Water contamination is one of the most urgent concerns confronting the world today. Heavy metal poisoning of aquatic systems has piqued the interest of various researchers due to the high toxicity and carcinogenic consequences it has on living organisms. Due to their exceptional attributes such as strong reactivity, huge surface area, and outstanding mechanical properties, nanomaterials are being produced and employed in water treatment. In this review, recent advances in the use of nanomaterials in nanoadsorptive membrane systems for wastewater treatment and heavy metal removal are extensively discussed. These materials include carbon-based nanostructures, metal nanoparticles, metal oxide nanoparticles, nanocomposites, and layered double hydroxide-based compounds. Furthermore, the relevant properties of the nanostructures and the implications on their performance for water treatment and contamination removal are highlighted. The hydrophilicity, pore size, skin thickness, porosity, and surface roughness of these nanostructures can help the water permeability of the nanoadsorptive membrane. Other properties such as surface charge modification and mechanical strength can improve the metal adsorption effectiveness of nanoadsorptive membranes during wastewater treatment. Various nanocomposite membrane fabrication techniques are also reviewed. This study is important because it gives important information on the roles of nanomaterials and nanostructures in heavy metal removal and wastewater treatment.

https://www.mdpi.com/1996-1944/15/15/5392/pdf?version=1659692362

Recent Advances in Adsorptive Nanocomposite Membranes for Heavy Metals Ion Removal from Contaminated Water: A Comprehensive Review

Abstract Metal ferrites have outstanding electrochemical characteristics owing to the numerous oxidation states of the metal ions, making them promising materials for addressing both sustainable energy conversion and storage and growing environmental issues. Therefore, three nanocrystallites transition metal ferrites, CoFe 2 O 4 , CuFe 2 O 4 and Co/CuFe 2 O 4 , were synthesized using citrate precursors and used as electrode materials for supercapacitor applications. Mixed transition metal ferrite nanoparticles were characterized by Fourier transform infrared (FT-IR), scanning electron microscope (SEM) complemented with energy-dispersive spectroscopy (EDX), transmission electron microscopy (TEM), Raman spectroscopy and thermal analysis (TGA). The findings illustrated the formation of a single-phase spinel ferrite as proved from XRD data. In addition, the particle shape and particle size obtained from TEM analysis revealed that the as-synthesised nanomaterial exhibited spherical shape with a size ranging from 30 to 50 nm. The result demonstrated that while using a three-electrode configuration, the electrochemical performance of the ferrite nanoparticles achieved a remarkable maximum specific capacitance of 893 Fg −1 at a scan rate of 5 mV s −1 . At a current density of 1 Ag −1 , Co–Cu ferrite exhibited outstanding cycling stability for 3000 cycles with 90% capacity retention. Based on the aforementioned data, it can be considered that the remarkable electrochemical performance of the Co–Cu ferrite nanocomposites can be considered as promising materials to be used for supercapacitor electrodes. 

/pdf/synthesis-and-characterization-of-mixed-ternary-transition-2xamgiur.pdf

Synthesis and characterization of mixed ternary transition metal ferrite nanoparticles comprising cobalt, copper and binary cobalt–copper for high-performance supercapacitor applications

We herein report the controllable synthesis of spherical cobalt ferrite nanoparticles with average crystallite size in the range of 3.6–12.9 nm using a facile, eco-friendly, hydrothermal method. The hydrothermal treatment was carried out by utilizing cobalt nitrate, ferric nitrate, and ammonium hydroxide in the presence and absence of Arabic gum as a surfactant agent. The purity and crystallinity of the products were tuned by varying reaction conditions such as reaction time (0.5–8 h), reaction temperature (120–180 °C), percentage of ethylene glycol (0–100% (v/v)), pH (8–9.6), and amount of Arabic gum (0–2 g). We characterized the prepared products using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy analysis (EDS), selected area electron diffraction (SAED) patterns, and UV-visible diffuse reflectance spectra (DRS). The optimal hydrothermal treatment was performed at 180 °C and pH 9.6 for 4 h in aqueous media. The results also revealed that the as-prepared spinel cobalt ferrite nanoparticles have an estimated optical band gap energy in the range of ca. 1.6–1.9 eV, indicating the semiconducting characteristics of the products.

