Abstract
Lanthanum(III)-terephthalic metal-organic framework copolymer (La-TPh CP) was synthesized by a ‎solvothermal method and characterized by SEM/EDX, TEM, FTIR, Raman, BET, and XRD. Raman ‎microscopy and XRD expose that terephthalic acid (H2BDC) acts as a bidentate ligand towards lanthanum ‎‎(La)(III) through the two carboxylate gropes. Both of FTIR and Raman microscopy emphasize the formation of ‎coordination bonds between the electron-acceptor La(III) atoms and the electron-donor oxygen atoms. SEM ‎shows that the (La-TPh CP) has a bar-like macro-structure with small dimensions, e.g., 200 nm. (La-TPh CP) ‎structure is proposed to be cationic metal-organic framework and extremely water-stable. Due to these features, ‎‎(La-TPh CP) was studded for the universal removal of cationic and anionic dyes, using synthetic cationic dye as ‎methylene blue (MB) and an anionic dye as congo red (CR) in an aqueous solution. 5 mg/L MB and 40 mg/L ‎CR was almost completely removed. Kinetic study for removal of CR shows the ideal order model is pseudo-‎second-order, and in the case of MB is pseudo-first-order. ‎