Modified sorbents based on walnut shell for sorption of toxic gases

In this article, low-cost carbon-based nanoporous materials were synthesized and impregnated in order to offer a sufficient protection for a wide range of toxic chemicals. The microstructure analysis of the samples reveals that the activation promotes the formation of a higher number of small pores and the development of a spongy texture of the sorbents leading thus to an increase in carbon content. The activated samples have apparent micro-mesoporosity confirmed by the corresponding isotherms of low-temperature adsorption of nitrogen. Furthermore, it has been shown that the activation procedure leads to samples with different acidity and this surface property has a marked influence on the performance of the materials. The results of a breakthrough time study for vapors of inorganic and organic substances indicate that the impregnations with Cu and Co are the most suitable for obtaining a universal sorbent. In this regard, an activated carbon impregnated with cobalt that can outperform commercial reference materials intended for this specific application has been developed in this work.