Novel activated carbon fiber cloth filter with functionalized silica nanoparticles for adsorption of toxic industrial chemicals

Abstract

Toxic industrial chemicals (TICs) are used for various civilian and military operations but can be hazardous to humans. There is interest in developing filters that can remove a wide range of airborne TICs (e.g., basic, acidic, organophosphate, and aromatic compounds) to reduce exposure in the work place and from terrorist attacks. A regenerable TIC air filter is particularly desirable because it removes the need for costly filter disposal and replacement. This study evaluates commercially available activated carbon fiber cloth (ACFC) and ACFC that has been modified with functionalized nanoparticles for their abilities to adsorb select TICs and for the regenerability of the adsorbents. The unmodified and modified ACFC samples were tested here for their ability to adsorb anhydrous ammonia (NH 3 ), hydrogen cyanide (HCN), and dimethyl methylphosphonate (DMMP) in dry and humid gas streams as representative basic, acidic, and organophosphate compounds, respectively. The unmodified ACFC was not an effective adsorbent for NH 3 (i.e., 2 and 3.1 mg NH 3 /g ACFC at 1000 ppm v NH 3 in dry and humid air respectively) or HCN (no detectable adsorption), but successfully adsorbed 840 mg DMMP/g ACFC at 100 ppm v DMMP. The modified ACFC showed significant improvements for NH 3 and HCN adsorption in dried air (i.e., 19.5 mg NH 3 /g ACFC at 1000 ppm v NH 3 and 4.7 mg HCN/g ACFC at 150 ppm v HCN, respectively) and in humid air (i.e., 41.4 mg NH 3 /g ACFC at 1000 ppm v NH 3 and 1.6 mg HCN/g ACFC at 50 ppm v HCN, respectively) when compared to the unmodified sample. The modified ACFC also showed 2-5 % degradation of its initial dry mass after regeneration and then showed no detectable degradation. The modified ACFC also had similar electrical resistance to that of unmodified ACFC (i.e., within 1 %), indicating that it can be regenerated using electrothermal heating.

Curable Imidazolium Poly(ionic liquid)/Ionic Liquid Coating for Containment and Decontamination of Toxic Industrial Chemical-Contacted Substrates

“…However, current adsorbent materials provide inadequate protection, as not all TICs are strongly adsorbed. Methods for modifying the surface of the carbon to alter its adsorptive abilities and the development of new adsorbent materials are active areas of interest. , Similarly, nonspecific application of oxidizing solutions is often employed for the decontamination of TICs, but this approach often utilizes corrosive reagents. , Furthermore, many TICs have a propensity to persist on and leach out of porous substrates, constituting a long-term hazard . Current oxidative decontamination strategies are insufficient at removing and degrading soaked-in contaminants…”

“…Methods for modifying the surface of the carbon to alter its adsorptive abilities and the development of new adsorbent materials are active areas of interest. 8,9 Similarly, nonspecific application of oxidizing solutions is often employed for the decontamination of TICs, but this approach often utilizes corrosive reagents. 10,11 Furthermore, many TICs have a propensity to persist on and leach out of porous substrates, constituting a long-term hazard.…”

Porous textile composites (PTCs) for the removal and the decomposition of chemical warfare agents (CWAs) – A review

“…Several difficulties have been identified such as pores obstruction of ACFs or the agglomeration of NPs which could reduce their activity [73]. Despite these obstacles, various NPs have been successfully implemented into the ACFs frameworks such as TiO 2 , Fe 2 O 3 , MnO 2 , CuO, Cu or Ag, making the composites particularly attractive for air [174,[274][275][276][277][278] and water decontamination [73,175,[279][280][281][282]. Recently, UiO-66 and UiO-66-NH 2 MOF have been deposited on functionalized ACFs using a layer-by-layer deposition (Fig.…”

“…The higher adsorption and retention measured with the ozonized ACF was associated to important hydrogen bonding between the oxygenated surface of ACF and trimethyl phosphate. Inorganic species such as SiO 2 NPs have also been incorporated to ACFs to test the adsorption capacity [278]. An important decrease of the adsorption capacity of DMMP was measured in the presence of SiO 2 NPs within the pores: 0.824 g/g of ACF vs 0.219 g/g of ACF-SiO 2 NPs.…”