuFC-PCG)。采用物理化学方法对KCuFC-PCG的结构和性质进行了表征。通过批量吸附实验,研究了pH值、吸附时间、Rb+初始质量浓度、温度和竞争离子对吸附的影响。结果表明,KCuFC-PCG吸附剂在pH值(5~9)范围内表现出良好的吸附能力,pH=8时表现最佳;在Rb+质量浓度为5 mg/L,pH=8,吸附6 h达到吸附平衡,KCuFC-PCG的对Rb+的吸附量为89.12 mg/g;动力学行为可用准二级动力学模型来描述,表明化学吸附为速率控制步骤;吸附过程符合Langmuir等温吸附模型,为单分子层吸附,最大吸附量为258.4 mg/g。以0.2 mol/L NH_(4)Cl作为解吸剂,解吸3 h,解吸率为77%。
Rubidium is a rare alkali metal with high economic value and promising applications,and it is of great importance to effectively extract rubidium from brines.A novel rubidium(Rb+)adsorbent(KCuFC-PCG)is prepared by synthesizing a hydrogel matrix(polyacrylamide/carboxymethylcellulose/graphene oxide hydrogel,PCG)immobilized with copper ferrocyanide(KCuFC)by thermal initiation polymerization.The structure and properties of KCuFC-PCG are characterized by physicochemical methods.The effects of pH,contact time,initial mass concentration of Rb+,temperature and competing ions on the adsorption are investigated by batch adsorption experiments.The results show that the KCuFC-PCG adsorbent exhibits good adsorption capacity in the pH range(5~9),with the best performance at pH=8.The adsorption equilibrium can be reached at 6 h under the conditions of 5 mg/L Rb+and pH=8,and the adsorption capacity of KCuFC-PCG is 89.12 mg/g.The kinetic behavior can be described by a quasi-secondary kinetic model,indicating that the adsorption process is dominated by chemisorption.The adsorption process is in accordance with the Langmuir isothermal adsorption model,and it is a single molecular layer adsorption with a maximum adsorption capacity of 258.4 mg/g.The desorption rate is 77%at 3 h with 0.2 mol/L NH_(4)Cl as desorbent.
作者
袁定坤
褚维凡
倪加惠
YUAN Ding-Kun;CHU Wei-Fan;NI Jia-Hui(School of Chemistry and Chemical Engineering,Hefei University of Technology,Hefei 230009,Chin)
出处
《应用化学》
CAS
CSCD
北大核心
2022年第11期1746-1756,共11页
Chinese Journal of Applied Chemistry
基金
科技部“科技助力经济2020”重点专项(No.SQ2020YFF0412719)资助。
关键词
羧甲基纤维素
亚铁氰化铜
水凝胶
吸附
铷离子
Carboxymethyl cellulose
Copper ferrocyanide
Hydrogel
Adsorption
Rubidium ion
