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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6

Modelling and Optimization of Uranium (VI) Ions Adsorption Onto Nano-ZnO/Chitosan Bio-composite Beads with Response Surface Methodology (RSM)

Nano-ZnO-chitosan bio-composite beads were prepared for the sorption of UO{sub 2}{sup 2+} from aqueous media. The resulting nano-ZnO/CTS bio-composite beads were characterized by TEM, XRD etc. The sorption of UO{sub 2}{sup 2+} by bio-composite beads was optimized using RSM. The correlation between four variables was modelled and studied. According to RSM data, correlation coefficients (R{sup 2} = 0.99) and probability F-values (F = 2.24 × 10{sup − 10}) show that the model fits the experimental data well. Adsorption capacity for nano-ZnO/CTS bio-composite beads was obtained at 148.7 mg/g under optimum conditions. The results indicate that nano-ZnO/CTS bio-composite beads are appropriate for the adsorption of UO{sub 2}{sup 2+} ions from aqueous media. Also, the suitability of adsorption values to adsorption isotherms was researched and thermodynamic data were calculated.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Highly Efficient Removal of Lead Ions from Aqueous Solutions Using Chitosan/Rice Husk Ash/Nano Alumina with a Focus on Optimization by Response Surface Methodology: Isotherm, Kinetic, and Thermodynamic Studies

In the present study, an adsorbent named chitosan/rice husk ash/nano-γ alumina was prepared and used for the removal of lead ions from aqueous solutions. It was characterized by FESEM, FTIR, XRD, and BET. The important and interactive effects of some considered parameters, such as the initial lead ion concentration, pH, adsorbent mass and contact time, were estimated and optimized by using the central composite design (CCD). The Maximum adsorption efficiency of lead ions under optimum conditions, including the pH of 5, adsorbent mass of 0.01 g, the initial lead ion concentration of 30 ppm, and the contact time of 105 min, was achieved to be 90.98%. The adsorption kinetic was consistent with the pseudo-second-order model (R{sup 2} = 0.9967). The lead adsorption isotherms were well fitted to the Langmuir model, indicating the maximum adsorption capacity of 181.82 mg g{sup −1}. Thermodynamic parameters (R{sup 2}: 0.9200, ΔH°: − 22871.81 kJ mol{sup −1}, ΔG{sup °}: − 10.63 kJ mol{sup −1}, and ΔS{sup °}: 118.37 kJ mol{sup −1} K{sup −1}) were calculated and indicating adsorption process was exothermic and spontaneous in the temperature range of 283.15–313.15 k. The maintenance above 70% capacity of the adsorbent was observed by the regeneration study of chitosan/rice husk ash/nano-γ alumina after six cycles. Comparison of adsorption efficiency of the studied adsorbent and other adsorbents in the removal of lead ions was also done in this paper. Consequently, the excellent properties of the presented nanocomposite could make it an ideal adsorbent for the removal of lead ions from aqueous solutions. Graphical Abstract: .

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Data from Response Surface Methodology Guided Adsorption and Recovery of Free Fatty Acids from Oil Using Resin

The presence of free fatty acids interferes with the conversion of plant oils to biodiesel. Four strong and weak base resins were evaluated for the removal of free fatty acids (FFA) from oil. Amberlite FPA 51 showed the highest adsorption capacity of FFA. A resin concentration above 3% could enable a higher percentage FFA adsorption. The adsorption process fitted a pseudo-first-order kinetic model and achieved equilibrium in approximately 8 h. A full factorial design was used to optimize the resin and FFA concentrations at a fixed temperature (40° C). A ratio of resin to fatty acid concentrations above 1.875 was sufficient for 70% adsorption and the amount adsorbed continued to increase with further added resin. A two-step washing of resin using hexane and ethanol recovered approximately 67.55% ± 4.05% of the initially added fatty acid. The resin that was used was regenerated with 5% NaOH and re-used for a minimum of three consecutive cycles. However, the adsorption capacity diminished to 75% of the initial cycle in cycles 2 and 3. Thus, the work presents a resin-based process for deacidification of oil to reduce fatty acid content of oil for biodiesel production.

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