Enhanced Performance of Highly Activated Carbon and Surface-Treated Porous Polymers as Physical Adsorbents for Chemical Warfare Agents

TL;DR

This study explores how surface properties and micropore uniformity of adsorbents, including porous polymers with polar groups, enhance their ability to physically adsorb chemical warfare agent mimics, leading to improved protective materials.

Contribution

It demonstrates that micropore uniformity and surface polarity are key factors in adsorbent performance, introducing porous polymers as effective alternatives to activated carbon for CWA protection.

Findings

Uniform micropores are critical for high adsorption capacity.

Polar surface modifications improve adsorption of formaldehyde.

Porous polymers can match activated carbon performance.

Abstract

The use of chemical warfare agents (CWAs) in modern warfare cannot be disregarded due to their ease of use and potential for large-scale incapacitation. An effective countermeasure involves the physical adsorption of these agents, preventing their entry through the respiratory tract by non-specific adsorption. In this study, we investigate the physical interaction between potential adsorbents and model gases mimicking CWAs, thereby identifying sufficient conditions for higher physical adsorption performance. Our findings reveal that the physical adsorption capacity is highly sensitive to the surface properties of the adsorbents, with uniform development of micropores, rather than solely high surface area, emerging as a critical factor. Additionally, we identified the potential of porous organic polymers as promising alternatives to conventional activated carbon-based adsorbents. Through a facile introduction of polar sulfone functional groups on the polymer surface, we demonstrated that these polar surface polymers exhibit physical adsorption capabilities for formaldehyde under ambient conditions comparable to high-performance activated carbons. Notably, the superior activated carbon possessed a high BET surface area of 2400 m^2/g and an exceptionally uniform micropore structure with an average pore size of approximately 11 Angstroms. This research paves the way for designing adsorbents with high physical adsorption capacities tailored for CWAs protection, offering a significant advancement in developing next-generation protective materials.