A novel route to synthesize MOFs-derived mesoporous dawsonite and application in elimination of Cu(II) from wastewater

摘要

Mesoporous dawsonite was successfully synthesized using metal-organic frameworks (MOFs) as the template and precursor by direct digestion of NH2-MIL-53(Al) with the help of bismuththiol and Na2CO3 and was applied to eliminate Cu(II) from wastewater. The mesoporous dawsonite was characterized by ICP, SEM-EDS, TEM, AFM, FTIR, XRD, XPS, EA, TGA, zeta potential and nitrogen adsorption-desorption isotherms. The influence factors on the adsorption were discussed, including initial Cu(II) concentration, temperature, solution pH, contact time, and co-cation. The results showed that the adsorption isotherm and adsorption kinetics of Cu(II) onto dawsonite obeyed Langmuir and pseudo-2nd-order kinetic equations, respectively. Thermodynamic analysis revealed adsorption of Cu(II) onto dawsonite was spontaneous and thermodynamically favorable. The efficient elimination of Cu(II) was ascribed to cation exchange and the inner-sphere complexation between Cu(II) and surface hydroxyl or carbonate groups of dawsonite. The high adsorption performance and reusability suggest the dawsonite prepared here is an efficient adsorbent to eliminate Cu(II) from wastewater.