Intensive adsorption of strontium ions by using the synthesized [Zn(bim)₂(bdc)]_n: Metal–organic framework in batch and fixed‐bed column experiments

Abstract

In the present study, a metal–organic framework ([Zn(bim)2(bdc)]n, MOF‐ZBB) compound was prepared and applied as an adsorbent for the removal of strontium ions from aqueous solutions. The influences of several variables such as pH, contact time, and temperature were studied in batch experiments. The effect of interfering cations (Ca2+, Mg2+, Na+, and K+) on the adsorption behavior was also investigated. The Freundlich, Langmuir, and Dubinin–Radushkevich isotherm models were used for the analysis of equilibrium data. The maximum adsorption capacity by applying the Langmuir equation was 123.451 mg g−1 at 75°C with a pH of 7. The thermodynamic study revealed that the adsorption process is endothermic and spontaneous. The results showed that the pseudo‐second‐order kinetic model for adsorption strontium ions onto MOF‐ZBB better described the adsorption process. Finally, the fixed‐bed column experiments were carried out at different feed flow rates to investigate the dynamic capacity of the adsorption process. The results revealed a decrease of about 80% in the efficiency of the column by increasing the flow rate from 1 to 4 ml min−1.

Synthesis, modification, and adsorption properties of Yb‐MOF: Kinetic and thermodynamic studies

“…This is because the inhibition of the adsorption of modified Yb‐MOF on Cu(II) and As(V) due to the competitive adsorption of the protonated active sites. [ 41 ] It is also possible that the structural skeleton of the modified Yb‐MOF collapses under acidic conditions with low pH values, resulting in the reduced removal rates of Cu(II) and As(V). The modified Yb‐MOF's adsorption capacity for Cu(II) is enhanced with the increase of pH value.…”

Enhanced removal of Ce(iii) and Sr(ii) ions from aqueous solution using ultrasonication-assisted sawdust-TiO2 sorbent

“…52 Recent research has shown that there are various adsorbents used in the adsorption of Ce(III) and Sr(II) from wastewater. For instance, the extraction and separation of cerium(III) using a modified graphite adsorbent, 53 adsorption of Ce(III) onto cellulose/graphene composite, 54,55 capture of cerium(III) using a ligand, 56 adsorption of Ce 3+ ions by a hydrophobic ionic liquid, 57 capture of Sr 2+ ions by a layered potassium neodymium phosphate, 58 removal of Sr 2+ ions by potassium phosphatoantimonate, 59 performance of membranes for the separation of Sr 2+ ions, 60,61 separation of strontium by resin, 62 layered potassium calcium phosphate for Sr(II) removal, 63 selective Sr 2+ uptake by oxalates, 64 adsorption of strontium ions by a metal-organic framework, 65 adsorption of Sr(II) in acid solution by a porous silica, 66 and adsorption of strontium radionuclide onto zeolites. 9 Newly, many researches have focused on the removal of contaminants from polluted water using the adsorption process in the presence of ultrasound waves, which greatly helps the transfer and entry of the adsorbate ions into the pores of the absorbent material.…”