Mallampati Srinivasa Reddy, Lee Byoung Ho, Mitoma Yoshiharu, Simion Cristian
Department of Civil and Environmental Engineering, University of Ulsan, Daehak-ro 93, Nam-gu, Ulsan 680-749, Republic of Korea.
Department of Civil and Environmental Engineering, University of Ulsan, Daehak-ro 93, Nam-gu, Ulsan 680-749, Republic of Korea.
Waste Manag. 2017 Feb;60:428-438. doi: 10.1016/j.wasman.2017.01.003. Epub 2017 Jan 12.
The separation of plastics containing brominated flame retardants (BFR) like (acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS), and polyvinyl chloride (PVC)) from automobile and electronic waste shredder residue (ASR/ESR) are a major concern for thermal recycling. In laboratory scale tests using a hybrid nano-Fe/Ca/CaO assisted ozonation treatment has been found to selectively hydrophilize the surface of ABS/HIPS and PVC plastics, enhancing ABS wettability and thereby promoting its separation from ASR/ESR by means of froth flotation. The water contact angles, of ABS/HIPS and PVC decreased, about 18.7°, 18.3°, and 17.9° in ASR and about 21.2°, 20.7°, and 20.0° in ESR respectively. SEM-EDS, FT-IR, and XPS analyses demonstrated a marked decrease in [Cl] and a significant increase in the number of hydrophilic groups, such as CO, CO, and (CO)O, on the PVC or ABS surface. Under froth flotation conditions at 50rpm, about 99.1% of combined fraction of ABS/HIPS in ASR samples and 99.6% of ABS/HIPS in ESR samples were separated as settled fraction. After separation, the purity of the recovered combined ABS/HIPS fraction was 96.5% and 97.6% in ASR and ESR samples respectively. Furthermore, at 150rpm a 100% PVC separation in the settled fraction, with 98% and 99% purity in ASR and ESR plastics, respectively. Total recovery of non-ABS/HIPS and PVC plastics reached nearly 100% in the floating fraction. Further, this process improved the quality of recycled ASR/ESR plastics by removing surface contaminants or impurities.
从汽车和电子垃圾粉碎残余物（ASR/ESR）中分离出含有溴化阻燃剂（BFR）的塑料（如丙烯腈-丁二烯-苯乙烯共聚物（ABS）、高抗冲聚苯乙烯（HIPS）和聚氯乙烯（PVC））是热回收的一个主要问题。在实验室规模的测试中，发现使用混合纳米铁/钙/氧化钙辅助臭氧化处理可选择性地使ABS/HIPS和PVC塑料表面亲水化，提高ABS的润湿性，从而通过泡沫浮选促进其与ASR/ESR的分离。在ASR中，ABS/HIPS和PVC的水接触角分别降低了约18.7°、18.3°和17.9°；在ESR中分别降低了约21.2°、20.7°和20.0°。扫描电子显微镜-能谱分析（SEM-EDS）、傅里叶变换红外光谱（FT-IR）和X射线光电子能谱（XPS）分析表明，PVC或ABS表面的[Cl]显著减少，亲水性基团（如CO、CO和(CO)O）的数量显著增加。在50转/分钟的泡沫浮选条件下，ASR样品中约99.1%的ABS/HIPS混合组分和ESR样品中99.6%的ABS/HIPS作为沉淀组分被分离出来。分离后，回收的ABS/HIPS混合组分在ASR和ESR样品中的纯度分别为96.5%和97.6%。此外，在150转/分钟时，沉淀组分中PVC的分离率达到100%，在ASR和ESR塑料中的纯度分别为98%和99%。非ABS/HIPS和PVC塑料在浮选组分中的总回收率接近100%。此外，该工艺通过去除表面污染物或杂质提高了回收的ASR/ESR塑料的质量。
