Superparamagnetic Spinel-Ferrite Nano-Adsorbents Adapted for Hg2+, Dy3+, Tb3+ Removal/Recycling: Synthesis, Characterization, and Assessment of Toxicity

Synthesis, and characterization of novel chitosan coated superparamagnetic iron oxide nanoparticles to optimization for adsorption of mercury from industrial effluent wastewater

Superparamagnetic iron oxide nanoparticles (SPIONs) were extensively used as novel adsorbents, if coated with a biopolymer-like low molecular weight chitosan that adsorbed and attracted the hazardous mercury, hence improving their versatility. The synthesis of chitosan-coated SPIONs adsorbent was carried out by the chemical co-precipitation method, and its properties were assessed using several types of analytical techniques including FESEM, SEM with EDX, TEM, AFM, VSM, DLS, XRD, FTIR, and TGA analysis. The process involved the application of chitosan as a coating on the SPIONs, which were subsequently used for the treatment of industrial effluent wastewater. This study aimed to remove mercury from the wastewater, which possessed a concentration of 50 ppm. The DPASV methodology is an excellent method for accurately measuring the concentration of Hg (II) utilizing both qualitative and quantitative methods by the 797 VA Computrace. The study found that Chitosan-coated SPIONs showed a remarkable maximum adsorption capacity of 94.4 % for Hg (II) at a pH of 6, using an adsorbent dosage of 10.0 mg/mL. A thermal adsorption study indicates that the adsorption process is thermodynamically favorable. The isotherm models were found to be a strong fit for this study. The adsorption process was well followed by the pseudo-second-order and external diffusion kinetic models. The findings indicated that the chitosan-coated SPIONs nanoparticles could be a cost-efficient adsorbent for the removal of Hg (II) from industrial effluent wastewater.

Synthesis of CoFe2O4@SiO2-NH2 and its application in adsorption of trace lead

In this work, an amine functionalized CoFe2O4 magnetic nanocomposite material CoFe2O4@SiO2-NH2 was prepared successfully by modifying coated-CoFe2O4@SiO2 magnetic nanoparticles with 3-aminopropyltriethoxysilane (APTES) and became an efficient adsorbent for the separation and analysis of trace lead in water. The CoFe2O4@SiO2-NH2 magnetic nanoparticles were characterized using SEM, TEM, XRD, FTIR, VSM and BET techniques. Then, the adsorption mechanism was preliminarily investigated through ZETA, XPS, and adsorption kinetic experiments. The adsorption process was fitted by pseudo-second-order kinetics and a Langmuir isotherm model. The main adsorption mechanism of CoFe2O4@SiO2-NH2 towards lead ions was the chelation between the amino groups of CoFe2O4@SiO2-NH2 and lead cations, as well as the strong Coulomb interaction between the electron donor atoms O and N in the surface of CoFe2O4@SiO2-NH2 and lead cations. The adsorption capacity is 74.5 mg g-1 and the adsorbent can be reused 5 times. Hence, this prepared CoFe2O4@SiO2-NH2 could find potential applications for the removal of trace metal ions in surface water.