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A significant quantity of hydrocarbons remains in the reservoir after production using primary and secondary techniques. Traditional recovery techniques produce about 33 % of the original oil in place. However, the utilization of chemicals such as surfactants and polymers facilitate the additional recovery of one‐third of this oil. Researchers are currently aiming at mixing surfactant and nanoparticles for their potential applications in petroleum industry. In this work, authors claimed to be the first to study usage of synthesized Mesoporous Silica Nanoparticles (MSN) with Sodium Dodecyl Sulphate (SDS) surfactant to understand its applicability in Chemical Enhanced Oil Recovery through evaluation of the surface tension & Interfacial tension, surfactant adsorption, contact angle, and core flooding experiments. Surface tension studies revealed a synergistic interaction between MSN and anionic surfactant molecules. With the introduction of 2500 ppm of anionic surfactant, the surface tension of deionized water reduces to 34.5 mN/m from 72.4 mN/m. The surface tension of the mixture was further lowered by ∼9.8 % with the addition of 300 ppm MSN. The Interfacial Tension results also showed the same trend. When 300 ppm of MSN was introduced, then IFT values decreases from 8.13 mN/m to 3.91 mN/m at 2500 ppm of anionic surfactant. Contact angle measurements after MSN injection went from 77.98° for SDS (2500 ppm) to 73.36°, 66.54°, and 41.95° for 100, 200, and 300 ppm of MSN, respectively. This demonstrates that the shift toward water‐wet behavior increased along with the MSN concentration. Additionally, adding 300 ppm of MSN lowered surfactant adsorption by ∼80 % at a surfactant concentration of 2500 ppm. Up to 72.27 % of the OOIP could be recovered using the chemical slug made of SDS surfactant, polymer, and MSN. The research data suggests that the MSN can increase the effectiveness of the chemical injection approach, which can be used to recover more oil. [ABSTRACT FROM AUTHOR]

Surfactant flooding is a prolific enhanced oil recovery technique. It alters the rock fluid interfacial interactions between reservoir fluids and rocks. However, a pair of impeding factors often limit the economic viability of the process and need to be optimized. The first is the surfactant loss on the adsorbent surface due to adsorption making it a potential environmental problem. The second is the Critical Micelle Concentration (CMC) which governs the amount of surfactant pumped. This study aimed to minimize the surfactant loss and the CMC, thereby optimizing the flooding efficiency and reducing the environmental concerns for nanoparticle applications. To achieve this, Silicon Carbide nanoparticles (SCN) were employed as additives to the surfactant solution. It was observed that the use of SCN reduces the surfactant adsorption by as much as 44 % and the critical micelle concentration by 14 %. The studies also observed that the concentration of SCN required to get these results is dramatically (more than 25 times) lower than previously reported literature on other nanoparticles. To adsorption isotherm studies provide an insight into the type of adsorption taking place. The adsorption isotherm follows the Langmuir model. [ABSTRACT FROM AUTHOR]

The thermally stable drilling fluid is the need of the oil and gas industry. The impetus for producing appropriate drilling fluid lies in the addition of novel polymeric additives. The addition of polymer improves the filtration and rheological properties of the drilling fluid. Poly(4‐styrene sulfonic acid‐co‐maleic acid) sodium salt (PSSM), a low‐molecular‐weight polymer, exhibited filtration and rheological control in the water‐based drilling fluid system containing bentonite and hydroxyethyl cellulose. The polymer was characterized using a thermogravimetric technique and found to be stable up to 250°C. The optimum concentration for PSSM is 1.0 w/v% as fluid loss from the drilling fluid reduced by ~63% on addition of 1.0 w/v% PSSM and by ~75% on addition of 2.0 w/v% PSSM. The addition of CuO and ZnO nanoparticles (NPs) to the PSSM‐induced drilling fluid further improved the rheological and filtration properties at elevated temperature. The thermal aging studies confirm the stability of the drilling mud up to 110°C in the presence of NPs. The addition of PSSM and NPs significantly improved the mud performance due to PSSM interactions with NPs and other mud additives even at high temperatures which suggests the applicability of these mud formulations for challenging high‐temperature wells. [ABSTRACT FROM AUTHOR]

