Flotation separation of polystyrene and polyvinyl chloride based on heterogeneous catalytic Fenton and green synthesis of nanoscale zero valent iron (GnZVI)
2020; Elsevier BV; Volume: 267; Linguagem: Inglês
10.1016/j.jclepro.2020.122116
ISSN1879-1786
AutoresYingshuang Zhang, Hongru Jiang, Hui Wang, Chongqing Wang, Yichen Du, Ling Wang,
Tópico(s)Environmental remediation with nanomaterials
ResumoIt arises sharp concern that waste plastics entrain hazardous substances and accumulate in living organisms, endangering the environment and human health. To achieve clean plastic management and obtain qualified recycled products, separation deserves intensive research in preference to other technologies in plastic recycling. In this research, we proposed a novel flotation separation of binary plastic mixtures, polystyrene (PS) and polyvinyl chloride (PVC), based on heterogeneous advanced oxidation technology (AOT) and the green synthesis of nanoscale zero valent iron (GnZVI). The optimal conditions for separating PVC and PS (PS as a sinking plastic) are 1.5 mM H2O2, H2O2/Fe0 molar ratio 40:1, treatment time 300 s, room temperature, and pH 6. We revealed the oxidation mechanisms of PS after AOT treatment through extensive characterizations, such as scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance spectroscopy (NMR). Surface-incorporated oxygenated functions, such as hydroxyl (C–OH) and carboxyl groups (OC–O), are introduced on PS through the scission of backbone chain and the addition of hydroxyl and hydroperoxy radicals, increasing the hydrophilicity of PS. Besides, we established a novel pretreatment kinetics based on flotation percentage and treatment time to research the flotation behavior of PS, providing a new research perspective for plastic flotation. With the characteristics of low reagents dosage, short treatment time, mild temperature, and slight pollution, the proposed flotation process is an applicable separation technology for plastic recycling.
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