Design and development of amine functionalized iron based metal organic frameworks for selective fluoride removal from water environment

Metal organic frameworks (MOFs) play a crucial role in adsorption method owing to its larger surface area and high porosity. In this work, a trivalent metal ion namely iron (Fe3+) fabricated benzene-1,4-dicarboxylic acid (BDC) and amine functionalized BDC namely 2-aminobenzene-1,4-dicarboxylic acid (ABDC) which gives Fe@BDC and Fe@ABDC based metal organic frameworks (MOFs) for selective fluoride removal. The prepared Fe@BDC and Fe@ABDC MOF composites were acquiring the enhanced defluoridation capacities (DCs) of 4.90 and 4.92 mg g(-1) towards fluoride adsorption. The synthesized Fe@BDC and Fe@ABDC MOF composites were portrayed by FTIR, TGA, SEM, BET, EDAX, XPS and XRD analysis. The responsible parameters towards defluoridation process viz., contact time; solution pH, initial fluoride concentration, adsorbent dosage, interfering anions and temperature were explored by batch level. The adsorption isotherms, kinetics and thermodynamic parameters were investigated for Fe@BDC and Fe@ABDC MOF composites towards fluoride adsorption. The fluoride adsorption mechanism of Fe@BDC and Fe@ABDC MOF composites was discussed in detail. The applicability of field test and recyclability of Fe@BDC and Fe@ABDC MOF composites were also explored.

Automated summary

In this study, Fe@BDC and Fe@ABDC based metal organic frameworks (MOFs) were prepared for selective fluoride removal, showing enhanced defluoridation capacities of 4.90 and 4.92 mg g(-1) respectively. The properties of the composites were characterized through various analysis methods, and the factors affecting adsorption parameters were explored. The fluoride adsorption mechanism, applicability of field test, and recyclability of the composites were discussed in detail.