Abstract
Ti-based metal-organic frameworks (NH2-MIL-125) were post synthetic modified through a facile strategy using bis-quinoline Mannich bases producing MIL-125-HQ. The modified material (MIL-125-HQ) was used as an absorbent for uptake of the heavy metals from wastewater. 1H NMR, FTIR, CHN and SEM-EDX analysis showed successful incorporation of hydroxyl quinoline moiety into the NH2-MIL-125 upon chemical reaction. The modified MIL-125-HQ showed high affinity for Pb(II) ions from water, and the amount of Pb(II) ions decrease sharply from 500 mg/L to 60 mg/L, within merely 30 min of exposure at pH7, 298 K and 2 g/L MIL-125-HQ. The maximum adsorption capacity of MIL-125-HQ for Pb(II), Cd(II), Cu(II) and Cr(III) was determined to be 262.1, 102.8, 66.9 and 53.9 mg/g, respectively.
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•A porous Titanium-based metal-organic framework (MIL-125) was successfully modified with new Mannich bases via transamination reaction.•The modified MIL-125-HQ was applied to the water as filter to remove heavy metals and the results showed higher adsorption capacity compared with other absorbers.•The pseudo-second-order and Langmuir model can well describe the adsorption (R2 > 0.99).