Daryoush Afzali

Application of iron nanoparticles as iron fertilizer can be a functional strategy to manage iron deficiency in agricultural crops. However, the toxicity of iron should not be ignored and its proper concentrations should be determined. The effect of iron nanoparticles and Fe (II) ethylenediaminetetraacetate (FeEDTA) on iron accumulation, photosynthetic pigments, soluble carbohydrate and protein, antioxidant enzymes activity, and lignification were compared in vitro in Solanum villosum. Culture media were prepared in two ways: 1) including 628 mg L⁻¹ FeEDTA as control, and 2) different concentrations of iron oxide nanoparticles (628 and 730 mg L⁻¹ in pH of 5.2, and 628 and 830 mg L⁻¹ in pH of 5.9). Seeds were germinated on culture media and biochemical parameters were measured at the end of the fourth week. The iron content, amount of chlorophyll, soluble carbohydrate and protein in leaves and stems of the plants grown using the nanoparticle concentration of 628 mg L⁻¹ decreased compared to the control, but the same parameters increased in concentrations of 730 and 830 mg L⁻¹. Iron nanoparticles decreased catalase and ascorbate peroxidase activities. Guaiacol peroxidase activity and carotenoid content showed no significant difference between FeEDTA and nanoparticle treatments. Leaf and stem lignin levels did not differ from control (FeEDTA). FeEDTA can be replaced by optimum concentrations of iron nanoparticle under in vitro conditions. In vivo experiments are needed to generalize these results for field-grown plants, because iron nanoparticles have some advantage over iron chelate, which is highly dependent on soil conditions. Abbreviations: APX: ascorbate peroxidase; CAT: catalase; FeEDTA: Fe (II) ethylenediaminetetraacetate; GP: guaiacol peroxidase; MS: Murashige and Skoog medium

In this study, tantalum(V) metal organic framework (Ta‐MOF) nanostructure was incorporated within polyvinyl alcohol (PVA) nanofibers to prepare an electrospun porous composite as a novel CH₄ adsorbent. The crystallinity, thermodynamic behavior, and textural properties of the products were investigated using instrumental analyses techniques. The results confirmed that the developed PVA/Ta‐MOF electrospun nanofibrous composite exhibits higher thermal stability, considerable porosity, and larger surface area compared to the parent Ta‐MOF. A 2^k factorial design was used for systematic study of the adsorption process. The results of response surface methodology (RSM) optimization indicated that the highest methane adsorption can be achieved at 24.40 °C and 3.70 bar in 23.60 min. These nano pore sorbents showed a significant potential for CH₄ adsorption due to the presence of Ta‐MOF at the surface of nanofibrous composite compared to many other conventional sorbents that have been already used. This study introduces a novel biocompatible/biodegradable nanofibrous composite material with high methane adsorption performance and potentials for other applications.

In this study, the sepiolite–iron oxide–manganese dioxide (Sep–Fe₃O₄–MnO₂) nanocomposite was synthesized and applied as a magnetically separable adsorbent for removal of Pb(II) ions from water in a batch system. The effects of initial Pb(II) concentration, adsorbent dosage, contact time, pH value, and temperature were investigated to optimize the conditions for maximum adsorption. The equilibrium adsorption data were analyzed with the Langmuir, Freundlich, and Temkin models. The adsorption process closely agreed with the Langmuir adsorption isotherm, and the monolayer saturation adsorption value was achieved as 131.58 mg g⁻¹. The adsorption kinetics follow the pseudo-second-order (PSO) model that illustrated the rate controlling step might be chemisorption. Thermodynamic investigations for the removal process were conducted by determining the values of ∆G°, ∆H°, and ∆S°. The adsorption behavior of Pb(II) on the Sep–Fe₃O₄–MnO₂ was a spontaneous and endothermic process. Several consecutive adsorption–desorption cycles confirmed that the proposed Sep–Fe₃O₄–MnO₂ nanocomposite could be reused after successive lead removal. Furthermore, the practical application of the adsorbent was successfully realized by the treatment of real Pb-contaminated water samples.

Reducing gas contaminants by affordable and effective adsorbents is a major challenge in the 21^st century. In the present study, thorium metal organic framework (Th‐MOF) nanostructures are introduced as highly efficient adsorbents. These compounds were manufactured via a novel route resulting from the development of microwave assisted reverse micelle (MARM) and ultrasound assisted reverse micelle (UARM) methods. The products were characterized utilizing XRD, SEM, TGA/DSC, BET, and FT‐IR analyses. Based on the results, the samples synthesized by MARM had uniform size distribution, high thermal stability, and significant surface area. Calculations using DFT/B3LYP indicated that the compounds have a tendency to the polymeric form, which could theoretically confirm the formation of Th‐MOF. Results of analysis of variance (ANOVA) showed that synthesis parameters played a critical role in the manufacturing of products with distinctive properties. Response surface methodology (RSM) predicted the possibility of creating Th‐MOF adsorbents with the surface area of 2579 m²/g, which was a considerable value in comparison with the properties of other adsorbents. Adsorption studies showed that, in the optimum conditions, the Th‐MOF products had high adsorption capacity for CO and CH₄. It is believed that the synthesis protocol developed in the present study and the systematic studies conducted on the samples which lead to products with ideal adsorption properties.