A novel method for selective adsorption of toxic H₂S gas using core–shell hybrid Nano adsorbent MIL-101(Cr)@MIPs@H₂S

Hydrogen sulfide (H₂S) presents a significant challenge in the gas industry due to its high toxicity, corrosiveness, and environmental impacts through the formation of SO₂ and acid rain during combustion. This study introduces a novel core-shell hybrid nanosorbent, MIL-101(Cr)@MIPs@H₂S, which is specifically designed for the efficient adsorption of H₂S through adsorption processes. The difference is that MIPs are selectively designed polymers with molecular cavities for specific target recognition, while NIPs are unprinted control polymers that exhibit non-specific binding. This research systematically investigated the optimization of operating parameters affecting adsorption efficiency through thirty carefully designed experiments. The Central Composite Design (CCD) method was utilized in the experiments. The key variables evaluated included adsorbent dosage (0.1-1 g), temperature (25-80 °C), H₂S concentration (10-1000 ppm), and flow rate (40-100 mL/min). The molar adsorption capacity was determined using the Soave-Redlich-Kwong equation, while comprehensive material characterization was performed using FTIR, XRD, FE-SEM, and BET techniques. Statistical analysis revealed that the adsorption process followed a quadratic model, with temperature and adsorbent dosage as the primary variables affecting the performance. MIL-101(Cr)@MIPs@H₂S exhibited superior adsorption efficiency (94.3%) and capacity (11 mg/g) compared to MIL-101(Cr)@NIPs@H₂S (9.9%, 5.97 mg/g), which was attributed to the enhanced site pattern compatibility. Equilibrium adsorption studies confirmed the compliance with pseudo-second-order kinetic models and the Langmuir isotherm. The synthesized nanosorbent exhibited exceptional selectivity for H₂S over competing gases such as CO₂ and CH₄ in mixed gas environments, demonstrating remarkable reliability and stability. This innovative hybrid material, combining the strengths of molecularly imprinted polymers and metal-organic frameworks in a core-shell structure, offers a promising solution for efficiently removing H2S from industrial gas streams, with potential applications across the energy sector where cleaner gas processing is required.