基于甲醇解选择性亲水化浮选分离PET/PVC

Flotation Separation of PET/PVC Based on Selective Hydrophilization by Methanolysis

采用甲醇预处理改性,经泡沫浮选分离聚对苯二甲酸乙二醇酯/聚氯乙烯(PET/PVC)混合塑料,探究ZnO、NaOH催化甲醇预处理效果。通过单因素试验讨论反应温度、反应时间、催化剂用量、甲醇浓度对浮选分离的影响。通过L_(16)(4^(3))正交试验,分析各因素对浮选分离影响显著性,得出PET/PVC混合塑料的最佳分离条件。结果表明:ZnO或NaOH催化下,甲醇可以选择性润湿PET表面而对PVC无影响,且ZnO的催化效果比NaOH的催化效果好。PET/PVC混合塑料完全分离的最优条件为:ZnO催化下,预处理反应温度25℃、反应时间25 min、甲醇用量20 m L、ZnO用量2.0 g/L;NaOH催化下,预处理反应温度20℃、反应时间25 min、甲醇用量20 m L、NaOH用量20 g/L。PET/PVC混合塑料完全分离为PET和PVC的回收再生产提供前提条件。

The polyethylene terephthalate/polyvinyl chloride(PET/PVC) mixed plastic was separated with foam flotation modified by methanol pretreatment, and the effects of ZnO and NaOH catalysts on methanol pretreatment were researched. The effects of reaction temperature, reaction time, catalyst dosage and methanol concentration on the flotation separation were discussed according to the single factor test. The significance of the influence of various factors on the flotation separation through L_(16)(4^(3)) orthogonal tests was analyzed, and the best separation conditions for PET/PVC mixed plastics were obtained. The results show that under ZnO or NaOH assisted catalysis, methanol can selectively wet PET surface without affecting PVC and the catalytic effect of ZnO is better than that of NaOH. The optimum conditions for the complete separation of PET/PVC blends are that under the catalysis of ZnO, the pretreatment temperature is 25 ℃, the reaction time is 25 min, the methanol dosage is 20 mL and ZnO dosage is 2.0 g/L. When NaOH was used as catalyst, the pretreatment reaction temperature is 20 ℃, the reaction time is 25 min, the methanol dosage is 20 mL, and the NaOH dosage is 20 g/L. The complete separation of PET/PVC blends provides a prerequisite for the recycling and reprocessing of PET and PVC.