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同濟大學環境科學與工程學院孫婧團隊研究了汙泥熱解對微塑料減少的影響，相關成果發表於Environmental Science & Technology Letters（IF=7.678）。
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Abstract
Sewage sludge is an important source of introducing microplastics into the environment, and thus, effective mitigation of microplastics in the sludge is in urgent need. Herein, the effect of pyrolysis on microplastics reduction in sewage sludge was investigated through a lab-scale study. The micro-Raman analysis showed that the microplastics concentrations in sludge residues decreased significantly from 550.8 to 960.9 particles/g to 1.4–2.3 particles/g with the pyrolysis temperature increasing to 500 °C, and no tiny (10–50 μm) microplastics remained. Polyethylene and polypropylene, the two most abundant microplastics in sewage sludge, were entirely degraded when the pyrolysis temperature reached 450 °C. However, during the pyrolysis process, new plastic polymers could be produced through the reaction between original microplastics with organics in sludge, and heavy metals in sludge can also be combined. Moreover, scanning electron microscopy analysis of spiked microplastics showed that incomplete pyrolysis at low temperatures could result in rough surface morphology of microplastics, making it more readily to adsorb contaminants. Overall, the results of this study provide the first insight into the effectiveness of microplastics control in sewage sludge through pyrolysis, but to avoid potential environmental risks induced by incomplete pyrolysis, a pyrolysis temperature of 450 °C should be reached at least.
汙泥是微塑料進入環境的重要來源，因此對汙泥中微塑料的有效處理迫在眉睫。本文通過實驗室研究，研究了汙泥熱解對微塑料減少的影響。微拉曼光譜分析表明，隨著熱解溫度的升高，汙泥殘渣中微塑料含量從550.8~960.9個/g降至1.4~2.3個/g，且沒有殘留微小（10~50μm）微塑料。聚乙烯和聚丙烯是汙泥中含量最豐富的兩種微塑料，在熱解溫度達到450℃時完全降解。而在熱解過程中，初始微塑料會與汙泥中的有機物反應生成新的微塑料聚合物，也會與汙泥中的重金屬結合在一起。此外，加標微塑料的掃描電鏡分析表明，低溫不完全熱解導致微塑料表面形貌粗糙，更容易吸附汙染物。綜上所述，本試驗首次研究了通過熱解控制汙泥中微塑料的有效性，為了避免不完全熱解導致的潛在環境風險，至少需要達到450℃的熱解溫度。
責任編輯：宋瀟
校對和審核：張陽 王農