Role of metal-organic framework composites in removal of inorganic toxic contaminants

Metal-organic frameworks with highly porous structures, especially their ability to form composites with various functional smart materials, can be employed as an efficient adsorbent in water refinement. Composite MOFs, combining MOF with other functional materials, can address some observed weaknesses of MOFs such as low stability in aqueous and acidic-base media, low thermal and chemical stability, and low absorption capacity. This paper focuses on the study of MOF composites and their applications for the removal of inorganic toxic com-pounds containing heavy metals, iodine, phosphate, nitrites, and chlorides from wastewater using adsorption and degradation techniques. MOF composites based on carbon compounds, nanoparticles, and polymers are intro-duced. In addition, the absorption mechanism and role of each portion of the composite for the absorption of analyte molecules are described. It is shown that physical adsorption, electrostatic interaction, coordination bond, ion exchange, and hydrogen bond play a significant role in trapping ions inside the composite structure.