文献类型：期刊文献

中文题名：DEAE功能化PGMA大孔微球回收铂及机制研究

英文题名：Adsorption Behavior and Mechanism of DEAE-Modified PGMA Macro Porous Spheres Towards Pt(IV)

作者：王福春 王万坤 苏祥 封森林

第一作者：王福春

机构：[1]吉首大学化学化工学院,湖南吉首416000;[2]贵州理工学院材料与能源工程学院,贵州贵阳550025

第一机构：吉首大学化学化工学院,湖南吉首416000

年份：2025

卷号：49

期号：9

起止页码：1386-1400

中文期刊名：稀有金属

外文期刊名：Chinese Journal of Rare Metals

收录：;北大核心:【北大核心2023】；

基金：贵州自然科学基金项目(黔科合基础[2019]1147号,黔科合基础[2019]1418号);贵州理工学院高层次人才科研启动经费项目(XJGC20190965)资助。

语种：中文

中文关键词：吸附;聚甲基丙烯酸缩水甘油酯(PGMA);大孔吸附树脂;二乙基氨基乙基(DEAE);铂(Pt)

外文关键词：adsorption;poly(glycidyl methacrylate)(PGMA);macro porous adsorbents;diethylaminoethyl(DEAE);platinum(Pt)

摘要：贵金属铂的高效回收具有重要研究价值,本文采用二乙基氨基乙基(DEAE)功能化聚甲基丙烯酸缩水甘油酯(PGMA)大孔微球(PGMADEAE)为吸附剂,从模拟废液中选择性回收铂离子(Pt(Ⅳ))。系统研究了溶液pH、吸附时间及Pt(Ⅳ)初始浓度等对Pt(Ⅳ)在PGMA-DEAE上的吸附性能的影响。结合溶液p H对Pt(Ⅳ)在PGMA-DEAE上的吸附效率影响规律、 PGMA-DEAE的pH滴定、 XRD、 XPS等分析结果,可以推测出:在pH为1~4.81时,随着溶液pH增加,溶液中H+浓度不断下降,Pt(Ⅳ)取代季胺基上H+与N元素配位能力增加,Pt(Ⅳ)在PGMA-DEAE上的吸附效率随溶液pH的增加而迅速增加。当pH> 4.81时,胺基的去质子化作用使得PGMA-DEAE表面电正性减弱,PGMA-DEAE与PtCl_(x)OH_(6-x)^(2-)静电吸引力不断减弱,Pt(Ⅳ)与N元素络合配位作用也受到了阻碍,Pt(Ⅳ)在PGMA-DEAE上的吸附效率下降。所以吸附机制为:PGMA-DEAE带正电的质子化季胺基与带负电的PtCl_(x)OH_(6-x)^(2-)的静电吸引对Pt(Ⅳ)的吸附起辅助作用,Pt(Ⅳ)与N元素的络合配位作用对Pt(Ⅳ)的吸附起主要作用。在25℃,pH为4左右时,PGMA-DEAE对Pt(Ⅳ)的最大饱和吸附容量为0.73 mmol·g^(-1)。PGMA-DEAE对Pt(Ⅳ)的吸附速率非常快,5 min即可达到吸附平衡。选择Co(Ⅱ),Cu(Ⅱ),Ni(Ⅱ),Fe(Ⅲ),Al(Ⅲ)和Cr(Ⅲ)等为代表竞争吸附金属离子,发现PGMA-DEAE在pH为1~4时对Pt(Ⅳ)有很好的分离选择性,添加乙二胺四乙酸二钠盐(EDTA)可进一步增加选择性分离系数,并将高选择性范围扩大到pH为2~6。12次吸附-解吸-活化再生循环实验表明PGMA-DEAE具有优良的稳定和循环再生性能。
Platinum is a kind of precious metal that is highly valued due to its rarity,difficult extraction,and diverse applications.The recovery of Pt(IV)from the leachate remains challenging due to its low concentrations and the presence of different impurity metals at high concentrations.Therefore,developing efficient technologies for recovering of Pt(IV)from low-concentration and complex systems is of utmost importance.The recovery of Pt(IV)from aqueous solutions has been accomplished through various separation technologies,whereas adsorption is gaining prominence due to its high efficiency,eco-friendliness,and applicability to solutions with low concentration of Pt(IV).Therefore,this study used diethylaminoethyl(DEAE)functionalized macro porous poly(glycidyl methacrylate)(PGMA)macro porous spheres(PGMA-DEAE)as adsorbents to selectively recover Pt(IV)from simulated wastewater and systematically studied its adsorption performance and mechanism.The average particle size of PGMA-DEAE was about 34μm.Scanning electron microscope(SEM)images showed their porous microsphere with a rough surface and good dispersibility.The results of the fully automatic nitrogen adsorption method and mercury intrusion method indicated that PGMA-DEAE has a rich macro porous structure with almost no micro porous structure.These macro porous structures could effectively improve the diffusion rate of metal ions in the adsorbent pores,increase the surface area of the adsorbent,and effectively enhance the adsorption capacity and rate of PCMA-DEAE for Pt(IV).The effect of pH,contact time,and initial concentrations of Pt(IV)was investigated.The pH of the solution had a significant impact on the adsorption performance of Pt(IV)on PGMA-DEAE within the experimental acidity range(C_(HCl)=2 mol·L^(-1)~pH=6).When C_(HCl)≥1 mol·L^(-1),the concentration of H^(+)in the solution was very high,and the amino groups on PCMA-DEAE tended to bind with