Adsorption of VOCs onto engineered carbon materials: A review

This review is designed to summarize and critique current life skills through sport research. In particular, life skills are defined, the conditions needed to examine life skills development are explored, and the possible theoretical explanations of how, when, under what conditions and why life skills develop in sport participants are discussed. A heuristic model of coaching life skills is offered. To conclude, future research directions are forwarded and include the need for: (a) quantitative and qualitative research; (b) the development of valid life skills through sport measures; (c) an examination of sport program type differences; (d) evaluation research; (e) longitudinal studies; (f) studies focusing on identifying theoretical explanations for the life skill development sport participation link; (g) the utilization of experimental designs; and (h) an examination of the transferability of life skills. The importance of conducting this type of research for both theoretical and practical reasons is emp...

Life skills development through sport: current status and future directions

Electrospinning (E-spin) is a unique technique to fabricate polymeric as well as metal oxide nanofibers. Research on electrospun nanofibers is a very active field in material science owing to their novel applications in diverse domains. The main focus of this review is to provide an insight into E-spin technique by understanding the working principle, influencing parameters and applications of nanofibers in different walks of life. Several hundreds of papers are published on the preparation, modification and applications of nanofibers produced by E-spin technique in the areas like sensor development, decontamination, energy storage, biomedical and catalysis etc. Details on the industrial scale development of E-spin technique, current scenario and future developments are also covered in this review.

Electrospun nanofibers: New generation materials for advanced applications

https://chemical.eng.usm.my/bassim/PDF/activated_carbons_microwaves.pdf

Recent developments in the preparation and regeneration of activated carbons by microwaves.

Biogas is a renewable energy source like solar and wind energies and mostly produced from anaerobic digestion (AD). The production of biogas is a well-established technology, but its commercial utilization is limited because on-site purification is needed before its transport or use. Biogas composition varies with the biomass digested and contains mainly methane (CH4) and carbon dioxide (CO2), as well as traces of hydrogen sulfide (H2S), ammonia (NH3), hydrogen (H2), nitrogen (N2), carbon monoxide (CO), oxygen (O2). In some cases dust particles and siloxanes are present. Several purification processes including pressurized water scrubbing, amine swing absorption, pressure swing adsorption, temperature swing adsorption, cryogenic separation and membrane technologies have been developed. Nevertheless, membrane technology is a relatively recent but very promising technology. Also, hybrid processes where membranes are combined with other processes are believed to have lower investment and operation costs compared with other processes. In this report, a discussion on the different materials used to produce membranes for gas separation is given including inorganic, organic and mixed matrix membranes, as well as polymer of intrinsic microporosity (PIM). Advantages and limitations for each type are discussed and comparisons are made in terms of permeability and diffusivity for a range of operating conditions.

https://pubs.rsc.org/en/content/articlepdf/2015/RA/C5RA00666J

Membrane gas separation technologies for biogas upgrading

Capture and recovery of hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) from gas streams using physical adsorption onto activated carbon fiber cloth (ACFC) is demonstrated on the bench-scale. This system is regenerated electrothermally, by passing an electric current directly through the ACFC. The adsorbate desorbs from the ACFC, rapidly condenses on the inside walls of the adsorber, and then drains from the adsorber as a pure liquid. Rapid electrothermal desorption exhibits such unique characteristics as extremely low purge gas flow rate, rapid rate of ACFC heating, rapid mass transfer kinetics inherent to ACFC, and in-vessel condensation. An existing system was scaled up 500%, and the new system was modeled using material and energy balances. Adsorption isotherms using methyl ethyl ketone (MEK) and ACFC were obtained while electricity passed through the ACFC and at temperatures above MEK's boiling point. These isotherms agreed within 7% to Dubinin-Radushkevich modeled isotherms that were extrapolated from independently determined gravimetric measurements obtained at lower temperatures. Energy and material balances for the electrothermal desorption of organic vapors and ACFC agree to within 7% of experimentally measured values. These results allow the modeling of electrothermal desorption of organic vapors from gas streams with in-vessel condensation to optimize operating conditions of the system during regeneration of the adsorbent.

