Applicability of reused industrial dry sanding powder for adsorption of arsenic

This study examined the potential reuse of powdered wastes (PW) generated during the sanding and sawing process in a local chemical company in Korea with the viewpoint of the recycling these wastes and minimizing the level of contamination. As the aluminium hydroxide inside the PW could be thermally converted to various types of aluminium oxides depending on the calcination temperature, the adsorptive properties could be changed and it may affect on adsorption ability. Calcination of the PW was performed for 3 h at 550°C, 750°C, and 950°C. From the results, amorphous aluminium oxide was thermally generated by calcinating the PW at 550°C and with further increase of temperature to 950°C, the crystallinity of amorphous aluminium oxide was gradually increased. The physicochemical analysis of calcined powdered wastes (CPW) at various temperatures showed that more developed porosity was noted in the CPW as the calcinations temperature increased, whereas surface area was significantly decreased from 175.5 m² g⁻¹ to 46.5 m² g⁻¹. The removal efficiency of arsenate on the CPW decreased as the calcinations temperature increased from 550°C to 950°C. The CPW₅₅₀ exhibited the highest adsorption capacities toward arsenate over pH range of 2–8 and showed a complete removal of the arsenate (10.0 mg L⁻¹) within the first 10 min. Adsorption kinetic studies showed that the rate of arsenic adsorption on the CPW decreased with the increase of the calcination temperature. When the maximum adsorption capacity of arsenic onto the CPW was calculated by Langmuir equation, the CPW₅₅₀ has the highest value as 43.9 mg g⁻¹.