Sodium selenate

This study investigated the effectiveness of magnetite/reduced graphene oxide (MRGO) in immobilizing selenium (Se) in contaminated soils and its impact on corn (Zea mays) growth and nutrient uptake. A factorial experiment was conducted in a completely randomized design with three replications under greenhouse conditions. Soil samples were contaminated with sodium selenate at Se concentrations of 0, 2, 4, 8, 16, and 32 mg/kg, equilibrated for two months, and subsequently treated with MRGO at 0, 0.25, 0.5, and 1 %, followed by a three-month incubation period. Corn plants were then cultivated from the seedling stage to the vegetative phase, and growth parameters, along with Se and nutrient concentrations in roots and shoots, were analyzed. MRGO significantly enhanced Se immobilization, increasing retention from 62-71 % to 82-90 % at 1 % MRGO. Se exhibited a biphasic effect on plant growth, promoting growth at 2 mg/kg but inducing toxicity at concentrations exceeding 4 mg/kg, leading to reduced biomass and nutrient uptake. MRGO mitigated Se toxicity by lowering Se accumulation in roots and shoots. However, in Se-free soils, higher MRGO levels negatively affected plant growth, likely due to nutrient adsorption. Trends in potassium (K), iron (Fe), and zinc (Zn) mirrored plant growth, peaking at 2 mg/kg Se and 1 % MRGO, whereas P (P) exhibited an inverse root-shoot distribution. These findings underscore MRGO's potential for Se immobilization in contaminated soils, improving plant performance at optimal Se levels. However, its application in Se-deficient soils requires careful management to prevent nutrient depletion (P, K, Zn, and Fe) and long-term declines in soil fertility.

The chem. reactivity, electronic properties, vibrational modes, and catalytic performance of the ion pair pyridinium hydrogen selenate ([C₅H₆N]⁺[HSeO₄]^-) were studied in relation to its mol. structure.This was done using both exptl. (single crystal X-ray diffraction, Hammett acidity function (H₀), FT-IR and UV-vis) and theor. methods (QTAIM, NBO, Hirshfeld surface (HS), MEP surface, NPA and FMO) at B3LYP/6-311++G(2d,2p) level of theory.To assess the catalytic properties of [C₅H₆N]⁺[HSeO₄]^-, Bu acetate synthesis was used as a model reaction.The studied ion pair crystallizes in a monoclinic centrosym. system (space group C2/c) with the following cell dimensions: a = 19.8109(11) Å, b = 6.2669(3) Å, c = 13.2165(7) Å, α = γ = 90.0°, and β = 109.059(2)°.Electrostatic hydrogen bond (Se-O···H-N) between [HSeO₄]^- and [C₅H₆N]⁺ contributes to the structural stability of [C₅H₆N]⁺[HSeO₄]^-.Appearance of IR peaks due to O···H and N-H bonds confirmed the presence of Se-O···H-N interaction.The UV-vis profile shows cation-anion interactions within the 235 nm-250 nm range.HS method exposed that O···H/H···O contacts are the most prominent in the title compoundMEP, NPA and H₀ established the hydrogen atom in [HSeO₄]^- as the most suitable site for nucleophilic attack.This influenced the acidity and catalytic behavior of [C₅H₆N]⁺[HSeO₄]^- in ester synthesis.Based on FMO, frontier orbital gap of 5.433 eV was calculated