Tenea Anda-Gabriela, Dinu Cristina, Rus Paul Alexandru, Ionescu Ioana Alexandra, Gheorghe Stefania, Iancu Vasile Ion, Vasile Gabriela Geanina, Pascu Luoana Florentina, Chiriac Florentina Laura
National Research and Development Institute for Industrial Ecology ECOIND Bucharest, 51-73 Drumul Podul Dambovitei Street, 060652, Bucharest, Romania.
Heliyon. 2024 Jul 29;10(15):e35364. doi: 10.1016/j.heliyon.2024.e35364. eCollection 2024 Aug 15.
The increasing presence of plastics in the environment has raised concerns about their potential impact, especially as carriers of heavy metals such as Cd, Ni, and Pb. However, the adsorption mechanism of heavy metals on microplastics remains poorly understood. In this study, we investigated the adsorption behavior of Cd, Ni, and Pb by polystyrene (PS) and polypropylene (PP) microplastics to better comprehend their interaction and potential environmental implications. Our results revealed that equilibrium adsorption of microplastics with different heavy metals was achieved within a 6-h contact time. The FTIR analysis findings, which suggest that physical interactions play a significant role in the adsorption of heavy metals onto microplastics, are further supported by the observed changes in surface morphology after adsorption. We explored the influence of solution pH, contact duration, and initial concentration on the adsorption capacity and found significant effects on the adsorption behavior. To model the adsorption process, we applied Langmuir and Freundlich adsorption isotherm models and observed that the Langmuir model better fit the experimental data. Furthermore, we compared the pseudo-first and pseudo-second-order kinetic models and found that the pseudo-second-order model provided a more accurate description of the adsorption kinetics. Notably, the adsorption percentages varied depending on the type of microplastic and experimental conditions. Overall, this study enhances our understanding of the adsorption mechanism of heavy metals on microplastics and provides valuable insights into their behavior in aquatic environments. These findings have implications for the development of effective strategies for mitigating pollution caused by microplastics and heavy metals in aquatic ecosystems.
环境中塑料的日益增多引发了人们对其潜在影响的担忧，尤其是作为镉、镍和铅等重金属的载体。然而，重金属在微塑料上的吸附机制仍知之甚少。在本研究中，我们研究了聚苯乙烯（PS）和聚丙烯（PP）微塑料对镉、镍和铅的吸附行为，以更好地理解它们之间的相互作用及其潜在的环境影响。我们的结果表明，不同重金属与微塑料在6小时的接触时间内达到平衡吸附。傅里叶变换红外光谱（FTIR）分析结果表明，物理相互作用在重金属吸附到微塑料上起着重要作用，吸附后表面形态的变化进一步支持了这一结果。我们探讨了溶液pH值、接触时间和初始浓度对吸附容量的影响，发现它们对吸附行为有显著影响。为了模拟吸附过程，我们应用了朗缪尔和弗伦德利希吸附等温线模型，发现朗缪尔模型更符合实验数据。此外，我们比较了准一级和准二级动力学模型，发现准二级模型能更准确地描述吸附动力学。值得注意的是，吸附百分比因微塑料类型和实验条件而异。总体而言，本研究增进了我们对重金属在微塑料上吸附机制的理解，并为其在水生环境中的行为提供了有价值的见解。这些发现对制定减轻水生生态系统中微塑料和重金属污染的有效策略具有重要意义。
