Preparation of a new adsorbent from activated carbon and carbon nanofiber (AC/CNF) for manufacturing organic-vacbpour respirator cartridge

Abstract

In this study a composite of activated carbon and carbon nanofiber (AC/CNF) was prepared to improve the performance of activated carbon (AC) for adsorption of volatile organic compounds (VOCs) and its utilization for respirator cartridges. Activated carbon was impregnated with a nickel nitrate catalyst precursor and carbon nanofibers (CNF) were deposited directly on the AC surface using catalytic chemical vapor deposition. Deposited CNFs on catalyst particles in AC micropores, were activated by CO2 to recover the surface area and micropores. Surface and textural characterizations of the prepared composites were investigated using Brunauer, Emmett and Teller’s (BET) technique and electron microscopy respectively. Prepared composite adsorbent was tested for benzene, toluene and xylene (BTX) adsorption and then employed in an organic respirator cartridge in granular form. Adsorption studies were conducted by passing air samples through the adsorbents in a glass column at an adjustable flow rate. Finally, any adsorbed species not retained by the adsorbents in the column were trapped in a charcoal sorbent tube and analyzed by gas chromatography. CNFs with a very thin diameter of about 10-20 nm were formed uniformly on the AC/CNF. The breakthrough time for cartridges prepared with CO2 activated AC/CNF was 117 minutes which are significantly longer than for those cartridges prepared with walnut shell- based activated carbon with the same weight of adsorbents. This study showed that a granular form CO2 activated AC/CNF composite could be a very effective alternate adsorbent for respirator cartridges due to its larger adsorption capacities and lower weight.

Application of Nanomaterials in Personal Respiratory Protection Equipment: A Literature Review

“…Active carbon granules are mainly used in air-purifying respirator cartridges or canisters to absorb organic vapors [42]. Nonetheless, several limitations, such as poor selectivity [43] and limited absorption capacity, have already been attributed to this type of filter [44].…”

Preparation and activation of activated carbon from waste materials-A review

“…and used temperature of 700°C to gave the highest BET surface area 737 m2/g. Surface and textural characterizations of activated carbon were respectively investigated by BET technique at a low temperature (77°K) of nitrogen and Scanning Electron Microscopy [20]. Characterization of Activated Carbon prepared from Albizia lebbeck by Physical Activation was investigated by K. Riaz Ahamed and T. Chandrasekaran.…”

Emission of Carbon Nanofiber (CNF) from CNF-Containing Composite Adsorbents

“…The breakthrough time of cyclohexane vapor for a cartridge prepared with CO 2 -activated AC/CNF was significantly longer than for those cartridges prepared with the original AC with the same weight of adsorbents. This study (9) suggested that the granular form of AC/CNF composite could be an efficient alternative adsorbent for respirator cartridges due to its larger adsorption capacities and lower weight.…”

“…Schlogl et al (8) grew carbon nanostructures (CNFs and CNTs) on a carbonaceous carrier (activated carbon-AC) for the removal of metal species in water purification. In a recent study by some of the present study's authors, (9) a composite of AC and CNFs (AC/CNF) was prepared. AC was impregnated with a nickel nitrate catalyst, and CNFs with a diameter between 10 to 20 mm were deposited on the catalyst particles in AC micropores using CVD.…”