材料期刊网

多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)对人类健康和生态环境的危害近年来备受关注,有关PAHs在DOM上吸附特征的研究已有大量报道.但DOM构成成分的复杂性给PAHs与DOM相互作用的研究工作带来了困难.将DOM分离为不同化学结构和元素组成的组分,并分析其不同组分对与PAHs相互作用的具体贡献十分必要.本研究利用离子交换树脂将胡敏酸(Humic acid,HA)按照疏水性和酸碱性分离为不同组分,使用透析平衡法确定不同结构的HA与菲(PHE)的结合平衡常数,并对结合后样品进行傅里叶变换红外光谱(FTIR)分析.结果显示,HA组分中的极性和脂肪族含量对PHE在HA上的结合有重要影响和不同的贡献机制.疏水性HA组分对PHE的结合亲和力高于亲水性HA组分,疏水性中性组分(HoN)与PHE之间的结合系数最高,亲水性酸性组分(HiA)对PHE在HA上的结合贡献最少,HoN对PHE的环境风险有重要影响.研究中首次通过对结合前后不同有机质组分的FTIR光谱图的对比分析,进一步证明脂肪族是HA中与PHE发生相互作用的主要组分.

The harm of polycyclic aromatic hydrocarbons (PAHs) to human health and ecological environment has attracted a great deal of research attention,and large number of studies about PAHs adsorption characteristics on DOM has been reported nowadays.However,due to the complex composition of DOM,it is difficult to explore the interaction between DOM and PAHs.It is highly necessary to analyze the specific contributions of DOM fractions,with different chemical structures and elemental compositions to the interactions between DOM and PAHs.According to the hydrophobicity and acid-base of DOM,ion exchange resins were used to separate humic acid (HA) in this study.The binding constants of Phenanthree (PHE) to different HA fractions were measured using the dialysis equilibrium method,Fourier-transformed infrared spectroscopy (FTIR) spectra of HA fractions were analyzed after binding.The results showed that the polarity and alphacility of HA fractions obviously affected and significantly contributed to the binding of PHE with HA fractions by different mechanisms.All hydrophobic fractions showed relatively higher sorption affinity than the hydrophilic fractions.HoN showed the highest binding coefficient with PHE,and HA had little contribution to the overall binding capability of PHE to HA.This indicated that HoN of DOM might play an important role in the environmental fate of PHE.Comparison between FTIR spectra of original HA fractions and the HA fractions after binding with PHE further proved that the aliphaticity of HA is the main component that interact with PHE.