Malvern zetasizer pro

Thirty of microliters of ZnO, CuO, Ag, and AgNW NM suspensions (100 µg/mL) in ethanol were dropped onto a carbon-coated 200-mesh copper grid (Zhongjingkeyi Technology, Beijing, China). The grids were observed using transmission electron microscopy (TEM; HT7800, HITACHI, Tokyo, Japan) operating at an acceleration voltage of 120 kV and equipped with a complementary metal oxide semiconductor (CMOS) digital camera.
The hydrodynamic size distribution of the ZnO, CuO, Ag, and AgNW nanomaterials was evaluated by dynamic light scattering (DLS) analysis using a Malvern Zetasizer Pro (Malvern Zetasizer Pro, Worcestershire, UK). The hydrodynamic behavior was assessed by dispersing these NMs (final concentration, 100 µg/mL) in Milli-Q (mQ) water and medium. At least three biological replicates were examined for each experiment.
The zeta potential distribution of the NMs was evaluated by electrophoretic light scattering (ELS) using a Malvern Zetasizer Pro. The hydrodynamic behavior was assessed by dispersing these nanomaterials (final concentration, 100 µg/mL) in Milli-Q (mQ) water. At least three biological replicates were examined for each experiment.

Four core floods have been conducted seeking to analyse effluents for nanoparticle and tracer concentration. Selected effluent samples were analysed using a Flow Field Flow Fractionation (FFF), Dynamic Light Scattering (DLS) and Multi-Angle Light Scattering (MALS). Each core flood comprised of (1) an initial flush with TW, (2) a low concentration nano injection, (3) TW flush, (4) a high concentration of nanofluid injection and (5) TW post flush.
To separate the solids by size in the sample prior to the measurement, effluent samples were fractionated using an AF2000 Flow FFF System (Postnova Analytics GmbH, Landsberg am Lech, Germany). Consequently, samples were analysed using a PN3621 Multi-Angle Light Scattering (MALS) and a PN3704 Dynamic Light Scattering (DLS) system (both from Postnova Analytics GmbH, Landsberg am Lech, Germany) to measure particle size, a nanoPartica SZ-100V2 Series (HORIBA Europe GmbH, Barleben, Germany) was used. Additionally, effects on particle size caused by the brine were investigated. Therefore, 0.1 wt% of each nanofluid was mixed with TW and FW and analysed using a Malvern Zetasizer Pro (Malvern Panalytical Ltd., Malvern, UK).

The NP films prepared on Si wafers via the EPD process were characterized as follows. The X-ray diffraction (XRD) patterns were collected using an AXS New D8 advance diffractometer (Bruker, Billerica, MA, USA) with a Cu K-α radiation source and a LynxEye line detector. The samples for XRD were prepared by drop-casting the Cu_2-xS NPs onto zero-background quartz. Field-emission scanning electron microscopy (FE-SEM) and energy-dispersive spectrometry (EDS) were performed using a Carl Zeiss SIGMA microscope. In addition, X-ray photoelectron spectroscopy (XPS) was performed on a K-alpha system (Thermo Fisher Scientific, Waltham, MA, USA) with an Al K-α source. FTIR spectroscopy was performed in a Nicolet 6700 spectrometer (Thermo Fisher Scientific) at room temperature. The FTIR samples were prepared as a powder. Zeta potential and dynamic light scattering (DLS) measurements were performed using a Malvern Zetasizer Pro (Malvern Instruments, Malvern, WR, UK) instrument with a universal dip cell kit for samples in non-aqueous (palladium electrodes with 2 mm spacing).

Nanomaterials A and B were provided by Evonik Operations GmbH (Hanau, Germany) in form of a dispersion. They exhibit a size of about 110 nm (see Table 4), and their concentration in distilled water varies from 22.5 to 27.9 wt.%. The base material of both is fumed amorphous silica (AEROSIL^® fumed silica, Evonik Hanau - Germany). The surface of nanomaterial A is coated with polyethylene glycol (PEG), while the surface of nanomaterial B has a diol functionality. ζ potential was assessed using a Nano Z manufactured by Malvern Zetasizer Pro (Malvern Panalytical Ltd., Malvern - United Kingdom), which relies on using the technique of dynamic light scattering (DLS). The dispersion was titrated over a pH range (3–10) as shown in Figure 1. The PEG-coated nanomaterial type A has a zeta potential of between −3 and −8.5 mV. The diol-coated nanomaterial type B exhibits a zeta potential which is lower (−14 to −18 mV) and rather constant over the whole pH range (Figure 1). With a pH of around 10, that is typical for alkaline flooding according to French and Burchfield [49 (link)]; the zeta potential is ~−8 mV (nanomaterial type A), and −16 mV (nanomaterial type B). Figure 2. shows Transmission Electron Microscopy (TEM) (Jeol 2010F, 200 KV, Tokyo Japan) images of the nanomaterials. The structure of the fumed silica with high fractal dimensions is clearly visible.

To prepare coacervates in the absence of protein, 25 μL of polyanion solution were mixed with a proper volume of PLL with the cation to anion ratio (C : A) 1 : 1 via gentle pipetting. The final volume was adjusted to 120 μL by adding a proper buffer. Salt concentration was adjusted using a 2 M NaCl buffer before mixing polymer solutions. The mixture was equilibrated at 4 °C, at least, for 3 h followed by centrifugation at 1000 G, 10 min (KUBOTA 5922, Kubota Corporation, Osaka, Japan). The supernatant (∼100 μL) was carefully aspirated and used for DLS measurement (Malvern ZETASIZER PRO, Malvern Panalytical Ltd, Malvern, UK) and TEM (JEM-2010, JEOL, Ltd, Japan) observation. The formation of coacervate was verified by visual observation of distinct macro-phase separation in the tube and microscopic observation of the distinct droplet formation by brightfield imaging using a BZ-X810 microscope (Keyence Corporation, Osaka, Japan) with 40× objective lens (PlanApoλ NA 0.95, Nikon, Tokyo, Japan). For microscope observation, first, coverslip (22 × 40 mm, 0.17 mm thickness) was attached to the pre-cleaned standard glass-slide (S2215, Matsunami) using two-sided tape to have little gap in between glass-slide and coverslip. Then, approximately 20 μL of dispersed coacervate solution was loaded into the gap and observed under the microscope.

The structure of AgNps was analyzed by FTIR spectroscopy using a Shimadzu IRSpirit spectrophotometer in ATR mode (400–4000 cm⁻¹). Transmission electron microscopy (TEM) images were obtained using a Hitachi High-Tech HT7700 microscope (Tokyo, Japan) at 100 kV and the AgNPs-CS solution (1 mg/mL) was deposited onto 300 mesh carbon coated copper grid and dried under vacuum. The average diameter of AgNps was investigated by Dynamic Light Scattering (DLS) measurements in ddH2O using a Malvern Zetasizer Pro (Malvern Pananalytical, Worcestershire, UK). The silver content from AgNps-CS (dispersed in 5% HNO₃ aqueous solution) was determined by atomic absorption spectroscopy (AAS) using a ContrAA 800 spectrometer from Analytik Jena (Jena, Germany) with air/acetylene flame at 328 nm.