Amel Taha

Recent attention has been drawn to green methods for preparing metal oxide nanoparticles due to their ease of preparation and environmental friendliness in comparison with chemical and physical methods. By using an eco-friendly reducing agent, Pimpinella anisum seed extract, this study describes a method for synthesizing CuO nanoparticles that are based on biological principles. Copper oxide nanoparticles were produced utilizing a precipitation technique involving Pimpinella anisum extract, (CuCl2.2H2O), and (NaOH).To determine the morphology of CuONPs and their elemental composition, shape, size, and type of bonds present in the sample, UV–Vis spectrophotometry, XRD, SEM , and EDS analysis have all been performed. Spectra of the UV-visible spectrum showed an absorption peak between 250 – 300 nm, which confirms the formation of CuO nanoparticles. FT-IR spectral showed bands related to CuO vibration at 529 cm-1 are, suggesting the production of CuO nanoparticles. Analysis by X-ray diffraction revealed that the CuO nanoparticles produced were monoclinic in phase and had mean size of 22 nm. Based on SEM analysis, the obtained nanoparticles have an aspherical shape. EDX analysis was used to confirm copper and oxygen presence. The weight percentage of the latter was (71.2% Cu and 28.8% O), respectively. Four pathogenic microorganisms were used to evaluate the antibacterial efficacy of green-synthesized CuO nanoparticles. As a result, the CuONPs prepared to have the potential for application as antimicrobial agents, suggesting that they may be useful for therapeutic applications in e future.

Water pollution with dye effluents from different industries is a broadly established environmental and health problem that needs serious attention. In this study, making use of Acacia nilotica seed extract, greenly synthesized MnO2 nanoparticles were loaded on the surface of biochar derived from palm waste (MnO2/PF), with specific surface areas of 70.97 m2/g. Batch experiments were adopted, aiming to evaluate the performance of palm fronds, biochar, and the MnO2/PF adsorbents in methyl orange (MO) removal from an aqueous solution. The feedstock and synthesized biochars were comprehensively characterized using XRD, SEM-EDX, FTIR, and BET surface area techniques. Moreover, the influences of the modification of palm fronds, initial dye concentrations, pH, and adsorbent dosage on MO uptake were examined. The results demonstrated that MnO2/PF biochar nanocomposite led to an increase in the removal efficiency by 6 and 1.5 times more than those of palm fronds and biochar, respectively. In addition, it was found that the second-order kinetic model presented the kinetic adsorption very well. This paper demonstrates that the depositing of greenly synthesized MnO2 nanoparticles on the date palm waste biochar forms a novel adsorbent (MnO2/PF) for the removal of MO from aqueous solutions. Furthermore, this adsorbent was easy to synthesize under moderate conditions without the need for chemical capping agents, and would thus be cost-effective and eco-friendly.

p-nitrophenol (pNP) is a highly toxic organic compound and is considered carcinogenic and mutagenic. It is a very stable compound with high resistance to chemical or biological degradation. As a result, the elimination of this pollutant has been very challenging for many researchers. Catalytic reduction is one of the most promising techniques, if a suitable catalyst is developed. Thus, this work aims to prepare an eco-friendly catalyst via a simple and low-cost route and apply it for the conversion of the toxic p-nitrophenol (pNP) into a non-toxic p-aminophenol (pAP) that is widely used in industry. Manganese oxide was prepared in an environmentally friendly manner with the aid of Lawsonia inermis (henna) extract as a stabilizing and capping agent and loaded on the surface of 13X molecular sieve zeolite. The UV-Vis spectrum, EDS, and XRD patterns confirmed the formation of the pure MnO2 loaded on the zeolite crystalline network. The TGA analysis showed that the samples prepared by loading MnO2 on zeolite (Mn2Z, Mn3Z, and Mn4Z) lost more mass than pure MnO2 (Mn) or zeolite (Z), which is mainly moisture adsorbed on the surface. This indicates a better dispersion of MnO2 on the surface of zeolite compared to pure MnO2, and thus a higher number of active adsorption sites. SEM images and EDS confirmed the dispersion of the MnO2 on the surface of the zeolite. Results showed a very fast reduction rate, following the order Mn2Z > Mn3Z > Mn4Z > Mn > Z. With sample Mn2Z, 96% reduction of pNP was achieved in 9 min and 100% in 30 min. For Mn3Z, Mn4Z, and Mn, 98% reduction was achieved in 20 min and 100% in 30 min. Zeolite was the slowest, with only a 40% reduction in 30 min. Increasing the amount of zeolite in the synthesis mixture resulted in lower reduction efficiency. The kinetic study indicated that the reduction of p-nitrophenol on the surface of the prepared nanocomposite follows the pseudo-first-order model. The results show that the proposed nanocomposite is very effective and very promising to be commercially applied in water treatment, due to its low cost, simple synthesis procedure, and reusability.