Ce no3 3 6h2o

CeO_x NCs were synthesized by a modified procedure described in the literature.^{31 (link)} 6.0 g of Ce(NO₃)₃·6H₂O (99%, Aldrich) was added to 70 mL distilled water with stirring till it was sufficiently dissolved. An NH₄OH (NH₃ content 28–30%, Aldrich, ACS reagent) solution was then added dropwise until a pH of 10 was reached. Then, cerium nitrate completely converted to cerium hydroxide and precipitated, which was separated by centrifugation and washed with deionized water repeatedly. Then, it was dissolved in 140 mL of a 0.1 M urea aqueous solution and adjusted to pH 2 by the addition of dilute hydrochloric acid (10%). The concentration of the obtained solution was assessed as 82 mM by calculating its xerogels at 600 °C for 2 h. The obtained CeO_x sol–gel solution was stored at room temperature to prepare ETLs.

A sandstone reservoir in Iran provided the crude oil and core. The density, API, and crude oil viscosity at a reservoir pressure of 1800 Psi and temperature of 60 °C are 0.846 cm/g, 28, and 9.9 cP, respectively. Core porosity, core permeability, and GOR were found to be 22.5%, 27.45 mD, 240 scf/STB, and 232, in that order. Figure 1 displays the SARA (saturate-aromatic-resin-asphaltene) test findings.Figure 1

Compositional specifications of the oil.

Na₂CO₃ (99.9%), Ce (NO₃)₃.6H₂O (98.5%), and Zn (NO₃)₂.6H₂O (99%) were obtained from Merck company. All the purchased materials were used at a high level of qualifications.

CNPs were synthetized by direct precipitation from an aqueous solution. They were stabilized by PAA as described previously [34 (link),35 (link)]. Briefly, Ce(NO₃)₃·6H₂O (0.1243 g; Merck, Milan, Italy) was dissolved in 50 mL distilled water. PAA (1.22%, Polyscience, Warrington, PA, USA) was added to obtain a 2:1 (v/v) ratio. A concentrated NH₄OH solution was added to obtain a pH of about 12 and the solution was kept under constant stirring for 48 h. After centrifugation (13,000× g), the supernatant was recovered in deionized H₂O. The final CNP suspension had a CeO₂ concentration of ~5 mg/mL, as determined by an inductively coupled plasma–optical emission spectrometry analysis. For the preparation of fluorescent CNPs (Em 580 nm), DiI fluorescent dye was added during the synthesis as previously described [35 (link)].
The nanoparticle characterizations were performed as previously described [34 (link),35 (link)]. The synthetized CNPs had a hydrodynamic diameter of 14 nm and a Z potential of −20 as evaluated with a Nano ZS90 DLS apparatus (Malvern Instruments, Malvern, UK). The X-ray diffraction (XRD) analysis was performed using a Bruker D8 Advance diffractometer (Bruker Corp., Billerica, MA, USA) operated at 40 kV and 40 mA, showing a dimension of about 5 nm.

All chemicals of reagent grade quality were obtained from commercial sources and used without further purification. CoSO₄·6H₂O (50.0 mmol), Ce(NO₃)₃·6H₂O (50.0 mmol), NiSO₄·6H₂O (50.0 mmol), and CuSO₄·5H₂O (50.0 mmol) were purchased from Merck (Milipore, Darmstadt, Germany). 1-Hydroxyethane-1,1-diphosphonic acid, sodium hydroxide, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium nitrate, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methyl-imidazolium chloride, 2,6-dimethylphenol, and 4,4′-dihydroxybiphenyl were obtained from Sigma-Aldrich Chemie GmbH (München, Germany), and urea from Alfa Aesar (Karlsruhe, Germany).

PVB was purchased from Kuraray Europe GmbH. PEG was purchased from Merck. The metal salts for doping of fused silica glass (HAuCl₄·xH₂O (≈50% Au basis), CoSO₄·7H₂O, and Ce(NO₃)₃·6H₂O were purchased from Merck. PLA filament for printing of support structures was purchased from Ultimaker, Netherlands.

Ethanol (Merck), NiCl₂.6H₂O (Sigma Aldrich), NaOH (Sigma Aldrich), Hydrazine Hydrate (64%–65%, Sigma Aldrich), Ethylene glycol (Merck), KOH (Sigma Aldrich), Cr(NO₃)₃.9H₂O (Merck), Ce(NO₃)₃.6H₂O (Merck). All the chemicals were used as received without further purifications.