环境阴离子与胡敏酸对铀在氧化石墨烯上的吸附影响研究

Influence of Environmental Ions and Humic Acid on the Sorption of Uranium(Ⅵ) on Graphene

利用批实验方法,研究CO_(3)^(2-)、HPO_(4)^(2-)、SO_(4)^(2-)、Cl-和腐殖酸(HA)对U(Ⅵ)在氧化石墨烯(GO)上吸附的影响。结果表明U(Ⅵ)在GO上的吸附强烈地受pH值影响。体系中CO_(3)^(2-)会与U(Ⅵ)离子相互配合生成可溶性配合物,使U(Ⅵ)离子在GO的吸附降低。HPO_(4)^(2-)会与GO以及铀酰离子络合产生三相配合物,从而对吸附有促进作用。SO_(4)^(2-)在吸附体系中与U(Ⅵ)离子在GO表面的吸附位点上产生竞争,并在低浓度时与铀酰络合形成可溶性络合物抑制了U(Ⅵ)在GO上的吸附。Cl^(-)对U(Ⅵ)离子吸附无显著影响。HA对U(Ⅵ)离子在pH<7.0时在GOs上的吸附有促进作用,而在碱性条件下有抑制作用。不同的吸附影响归因于环境离子与U(Ⅵ)的络合,以及与GOs结合能力有关。

The influences of CO_(3)^(2-)、HPO_(4)^(2-)、SO_(4)^(2-)、Cl- and humic acids(HA)on the sorption of U(Ⅵ)on graphene oxides(GOs)were investigated by batch experiments.The results suggest that the pH influence the sorption greatly.The formation of dissolved U-CO_(3)^(2-)-complexes results in the decrease of U(Ⅵ)sorption,while the complexes of GOs-U(Ⅵ)-PO43-can lead to the increase of the U(Ⅵ)sorption.The existing SO32-may prohibit the U(Ⅵ)sorption weakly due to the occupation of the active sites and then compete with U(Ⅵ)sorption,also SO_(3)^(2-)can form the dissolved complexes in acidic condition in some extent for the decrease of sorption.Cl^(-)has no obviously influence on U(Ⅵ)sorption to GOs.HA can increase U(Ⅵ)sorption at pH<7.0,whereas decrease U(Ⅵ)sorption at alkaline conditions.Different ions may play different roles on U(Ⅵ)sorption to GOs,which are relate to the complexation of environmental ions and U(Ⅵ),and the bonding of environmental ions on GOs.