Worm-mic-derived hierarch porous monos: Ultra SL uptake

A novel gel-templated strategy, featuring the unique employment of cationic worm-like micelles as a 3D gel template, was developed to fabricate hierarchically porous MgFe-layered double hydroxide (BTAC-MgFe-LDH) monoliths with ultra-high adsorption capacity toward sulfonated lignite (SL). Specifically, behentrimonium chloride (BTAC) and sodium salicylate self-organize into such cationic worm-like micelles, which serve as a 3D gel scaffold to mediate the co-precipitation of metal ions. After subsequent removal of this gel network, interconnected meso- and macropores (5–80 nm) are formed-these pores boost the specific surface area to 103.93 m² g⁻¹ (over double that of conventional LDH) and the pore volume to 0.63 cm³ g⁻¹ (four times higher than conventional LDH). For the resulting monolithic gel-derived adsorbent, 97.1% SL removal is achieved within 20 min at pH 3 and 25°C; its adsorption follows pseudo-second-order kinetics, with a Langmuir maximum capacity of 64.93 mg g⁻¹ (experimental result: 92.1 mg g⁻¹). Thermodynamic parameters (ΔH = - 21.08 J mol −1 ; ΔS = - 44.61 J mol −1 k −1 ) confirm spontaneous, exothermic adsorption dominated by electrostatic interactions and interlayer anion exchange. The BTAC-MgFe-LDH still retains over 64% of its capacity after five cycles, this result confirms that the gel-based approach provides a scalable, eco-friendly route to fabricate robust monolithic materials, which are effective at removing macromolecular organic pollutants from oilfield wastewater.