Zirconium preconcentration from zircon raffinate using gamma radiation-induced polymerization of reduced graphene oxide composite.

Zirconium is commonly used as a cladding material for nuclear reactors. The purity of the zirconium material seeks to control reactor efficiency. A novel composite of reduced graphene oxide-grafted polyacrylic acid, malic acid, and trioctylamine (rGO-g-PAA-MA/TOA) was prepared using in situ radical polymerization with gamma radiation at a dose of 25 KGy from a 60Co cell to preconcentrate zirconium Zr(IV) from zircon raffinate. Five distinct rGO-g-PAA-MA/TOA composite compositions were created and evaluated. The best composite composition was 62.95% acrylic acid, 15.8% malic acid, and 15.8% trioctylamine. After 60 min, the sorption reaction reached equilibrium at pH 0.35 and 20 °C. The pseudo nth order indicated that the order of the sorption reaction was 1.8476. The Elovich model and Dubinin-Radushkevich model controlled the kinetic mechanism and adsorption isotherm of the sorption reaction, respectively; based on estimated regression plots and quantitatively with three different error functions: coefficient of determination (R2), chi-square statistic (χ2), and corrected Akaike information (AICc). The adsorption capacity of rGO-g-PAA-MA/TOA was 75.06 mg g-1. Exothermic reaction and spontaneous sorption took place. Using 2 M H2SO4, 98% of the zirconium was efficiently desorbed. The separation of contaminated Ti(IV) from desorbed Zr(IV) by raising pH to 2.5 through hydrolysis and ZrO2 formation.

Valorization of Wild-Type Cannabis indica by Supercritical CO2 Extraction and Insights into the Utilization of Raffinate Biomass

Supercritical CO2 extraction (SCCO2) extraction of cannabis oil from Indian cannabis (Cannabis indica) leaves was optimized through a central composite design using CO2 pressure (150-250 bar), temperature (30-50 °C) and time (1-2 h). From the regression model, the optimal CO2 pressure, extraction temperature and time were 250 bar, 43 °C and 1.7 h, respectively resulting in the experimental yield of 4.9 wt% of cannabis oil via SCCO2 extraction. The extract contained cannabidiol, tetrahydrocannabivarin, Δ9-tetrahydrocannabinol and Δ8-tetrahydrocannabinol as well as two terpenoids such as cis-caryophyllene and α-humulene. Besides SCCO2 extraction of cannabis oil, the raffinate biomass was utilized to extract polyphenols using water as the extraction medium. Cannabis oil and water extractive were investigated for their half-maximal inhibitory concentration (IC50) values, which were found to be 1.3 and 0.6 mg/mL, respectively. This is comparable to the commercially available antioxidant such as butylated hydroxytoluene with an IC50 value of 0.5 mg/mL. This work on SCCO2 extraction of cannabinoids and other valuable bioactive compounds provides an environmentally sustainable technique to valorize cannabis leaves.

Nd(III) hypersensitive peak as an optical absorption probe for determining nitric acid in aqueous solution: An application to aqueous raffinate solutions in nuclear reprocessing.

A new method using Nd(III) absorption peak as a probe is described for the measurement of nitric acid concentration in aqueous solution. The hypersensitive peak of Nd(III) at 575.1 nm shows a substantial enhancement in the absorbance in comparison to other absorption peaks with increasing nitric acid concentration. The integrated area and absorbance of this hypersensitive peak show a linear dependency over a large dynamic range of 0.5-15.5 M of nitric acid. A methodology for the correction of spectral interference to the probing absorption peak of Nd(III) is also reported. The method is applied for the measurement of nitric acid in synthetic high level liquid waste solution and shown to be comparable to that obtained by titrimetric method. The present method can be easily adopted for the measurement of nitric acid concentration in aqueous raffinate solutions of nuclear reprocessing streams.

Application of oxidation-reduction potential (ORP) as a controlling parameter during the synthesis of Fe3O4@PVA nanocomposites from industrial waste (raffinate).

The objective of this study was to develop a process for the synthesis of magnetite nanocomposites from raffinate of hydrometallurgical plants containing iron ions. Towards this goal, a three-step process was developed. After the reduction of Fe(III) to Fe(II) in the first stage, Al3+ in the raffinate was precipitated as Al(OH)3 and finally magnetite NPs were synthesized by chemical co-precipitation method via controlling the oxidation-reduction potentials (ORPs). The produced nanomaterials were analyzed using XRD, TEM, VSM, TGA, and FTIR. The TG, XPS, and FTIR results affirmed the existence of PVA while TEM images illustrated the spherical nanoparticles with an average size of about 19 ± 4 nm. Evaluation of VSM data indicated the highly ferromagnetic behavior for Fe3O4 and Fe3O4@PVA products at the room temperature with a saturation magnetization of 46.98 and 35.78 emu/g, respectively.

Partial propane extraction of aromatic compounds from dehydrated basils (Ocimum Lamiaceae).

BACKGROUND: Many conventional extraction methods for basils (Ocimum sp. Lamiaceae) produce only the extract as a usable product and leave the extracted herb as a waste product. We demonstrate partial extraction of chemically and morphologically diverse basil cultivars using propane at low temperature (20-27 °C) and pressure (950-1200 kPa) and evaluate the process for production of dual products, the extracted herb (raffinate) and the herb extract in terms of aromatic content and color. RESULTS: The extracts contained aromatic compounds that were characteristic of but not always identical in terms of relative abundance to the dehydrated herb. Extraction decreased total aromatics in the raffinate by 12-43% but the individual aromatic proportions remained essentially the same, preserving flavor characteristics of the raffinate. Color was mostly unchanged by the extraction process. CONCLUSION: Partial propane extraction resulted in two useful basil products (an extract and extraction raffinate). Aromatic extractability was tissue and cultivar dependent for basils. Therefore, partial extraction protocols should be optimized according to cultivar/plant tissue abundance to provide consistent aromatic intensity of these potential food products. © 2019 Society of Chemical Industry.

Recovery of Butanol by Counter-Current Carbon Dioxide Fractionation with its Potential Application to Butanol Fermentation.

A counter-current CO2 fractionation method was applied as a mean to recover n-butanol and other compounds that are typically obtained from biobutanol fermentation broth from aqueous solutions. The influence of operating variables, such as solvent-to-feed ratio, temperature, pressure and feed solution composition was experimentally studied in terms of separation efficiency, butanol removal rate, total removal and butanol concentration in the extract at the end of the continuous cycle. With respect to the temperature and pressure conditions investigated, results show that the highest separation efficiency was obtained at 35 °C and 10.34 MPa. At these operating conditions, 92.3% of the butanol present in the feed solution was extracted, and a concentration of 787.5 g·L-1 of butanol in the extract was obtained, starting from a feed solution of 20 g·L-1. Selectivity was calculated from experimental data, concluding that our column performs much better than a single equilibrium stage. When adding ethanol and acetone to the feed solution, ethanol was detected in the water-rich fraction (raffinate), whereas the highest concentration of acetone was found in the butanol rich fraction (extract).