Nonidealities in Vapor-Phase Coadsorption of Organic Compounds and Water on Activated Carbon

Abstract The merits of activated carbon for removal of organic compounds from wastewater have been well documented in the literature. On the other hand there is a lack of published data on the use of activated carbon for the removal of trace metals from wastewater. Experiments were designed to assess the possibility that activated carbon treatment would remove aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, silver and zinc from wastewater. All metals studied were tested over the pH range 3-11. Greater than 99.5% removal was achieved by pH adjustment and activated carbon treatment for most of the metals tested.

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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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Hierarchically Porous Silk/Activated-Carbon Composite Fibres for Adsorption and Repellence of Volatile Organic Compounds

Molecules ◽

10.3390/molecules25051207 ◽

2020 ◽

Vol 25 (5) ◽

pp. 1207

Author(s):

Aled D. Roberts ◽

Jet-Sing M. Lee ◽

Adrián Magaz ◽

Martin W. Smith ◽

Michael Dennis ◽

...

Keyword(s):

Activated Carbon ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Carbon Composite ◽

Hierarchically Porous ◽

Surface Areas ◽

Regenerated Silk Fibroin ◽

Volatile Organic ◽

Fibre Spinning ◽

Solution Blow Spinning

Fabrics comprised of porous fibres could provide effective passive protection against chemical and biological (CB) threats whilst maintaining high air permeability (breathability). Here, we fabricate hierarchically porous fibres consisting of regenerated silk fibroin (RSF) and activated-carbon (AC) prepared through two fibre spinning techniques in combination with ice-templating—namely cryogenic solution blow spinning (Cryo-SBS) and cryogenic wet-spinning (Cryo-WS). The Cryo-WS RSF fibres had exceptionally small macropores (as low as 0.1 µm) and high specific surface areas (SSAs) of up to 79 m2·g−1. The incorporation of AC could further increase the SSA to 210 m2·g−1 (25 wt.% loading) whilst also increasing adsorption capacity for volatile organic compounds (VOCs).

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Water-Enhanced Flux Changes under Dynamic Temperatures in the Vertical Vapor-Phase Diffusive Transport of Volatile Organic Compounds in Near-Surface Soil Environments

Sustainability ◽

10.3390/su13126570 ◽

2021 ◽

Vol 13 (12) ◽

pp. 6570

Author(s):

Asma Akter Parlin ◽

Monami Kondo ◽

Noriaki Watanabe ◽

Kengo Nakamura ◽

Mizuki Yamada ◽

...

Keyword(s):

Air Quality ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Vapor Phase ◽

Inverse Correlation ◽

Diffusive Transport ◽

Near Surface ◽

Voc Emissions ◽

Transport Behavior ◽

Volatile Organic

The quantitative understanding of the transport behavior of volatile organic compounds (VOCs) in near-surface soils is highly important in light of the potential impacts of soil VOC emissions on the air quality and climate. Previous studies have suggested that temperature changes affect the transport behavior; however, the effects are not well understood. Indeed, much larger changes in the VOC flux under in situ dynamic temperatures than those expected from the temperature dependence of the diffusion coefficients of VOCs in the air have been suggested but rarely investigated experimentally. Here, we present the results of a set of experiments on the upward vertical vapor-phase diffusive transport of benzene and trichloroethylene (TCE) in sandy soils with water contents ranging from an air-dried value to 10 wt% during sinusoidal temperature variation between 20 and 30 °C. In all experiments, the flux from the soil surface was correlated with the temperature, as expected. However, the changes in flux under wet conditions were unexpectedly large and increased with increasing water content; they were also larger for TCE, the volatility of which depended more strongly on the temperature. Additionally, the larger flux changes were accompanied by a recently discovered water-induced inverse correlation between temperature and flux into the overlying soil. These results demonstrated that the flux changes of VOCs under dynamic temperatures could be increased by volatilization-dissolution interactions of VOCs with water. Future extensive studies on this newly discovered phenomenon would contribute to a better understanding of the impacts of soil VOC emissions on the air quality and climate.

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