The potential use of novel iron based mineral catalysts as an effective and available material for electrocatalytic oxidation of refractory contaminants by heterogeneous electro-Fenton (HEF) process was studied for the first time. For this purpose, four natural catalysts, namely ilmenite (FeTiO₃), pyrite (FeS₂), chromite (FeCr₂O₄), and chalcopyrite (CuFeS₂) were selected as the source of ferrous iron (Fe²⁺) ions. The catalyst samples were appropriately characterized by X-ray diffraction (XRD) and RAMAN analysis. The degradation kinetics and mineralization rate of 0.2 mM antibiotic cefazolin (CFZ), as a contaminant of emerging concern, were comparatively investigated by HEF using the catalysts mentioned above. The effect of important experimental parameters such as catalysts loading and current on the process efficiency was investigated. Moreover, the performance of these new mineral catalysts was compared in term of CFZ degradation kinetics, mineralization power, mineralization current efficiency and electrical energy consumption. A greater enhancement in degradation/mineralization of CFZ was obtained when using chalcopyrite as the catalyst in HEF. The stability and reusability experiments demonstrated negligible decrease in catalytic activity of chalcopyrite after five consecutive runs. Besides, the rate constant for CFZ oxidation by hydroxyl radicals was estimated according the pseudo-first-order reaction kinetics. The empirical assessment, in addition to economic evaluation, confirmed that iron based mineral catalysts and specifically chalcopyrite could be an appropriate and cost-effective alternative catalyst for HEF due to its high catalytic activity, availability, eco-friendly nature and low energy consumption compared to other synthesized catalysts.

Amid global environmental challenges, particularly air pollution caused by toxic and acidic gases like H₂S, SO₂, CO₂, and NO₂, public health is increasingly at risk. Metal–organic frameworks (MOFs), distinguished by their crystalline structure, high porosity, tunable pore size, and diverse functionalities, hold great promise for mitigating the capture of these harmful pollutants. In this study, molecular simulation calculations were conducted to investigate the adsorption and diffusion mechanisms of the toxic and acidic gases H₂S, SO₂, CO₂, and NO₂ on the novel iron carboxylate (III) Metal–Organic Framework, MIL-100(Fe). The adsorption energy and total energy of the systems were calculated for each gas, with negative values indicating successful adsorption of the gas by MIL-100(Fe). The MIL-100(Fe)/H₂S system exhibited the most negative total energy, indicating its superior stability among the studied gas–MOF systems. The highest adsorption energy value was observed for H₂S gas at -49.28 kcal/mol, indicating a strong interaction between H₂S molecules and the MIL-100(Fe) framework. Additionally, gas permeability and diffusion coefficient calculations revealed a trend of H₂S > CO₂ > NO₂ > SO₂, with H₂S exhibiting the highest diffusion coefficient of 7.71 Ų/ps, further supporting its stronger interaction with the MIL-100(Fe)’s adsorption sites. These molecular simulation calculations confirm that MIL-100(Fe) is highly effective at adsorbing toxic gases such as H₂S, SO₂, CO₂, and NO₂, highlighting its potential as a promising adsorbent for air purification applications.