H^(+),making it difficult to coordinate with Pt(IV).At this time,the adsorption efficiency of Pt(IV)was low.Therefore,at high acidity(C_(HCl)≥1 mol·L^(-1)),especially with the appropriate addition of Pt(IV)complexing agents(such as thiourea),it was suitable for Pt(IV)to desorb from PGMA-DEAE.Within the pH range of 1~6,Pt(IV)existed as negatively charged complex anions(PtCl_(x)(OH)_(6-x)^(2-))in the solution.Therefore,at pH<4.81,on the one hand,at lower pH values,Pt(IV)in the solution was prone to exist as negatively charged complex anions in the solution,which could be adsorbed in the form of ion association with positively charged PCMA-DEAE.On the other hand,the concentration of H^(+)in the solution significantly decreased,and the coordination ability between the amino group and H'on PCMA-DEAE decreased,while the coordination ability with P(IV)rapidly increased.Pt(IV)quickly replaced the H'bound to the amino group and was adsorbed by PCMA-DEAE.Therefore,in the pH range of 1~4,the adsorption rate of Pt(IV)increased with the increasing solution pH.However,after pH>4.81,with the deprotonating of ammonium ions,the surface electro positivity of PGMA-DEAE decreased continuously,and the electrostatic attraction to the negatively charged PtCl_(x)(OH)_(6-x)^(2-)decreased continuously,resulting in a slow decrease in the adsorption efficiency of Pt(IV).Therefore,at pH=4,the adsorption efficiency of Pt(IV)reached its maximum value.The adsorption of Pt(IV)by PGMA-DEAE could be described by the pseudo second order kinetic adsorption model very well,and the adsorption speed of Pt(IV)was very fast,which could reach equilibrium within 5 min.The adsorption isotherm indicated that the adsorption of Pt(IV)on PCMA-DEAE could be explained by Langmuir isotherm model very well,and the maximum adsorption capacity of Pt(IV)on PCMA-DEAE was 0.73 mmol·g^(-1)at pH=4 and 25℃.After 12 cycles of adsorption desorption activation regeneration,there was no significant decrease in both adsorption and desorption rates,indicating that the PGMA-DEAE adsorbent had good stability and recyclability.PGMA-DEAE also had excellent selectivity for Pt(IV)over some base metals.At pH=1~4,PGMA-DEAE showed a high relative separation coefficient,the selectivity separation coefficients of Pt(IV)from Fe(II),Co(II),Ni(II),Cu(II),Al(II),and Cr(II)were all more than 100,and the selectivity for Pt(IV)was significantly enhanced upon the addition of EDTA,broadening the pH range to 2~6 for their selective recovery.These results proved that PCMA-DEAE had excellent adsorption performance for Pt(IV)in simulated waste liquid.Based on characterization analysis such as XRD,FTIR,XPS,Zeta potential,and pH titration,it could be inferred that,on the one hand,at pH<4.81,Pt(IV)existed in the solution as a complex anion,and the tertiary amine on PGMA-DEAE formed positively charged ammonium ions through protonation.Pt(IV)can be adsorbed in the form of ion association through electrostatic attraction at lower pH values.On the other hand,in the pH range of 1-6,the concentration of H^(+)in the solution was low,and protons in ammonium ions were easily replaced by other elements.Pt(IV)with empty orbitals coordinated with lone pair electrons on the tertiary amine N element and was adsorbed in a complex form.The adsorption mechanism of complex coordination was more conducive to the adsorption of Pt(IV).