Removal of metal ions by adsorption on Al based metal organic frameworks

Abstract

The electroplating wastewater contains heavy metals at levels that considered to be hazardous to the surrounding environment and is risky to public health. Herein, removal of Cu(II) and Ag(I) ions from the wastewater was studied by using Al-based metal organic frameworks (Al-MOFs). Using different organic linkers, three different Al-MOFs were synthesized and namely Al-BDC-H, Al-BDC-COOH Al-BDC-SO3H. The synthesized Al-MOFs showed with different geometrical shapes represented in plate-like, flacks-like and agglomerated particles structures for Al-BDC-H, Al-BDC-COOH and Al-BDC-SO3H, respectively. The three synthesized Al-MOFs were applied in removal of Ag(I) and Cu (II) ions from wastewater and the adsorption followed the order of Al-BDC-H < Al-BDC-COOH < Al-BDC-SO3H. The obtained Al-MOF showed higher affinity for Ag(I) ions compared with Cu (II) ions. At using of Al-BDC-SO3H, the maximum adsorption capacities were 214.9 mg/g for Ag(I) ions and 134.5 mg/g for Cu (II) ions. In comparison with Al-BDC-H and Al-BDC-COOH, the adsorption capacity was enlarged by factor of 3.4 – 3.7 and 1.7 – 1.9 by applying of Al-BDC-SO3H, respectively. After 5 recycles, the adsorption capacity of Al-BDC-SO3H was lowered by 15.3–––17.8 %. The applied Al-BDC-SO3H exhibited higher adsorption capacities with good stability compared with Al-BDC-H and Al-BDC-COOH.