An emulsion-templated and amino diol-dictated porous material as an efficient and well recyclable boric acid scavenger

A facile way to fabricate a pH-stable, durable, and porous material with active amines (NHx, x= 1,2)-derived diol groups on a pore surface is reported. Branched polyethyleneimine (PEI) in water forms a supramolecular complex with sodium dodecyl benzene sulfonate (SDBS), and this complex acts as an emulsifier . For the microcrystal cellulose (MC)-dispersed aqueous solution of PEI, SDBS is charged to turn the mixture into a medium internal phase air–in–water (A/W) emulsion upon oscillation. The emulsion is solidified by the partial crosslinking of PEI with polyethylene glycol diglycidyl ether (0.2 eq. of PEI NH groups) and further developed into an open-cellular monolith by removing the SDBS and water in the system. Under optimized conditions [pH 10, PEI at 20 % in water, and MC/PEI (50 % mass ratio)], the porous monolith (MC@PEI) shows a specific surface area of up to 14.9 m 2 g −1 . The amino groups are easily transformed into diols by treating with glycidol , and the resulting MC@PEI-diol can act as a scavenger to extract the trace boric acid in water. The adsorption follows the Langmuir model and shows chemical adsorption character with a boron-loading capacity of up to 2.68 mmol g −1 . Presaturing the scavenger with anionic dyes (488 mg g −1 ) exerts limited impact on the loading ability of BA. Additionally, the scavenger combines chemical stability in the absence of pH-labile bonds and mechanical durability for the composite structure with rigid MC skeleton and flexible PEI muscle.