不同纳米材料对As(Ⅲ)的吸附机制

The mechanism for arsenic(Ⅲ) adsorption from aqueous solutions via different nanomaterials

为明确不同纳米材料对水中As(Ⅲ)的吸附效果和机制,筛选出经济有效的As污染吸附材料,采用批处理振荡平衡法,研究了多层氧化石墨烯(多层GO)、20 nm羟基磷灰石(P20)、40 nm羟基磷灰石(P40)以及纳米零价铁(n Fe)对As(Ⅲ)的吸附差异性。结果表明,不同纳米材料对As(Ⅲ)的吸附能力存在显著差异(P<0.05),吸附容量的大小顺序为多层GO(17.4 mg·g^(-1))>P20(2.74 mg·g^(-1))>P40(2.17 mg·g^(-1))>n Fe(0.976 mg·g^(-1))。其中,多层GO对As(Ⅲ)的吸附效果最好,其饱和吸附量是nFe的17.8倍。通过能量弥散X射线谱(EDS)、X-射线光电子能谱(XPS)、傅里叶红外光谱(FTIR)等对不同纳米材料吸附As(Ⅲ)前后进行分析,证实了多层GO的吸附机制是以单层化学吸附为主;P20、P40、nFe吸附机制为材料表面的聚沉吸附及含氧官能团与As(Ⅲ)发生络合等反应的吸附。实验结果表明多层GO可作为吸附材料用于As(Ⅲ)污染水体的修复。

Batch sorption experiments were conducted tO investigate the adsorption of arsenic （ m ） from aqueous solution via multilayer graphene oxide （multilayer GO ）, 20 nm hydroxylapatite （P20）, 40 nm hydroxylapatite （P40）, and nano zerovalent iron （nFe）. The results showed significant differences（P〈0.05 ） in the adsorption capacity of the different nanomatcrials for arsenic（ Ⅲ ）. The order of absorptivity of these nanomaterials for arsenic （ Ⅲ ） was multilayer GO （ 17.4 mg·g^-l ） 〉P20 （ 2 .74 mg·g^-1 ） 〉P40 （ 2.17 mg·g^-t ） 〉nFe （ 0.97 6 mg·g^-i ）. The ab- sorptivity of multilayer GO was 17.8 times that of nFe. Through characterization of the different nanomaterials using Energy-dispersive X- ray Spectroscopy （EDS）, X-ray Photoelectron Spectroscopy （XPS）, and Fourier Transform Infrared Spectroscopy （FTIR）, it was confirmed that the adsorption mechanism of muhilayer GO included chemical adsorption and physical adsorption, whereas the adsorption mechanisms of P20P40 and nFe consisted of coagulation adsorption and complexation of oxygen-containing functional groups.