高密度聚乙烯管在臭氧、氯和加熱老化後釋放的塑膠微粒

Abstract

高密度聚乙烯(High-density polyethylene, HDPE)管因其化學穩定性和物理特性為水處理和輸送中會使用到的管線材料。近年來，人們對於HDPE管在使用過程中釋放塑膠微粒(Microplastics, MPs)的關注日益增加。因為塑膠微粒可能對環境和人體健康造成影響，了解HDPE管在不同老化條件下釋放的塑膠微粒是重要的課題。本研究的目的是要探討HDPE管在臭氧、氯、加熱老化條件下所釋放塑膠微粒的情形，藉由靜態老化和循環沖刷實驗來模擬HDPE管在不同老化條件下釋放塑膠微粒。透過分析塑膠微粒的數量、粒徑分佈和表面形態的變化，評估了在臭氧、氯和加熱老化對塑膠微粒釋放的影響。研究結果顯示，隨著老化條件的增強，HDPE管塑膠微粒的釋放數量增加。在臭氧老化下，靜態老化和循環沖刷實驗中，塑膠微粒釋放數量分別從控制實驗的654 #/L和82 #/L上升到受30 mg/L 臭氧老化的1180 #/L和177 #/L。在氯老化下，靜態老化和循環沖刷實驗中，塑膠微粒釋放數量分別從控制實驗的528 #/L和103 #/L上升到受260 mg/L氯老化的933 #/L和118 #/L。而在加熱老化下，靜態老化和循環沖刷實驗中，塑膠微粒釋放數量分別從控制實驗的433 #/L和65 #/L上升到受80°C老化的932 #/L和173 #/L。臭氧老化會增加 <10 m和10 m-50 m塑膠微粒的釋放。氯老化會增加<10 m塑膠微粒的釋放。加熱老化會增加所有粒徑塑膠微粒的釋放。HDPE管表面的裂痕數量隨著三種老化條件的增強而增加，從而導致塑膠微粒的釋數量增加。總體而言，根據本研究結果，在靜態老化和循環沖刷實驗中，隨著臭氧濃度、氯濃度和加熱老化的提高會增加HDPE管釋放塑膠微粒的數量。

High-density polyethylene (HDPE) pipes are used for water treatment and water transit due to their excellent chemical stability and physical properties. In recent years, the release of microplastics (MPs) from HDPE pipes has gained increasing attention due to their potential environmental and human health risks. This study investigated the release of MPs from HDPE pipes under three different aging conditions, including ozonation, chlorination, and heating. Both stagnant and circulating experiments were conducted. The impact of ozonation, chlorination, and heating aging on the release of MPs was assessed by analyzing the MPs concentration, size distributions, and surface morphology. The results showed that the release of MPs from HDPE pipes increased with enhanced aging. In ozonation, the release of MPs increased from 654 #/L and 82 #/L in the control experiment to 1180 #/L and 177 #/L under 30 mg/L ozone in the stagnant and circulating experiments, respectively. In chlorination, the release of MPs increased from 528 #/L and 103 #/L in the control experiment to 933 #/L and 118 #/L under 260 mg/L chlorine in the stagnant and circulating experiments, respectively. In heating aging, the release of MPs increased from 433 #/L and 65 #/L in the control experiment to 932 #/L and 173 #/L under 80°C in the stagnant and circulating experiments, respectively. Ozonation significantly enhanced the release of MPs with a size of <10 m and 10 m-50 m. Chlorination significantly enhanced the release of MPs with a size of <10 m. Heating aging had a significant impact on the release of MPs of all sizes. The surface of HDPE pipes exhibited intensified cracks with enhanced aging, which likely contributed to the increased release of MPs. In summary, the results from this study indicated that enhanced aging with ozone, chlorine, and heating could lead to a greater release of MPs from HDPE pipes in both stagnant and circulating experiments.