Chemical and Biochemical Engineering, University of Western Ontario, London, ON, N6A5B9, Canada.
Civil and Environmental Engineering, University of Western Ontario, London, ON, N6A5B9, Canada.
Environ Res. 2022 Sep;212(Pt D):113401. doi: 10.1016/j.envres.2022.113401. Epub 2022 May 4.
Microplastics pollution in the aquatic system has received significant attention due to their recalcitrant nature and ecotoxicological threat. Municipal wastewater typically contains various microplastics with synthetic microfibers as a significant constituent from the laundry process. The fate of microfibers in conventional wastewater processes is not clearly understood. In this study, the effect of coagulation on microfibers obtained from a lint screen of a domestic dryer and resuspended in pure water, and also in laundry wastewater was investigated using ferric chloride and polyaluminum chloride (PACl). The removal efficiency of the microfibers resuspended in pure water varied from 86% to 96% depending on the fiber size ranges: < 90 μm, 90-125 μm, and >125 μm with the smaller size microfibers showing a lower removal efficiency. Surfactant present in detergent in laundry wastewater reduced the microfibers removal efficiency to 0-37%, however, the addition of PACl increased microfibers removal to 90%. The optimal PACl concentrations for ≥90% removal were 1.75, 2, 4, and 6 mg/L for 0.5, 2, 4, 8 mg/L detergent, respectively. Zeta potential, FTIR, and SEM analysis were applied to observe the surface changes of microfibers during coagulation indicating possible mechanisms of coagulation. The dominant mechanisms for coagulation of microfibers by FeCl and PACl seem to be charge neutralization and adsorption-bridging. This work provided some insights about the fate of laundry microfibers in primary treatment processes.
由于其顽固的性质和生态毒性威胁，水生系统中的微塑料污染受到了极大关注。城市废水中通常含有各种微塑料，其中来自洗衣过程的合成微纤维是一个重要组成部分。微纤维在常规废水处理过程中的命运尚不清楚。在这项研究中，使用三氯化铁和聚合氯化铝（PACl）研究了从家用干衣机的绒毛过滤器中获得的微纤维在纯水中以及在洗衣废水中的凝聚效果。悬浮在纯水中的微纤维的去除效率根据纤维尺寸范围而变化，范围从 86%到 96%：<90μm、90-125μm 和>125μm，其中较小尺寸的微纤维去除效率较低。洗衣废水中存在的表面活性剂会降低微纤维的去除效率至 0-37%，但是添加 PACl 会将微纤维的去除效率提高到 90%。对于 0.5、2、4 和 8mg/L 的洗涤剂，分别为 1.75、2、4 和 6mg/L 的 PACl 是去除效率达到≥90%的最佳 PACl 浓度。Zeta 电位、FTIR 和 SEM 分析用于观察微纤维在凝聚过程中的表面变化，表明可能的凝聚机制。FeCl 和 PACl 对微纤维的凝聚机制似乎主要是电荷中和和吸附架桥。这项工作为了解洗衣微纤维在初级处理过程中的命运提供了一些见解。
