The adsorption of heavy metals using metal-organic framework-based adsorption technology has been pointed out as a promising technique for the removal of these toxic elements from water. However, their adsorption capacity needs to be enhanced. Thus, the current work reports the effect of using a mixed-ligand strategy on the MOF framework and its effect on the removal of copper ions from water by adding terephthalic acid (BDC) linker to the ZIF-8precursors (2-methylimidazole (mI) and Zn²⁺) under solvothermal synthesis, leading to the formation of a hierarchical microporous mesoporous MOF, named Zn-mI-BDC, which was characterized by SEM, EDX, XRD, TGA, BET, and FTIR. As a result, all of these techniques revealed that the addition of a controlled amount of BDC did not alter the crystallinity of ZIF-8, resulting in the creation of a pore size of 4.2 nm. The new hierarchical porous MOF was tested for the adsorption of copper and exhibited an enhanced adsorption capacity compared to pristine ZIF-8 and many other standard adsorbents. The adsorption isotherm matched well with the Langmuir isotherm model, suggesting that the adsorption process chemisorption had a dominant role in the adsorption of Cu²⁺ species. Therefore, the current work is considered as an important step toward the use of a mixed-ligand strategy in enhancing the adsorption capacity of heavy metals using MOF materials.

The exploration of metal–organic frameworks (MOFs) in the adsorption of phosphate is a growing research area. However, the manufacturing and processability of MOFs for practical applications are often hindered by their cost and their powder form. This study pioneers the use of water-soluble organic ligands, specifically disodium terephthalate (DST) sourced from waste plastic, in the design and assembly of different MOFs such as Fe-MOF, Zr-MOF and Al-MOF in an aqueous medium. The Fe-MOF had a superior phosphate adsorption capacity (72.16 mg g⁻¹) which led us to process the Fe-MOF into PET composite chips to enhance its recovery and recycling processes. The effect of some parameters such as contact time, the initial concentration, pH, and temperature was investigated. This innovative approach showcases the potential of sustainable MOF materials in addressing phosphate removal challenges while promoting environmental awareness.