open access

https://hdl.handle.net/2115/52884

Geosmin and 2-methylisoborneol removal using superfine powdered activated carbon: Shell adsorption and branched-pore kinetic model analysis and optimal particle size

英語

Contact time

2013-05-15

Elsevier

Water Research

47(8)

2873-2880

2-Methylisoborneol (MIB) and geosmin are naturally occurring compounds responsible for musty-earthy taste and odor in public drinking-water supplies, a severe problem faced by many utilities throughout the world. In this study, we investigated adsorptive removal of these compounds by superfine powdered activation carbon (SPAC, particle size <1 mu m) produced by novel micro-grinding of powdered activated carbon; we also discuss the optimization of carbon particle size to efficiently enhance the adsorptive removal. After grinding, the absorptive capacity remained unchanged for a 2007 carbon sample and was increased for a 2010 carbon sample; the capacity increase was quantitatively described by the shell adsorption model, in which MIB and geosmin adsorbed more in the exterior of a carbon particle than in the center. The extremely high uptake rates of MIB and geosmin by SPAC were simulated well by a combination of the branched-pore kinetic model and the shell adsorption model, in which intraparticle diffusion through macropores was followed by diffusion from macropore to micropore. Simulations suggested that D-40 was on the whole the best characteristic diameter to represent a size-disperse group of adsorbent particles; D-40 is the diameter through which 40% of the particles by volume pass. Therefore, D-40 can be used as an index for evaluating the improvement of adsorptive removal that resulted from pulverization. The dose required for a certain percentage removal of MIB or geosmin decreased linearly with carbon particle size (D-40), but the dose reduction became less effective as the activated carbon was ground down to smaller sizes around a critical value of D-40. For a 60-min contact time, critical D-40 was 2-2.5 mu m for MIB and 0.4-0.5 mu m for geosmin. The smaller critical D40 was when the shorter the carbon-water contact time was or the slower the intraparticle mass transfer rate of an adsorbate was. (C) 2013 Elsevier Ltd. All rights reserved.

学術雑誌論文

Accepted Manuscript

0043-1354