title: A novel process for separation of polycarbonate, polyvinyl chloride and polymethyl methacrylate waste plastics by froth flotation.
abstract: A novel process was proposed for separation of ternary waste plastics by froth flotation. Pretreatment of plastics with potassium permanganate (KMnO4) solution was conducted to aid flotation separation of polycarbonate (PC), polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) plastics. The effect of pretreatment parameters including KMnO4concentration, treatment time, temperature and stirring rate on flotation recovery were investigated by single factor experiments. Surface treatment with KMnO4changes selectively the flotation behavior of PC, PVC and PMMA, enabling separation of the plastics by froth flotation. Mechanism of surface treatment was studied by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectrum (XPS). Effect of frother concentration and flotation time on flotation behavior of plastic mixtures was further studied for flotation separation. The optimized conditions for separation of PC are KMnO4concentration 2mmolL-1, treatment time 10min, temperature 60°C, stirring rate 300rpm, flotation time 1min and frother concentration 17.5mgL-1. Under optimum conditions, PVC and PMMA mixtures are also separated efficiently by froth flotation associated with KMnO4treatment. The purity of PC, PVC and PMMA is up to 100%, 98.41% and 98.68%, while the recovery reaches 96.82%, 98.71% and 98.38%, respectively. Economic analysis manifests remarkable profits of the developed process. Reusing KMnO4solution is feasible, enabling the process greener.
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, China.
authors.forename: Chong-Qing
authors.initials: CQ
authors.lastname: Wang
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, China. Electronic address: huiwang1968@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, China.
authors.forename: Luo-Luo
authors.initials: LL
authors.lastname: Huang
mesh_terms: D010969:Plastics; D011076:Polycarboxylate Cement; D019904:Polymethyl Methacrylate; D011143:Polyvinyl Chloride; D018508:Water Purification
chemical_list: D010969:Plastics; D011076:Polycarboxylate Cement; C005506:polycarbonate; D011143:Polyvinyl Chloride; D019904:Polymethyl Methacrylate
keywords: Froth flotation; Potassium permanganate; Separation; Surface treatment; Waste plastics