Direct observation of solid-phase adsorbate concentration profile in powdered activated carbon particle to elucidate mechanism of high adsorption capacity on super-powdered activated carbon

Ando, Naoya; Matsui, Yoshihiko; Matsushita, Taku; Ohno, Koichi

doi:10.1016/j.watres.2010.08.050

Cited by 16 publications

(14 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, when relatively large molecular organic compounds exist, their adsorption capacity could be enhanced greatly due to PAC particle size reduction. This result is in agreement with the literature report [8,26]. Micropores of activated carbons could only be approached by small molecular matters.…”

supporting

confidence: 93%

Adsorption Behavior of DOM by PACs with Different Particle Sizes

Shi

Fang

et al. 2014

CLEAN Soil Air Water

View full text Add to dashboard Cite

Particle size of powdered activated carbon (PAC) is an important factor influencing the adsorption behavior of organic matter, but the effect of PAC particle size on the removal of different fractions of dissolved organic matter (DOM) is still not well understood. In this work, natural water from a site with anthropogenic influence was used as test water, and the adsorption behavior of different DOM fractions onto three PACs with different particle size was investigated. The results demonstrated that the DOM removal was enhanced 83.3% when the PAC particle size decreased from 76.0 to 19.1 mm. The majority of increased adsorption capacity could be ascribed to microbial by-product and humiclike fractions, or to mid-molecular weight fraction DOM. With the decrease of PAC particle size, the adsorption kinetic constant of low-molecular fraction was greatly enhanced, but the adsorption capacity was enhanced less significantly. By comparing the Brunauer-Emmett-Teller surface area and pore size distribution of PACs with different particle sizes, it was confirmed that the improvement of adsorption by reducing PAC particle size could be attributed to the increase of accessible PAC surface area and decrease of diffusion distance for DOM molecules.

show abstract

supporting

confidence: 93%

Adsorption Behavior of DOM by PACs with Different Particle Sizes

Shi

Fang

et al. 2014

CLEAN Soil Air Water

View full text Add to dashboard Cite

show abstract

“…S6). At equilibrium, NOM can be expected to have a larger adsorption capacity on S-PAC since NOM mainly adsorbs close to the external adsorbent particle surface and does not completely penetrate into internal pores (Ando et al, 2010(Ando et al, , 2011Matsui et al, 2011). However, here, under high NOM concentrations and short contact times, the unchanged NOM adsorption rate and increased atrazine adsorption rate results in reduced NOM competition with S-PAC, probably because there were more pores available than in PAC.…”

Section: Contaminant Removalmentioning

confidence: 91%

Superfine powdered activated carbon (S-PAC) coatings on microfiltration membranes: Effects of milling time on contaminant removal and flux

Amaral

Partlan

et al. 2016

Water Research

View full text Add to dashboard Cite

In microfiltration processes for drinking water treatment, one method of removing trace contaminants is to add powdered activated carbon (PAC). Recently, a version of PAC called superfine PAC (S-PAC) has been under development. S-PAC has a smaller particle size and thus faster adsorption kinetics than conventionally sized PAC. Membrane coating performance of various S-PAC samples was evaluated by measuring adsorption of atrazine, a model micropollutant. S-PACs were created in-house from PACs of three different materials: coal, wood, and coconut shell. Milling time was varied to produce S-PACs pulverized with different amounts of energy. These had different particles sizes, but other properties (e.g. oxygen content), also differed. In pure water the coal based S-PACs showed superior atrazine adsorption; all milled carbons had over 90% removal while the PAC had only 45% removal. With addition of calcium and/or NOM, removal rates decreased, but milled carbons still removed more atrazine than PAC. Oxygen content and specific external surface area (both of which increased with longer milling times) were the most significant predictors of atrazine removal. S-PAC coatings resulted in loss of filtration flux compared to an uncoated membrane and smaller particles caused more flux decline than larger particles; however, the data suggest that NOM fouling is still more of a concern than S-PAC fouling. The addition of calcium improved the flux, especially for the longer-milled carbons. Overall the data show that when milling S-PAC with different levels of energy there is a tradeoff: smaller particles adsorb contaminants better, but cause greater flux decline. Fortunately, an acceptable balance may be possible; for example, in these experiments the coal-based S-PAC after 30 min of milling achieved a fairly high atrazine removal (overall 80%) with a fairly low flux reduction (under 30%) even in the presence of NOM. This suggests that relatively short duration (low energy) milling is viable for creating useful S-PAC materials applied in tandem with microfiltration.

show abstract

“…17,18 Recently, works on the super powdered activated carbon (SPAC) and carbon nanotubes (CNT) have demonstrated their effective removal of natural organic matters (NOM) and odor pollutants due to their morphology and surface chemistry. 19,20 But only a few studies have involved in the application of carbon nanotubes to the emerging contaminants removal. 21,22 Apparently, most of studies are focused on adsorption to ECs alone.…”

Section: -10mentioning

confidence: 99%

Removal of emerging contaminants by pre-mixed PACl and carbonaceous materials

et al. 2015

View full text Add to dashboard Cite

In this study, pre-mixed poly aluminum chloride (PACl) and super powdered activated carbon (SPAC)/ carbon nanotubes (CNT) were employed for the removal of emerging contaminants (ECs) from various water sources. Salicylic acid (SALA), ibuprofen (IBP) and diclofenac (DCF) were the targeted ECs. The synergistic effect of the combined coagulation and adsorption process as well as their individual removal performance are discussed in this paper. The results of the three ECs removal indicate that pre-mixed PACl and SPAC/CNT has a better removal ability compared with PACl or SPAC/CNT alone. The maximum adsorption capacities increase at least 5 times after the addition of PACl, attributed to the charge neutralization and adsorption on the flocs. The removal efficiency of ECs by coagulation improves with the addition of SPAC/CNT as a result of the bridging effect as well as adsorption of ECs by carbon materials. The removal efficiency for these three ECs generally exhibited the following trends:SALA (log P ¼ 1.98) < IBP (log P ¼ 3.84) < DCF (log P ¼ 4.26), indicating that the hydrophobicity of the ECs plays an important role.

show abstract

Direct observation of solid-phase adsorbate concentration profile in powdered activated carbon particle to elucidate mechanism of high adsorption capacity on super-powdered activated carbon

Cited by 16 publications

References 11 publications

Adsorption Behavior of DOM by PACs with Different Particle Sizes

Adsorption Behavior of DOM by PACs with Different Particle Sizes

Superfine powdered activated carbon (S-PAC) coatings on microfiltration membranes: Effects of milling time on contaminant removal and flux

Removal of emerging contaminants by pre-mixed PACl and carbonaceous materials

Contact Info

Product

Resources

About