Preparation and application of ZIF-67/gelatin porous composite membrane via high internal phase emulsion

The high internal phase emulsion (HIPE) template method is widely used to prepare porous functional materials because of its designable emulsion components and adjustable porosity. Herein, amphiphilic gelatin (GE) as the sole emulsion stabilizer, and no additional emulsifiers were added to prepare a stable GE-HIPE membrane and its zeolitic imidazolate framework-67 (ZIF-67) hybrid composite membrane. The ZIF-67/GE-HIPE composite membrane has good lipophilicity by constructing dual micro-nano structures by HIPE template and in situ growth of ZIF-67. When ZIF-67 was grown in situ, the water contact angle (CA) increased from 58.1 +/- 2 degrees for the GE membrane to 121 +/- 1.9 degrees for ZIF-67/GE-HIPE composite membranes. Besides, the minimum CA of organic solvent is 4.5 +/- 0.7 degrees (n-hexane). The ZIF-67/GE-HIPE composite membranes exhibit good O/W emulsion separation properties and adsorption removal ability of organic pollutants. After 10 times of recycling emulsion separation, the emulsion separation capacity of the membrane was still greater than 99.4%. The lipophilic dye removal rate of the ZIF-67/GE-HIPE composite membrane was 2.37 times higher than that of GE-HIPE, and the adsorption process conforms to the pseudo-second-order model. Thus, this work provides a strategy for the preparation of GE-based hydrophobic modified membrane and also presents a typical treatment of adsorption-separation of lipophilic substances.

Automated summary

The HIPE template method, using amphiphilic gelatin (GE) as the sole emulsion stabilizer, was used to prepare a stable GE-HIPE membrane and its zeolitic imidazolate framework-67 (ZIF-67) hybrid composite membrane. The ZIF-67/GE-HIPE composite membrane exhibited good lipophilicity and showed promising emulsion separation properties and organic pollutant adsorption removal ability. This work provides a strategy for the preparation of GE-based hydrophobic modified membrane and demonstrates a typical treatment of adsorption-separation of lipophilic substances.