Evaluation of Fe-Mg Binary Oxide for As (III) Adsorption-Synthesis, Characterization and Kinetic Modelling.

Nanotechnology has received much attention in treating contaminated waters. In the present study, a facile co-precipitation method was employed to synthesize a novel iron and magnesium based binary metal oxide using a stoichiometrically fixed amount of FeNO3·9H2O and MgNO3·6H2O in a proportion of molar concentration 1:1 and was later evaluated in removing As (III) from contaminated waters. Characterization of the prepared nanomaterial was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX) and ultraviolet-visible spectrophotometry (UV-VIS). Experimental studies on batch scale were carried out, examining the effect of varying initial concentrations of metal, adsorbent dosage, application time and initial pH on removal efficiency. Arsenic removal increased on increasing adsorbent dosage (0.1-1 g/L) but trend reversed on increasing initial arsenic concentration attaining qmax of 263.20 mg/g. Adsorption was quite efficient in pH range 4-8. Freundlich fitted better for adsorption isotherm along with following Pseudo-2nd order kinetics. The reusability and effect of co-existing ions on arsenic adsorption, namely SO42-, CO32- and PO43- were also explored with reusability in 1st and 2nd cycles attained adsorptive removal up to 77% and 64% respectively. The prepared nano-adsorbent showed promising results in terms of high arsenic uptake (qmax of 263.20 mg/g) along with facile and cost-effective synthesis. Thus, the co-precipitation technique used in this work is a simple one step procedure without any use of any precursor as compared to most of the other procedures used for synthesis.

Nanoparticles enhances the salinity toxicity tolerance in Linum usitatissimum L. by modulating the antioxidative enzymes, photosynthetic efficiency, redox status and cellular damage.

The contribution of nanoparticles (NPs) in physiology of the plants became the new area of interest for the physiologists; as it is very much cost effective compared to the phytohormones. Our present investigation was also based on this interest in which the same doses (50 mg/L) of four different NPs were sprayed on stressed and non-stressed foliage. The experiment was conducted to assess the impact of four NPs viz., zinc oxide (ZnO), silicon dioxide (SiO2), titanium dioxide (TiO2), and ferric oxide (Fe2O3) on the morphology and physiology of linseed in the presence of sodium chloride (NaCl). Plants responded positively to all the treated NPs and improved the growth, carbon and nutrient assimilation, while salt stress increased the content of proline, hydrogen peroxide and superoxide anion. Application of NPs over the stressed plants further increased the antioxidant enzymatic system and other physiochemical reactions. Results indicate that application of NPs increased the growth and physiology of the plant and also increased the salt tolerance capacity of the plant.

Investigation of kinetics and adsorption isotherm for fluoride removal from aqueous solutions using mesoporous cerium-aluminum binary oxide nanomaterials.

Herein, we report the synthesis of Ce-Al (1 : 1, 1 : 3, 1 : 6, and 1 : 9) binary oxide nanoparticles by a simple co-precipitation method at room temperature to be applied for defluoridation of an aqueous solution. The characterization of the synthesized nanomaterial was performed by XRD (X-ray diffraction), FTIR (Fourier transform infrared) spectroscopy, TGA/DTA (thermogravimetric analysis/differential thermal analysis), BET (Brunauer-Emmett-Teller) surface analysis, and SEM (scanning electron microscopy). Ce-Al binary oxides in 1 : 6 molar concentration were found to have the highest surface area of 110.32 m2 g-1 with an average crystallite size of 4.7 nm, which showed excellent defluoridation capacity. The adsorptive capacity of the prepared material towards fluoride removal was investigated under a range of experimental conditions such as dosage of adsorbents, pH, and initial fluoride concentration along with adsorption isotherms and adsorption kinetics. The results indicated that fluoride adsorption on cerium-aluminum binary metal oxide nanoparticles occurred within one hour, with maximum adsorption occurring at pH 2.4. The experimental data obtained were studied using Langmuir, Freundlich, and Temkin adsorption isotherm models. The nanomaterial showed an exceptionally high adsorbent capacity of 384.6 mg g-1. Time-dependent kinetic studies were carried out to establish the mechanism of the adsorption process by pseudo-first-order kinetics, pseudo-second-order kinetics, and Weber-Morris intraparticle diffusion kinetic models. The results indicated that adsorption processes followed pseudo-second-order kinetics. This study suggests that cerium-aluminum binary oxide nanoparticles have good potential for fluoride removal from highly contaminated aqueous solutions.

Application of Fe-Cu binary oxide nanoparticles for the removal of hexavalent chromium from aqueous solution.

The adsorption process has been used as an effective technique for the removal of metal ions from aqueous solutions. Groundwater remediation by nanoparticles has received interest in recent years. In the present study, a binary metal oxide of Fe-Cu was prepared and used for the removal of hexavalent chromium from aqueous solution. Batch experiments were performed to investigate the effects of initial Cr (VI) concentration, dose of adsorbent, and pH of solution on the removal efficiency of Cr (VI). The prepared nanostructured Fe-Cu binary oxides were able to reduce the concentration of Cr (VI) in aqueous solution. Binary metal oxides nanoparticle exhibited an outstanding ability to remove Cr (VI) due to high surface area, low particle size, and high inherent activity. The percentage removal efficiency of Cr (VI) increased with nanoparticles doses (0.1 g L(-1)-2.5 g L(-1)), whereas it decreased with initial Cr (VI) concentration (1 mg L(-1)-25 mg L(-1)) and with pH (3-9). The Freundlich model was found to be the better fit for adsorption isotherm. The prepared nanomaterial was characterized using powder X-ray diffraction, scanning electron microscopy (SEM), and ultraviolet (UV)-visible spectroscopy. It showed that the Fe-Cu binary oxides were formed in single phase. SEM micrograph showed aggregates with many nano-sized particles. UV-visible spectroscopy showed quantum confinement effect.