Adsorption of cupric, cadmium and cobalt ions from the aqueous stream using the composite of iron(II,III) oxide and zeolitic imidazole framework-8

Abstract

In recent research, the composite of Fe3O4 and metal-organic frameworks have shown great potential in removing potentially toxic metals from water. We conducted the adsorption studies of potentially toxic metal ions (Cu2+, Co2+ and Cd2+) using the composite of Fe3O4 and zeolitic imidazole framework-8 (Fe3O4@ZIF-8) for the first time. The solvothermal technique was used to synthesize the Fe3O4. The magnetic ZIF-8 offers high thermal stability, greater adsorption surface, good removability, and high chemical and thermal stability. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized samples. The SEM and XRD results revealed the high purity and structural integrity of ZIF-8 crystallites. To remove potentially toxic metals (Cu2+, Co2+ and Cd2+), the influence of adsorbent dosage, contact time, pH, and adsorbate concentration on the adsorption performance of Fe3O4@ZIF-8 was investigated. Langmuir isotherm accurately represented the adsorption processes, with absorption magnitudes of Fe3O4@ZIF-8 determined to be 46.82 mg g−1, 71.29 mg g−1 and 54.49 mg g−1 for Cu2+, Co2+ and Cd2+, respectively. According to the adsorption mechanism analysis, the primary Cu2+, Co2+ and Cd2+ removal methods of Fe3O4@ZIF-8 were ion exchange and coordination bonds. The uptake capacity of Cu2+, Co2+ and Cd2+ solution by Fe3O4@ZIF-8 were not significantly affected by the presence of counter ions. The material exhibited superior regenerative properties for Cu2+, Co2+ and Cd2+ ions from the water up to three cycles. This study concluded that the Fe3O4@ZIF-8 could be a viable candidate for eliminating potentially toxic metals (Cu2+, Co2+ and Cd2+).

Selective Co(II) Adsorption Using Hollow ZIF-8 Nanostructures with Embedded Fe3O4 Nanoparticles

“…R L values were from 0 to 0.25, indicating the favorable adsorption of Co­(II) by Fe 3 O 4 /HZIF-8 under different conditions. The maximal uptake capacity of Fe 3 O 4 /HZIF-8 was calculated to be 155.8 mg g –1 , which is more efficient than the previously reported adsorbents, such as iron/graphene, imprinted silica, biogenic glutamic acid-based resin, Fe 3 O 4 /bentonite, β-cyclodextrin-modified graphene oxide, and PVA/chitosan magnetic composite. − In addition, adsorption experiments of pure solid ZIF-8, hollow ZIF-8, Fe 3 O 4 /ZIF-8, and Fe 3 O 4 /HZIF-8 with different Fe 3 O 4 contents were also studied (Figure S7). The excellent adsorption properties of Fe 3 O 4 /HZIF-8 may be attributed to the following reasons: (I) more N atoms were exposed during the etching treatment, which can coordinate with Co­(II); (II) TA shell growing on the outer layer of ZIF-8 contributed to the adsorption of Co­(II) due to the existence of −CO on TA molecules; and (III) the loading of citrate-functionalized Fe 3 O 4 provided the numerous carboxyl groups, which can be employed as adsorption sites for removing Co­(II).…”

Schiff-Base Chemistry-Coupled Catechol Oxidase-Like Nanozyme Reaction as a Universal Sensing Mode for Ultrasensitive Biosensing

“…The survey spectra of CHzyme in Figure C confirmed the presence of C, O, N, and Cu elements, while the survey spectra of His exhibited the absence of Cu element, demonstrating the successful combination of Cu and His. The binding energy (BE) at ∼934.48 and ∼954.39 eV of the Cu 2p spectrum in Figure D could be assigned to Cu 2p 3/2 and Cu 2p 1/2 of Cu­(II), respectively. − The peaks at ∼932.47 and ∼952.43 eV could belong to Cu 2p 3/2 of Cu­(I) and Cu 2p 1/2 of Cu­(II), respectively. , The peaks at ∼944.22 and ∼941.68 eV were connected with Cu­(II). , Additionally, the BE at ∼284.78, ∼285.80, and ∼287.97 eV in C 1s spectrum of His could be corresponded to CC/CC, CO, and CN, respectively. − Three peaks at ∼284.66, ∼285.60, and ∼287.46 eV in the C 1s spectrum of CHzyme could be assigned to CC/CC, CO, and CN, respectively (Figure E). − Meanwhile, two peaks at ∼530.67 and ∼531.42 eV in O 1s of His could be attributed to the CO bond and −OH. , Three peaks in O 1s of CHzyme at ∼530.35, ∼531.09, and ∼532.05 eV could be attributed to CuO, CO, and −OH, respectively, demonstrating the successful coordination between Cu and oxygen atoms (Figure F). − To demonstrate the coordination of Cu­(II) and N atoms in His, the N 1s spectrum of CHzyme was further researched (Figure G). Two peaks at ∼400.23 and ∼398.26 eV in N 1s of His could be attributed to amino groups and the CN bond, respectively. , The BE of ∼400.28 and ∼398.39 eV of CHzyme could be assigned to amino groups and the CN bond in His, respectively. , The peak at ∼399.20 eV exhibited the existing Cu–N bonds, confirming the successful coordination between Cu and N atom in CHzyme .…”

Synthesis, Application, and Efficiency of the Cellulose@Fe3o4@Zif-8 Carbon Aerogel Magnetic in the Removal of Gasoil from Aqueous Solutions

“…They have interesting characteristics that make them good candidates for many uses, such as gas storage, catalysis, and environmental remediation. The excellent thermal and chemical stability of Zeolitic Imidazolate Frameworks (ZIFs) has made them a prominent subclass within the larger family of MOFs (Kuwer et al 2021).…”