Highly efficient porous carbons for the removal of W(VI) oxyanion from wastewaters

ABSTRACT: Pyrolysis chars derived from rice wastes were chemically activated and used in W(VI) oxyanion adsorption assays in synthetic and mining wastewaters. For comparison purposes, a commercial activated carbon (CAC) was also used. Different experimental conditions were tested in the adsorption assays: solid/liquid ratio (S/L), initial pH, contact time, and initial W concentration. The porous carbon P2C+KOH presented the overall best performance in both media, due to its high surface area (2610 m2 g-1), mesopore volume (1.14 cm3 g-1), and neutral pHpzc (6.92). In the synthetic wastewater, the highest uptake capacity of P2C+KOH (854 mg g-1) was found in the assays with an S/L 0.1 g L-1, an initial pH 2, and an initial W concentration of 150 mg L-1, for 24 h. This value was almost 8 times higher than the one obtained for CAC (113 mg g-1). In the mining wastewater, P2C+KOH showed an even higher uptake capacity (1561 mg g-1) in the assay with the same experimental conditions, which was almost 3 times higher than for CAC (561 mg g-1). These results suggest that P2C+KOH seems to be an efficient alternative to CAC in the W(VI) adsorption from liquid effluents.

Keywords

Rice wastes Wastewater treatment Pyrolysis Tungsten Adsorption Activated carbons

URI

http://hdl.handle.net/10400.9/3631

Citation

Dias, Diogo... [et.al.] - Highly efficient porous carbons for the removal of W(VI) oxyanion from wastewaters. In: Journal of Hazardous Materials, 2021, Vol. 412, article nº 125201