H2O as an efficient green initiator to construct renewable hydrophobic porous materials for pollutant removal

Abstract

The utilization of H₂O as solvent is widely favored in the field of material synthesis due to its environmentally friendly properties. However, in the synthesis process of renewable hydrophobic materials, the limited solubility of containing hydroxyl carbohydrate in H₂O poses challenges to achieving effective collisions. Herein, H₂O-assisted grinding facilitated the generation of active hydroxyl groups in sodium methylsilicate, thereby promoting condensation or encapsulation with diversified substrates (e.g., molecules, lignin, cellulose, fulvic acid, plants, hydroxide, metal salts, elementary substance, oxides, and metal-organic framework-5 (MOF-5)) through node-node, node-line, node-sheet connections and surface-modified strategies. The reactions were catalyzed exclusively by H₂O and accompanied by the CO₂ fixation. The first utilization of sodium methylsilicate enabled the successful fabrication of organic/plant/metal-based hydrophobic porous materials and silicon-modified materials from renewable and cost-effective substrates through mechanical activation. H₂O-assisted grinding enabled the prepared hydrophobic porous materials with surface areas of 129–388 m²/g and yields of 66%–90%, overcoming challenges in liquid-phase methods. Notably, H₂O in the untreated plant tissues can initiate the system to directly synthesize renewable hydrophobic porous materials and capture CO₂ from the atmosphere to produce NaHCO₃ as the byproduct. Meanwhile, the obtained hydrophobic material has been successfully applied in oil-water separation (permeability of petroleum ether >801 L/(m²·h)), medical waste adsorption (propofol separation rate >85%), pollutant degradation (Rhodamine B, Congo red, and Nile red dye removal rate of 90%–99.99%), and flood control engineering (remained well waterproof after 10 days). The work proposed a general and facile H₂O-assisted grinding strategy to prepare various renewable hydrophobic materials, enabling efficient utilization of naturally abundant hydroxyl‑containing renewable resources and demonstrating promising potential for environmental applications.