Adsorption removal of organic dyes on covalent triazine framework (CTF)

• Covalent triazine framework (CTF) is used as adsorbent to remove organic dyes in aqueous solution.
• CTF shows adsorption capacity of 1.01 mmol/g for Rhodamine B.
• CTF can be regenerated for at least four cycles without losing the adsorption capacity.
• Kinetics and mechanism of dyes adsorbed on CTF are investigated.
• CTF is efficient for adsorption removal of various organic dyes.

Covalent triazine framework (CTF) with microporous structure and high surface area are synthesized and used as adsorbent for adsorption removal of organic dyes in aqueous solution. It shows adsorption capacity of 1.01 mmol/g for Rhodamine B (RhB), which is far higher than that reported for traditional adsorbents such as activated carbon (AC), which shows adsorption capacity of 0.36 mmol/g for RhB under otherwise identical conditions. Within 55 min the material shows uptake of 0.48 mmol/g for RhB at weight ratio of RhB/CTF = 0.24, and the initial pH can be adjusted in a wide range, from 1 to 11, without significantly affecting the uptake. Further studies indicate that the CTF can be regenerated and no appreciable loss in the uptake of RhB is observable even after four cycles. Mechanism and kinetic investigations indicate that the adsorption of RhB onto CTF obeys the Langmuir isothermal adsorption model with pseudo-second-order equation. Besides, the CTF is also applicable to adsorption removal of other organic dyes including reactive brilliant red X-3B and direct scarlet 4BS, with uptake of 0.43 mmol/g for X-3B and 0.18 mmol/g for 4BS within 55 min.

Covalent triazine framework (CTF) is a good adsorbent material for organic dyes comparing to the traditional ones such as AC and SBA-15 (A). It can be reused for at least four cycles without losing the adsorption ability (B) and is applicable to various organic dyes..Figure optionsDownload as PowerPoint slide