Synthesis of ZIF-8 and ZIF-67 using mixed-base and their dye adsorption

• ZIF-8 and ZIF-67 with modified textural structure are prepared using mixed bases.
• Enhanced rhodamine B adsorption is found for ZIF-8 and ZIF-67 prepared with triethylamine.
• ZIF-67 prepared with triethylamine has better methyl orange adsorption than ZIF-8.

ZIF-8 and ZIF-67 were prepared by using mixed-base ammonium hydroxide and triethylamine (TEA). These two bases could promote the ZIF synthesis, and the yields are significantly improved. The texture structure and morphologies of ZIF prepared with mixed-base also have obvious changes. Three typical dyes, neutral rhodamine B (RB), anionic methyl orange (MO) and cationic methylene blue (MB), were examined for the dye adsorption by using various ZIFs. ZIF-8 and ZIF-67 prepared with TEA have enhanced RB adsorptions that are 2.3–3.8 times of those prepared without TEA, and ZIF-8 exhibited better adsorption performance than ZIF-67. For MO adsorption, ZIF-67 crystals have better adsorption performance than ZIF-8, and ZIF-67 prepared with TEA has a decreased MO adsorption. For MB adsorption, the addition of TEA does not change the MB adsorption for both ZIF-8 and ZIF-67.

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