The effect of pH on the sorption of gold nanoparticles on illite  

作　　者：Yuhong Fu Quan Wan Zonghua Qin Xin Nie Wenbin Yu Shanshan Li 

机构地区：[1]School of Geographic and Environmental Sciences,Guizhou Normal University,Guiyang 550025,Guizhou,China [2]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,Guizhou,China [3]CAS Center for Excellence in Comparative Planetology,Hefei 230026,Anhui,China [4]School of Chemistry and Materials Science,Guizhou Normal University,Guiyang 550025.Guizhou,China

出　　处：《Acta Geochimica》2020年第2期172-180,共9页地球化学学报（英文）

基　　金：financially supported by the National Natural Science Foundation of China(41872046);Doctoral Research Startup Project in 2017 of Guizhou Normal University in China;Project of Science and Technology Supporting Plan,Guizhou Province(Qian Sci.Co.[2017],No.2580)。

摘　　要：Sorption between nanoparticles(NPs)and minerals may critically affect the migration of associated elements as well as the environmental impact of NPs.Since illite is widely present in soil,sediment,and water,we have experimentally investigated the sorption behavior of citrate-coated gold nanoparticles(AuNPs)as model NPs on illite under different pH and mineral mass conditions.We demonstrated that sorption of these negatively charged AuNPs strongly depended on the suspension pH.At pH above 8,which coincided with the apparent point of zero charge(pH 7.9)of our illite sample,only marginal sorption of AuNPs was observed.At pH 3-8,significant sorption of AuNPs on illite was found,with almost complete sorption occurring at more acidic conditions(pH 3-4).TEM observations revealed that sorption took place through the attachment AuNPs on illite edges.At pH 2,AuNPs mostly formed chain-like fused structures and precipitated out of the suspension.Based upon the above pH dependence,residual organic ligand content after sorption,and complementary sorption results with positively charged AuNPs,we conclude that the sorption process is mainly driven by the electrostatic attraction between negatively charged AuNPs and positively charged illite edges,with possible competitive involvement of citrate molecules.We expect that our findings will improve our understanding of NP-mineral interaction and the environmental fate of NPs.

关 键 词：GOLD nanoparticles ILLITE SORPTION CHARGE ELECTROSTATIC interaction 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O647.3[理学—物理化学]