Tribocharging of macerals with various materials: Role of surface oxygen-containing groups and potential difference of macerals

• Autor: He, Xin ; Sun, Hao ; Zhao, Bin ; Chen, Xiaowei ; Zhang, Xinxi ; Komarneni, Sridhar
• Assuntos: Aluminum ; Atomic force microscopy ; Charge-to-mass ratio ; Copper ; Environmental factors ; Macerals ; Mass ratios ; Microscopy ; Oxygen ; Photoelectron spectroscopy ; Polarity ; Polyamide resins ; Polyamines ; Polyethylene ; Polyethylene terephthalate ; Polyvinyl chloride ; Separation ; Stainless steel ; Surface charge ; Surface potential difference ; Surface stability ; Triboelectrostatic separation ; Tribology ; X ray photoelectron spectroscopy
• É parte de: Fuel (Guildford), 2018-12, Vol.233, p.759-768
• Descrição: [Display omitted] •Polyamide was the optimum among six materials tested for tribocharging of macerals.•Inertinite showed polar and hydrophilic groups but vitrinite showed nonpolar groups.•The presence of polar and non-polar groups led to their opposite charge polarity.•The potential difference between vitrinite and inertinite was found to be −0.42 V. Triboelectrostatic separation of vitrinite and inertinite depends on their differences in tribocharging behavior. In the present study, charge-to-mass ratios of two macerals with six tribocharging materials, i.e., aluminum, stainless steel, copper, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyamide (PA) were conducted for the first time under various environmental factors. PA was found to be the preferred material for tribocharging because vitrinite and inertinite displayed opposite charge polarity with it. Characterization of surface oxygen-containing groups on macerals and their quantitative estimation were conducted by X-ray photoelectron spectroscopy (XPS) technique. Polar groups such as OH and COOH were detected to be the major proportion in inertinite whereas vitrinite exhibited mainly nonpolar groups of O, which indicate tendency of their surface charge. For the first time, atomic force microscopy (AFM) was utilized to investigate the surface topography and potential difference of macerals. Inertinite showed 0.42 V higher surface potential than vitrinite, which well fits with their charge polarity and movement during triboelectrostatic separation. However, the instability of surface potential difference on inertinite may leads to disorder in its charge polarity, which makes Cu as an alternative material because both macerals have great charge gap with Cu and they also have same charge polarity.
  
• Editor: Kidlington: Elsevier Ltd
  
• Idioma: Inglês