Supercritical <scp>CO<sub>2</sub></scp>‐assisted formation of metal–organic framework‐loaded porous polystyrene membranes for dye removal
Kiyoshi Matsuyama, Yuka Kawahara, Ayano Shoji, Takafumi Kato, Tetsuya Okuyama
Abstract
Abstract Metal–organic frameworks (MOFs) are efficient adsorbents for the removal of hazardous materials. An MOF based on 1,3,5‐benzenetricarboxylic acid (BTC), Cu 3 (BTC) 2 , is prepared via phase separation using supercritical CO 2 (scCO 2 ) as a nonsolvent for the polymer solution. The prepared MOF is then loaded onto microporous polystyrene membranes. To evaluate the performance of Cu 3 (BTC) 2 ‐loaded microporous polystyrene membranes for pollutant removal from water, they are tested for the separation of methylene blue (MB) dye from an aqueous solution. Prior to the preparation of the Cu 3 (BTC) 2 ‐loaded microporous polystyrene membranes, Cu 3 (BTC) 2 is activated with scCO 2 . After the activation with scCO 2 , the internal surface area of Cu 3 (BTC) 2 and its MB adsorption increase. A toluene solution of polystyrene containing Cu 3 (BTC) 2 particles is prepared, and scCO 2 is introduced to induce the phase separation of the polymer solution. A Cu 3 (BTC) 2 ‐loaded microporous polystyrene membrane is obtained without the collapse of the structure after the release of the CO 2 pressure. MB can be readily and rapidly removed from aqueous solutions using Cu 3 (BTC) 2 ‐loaded microporous polystyrene membranes. The removal efficiencies for aqueous MB solution were high, and removal efficiencies reached 92.8%.