Çiftçi Gökçe, Türkeli Ülkü Dide, Özen Elif Yaren, Özdemir Melek, Sanin F Dilek, İmamoğlu İpek
Department of Environmental Engineering, Middle East Technical University, 06800 Ankara, Turkey E-mail:
Water Sci Technol. 2023 Mar;87(5):1072-1081. doi: 10.2166/wst.2023.040.
This study aims to elucidate interaction of organics with microplastics in a comparative manner via the use of two model compounds (i.e., triclosan (TCS) and malachite green (MG)) having different physicochemical properties, onto polyethylene (PE). TCS, is hydrophobic with low solubility, while MG is hydrophilic with high aqueous solubility. Kinetic studies indicate faster sorption (t = 24 h) and equilibrium studies show much higher capacity (q = 6,921 μg/g) for TCS, when compared to those of MG (t = 5 d, q = 221 μg/g). While pseudo-kinetic model fits sorption of both organics to PE, equilibrium isotherms as well as the results on effect of particle size and pH indicate dissimilar sorption mechanisms. Considering pH = 2, observation of favourable sorption of TCS in acidic regions and sorption being unaffected by particle size was explained by TCS sorption to be dominated by hydrophobic interactions in amorph regions of PE. Higher removal of MG was observed at lower surface charge of PE, and a clear favourable impact of surface area on MG sorptive capacity pointed to the presence of non-specific van der Waals type interactions on the surface of PE. Mechanistic evaluations presented here contribute to our understanding of interaction of MPs with organics in aquatic ecosystems.
本研究旨在通过使用两种具有不同物理化学性质的模型化合物（即三氯生（TCS）和孔雀石绿（MG）），以比较的方式阐明有机物与聚乙烯（PE）上微塑料的相互作用。三氯生具有疏水性且溶解度低，而孔雀石绿具有亲水性且在水中的溶解度高。动力学研究表明，与孔雀石绿相比（t = 5天，q = 221μg/g），三氯生的吸附速度更快（t = 24小时），平衡研究显示其吸附容量更高（q = 6,921μg/g）。虽然准动力学模型适用于两种有机物在PE上的吸附，但平衡等温线以及粒径和pH值影响的结果表明吸附机制不同。考虑到pH = 2，在酸性区域观察到三氯生的有利吸附且吸附不受粒径影响，这是因为三氯生在PE无定形区域的吸附主要由疏水相互作用主导。在PE表面电荷较低时观察到孔雀石绿的去除率较高，且表面积对孔雀石绿吸附容量有明显的有利影响，这表明PE表面存在非特异性范德华力型相互作用。此处的机理评估有助于我们理解水生生态系统中微塑料与有机物的相互作用。