/pdf/a-controllable-one-pot-hydrothermal-synthesis-of-spherical-2rv0taw7.pdf

A controllable one-pot hydrothermal synthesis of spherical cobalt ferrite nanoparticles: synthesis, characterization, and optical properties

The reductions of nitro groups in nitroaromatic compounds to amino-aromatic have great opportunities in synthetic chemistry. Previously the process of nitroaromatic reduction used catalytic systems operated under hard conditions, leading to missing the pure and high yield of the final products. Here, a cobalt ferrite, copper ferrite, and cobalt-doped copper ferrite nanocatalyst were prepared using the citrate spontaneous combustion method. In addition to the properties of the prepared nanocatalyst, the present methodology describes the effective reduction of a variety of nitroaromatic compounds into corresponding anilines under visible light illumination. The cobalt-doped copper ferrite photocatalyst showed excellent activity up to 99% by converting nitroaniline into amino-aniline. The optimized catalytic conditions (room temperature, atmospheric pressure, and visible light irradiation) were applied in the reduction of a series of nitroarenes giving a high conversion rate (93–98%) and selectivity (95–99%). The photocatalytic system has the advantage due to the lack of filtration in the recycling experiments and the high stability of up to six cycles.

Selective photocatalytic reduction of nitroarenes into amines based on cobalt/copper ferrite and cobalt-doped copper ferrite nano-photocatalyst

Mg and Cu incorporated CoFe2O4 catalyst: characterization and methane cracking performance for hydrogen and nano-carbon production

Different concentrations of cobalt ferrite nanoparticles have been incorporated into epoxy resin. The synthesized compositions have been investigated via XRD, FTIR and FESEM. The morphological features indicate that cobalt ferrite has been configured in agglomerated grains with dimensions in range of 0.31-0.72 µm. The focus of this work is to highlight the importance of nanofillers in the mechanical properties of the epoxy resin. The strength and moduli of Epoxy, Epoxy- CoFe2O4 nanocomposite was investigated. The mechanical properties of the compositions were examined using tensile tests. It was noted that toughness has been enhanced significantly from 1.71 to 2.38 MJ/m3 at 0.0 and 0.04 wt. % respectively then it deteriorated. The tensile strength also showed the same trend and progressed from 9.05 to 11.7 MPa at 0.0 and 0.04 wt. % respectively. On the other hand, maximum strain before break displayed different behavior and reached its high value (41.25 %) at 0.01 wt. %.

The effect of adding cobalt ferrite nanoparticles on the mechanical properties of epoxy resin

Cobalt ferrite, Copper ferrite and cobalt doped copper ferrite nanoparticles have been synthesized and characterized using different characterization methods (XRD, FTIR and FESEM). The prepared nanoparticles have been used as promising fillers of the polyvinylidene fluoride (PVDF) polymer. The PVDF/(Cu–CoFe2O4, CoFe2O4, and CuFe2O4) nanocomposites films have been prepared via a simple solution casting technique. The optical properties and the piezoelectric response of the prepared nanocomposite films have been studied. This study showed that Cu–CoFe2O4 and CoFe2O4, have enhanced the interfacial polarization density and dielectric constant. The prepared nanofillers reduced the PVDF band gap energy value. The optical conductivity value of PVDF/(Cu–CoFe2O4 and CoFe2O4) increased five times compared with the pure PVDF. Also, an increase in the piezoelectric response has been recorded by adding the nano-fillers to the pure PVDF. 

/pdf/the-effect-of-cofe2o4-cufe2o4-and-cu-cofe2o4-nanoparticles-2oqaqi6p.pdf

The effect of CoFe2O4, CuFe2O4 and Cu/CoFe2O4 nanoparticles on the optical properties and piezoelectric response of the PVDF polymer

In the present work, nanocomposites of CeO2/ZnO and CeO2/SiO2 were prepared to be used as adsorbing materials for the Cr (VI) heavy metal from water. According to the non-toxic and low-cost properties of zinc oxide and silica, they have been prepared as a nanocomposite with anti-oxidant cerium oxide. The prepared CeO2/SiO2 nanocomposite showed larger removal efficiency for Cr (VI) from aqueous solution of (55%) at optimum conditions of pH = 7 after 100 min. The adsorption kinetics for Cr (VI) on surface of CeO2/Zno and CeO2/SiO2 were well fitted with pseudo-second-order kinetic model. The adsorption mechanism follows monolayer Langmuir isotherm model. The prepared samples were investigated and characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-spectroscopy, field emission scanning electron microscopy (FESEM) and N2 adsorption–desorption isotherm (BET) isotherm. The efficiency of the prepared samples for removing of Cr (VI) from aqueous solution was investigated in different experimental conditions (different PH and contact time).

Mai M. El-Masry

Papers

The effect of adding cobalt ferrite nanoparticles on the mechanical properties of epoxy resin

The effect of CoFe2O4, CuFe2O4 and Cu/CoFe2O4 nanoparticles on the optical properties and piezoelectric response of the PVDF polymer

Selective photocatalytic reduction of nitroarenes into amines based on cobalt/copper ferrite and cobalt-doped copper ferrite nano-photocatalyst

Comparative study between CeO2/Zno and CeO2/SiO2 nanocomposites for (Cr6+) heavy metal removal