Efficient removal of uranium, cadmium and mercury from aqueous solutions using grafted hydrazide-micro-magnetite chitosan derivative

Abstract

Magnetic chitosan microparticles are functionalized by grafting a new hydra-zide derivative to produce HAHZ-MG-CH, which is applied to the sorption of metal cations. The functionalization (appearance of new groups) and synthesis mechanisms are confirmed using elemental analyses, FTIR and XPS spectrom-etry, TGA and EDX analysis, SEM observation and titration. HAHZ-MG-CH bears high nitrogen content (& 10.9 mmol N g-1). Maximum sorption capacities at pH 5 reach up to 1.55 mmol U g-1 , 1.82 mmol Hg g-1 and 2.67 mmol Cd g-1. Sorption isotherms are preferentially fitted by the Langmuir model. In acidic solutions, the sorbent has a marked preference for Hg(II) over U(VI) and Cd(II), while at mild pH uranyl species are preferentially bound. The sorbent has a lower affinity for Cd(II) in multicomponent solutions. Sorption occurs within 60 min of contact. The pseudo-first-order rate equation fits well kinetic profiles. HCl solutions (0.5 M) successfully desorb all the metal ions (yield exceeds 97% at the first cycle). The sorbent can be recycled for 5 cycles of sorption and desorption: the loss in efficiencies does not exceed 8%. The sorbent removes Hg(II), Cd(II) and Pb(II) from local contaminated groundwater at levels compatible with irrigation and livestock uses but not enough to reach the levels for drinking water regulations.

Green Synthesis of Zinc Oxide Nanoparticles (ZnO-NPs) Using Arthrospira platensis (Class: Cyanophyceae) and Evaluation of their Biomedical Activities

“…The FT-IR spectra exhibit seven intense peaks at 3415, 1600, 1410, 1341, 1025, 676, and 503 cm −1 . The broad absorption peak at 3415 cm −1 is related to N–H overlapped with a stretching O–H band [ 33 ]. The breadth of this broad peak could be attributed to the formation of intra- and intermolecular hydrogen bonds [ 40 ].…”

“…The absorption wave of CH 2 or CH 3 of proteins is responsible for the vibration bending of the C–H at wavenumber 1341 cm −1 [ 40 ]. The observed band at 1410 cm −1 has corresponded to the C–N stretching bond of amino acid, whereas the band observed at wavelength 1025 cm −1 can be attributed to C–O–C ether of polysaccharides [ 33 , 43 ]. The successful formation of Zn–O was confirmed by the absorption band observed at 503 cm −1 .…”

“…For the analysis, the samples were prepared under the pressure of 10 −8 mbar, and the energy was calibrated with an Ag 3d 5/2 signal (ΔBE: 0.45 eV) and C 1s signal (ΔBE: 0.82 eV). The size of the spot was 500 μm and the full and narrow-spectrum pass energies were 50 and 20 eV, respectively [ 33 , 34 ].…”

Adsorption Processing for the Removal of Toxic Hg(II) from Liquid Effluents: Advances in the 2019 Year

“…Magnetic chitosan microparticles were functionalized by grafting a new hydrazide derivative to produce HAHZ-MG-CH [33], which presented a high nitrogen content (10.9 mmol/g). Mercury (II) maximum sorption capacity at pH 5 was of 1.79 mmol/g (also data for U and Cd were included in the work).…”

A Density Functional Theory Study on using Montmorillonite to Reduce Air Pollution

“…Many studies have successfully applied technology and material science to solve environmental problems. Some researchers have used composite magnetite-chitosan microparticles [10], ZnS nanoparticles [11], and graphene oxide-supported organo-montmorillonite (MMT) composites [12] to remove Cd from a contaminated solution. The addition of nanobiochar [13] and functionalized MMT clay [14]- [16] was also reported to be an effective way to remove Cd in contaminated soil because those materials have a large surface area and can immobilize Cd through sorption.…”