Activated Carbon Fiber Cloth Electrothermal Swing Adsorption System

In 1997, 6.04 x 10\u8 kg of hazardous air pollutants were emitted into the atmosphere from the United States. A bench-scale activated-carbon fiber-cloth adsorption, electrothermal desorption, and condensation system was designed, built, and operated to demonstrate its ability to capture and recover organic hazardous air pollutants from airstreams. The annular-cartridge configuration of the activated carbon fiber cloth allows low pressure drop and rapid electrothermal regeneration. Adsorption and electrothermal desorption cycling of the system with an airstream containing 1,000 ppmv methyl ethyl ketone (MEK) resulted in closure within 8% by mass. Competitive adsorption between water vapor and MEK reduced MEK adsorption capacity 43% as relative humidity of the gas increased from 4 to 90% at 22°C dry-bulb temperature. Increasing the dry-bulb temperature of the gas stream by 10°C at a constant dew-point temperature resulted in a 37% increase in MEK adsorption compared to the high relative humidity test case, while allowing the water vapor to penetrate the adsorber. The automated system achieves MEK capture efficiency >99.9% by mass while recovering the liquid MEK for reuse.

Adsorption and Electrothermal Desorption of Hazardous Organic Vapors

Understanding the adsorption of water vapor onto activated carbons is important for designing processes to re- move dilute contaminants from humid gas streams, such as providing protection against chemical warfare agents (CWAs), or against toxic industrial compounds (TICs) used in a terrorist chemical attack. Water vapor isotherms for Calgon BPL granular activated carbon (GAC), mil- itary ASZM-TEDA GAC, electrospun activated carbon nanofibers (ACnF), Calgon Zorflex ™ activated carbon cloth, and Novoloid-based activated carbon fiber cloth (ACFC) are presented. Of particular interest are the ACFC isotherms, which exhibit an unusually high degree of hydrophobicity. The ACFC isotherms also show a correlation between water vapor adsorption hysteresis and the level of activation. Water vapor isotherm models from the literature are compared.

Water adsorption with hysteresis effect onto microporous activated carbon fabrics

Organized Youth Activities as Contexts for Positive Development

Activated-carbon-fiber cloth (ACFC) is an alternative adsorbent to granular activated carbon (GAC) for removing and recovering organic vapors from gas streams. Electrothermal desorption (ED) of ACFC provides rapid regeneration while requiring less energy compared to traditional regeneration techniques used with GAC. This paper provides proof-of-concept results from a bench-scale ACFC adsorption system. The automated system captured 1,000 ppmv of hazardous air pollutants/volatile organic compounds (HAPs/VOCs) from air streams and demonstrated the use of ED, using ac voltage, to recover the HAP/VOC as a pure liquid. The desorbed HAP/VOC condensed onto the inner walls of the adsorber and was collected at the bottom of the vessel, without the use of ancillary cooling. Seventy percent of the HAP/VOC was collected per cycle as condensate, with the balance being retained in the regenerated adsorber or recycled to the second adsorber. ED with in-vessel condensation results in minimal N\d2 consumption and short regeneration cycle times allowing the process to be cost competitive with conventional GAC-based adsorption processes. This technology extends the application of carbon adsorption systems to situations that were previously economically and physically impractical.

/pdf/capture-of-organic-vapors-using-adsorption-and-4vkeu1f61u.pdf

Patrick D. Sullivan

Papers

Activated Carbon Fiber Cloth Electrothermal Swing Adsorption System

Adsorption and Electrothermal Desorption of Hazardous Organic Vapors

Water adsorption with hysteresis effect onto microporous activated carbon fabrics

Organized Youth Activities as Contexts for Positive Development

Capture of Organic Vapors Using Adsorption and Electrothermal Regeneration