In this present study, silver nanoparticles (Ag/AgCl NPs) were synthesized using an aqueous leaf extract of Oedera genistifolia as a reducing agent. The biosynthesized Ag/AgCl NPs was characterized by UV-visible spectrophotometry, transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). In addition, sequel to antibacterial assay, the cytotoxic effect of the phytofabricated Ag/AgCl NPs was assessed against the HeLa cell line (human cervix adenocarcinoma). The results of the characterization of the synthesized Ag/AgCl NPs indicate the successful synthesis using plant extract as a reducing agent, with UV-Vis spectra between 290–360 nm. TEM results showed that Ag/AgCl NPs was spherical in shape with an average size of 34.2 nm. EDX analysis revealed that the particles were predominantly composed of carbon, oxygen, chlorine, and silver, while FTIR identified major phytochemical compounds, which could be responsible for bio-reducing and capping potential. XRD analysis showed the crystallinity of Ag/AgCl NPs, with a face-centred cubic structure. The studied Ag/AgCl NPs had no cytotoxic effect on HeLa cells and exhibited antibacterial activity (minimum inhibitory concentration (MIC) 0.25–1 mg/mL; minimum bactericidal concentration (MBC) 2–16 mg/mL) against both the Gram-negative and Gram-positive bacteria investigated. Findings from this study suggest that this plant as a good candidate for producing new antibacterial drugs.

In this study, we report on the biosynthesis of gold nanoparticles (AuNPs) by using Callistemon citrinus (C. citrinus) seed extract as both reducing and capping agent as well as its characterization. Likewise, the in vitro antiparasitic activities of both biosynthesized gold nanoparticles and crude seed extract of the plant were evaluated. The formation of biosynthesized AuNPs was confirmed by a color change immediately when the seed extract was added to the gold chloride (III) solution. Characterization of the AuNPs was done using analytical tools like ultraviolet–visible spectroscopy, X–ray diffraction, scanning electron microscopy (SEM), energy dispersive X–ray (EDX), transmission electron microscopy (TEM) and Fourier transformed infra–red (FTIR). FTIR showed an absorption peak at 230 nm consistent with the absorption band for gold nanoparticles, the morphology and composition of AuNPs was ascertained by SEM and EDX micrographs; uneven spherical-shaped nanoparticles was established by SEM analysis, and an average particle size of about 37 nm was confirmed by the TEM analysis. The crude seed extracts exhibited antitrypanosoma activities with an IC50 of 11.06 µg/mL. Both the crude seed extract and AuNPs were inactive against plasmodial parasite, while the antibacterial assay showed that AuNPs is potent against gram positive and gram negative bacterial strains. GRAPHICAL ABSTRACT

The great amount of research on magnetic nanoparticles for application in wastewater decontamination has generated new and exciting materials in recent times. The effect of magnetic nanoparticles must be known to show low cytotoxicity and be ascertained prior to their use for wastewater treatment. Synthesized chelating ligands considerably improve the adsorbing capabilities of magnetic nanoparticles in wastewater. This paper (with over 100 refs) discusses the influence of surface modification on the efficiency of magnetic nanoparticles for the removal of heavy metals in wastewater. The progress made on or/and prospect of magnetic nanoparticles functionalization for wastewater decontamination are also extensively highlighted. This review is specifically targeted at reviewing the different strategies that could be employed for surface modification of magnetic nanoparticles for application in the removal of heavy metals from wastewater.

The continuous demand for clean and affordable water needed for the survival of man is now a major challenge globally. Therefore, the treatment of wastewater generated from printing, textile and dyeing industries containing soluble dyes like rhodamine B (Rh-B) is of utmost important. This study investigates the efficiency of new multifunctionalized superparamagnetic nanoparticles (MNP-Tppy) for the removal of cationic Rh-B from aqueous solution. To afford MNP-Tppy, the surface of MNP was covalently functionalized with terpyridine ligand to enable an anionic charge on the adsorbent. The results of characterization including Brunauer-Emmett-Teller (BET) analysis, thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) and fourier transform infra–red spectroscopy (FTIR) indicate that this superparamagnetic nanoparticle functionalized with multiple nitrogen atoms was successfully synthesized. Adsorption experiments involving the effect of pH, time, temperature, adsorbent dose and adsorbate concentration show that the maximum adsorption of Rh-B using MNP-Tppy was observed at pH 9 and removal was observed to increase as solution pH increases. Similarly, time variation shows that adsorbate removal increases as adsorption time increases until the removal attained equilibrium at 15 min. Kinetic studies conducted among four kinetic models using the data obtained from effect of time indicate that the adsorption process can best be described by the pseudo-second order model. Isotherm studies conducted at three different temperatures revealed that Langmuir isotherm model fitted well for the equilibrium data with q_m value of 113.64 mg g⁻¹ and thermodynamic studies showed that the adsorption process involving the removal of Rh-B from aqueous solution by MNP-Tppy is spontaneous, endothermic and realistic in nature. Lastly, Reusability experiments indicate that MNP-Tppy can be regenerated and re-used.