Electrochemical Adsorption of Cs+ Ions on H-Todorokite Nanorods

Synthesis of a nitrogen-rich dendrimer grafted on magnetic nanoparticles for efficient removal of Pb(ii) and Cd(ii) ions

Rapid industrialization, urbanization, and human activities in catchments have presented a significant global challenge in removing heavy metal contaminants from wastewater. Here, a study was conducted to synthesize a nano-magnetic dendrimer based on a trimesoyl core that can be easily separated from the environment using an external magnet (Fe3O4@NR-TMD-G1, Fe3O4@NR-TMD-G2). The synthesized structure was characterized using various conventional techniques such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and Brunauer-Emmett-Teller surface area analysis (BET). The prepared adsorbent showed good binding ability and excellent adsorption efficiency toward Pb(ii) and Cd(ii) metal ions from aqueous media (98.5%, 93.6%). The effect of different conditions including pH, adsorbate concentration, adsorbent dosage, isotherm, kinetics, and adsorption mechanism was considered. The highest adsorption efficiency was achieved at 25 °C and pH 4 using 0.08 g of Fe3O4@NR-TMD-G1, within 25 minutes for Pb(ii) and 120 minutes for Cd(ii), respectively. Batch adsorption experiments revealed that Fe3O4@NR-TMD-G1 was more effective in removing Pb(ii) and Cd(ii) compared to Fe3O4@NR-TMD-G2, with maximum capacities of 130.2 mg g-1 and 57 mg g-1, respectively. The adsorption process followed the Langmuir isotherm with a high correlation coefficient (R 2 = 0.9952, 0.9817) and non-linear pseudo-second-order kinetic model. Density functional theory (DFT) analysis indicated that the adsorbent transferred electrons to Pb(ii) and Cd(ii), forming stable chelates on the nanostructure surface. The heavy metal ions could be adsorbed by coordination to the heteroatoms of the nanostructure and also by electrostatic interactions. The recycled hybrid nanomaterial was dried and applied to different adsorption-desorption tests and the desorption efficiency was found to be 98%. So, the newly synthesized dendritic magnetic nanostructure demonstrated significant potential in efficient removal of metal ions from water and wastewater, highlighting its importance in addressing the global challenge of heavy metal contamination.

A Carbonized Zeolite/Chitosan Composite as an Adsorbent for Copper (II) and Chromium (VI) Removal from Water

To address Cu(II) and Cr(VI) water pollution, a carbonized zeolite/chitosan (C-ZLCH) composite adsorbent was produced via pyrolysis at 500 °C for two hours. C-ZLCH was characterized using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and zeta potential measurements. The batch experiments were performed by varying the initial pH, concentration, and contact time. The optimal pH values for Cu(II) and Cr(VI) were 8.1 and 9.6, respectively. The highest adsorption capacities for Cu(II) and Cr(VI) were 111.35 mg/g at 60 min and 104.75 mg/g at 90 min, respectively. The effects of chemicals such as sodium (Na⁺), glucose, ammonium (NH₄⁺), and acid red 88 (AR88) were also studied. Statistical analysis showed that sodium had no significant effect on Cu(II) removal, in contrast to Cr(VI) removal. However, there was a significant effect of the presence of glucose, ammonium, and AR88 on both Cu(II) and Cr(VI) removal. The adsorption isotherm and kinetic models were fitted using Langmuir and pseudo-second-order models for Cu(II) and Cr(VI), respectively.

Mechanism of Cd(II) and Cu(II) Adsorption onto Few-Layered Magnetic Graphene Oxide as an Efficient Adsorbent

Heavy metal contamination caused by industrial discharge is a challenging environmental issue. Herein, an efficient adsorbent based on few-layered magnetic graphene oxide (FLMGO) was fabricated, characterized, and utilized to remove aqueous Cd(II) and Cu(II). Results present that the two components graphene oxide (GO) and Fe₃O₄ of FLMGO promote mutually, enabling FLMGO to outperform either GO or Fe₃O₄. Specifically, FLMGO adsorbs Cd(II) and Cu(II) with adsorption quantities of 401.14 and 1114.22 mg·g^-1 in 5 and 7 min, respectively. Moreover, FLMGO can be readily recovered via magnetic separation using a hand-held magnet. Adsorptions are spontaneous, endothermic, and entropy increasing, which are the best described by the Freundlich and pseudo-second-order model. The interaction mechanism is as follows: lone pair electrons in C=O- and C-O-related groups were coordinated toward Cd(II) and Cu(II) to induce chemical interaction. The high adsorption efficiency endows FLMGO with encouraging application potential in heavy metal remediation.