The Use of Froth Flotation for Selective Separation of Plastic Wastes from Soil

Abstract


 
 
 
 
 The Use of Froth Flotation for Selective Separation of Plastic Wastes from Soil
 
 
 
 
 
 
 
 
 
 Kofi Moro and Dorothy A. Dechie
 
 
 
 
 
 Abstract — In recycling of plastics, unless the goal is to form composites or materials having special properties, it is not advisable to mix plastics of different kinds because of the differences in their molecular weights and chain lengths. Hence, there is the need to separate these plastics when they are mixed before recycle can be done. This project investigated the selective separation of Polypropylene (PP), Polystyrene (PS) and Polyethylene terephthalate (PET) plastics out of soils using froth flotation. Pulverized samples were prepared from post-consumer plastic sources (PP, PS and PET) and soil and mixed uniformly to form a composite sample. The composite sample was subjected to froth flotation. Two tests were performed. A first test, where there was no addition of a depressant (tannic acid), and a second test, where there was addition of tannic acid to depress some of the plastics in order to selectively separate them. Recoveries from each test work indicated that, plastics are naturally hydrophobic and can be floated out of soils without modifying their surface properties. However, selective separations of the plastics were achieved when tannic acid was used to modify the surface properties of the plastic types.

Hydrophobisation of Silica Nanoparticles Using Lauroyl Ethyl Arginate and Chitosan Mixtures to Induce the Foaming Process

“…Flotation has already been used to remove pollutants from water. However, every literature report describes only the separation of hydrophobic contaminants from other hydrophilic clays or minerals [ 8 , 9 ]. We believe it will be possible to modify the classical flotation process and apply it to negatively charged and hydrophilic nanoparticles using proper chemicals for particle surface charge neutralisation and hydrophobisation.…”