The recycling of packaging plastics is hindered by the various plastic mixtures and their similar surface properties. Plastic separation is a key step to improve recycling efficiency of waste plastics. We proposed a simple and efficient protocol to separate polyethylene terephthalate (PET) from polycarbonate (PC), acrylonitrile-butadienestyrene copolymer (ABS), and polyvinyl chloride (PVC) by converting PET surface from hydrophobicity to hydrophilicity. PET surface was modified by potassiumhydroxide (KOH)and ethylene glycol ((CH2OH)2) with the aid of sonication. Contact angle, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to research the reactions on PET surface. It can be confirmed that the reaction of base-catalyzed transesterification occurs, leading to a hydrophilic PET plastic. We investigated the effects of ultrasonic power, ultrasonic time, (CH2OH)2 dosage, KOH dosage, flotation time, and frother concentration on the flotation separation. The flotation recovery and purity of PET are 98.8% and 100%, respectively when (CH2OH)2 dosage is 10 mL, KOH dosage is 2 g, ultrasonic time is 5 min, ultrasonic intensity is 160 W, flotation time is 4 min, and frother concentration is 52.7 mg/L. This study provided a novel surface modification with reliable mechanisms for the flotation of PET from plastic mixtures.

中文翻译：

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通过超声处理辅助的乙二醇预处理从废包装塑料中浮选分离聚对苯二甲酸乙二醇酯。

各种塑料混合物及其相似的表面性能阻碍了包装塑料的回收利用。塑料分离是提高废塑料回收效率的关键步骤。我们提出了一种简单有效的方案，通过将PET表面从疏水性转变为亲水性，将聚对苯二甲酸乙二醇酯（PET）与聚碳酸酯（PC），丙烯腈-丁二烯苯乙烯共聚物（ABS）和聚氯乙烯（PVC）分开。借助超声处理，用氢氧化钾（KOH）和乙二醇（（CH2OH）2）对PET表面进行改性。接触角，傅立叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）用于研究PET表面的反应。可以证实发生了碱催化的酯交换反应，从而产生了亲水性PET塑料。我们调查了超声功率，超声时间，（CH2OH）2用量，KOH用量，浮选时间和起泡剂浓度对浮选分离的影响。当（CH2OH）2用量为10 mL，KOH用量为2 g，超声时间为5分钟，超声强度为160 W，浮选时间为4分钟时，PET的浮选回收率和纯度分别为98.8％和100％。起泡剂浓度为52.7 mg / L。这项研究提供了一种新颖的表面改性方法，该方法具有可靠的机制，可从塑料混合物中浮选PET。超声强度为160 W，浮选时间为4分钟，起泡剂浓度为52.7 mg / L。这项研究提供了一种新颖的表面改性方法，该方法具有可靠的机理，可从塑料混合物中浮选PET。超声强度为160 W，浮选时间为4分钟，起泡剂浓度为52.7 mg / L。这项研究提供了一种新颖的表面改性方法，该方法具有可靠的机制，可从塑料混合物中浮选PET。