Effective removal of chemical warfare agent simulants using water stable metal-organic frameworks: mechanistic study and structure-property correlation

Removal of chemical warfare agents (CWAs), which are deadly poisonous chemicals which bind to the neurotransmitter acetylcholine esterase or form painful blisters in the exposed parts of the body, affecting the nervous system of humans and other living beings, is a primary concern in every aspect. Here we present the adsorptive removal of two of the CWA simulants, 2-chloro ethyl ethyl sulfide (2-CEES) and/or its hydrolysis products and dimethyl methyl phosphonate (DMMP) from aqueous medium using two Zr-based metal-organic frameworks (MOFs), NU-1000 and UiO-67, respectively. We have studied the kinetics of this adsorption process using ICP-AES data. The data show that the kinetics follows a pseudo-second-order model and the interactions between adsorbates and adsorbents are chemical in nature. DRIFT spectral data provide evidence of the chemical interactions. We have correlated this adsorption behavior with the corresponding crystal structures.