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Reversing the Dye Adsorption and Separation Performance of Metal–Organic Frameworks via Introduction of −SO3H Groups

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journal contribution
posted on 03.04.2017, 00:00 by Xudong Zhao, Keke Wang, Zhuqing Gao, Huihui Gao, Zhixia Xie, Xiaoyu Du, Hongliang Huang
In this work, two hydrostable Cr-based metal–organic frameworks (MOFs), MIL-101­(Cr) and MIL-101­(Cr)-SO3H, were successfully synthesized and applied in the adsorption and separation of ionic dye fluorescein sodium (FS) and cationic dye safranine T (ST). Interestingly, MIL-101­(Cr) can efficiently adsorb FS dye but hardly adsorbs ST dye, and MIL-101­(Cr)-SO3H exhibits the thoroughly opposite phenomenon. More importantly, the reversed adsorption with high selectivity on the two MOFs can also be attained in the mixed solutions of the dyes. Finally, a mechanism analysis indicates that this significant reversal in performance for the dyes is mainly attributed to the opposite surface charges of the two MOFs caused by −SO3H groups.