College of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, Zhejiang, China; National & Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou University, Wenzhou 325035, China.
College of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, Zhejiang, China; National & Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou University, Wenzhou 325035, China; Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China.
Sci Total Environ. 2022 Aug 1;832:155142. doi: 10.1016/j.scitotenv.2022.155142. Epub 2022 Apr 9.
CaCO filler masterbatch (CFM) is one of the most commonly used fillers in polypropylene (PP) and polyethylene (PE) products, and its is used to enhance the toughness of the polymer matrix. This is the first study to investigate the loss of CaCO and its impact on the adsorption ability of microplastics from plastic woven bags throughout the natural aging process. PP wire (PPw, 85% PP + 15% CFM) and PE film (PEf, 80% PE + 20% CFM) samples from plastic woven bags underwent a 250 d aging process in an open-air environment. Changes in the surface properties, morphology, CaCO content, and density of PPw microplastics (PPw-MP) and PEf microplastics (PEf-MP) after various durations of aging were investigated by scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. The results showed that CaCO separated and agglomerated on the surfaces of PPw-MP and PEf-MP after 30 d. After 250 d, 42% of CaCO was lost from PPw-MP and 28% was lost from PEf-MP, decreasing the density of the microplastic samples. CFM presented a considerably higher adsorption affinity toward Cu(II) than PP particles and PE particles; therefore, its presence in plastic matrix increased the adsorption ability of the products. The adsorption of Cu(II) on PPw-MP and PEf-MP decreased with aging because of the loss of CaCO and poor development of O-containing functional groups. The q value (maximum adsorption quantity of Langmuir model) decreased from 11.01 mg/g in unaged PPw-MP to 1.35 mg/g in aged PPw-MP, and from 9.00 mg/g in unaged PEf-MP to 1.05 mg/g in aged PEf-MP. Overall, the findings demonstrate that CaCO was crucial for the heavy metal-plastic interactions of the samples. Therefore, the results provide a basis to further clarify the potential environmental risks of plastic woven bags associated with heavy metal mobility.
碳酸钙填充母粒（CFM）是聚丙稀（PP）和聚乙烯（PE）产品中最常用的填充料之一，用于增强聚合物基质的韧性。这是首次研究在自然老化过程中，塑料编织袋中碳酸钙的损失及其对微塑料吸附能力的影响。取自塑料编织袋的 PP 线（PPw，85%PP+15%CFM）和 PE 膜（PEf，80%PE+20%CFM）样品在露天环境下进行了 250 天的老化过程。通过扫描电子显微镜、红外光谱和热重分析研究了不同老化时间后 PPw 微塑料（PPw-MP）和 PEf 微塑料（PEf-MP）的表面特性、形貌、CaCO 含量和密度的变化。结果表明，在 30 天后，PPw-MP 和 PEf-MP 的表面出现了 CaCO 的分离和团聚。在 250 天后，PPw-MP 中有 42%的 CaCO 流失，PEf-MP 中有 28%的 CaCO 流失，导致微塑料样品的密度降低。CFM 对 Cu(II)的吸附亲和力明显高于 PP 颗粒和 PE 颗粒；因此，它在塑料基质中的存在增加了产品的吸附能力。由于 CaCO 的流失和含 O 官能团发育不良，Cu(II)在 PPw-MP 和 PEf-MP 上的吸附随着老化而降低。q 值（Langmuir 模型的最大吸附量）从未老化的 PPw-MP 的 11.01mg/g 降低到老化的 PPw-MP 的 1.35mg/g，从未老化的 PEf-MP 的 9.00mg/g 降低到老化的 PEf-MP 的 1.05mg/g。总的来说，研究结果表明，CaCO 对样品中重金属-塑料的相互作用至关重要。因此，这些结果为进一步阐明与重金属迁移相关的塑料编织袋的潜在环境风险提供了依据。
