水复合污染仍然是水处理领域的巨大挑战。特别是对于微塑料(MP),作为一种新兴的污染物,近年来,它在水中的广泛分布和持续的生态环境影响受到了极大的关注。然而,常规混凝对MP复合污染的去除特性和机理相当不足。在这项研究中,MP(聚乙烯,通过聚合氯化铝(PAC)和阴离子聚丙烯酰胺(APAM)研究了PE)和诺氟沙星(NOR)。与单一系统相比,复合体系平台期PE的去除效率显著提高(>99.0%),而与添加APAM无关,NOR的去除效率略有下降至42%左右。扫描电子显微镜(SEM),傅里叶变换红外光谱(FTIR),实验数据的zeta电位和单因素方差分析(ANOVA)用于探讨凝血机制。结果表明,单个PE和NOR的去除主要受PAC和APAM的电荷中和和吹扫絮凝控制。和通过形成Al-NOR络合物的吸附,分别。重要的是,在复合系统中,不仅通过更强的电荷中和作用增强了PE的去除,而且通过形成PE-NOR-Al配合物增强了吸附作用。此外,在中性和弱碱性条件下,PE和NOR的去除效率高于弱酸性和强碱性条件。金属离子和腐殖酸的存在对PE和NOR的去除效果有明显的抑制和促进作用。这项研究可以为了解混凝去除MP复合污染物的特性和机理提供一个新的视角。
Water composite pollution is still a great challenge in the field of water treatment. Especially for microplastic (MP), as an emerging pollutant, its wide distribution in water and persistent eco-environmental influence have received great concerns in recent years. Nevertheless, the removal characteristics and mechanism of conventional coagulation on MP composite pollution is quite insufficient. In this study, the coagulation removal performance and mechanisms of MP (polyethylene, PE) and norfloxacin (NOR) was investigated by polyaluminium chloride (PAC) and anionic polyacrylamide (APAM). Compared with single system, the removal efficiency of PE was significantly improved (>99.0%) under plateau stage in composite system, while the removal efficiency of NOR was slightly decreased to around 42% regardless of the addition of APAM. The scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), zeta potential and One-way analysis of variance (ANOVA) of experimental data were used to explore the coagulation mechanisms. The results demonstrated that the removal of individual PE and NOR was mainly controlled by charge neutralization and sweep flocculation by PAC and APAM, and adsorption by formation of Al-NOR complex, respectively. Importantly, in composite system, the removal of PE was enhanced not only by the stronger charge neutralization but also the adsorption via the formation of PE-NOR-Al complex. Furthermore, the removal efficiency of PE and NOR in neutral and weak alkaline conditions was higher than that in weak acidic or strong alkaline conditions. The presence of metal ions and humic acid had obvious inhibition and promoting effects on the removal efficiency of PE and NOR. This study can provide a new perspective on fundamental understanding in characteristics and mechanisms of MP composite pollutants removed by coagulation.