The application of nanomaterials as a method to overcome plant stress and increase crop yield is relatively new as compared to the use of fertilizers and pesticides in agricultural production. In the present study, manganese (III) oxide nanoparticles (MnNPs) were investigated as a nanopriming agent to alleviate salinity stress in Capsicum annuum L. during germination at 100 mM NaCl. In general, the root growth in both nonsalt and salt-stressed seedlings was significantly improved by MnNPs (0.1, 0.5, 1 mg/L). Scanning electron microscopy and energy-dispersive spectroscopy showed the penetration of MnNPs through the seed coat and the formation of nanoparticle–corona complex. MnNPs have different surface chemistries when present in water or NaCl, which may lead to their different affinities to proteins and alter the N–H bonding according to Fourier transform infrared spectroscopy. Salt stress inhibited root growth, induced proteins and lignin pattern changes, and redistributed the manganese, sodium, potassium, and calcium contents between the shoot and root. However, neither the redistributions nor manganese superoxide dismutase expression were affected by MnNPs but by MnSO4. This study describes how nanopriming elicits compositional changes and molecular interactions among key biomolecules and implies the role of MnNPs in plant salt stress management in order to promote sustainable agriculture.

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As nitrate pollution in groundwater continues to escalate, more is being discovered about the detrimental health implications associated with concentrated nitrate ingestion. Thus, there is a great necessity for the effective and sustainable remediation of nitrate from water. The electrocatalytic reduction of nitrate (ERN) has been identified as a promising technology with respect to selective product formation (N 2(g) and NH3/NH4 +), adaptable instrument configurations, and compatibility with renewable energy sources. Electrocatalysts with appreciable selectivity for nitrate reduction to nitrogen gas are of great importance for drinking water applications. On the other hand, ammonia-selective catalysts are desirable for resource recovery. Traditional catalysts for ERN applications include expensive platinum group metals, which makes the widespread utilization of this technology economically unfavorable. Alternatively, research within the last five years has shown cost-effective catalytic materials such as bimetallic systems, graphitic composites, metal oxides, and metal sulfides exhibiting substantial activity/selectivity for ERN applications. Future ERN catalysts must not only express significant activity/selectivity but also be capable of stable and consistent performance under varying water chemistries. Combating electrocatalyst aging and fouling processes will be key in material design for catalysts capable of efficient remediation of nitrate from water under continuous long-term operation.

A Rancieite type material (K2Mn4O9) nanomaterial was synthesized and tested for the removal of chromium (III) and chromium (VI) from aqueous solutions. The synthesized nanomaterial was characterized using powder XRD and SEM. XRD showed weak diffraction peaks at only at the angles associated with K2Mn4O9. The SEM corroborated that the nanoparticles were present; however, the nanoparticles were clustered into larger aggregates. Batch studies were performed to determine the optimum pH, capacity, time dependency, interferences, and the thermodynamics of the binding. The optimum pH for the binding of Cr(III) and Cr(VI) were determined to be pH 5 and pH 2, respectively. Isotherm studies were performed at temperatures of 4 , 25 , and 45 for Cr(III) and Cr(VI) and showed binding capacities of 21.7 mg/g, 36.5 mg/g, 41.8 mg/g for Cr(III). The Cr(VI) binding capacities were 4.22 mg/g, 4.08 mg/g, and 3.25 mg/g at the respective temperatures. The thermodynamic studies showed that the binding processes for the reactions were spontaneous and endothermic, with a ΔH was 17.54 kJ/mol for Cr(III) and 6.05 kJ/mol for Cr(VI). The of sorption for Cr(III) were determined to be −3.88 kJ/mol, −5.83 kJ/mol and −7.03 kJ/mol at the aforementioned temperatures. The ΔG values for the Cr(VI) sorption were determined to be −4.89 kJ/mol, −5.64 kJ/mol, and −6.05 kJ/mol. In addition, the ΔS values for Cr(III) and Cr(VI) were determined to be 77.92 J/mol and 39.49 J/mol, respectively. The thermodynamics indicate that the binding of Cr(III) and Cr(VI) is spontaneous and endothermic.

Upconversion (UC) particles are currently under intensive investigation, normally for their visible instead of ultraviolet (UV) light luminescence under near-infrared (NIR)irradiation. As a commonly studied host, NaYF 4 in particular is known to have low phonon energy and high UC efficiency. Here, we present our work on enhancing UC luminescence in the UV region by adding a third dopant into a binary-doped NaYF 4 :Yb 3+ ,Tm 3+ host. More specifically, neodymium (Nd 3+ ) or gadolinium (Gd 3+ ) ions was co-doped into parent NaYF 4 :20mol%Yb 3+ ,0.5mol%Tm 3+ UC particles to enhance their UV UC luminescence. Experimental results demonstrated that these particles exhibited the highest degree of UV UC enhancements when co-doped with 0.05mol% Nd 3+ or 2.0mol% Gd 3+ , expanding the potential of this type of materials into many possible applications by directly converting NIR irradiation into UV light.Fundamentally, the UV UC emission dependence of these triply doped NaYF 4 :Yb 3+ ,Tm 3+ particles with different Nd 3+ and Gd 3+ doping concentrations was investigated in terms of ground state absorption, excited state absorption and energy transfer UC mechanisms.

Tin oxide, SnO2, nanomaterial was synthesized and tested for the removal of Cu2+ and Ni2+ ions from aqueous solutions. Various parameters for the binding were investigated in batch studied, which included pH, time, temperature, and interferences. In addition, isotherm studied were performed to determine the maximum binding capacity for both Cu2+ and Ni2+ ions. The optimal binding pH determined from the effects of pH were to be at pH 5 for both the Cu2+ and Ni2+ ions. The isotherm studies were performed at temperatures of 4°C, 25 °C, and 45 °C for both the Cu2+ and Ni2+ ions and were found to follow the Langmuir isotherm model. The binding capacities for the Cu2+ ions were 2.63 mg/g, 2.95 mg/g and 3.27 mg/g at the aforementioned temperatures, respectively. Whereas the binding capacities for Ni2+ were 0.79 mg/g, 1.07 mg/g, and 1.46 mg/g at the respective temperatures. The determined thermodynamic parameters for the binding showed that the binding processes for the reactions were endothermic, as the ΔG was observed to decrease with decreasing temperatures. As well the ΔH was 28.73 kJ/mol for Cu2+ (III) and 13.37 kJ/mol for Ni2+. The ΔS was observed to be 92.65 J/mol for Cu2+ and 54.53 J/mol for Ni2+. The free energy of adsorption for the Cu2+ was determined to be 13.99 kJ/mol and the activation energy for the binding of Ni2+ was determined to be 8.09 KJ/mol. The activation energy data indicate that the reaction was occurring through chemisorption