Mathew Juviya, Bhardwaj Gaurav, Pulicharla Rama, Rezai Pouya, Brar Satinder Kaur
Department of Civil Engineering, Lassonde School of Engineering, York University, Toronto, Canada.
Department of Mechanical Engineering, Lassonde School of Engineering, York University, Toronto, Canada.
Sci Total Environ. 2024 Nov 15;951:175595. doi: 10.1016/j.scitotenv.2024.175595. Epub 2024 Aug 16.
For accurate and reliable analysis of microplastics (MPs) in wastewater (WW), it is imperative to comprehend the significance of pre-treating WW before analysis. The suspended solids (SS) in the matrix tend to adhere to the MPs during filtration, which interferes with the detection of the MPs. In this regard, the present study aims to develop and optimize a pretreatment method to improve the extraction efficiency of MPs from WW by reducing the SS. A combination of the Fenton reaction and ultrasonication, ferro-sonication (Fe-UlS), was proposed to digest and eliminate the SS from WW. This hybrid pretreatment, Fe-UlS, was optimized for ultrasonication amplitude, treatment time, and hydrogen peroxide dose using response surface methodology (RSM) with a Box-Behnken design, achieving a desirability of 0.984. The optimum conditions for the Fe-UlS, such as the (1:1) Fenton reagent ratio (0.05 M FeSO: 30 % HO), ultrasonication amplitude (31 %), and total process time (30 min) were found to be statistically significant (p < 0.05). The developed method was then employed for the extraction of spiked polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) MPs in real WW and found efficient in removing 83 % of the TSS present in the primary influent were in 30 min at a temperature of 45 °C. Also, the method did not affect the physio-chemical characteristics of the MPs; however, the thermal analysis of PE and PP MPs showed a statistically significant decrease in the melting temperature, as proven by paired t-test analysis. Further, a non-targeted liquid chromatography-mass spectrometry (LC-MS) analysis proved that Fe-UlS is a stable process, as it did not cause any leaching of MPs under the optimum pretreatment conditions. Finally, Laser Direct-Infrared Imaging (LD-IR) analysis was conducted to validate the developed Fe-UlS pretreatment approach for MP analysis in real WW. About 3434 MPs were detected in 100 mL of WW primary influent, within the size range of 9 to 500 μm. This hybrid pretreatment approach not only streamlines WW sample processing but also reduces the required concentration of Fenton reagent and processing time, yielding accurate and reliable results for monitoring MPs in WW.
为了准确可靠地分析废水中的微塑料（MPs），必须了解分析前对废水进行预处理的重要性。基质中的悬浮固体（SS）在过滤过程中容易附着在微塑料上，从而干扰微塑料的检测。在这方面，本研究旨在开发和优化一种预处理方法，通过减少悬浮固体来提高从废水中提取微塑料的效率。提出了一种将芬顿反应和超声处理相结合的铁超声处理（Fe-UlS）方法，以消化和去除废水中的悬浮固体。采用响应面法（RSM）和Box-Behnken设计对这种混合预处理方法Fe-UlS的超声振幅、处理时间和过氧化氢剂量进行了优化，可取性达到0.984。发现Fe-UlS的最佳条件，如（1:1）的芬顿试剂比例（0.05 M硫酸亚铁：30%过氧化氢）、超声振幅（31%）和总处理时间（30分钟）具有统计学意义（p < 0.05）。然后将所开发的方法用于实际废水中加标的聚乙烯（PE）、聚丙烯（PP）和聚对苯二甲酸乙二酯（PET）微塑料的提取，发现在45°C温度下30分钟内可有效去除原进水83%的总悬浮固体（TSS）。此外，该方法不会影响微塑料的物理化学特性；然而，对PE和PP微塑料的热分析表明，经配对t检验分析证明，其熔点有统计学意义的下降。此外，非靶向液相色谱-质谱（LC-MS）分析证明Fe-UlS是一个稳定的过程，因为在最佳预处理条件下它不会导致微塑料的任何浸出。最后，进行了激光直接红外成像（LD-IR）分析，以验证所开发的Fe-UlS预处理方法用于实际废水中微塑料分析的有效性。在100 mL的废水原进水中共检测到约3434个微塑料，尺寸范围为9至500μm。这种混合预处理方法不仅简化了废水样品处理，还降低了所需的芬顿试剂浓度和处理时间，为监测废水中的微塑料提供了准确可靠的结果。
