Synthesis of a novel inorganic cation exchanger based on molybdate: Applications for removal of Pb2+, Fe3+ and Mn2+ ions from polluted water

Boosting brackish water treatment via integration of mesoporous γ-Al2O3NPs with thin-film nanofiltration membranes

In this study, a simple method based on non-ionic surfactant polysorbates-80 was used to create mesoporous γ-Al₂O₃NPs. The properties of the prepared mesoporous alumina nanoparticles (Al₂O₃NPs) were verified using ATR-FTIR, XRD, SEM, TEM, DLS, and BET surface area analysis. Then, thin-film nanocomposite (TFN) nanofiltration membranes were fabricated by interfacial polymerization of embedded polyamide layers with varied contents (0.01 to 0.15 wt.%) of mesoporous γ-Al₂O₃NPs. The surface roughness, porosity, pore size, and contact angle parameters of all the prepared membranes were also determined. The performance of the fabricated membranes was investigated under various mesoporous γ-Al₂O₃NPs loads, time, and pressure conditions. Mesoporous γ-Al₂O₃NPs revealed an important role in raising both the membrane hydrophilicity and the surface negativity. The addition of 0.03 wt.% mesoporous γ-Al₂O₃NPs to the TFN membrane increased water flux threefold compared to the TF control (TFC) membrane, with maximum water flux reaching 96.5, 98, 60, and 52 L/(m².h) for MgSO₄, MgCl₂, Na₂SO₄, and NaCl influent solutions, respectively, with the highest salt rejection of 96.5%, 92.2%, 98.4%. The TFN-Al₂O₃ membrane was also able to soften water and remove polyvalent cations such as Mg²⁺ with a highly permeable flux. The TFN-Al₂O₃ membrane successfully removed the hardness of the applied water samples below the WHO limit compared to using merely the TFC membrane. Furthermore, the TFN-Al₂O₃ nanofiltration membrane unit proved to be a promising candidate for the desalination of real brine like that collected from the Safaga area, Egypt.

Magnetic Fe3O4@Mg/Al-layered double hydroxide adsorbent for preconcentration of trace metals in water matrices

A magnetic Fe₃O₄@MgAl-layered double hydroxide (MLDH) nanocomposite was successfully synthesized and applied as an effective adsorbent for preconcentration of trace As(III), Cd(II), Cr(III), Co(II), Ni(II), and Pb(II) ions from complex matrices. The quantification of the analytes was achieved using the inductively coupled plasma optical emission spectrometry (ICP-OES) technique. The nanocomposite was then characterized using BET, FTIR, SEM, and EDS. Due to its high adsorption surface area, compared to traditional metal oxide-based adsorbents, MLDH nanocomposite exhibited high extraction efficiency. Several experimental parameters controlling the preconcentration of the trace metals were optimized using response surface methodology based on central composite design. Under optimum conditions, the linearity ranged from 0.1 to 500 µg L⁻¹ and the correlation of coefficients (R²) were higher than 0.999. The limits of detection (LODs) and quantification (LOQs) were 0.11–0.22 µg L⁻¹ and 0.35–0.73 µg L⁻¹, respectively. The intra-day (n = 10) and inter-day precisions (n = 5 working days) expressed in the form of percent relative standard deviations (%RSDs) were below 5%. The proposed method was successfully applied for the analysis of the As(III), Cd(II), Cr(III), Co(II), Ni(II), and Pb(II) ions in different environmental water samples.

Facile synthesis of Fe2O3 nanoparticles from Egyptian insecticide cans for efficient photocatalytic degradation of methylene blue and crystal violet dyes

In this study, Fe₂O₃ (hematite) nanoparticles with different crystallite sizes (40-59 nm) were synthesized from Egyptian insecticide cans using the combustion method. The organic fuels were urea, glycine, L-alanine, and L-valine. Fe₂O₃ nanoparticles were characterized utilizing different devices such as BET, PL, FT-IR, XRD, HR-TEM, FE-SEM, UV-Vis, and DTG. Crystal violet (CV) and methylene blue (MB) dyes were efficiently removed from aqueous solution by photocatalytic degradation under UV irradiation in the presence of Fe₂O₃ and H₂O₂. The % degradation of 50 mL crystal violet or methylene blue dye (20 mg/L) using 0.1 g Fe₂O₃ in the presence of H₂O₂ was 100% after 30 or 40 min, respectively. Also, the degradation processes are fitted well with the first order model. Besides, the photocatalytic activity of Fe₂O₃ unaltered even after it was reused three times. Hence, the synthesized Fe₂O₃ nanoparticles can be considered a promising and efficient photocatalyst for the degradation of crystal violet and methylene blue dyes.

Characteristic synergistic cytotoxic effects toward cells in graphene oxide dressing with cadmium and copper ions

The increasing applications of graphene oxide (GO) in bio-medicine, environment and other fields enhance the exposure possibility of human beings to GO. Studies have been performed to address the in vitro toxicity of GO; however, little information on the in vivo biological consequence of GO with other common disasters is available, especially when cells are co-exposed to GO and common metal ions. To explore the influence and possible mechanisms of such co-exposure scenarios, a series of tests of cell viability, membrane integrity, reactive oxygen species (ROS), cell morphology, and Cd²⁺ distribution, were conducted. The results showed that the synergistic toxic mechanisms of GO and Cd²⁺, initiated from the adhesion of GO on HeLa cells, and followed by the recruitment of Cd²⁺ ions around the cell membrane, impaired the membrane integrity, morphology and adhesion capability, and triggered cell toxicity. The synergistic toxic mechanism of GO and Cu²⁺ mainly correlated to ROS, while no obvious relationship with membrane integrity was observed. The findings are envisaged to facilitate the application of GO in biology and related fields.