Development of a fluidized-bed technique for the regeneration of powdered activated carbon

TiO2-coated granular activated carbon was employed for the removal of toxic microcystin-LR from water. High surface area of the activated carbon provided sites for the adsorption of microcystin-LR, and the adsorbed microcystin-LR migrated continuously onto the surface of TiO2 particles which located mainly at the exterior surface in the vicinity of the entrances of the macropores of the activated carbon. The migrated microcystin-LR was finally degraded into nontoxic products and CO2 very quickly. These combined roles of the activated carbon and TiO2 showed a synergistic effect on the efficient degradation of toxic microcystin-LR. A continuous flow fluidized bed reactor with the TiO2-coated activated carbon could successfully be employed for the efficient photocatalytic of microcystin-LR.

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Effect of operational modes on the removal of a synthetic organic chemical by powdered activated carbon during ultrafiltration

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0098 ◽

2001 ◽

Vol 1 (5-6) ◽

pp. 39-47

Author(s):

Y. Matsui ◽

A. Yuasa ◽

F. Colas

Keyword(s):

Activated Carbon ◽

Cross Flow ◽

Powdered Activated Carbon ◽

Organic Chemical ◽

Filtration Cycle ◽

Dead End ◽

Synthetic Organic Chemical ◽

The Cross ◽

Short Time ◽

Operational Modes

The effects of operational modes on the removal of a synthetic organic chemical (SOC) in natural water by powdered activated carbon (PAC) during ultrafiltration (UF) were studied, through model simulations and experiments. The removal percentage of the trace SOC was independent of its influent concentration for a given PAC dose. The minimum PAC dosage required to achieve a desired effluent concentration could quickly be optimized from the C/C0 plot as a function of the PAC dosage. The cross-flow operation was not advantageous over the dead-end regarding the SOC removal. Added PAC was re-circulated as a suspension in the UF loop for only a short time even under the cross-flow velocity of gt; 1.0 m/s. The cross-flow condition did not contribute much to the suspending of PAC. The pulse PAC addition at the beginning of a filtration cycle resulted in somewhat better SOC removal than the continuous PAC addition. The increased NOM loading on PAC which was dosed in a pulse and stayed longer in the UF loop could possibly further decrease the adsorption rate.

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Fate of Toxic Organic Compounds in Activated Sludge and Integrated PAC Systems

Water Science & Technology ◽

10.2166/wst.1987.0227 ◽

1987 ◽

Vol 19 (3-4) ◽

pp. 471-482 ◽

Cited By ~ 19

Author(s):

W. J. Weber ◽

B. E. Jones ◽

L. E. Katz

Keyword(s):

Activated Carbon ◽

Activated Sludge ◽

Organic Compounds ◽

Powdered Activated Carbon ◽

Carbon Adsorption ◽

Powdered Carbon ◽

Benzene Toluene ◽

Adsorptive Properties ◽

Carbon Concentrations ◽

Toxic Organic Compounds

The addition of powdered activated carbon (PAC) to activated sludge treatment systems to enhance removal of specific toxic organic compounds from wastewater was evaluated. Nine organic compounds encompassing a range of solubility, volatility, biodegradability, and adsorptive properties were studied. Kate and equilibrium investigations were conducted to quantify the removal mechanisms of volatilization, biodegradation, biosorption, and carbon adsorption. Results from steady-state bioreactor studies showed that the addition of less than 100 mg/ℓ powdered activated carbon to the influent did not enhance the removal of the biodegradable target compounds investigated: benzene, toluene, ethylbenzene, o-xylene, chlorobenzene, and nitrobenzene. Significantly improved removals of the poorly degradable and non-biodegradable compounds 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, and lindane occurred at influent powdered carbon concentrations in the 12.5 to 25 mg/ℓ range. Influent powdered carbon concentrations of 100 mg/ℓ effected overall removals of greater than 90%. The addition of powdered activated carbon not only reduced effluent concentrations but also reduced the amounts of the volatile compounds stripped to the atmosphere.

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