Impact of the surface aging of potable water plastic pipes on their lead deposition characteristics
Impact of the surface aging of potable water plastic pipes on their lead deposition characteristics
复制标题
DOI：
10.1039/d3ew00043e
复制
发表时间：
2023-08-07
影响因子：
5
通讯作者：
Salehi，Maryam
中科院分区：
文献类型：
--
作者：
Hadiuzzaman，Md;Ladner，David A. A.;Salehi，Maryam
由于塑料水管具有成本低、无腐蚀、安装方便等特点，使用塑料水管代替腐蚀的金属管道和建造新的饮用水管道系统正在迅速增加。然而，与金属管道不同的是，人们对塑料饮用水管道中重金属的命运了解有限。研究了停滞状态下塑料管表面老化对铅沉积的影响。研究了交联聚乙烯- a （PEX-A）和高密度聚乙烯（HDPE）管材在高温下暴露于浓氯溶液中的加速老化现象。通过衰减全反射-傅里叶变换红外光谱（ATR-FTIR）和x射线光电子能谱（XPS）分析，研究了塑料管材因老化引起的表面化学变化。通过为期5天的铅暴露试验，研究了铅在新管道和旧管道上的沉积动力学。此外，还研究了初始铅浓度[50 ~ 1000 μ L−1]对铅在塑料管上沉积速率的影响。ATR-FTIR和XPS分析显示，经过14天的加速老化，PEX-A管和HDPE管表面形成了几个氧化碳官能团[> C-O, >CO, > O-CO]。在HDPE管道上进行的Zeta电位测量显示，老化管道的负表面电荷略高于新管道。动力学实验表明，老化PEX-A （387 μ m−2）和HDPE （418 μ m−2）管道在平衡状态下的Pb沉积水平显著高于新PEX-A （288 μ m−2）和HDPE （335 μ m−2）管道。Pb在新的和老化的PEX-A和HDPE管材上的沉积遵循一级动力学模型，表明Pb在管材表面受到约束。随着初始Pb浓度的增加，老化PEX-A的Pb沉积速率显著高于新生PEX-A （p值< 0.05）。然而，对于新的和旧的HDPE管，这一比率无显著差异（p值> 0.05）。本研究为今后研究饮用水基础设施中重金属的去向提供了基础。
The use of plastic potable water pipes to replace corroded metallic plumbing and construct new potable water plumbing systems is rapidly increasing due to the low cost, noncorrosive characteristics, and easy installation of plastic water pipes. However, unlike for metallic pipes, the understanding of the fate of heavy metals within plastic potable water pipes is limited. This study elucidates the effect of plastic pipe surface aging on lead (Pb) deposition under stagnant conditions. Accelerated aging of crosslinked polyethylene-A (PEX-A) and high-density polyethylene (HDPE) pipes was conducted through exposure to a concentrated chlorine solution at an elevated temperature. Variations in the surface chemistry of the plastic pipes due to aging were examined via attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. The kinetics of Pb deposition onto new and aged pipes were studied through 5 day Pb exposure experiments. Moreover, the influence of the initial Pb concentration [50–1000 μg L−1] on the rate of Pb deposition onto the plastic pipes was investigated. The ATR-FTIR and XPS analysis revealed the formation of several oxidized carbon functional groups [>C–O, >CO, >O–CO] on the PEX-A pipe and HDPE pipe surfaces after 14 days of accelerated aging. Zeta potential measurements conducted on the HDPE pipes showed a slightly more negative surface charge for the aged pipes than for the new pipes. Kinetics experiments showed that the aged PEX-A (387 μg m−2) and HDPE (418 μg m−2) pipes deposited significantly greater levels of Pb compared to the new PEX-A (288 μg m−2) and HDPE (335 μg m−2) pipes at equilibrium. Pb deposition onto the new and aged PEX-A and HDPE pipes followed a first-order kinetics model implying surface confinement of the Pb species. As the initial Pb concentration was increased, a significantly greater rate of Pb deposition (p-value < 0.05) was found for aged PEX-A compared to new PEX-A. However, for new and aged HDPE pipes this rate was not significantly different (p-value > 0.05). This study provides the groundwork for future investigations into the fate of heavy metals in potable water infrastructure.