Cerium oxide (CeO2) nanoparticles of size 3–5 nm and surface area 257 m2 g−1 were synthesized using simple, single‐pot, and surfactant‐free aerogel process. Efforts were made to tune the surface area and porosity of CeO2 nanoparticles by changing the concentration of precursors. CeO2 nanoparticles were characterized by TEM, SEM, XRD, N2‐BET, and FTIR. Prepared CeO2 was used to remove As(III) and As(V) from water at variable contaminant concentrations (25–100 ppm) and pH (3–10). The adsorption process found extremely fast for the first few minutes of exposure. CeO2 nanoparticles indicated adsorption capacities of 71.9 and 36.8 mg g−1 against As(III) and As(V), respectively. The adsorption data best fitted with Redlich–Peterson model, depicting monolayer adsorption. The adsorption followed pseudo‐second‐order kinetics and intraparticle diffusion with three‐step diffusion process. The effect of co‐existing anions (H2 PO 4 −, SO 4 2 −, and HCO 3 −) indicated 80–96% reduction in adsorption capacity. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 221–231, 2018 [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of two nontoxic, thermogelling drug delivery systems which are liquid at room temperatures but become a gel at physiological temperature (37°C) potentially leading to release of a drug molecule. We selected temperature as the stimulus for drug release as it is physiologically invariant. A free radical polymerization of N-isopropylacrylamide (NIPAM) and N-vinylpyrrolidone (VP) was carried out under nitrogen atmosphere in double-distilled water at two different temperatures (30°C and 70°C), and the copolymers obtained were characterized by various analytical techniques. The molar ratios of the two monomers were altered with increasing NIPAM content and their cloud point temperature or least critical solution temperature (LCST) was determined. The copolymer at 9:1 ratio of NIPAM to VP resulted in the formation of nanoparticle-based gel (NG1) at 30°C; however, at 70°C, a microgel (MG1) was formed. The LCST of the nanogel and microgel was 33.5-34°C and 36.5-37°C, respectively. Thus, both the copolymers are water soluble at room temperature, but distinct phases appear at physiological temperatures. We hypothesized that these copolymers on entrapment with a drug could be used for topical application to the skin or eye for controlled drug delivery applications. Toxicological studies revealed that the copolymers are nontoxic in HeLa cells. Finally, our experiments show that a model drug [bovine serum albumin (BSA)] is released at 37°C with zero-order kinetics and confirmed using multiple well-known mathematical models. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. [ABSTRACT FROM AUTHOR]

The article presents a study examining the kinetics of adsorption of 2-chloroethylethyl sulfide (2-CEES) and sulfur mustard (HD) on silica nanoparticles that were impregnated with reactive chemicals. The effectiveness of the chemicals against HD is noted, as well as the static conditions under which the kinetics of adsorption of 2-CEES and HD were studied. Linear driving force and Fickian diffusion models were used for the examination, noting that the study determined kinetic parameters including equilibration constant, equilibration capacity, and diffusional exponent.

In this study, liver-directed gene transfer in rats with calcium phosphate (CaP) nanoparticles and the effect of the route of administration and surgical manipulations on transfection efficiency is reported. Formulations of CaP nanoparticles entrapping plasmid DNA (pDNA) were prepared by the reverse micellar method using two different surfactants. Transmission electron microscopy, scanning electron microscopy and dynamic light scattering were used to characterize the CaP–DNA nanocomposites. The morphological characteristics of the formulations showed a strong dependency on temperature. Gel electrophoresis experiments indicated that there was no degradation of the encapsulated pDNA, and in vitro cell transfection in HEK-293 and primary hepatocytes from rats as well as in vivo intraductal delivery experiments suggested that CaP nanoparticles led to significant and prolonged transgene expression. Therefore, our methodology gives a stable and viable formulation for hepatic gene therapy. Low-DNA dosage entrapped in CaP nanoparticles makes it an effective gene delivery system for clinical applications. [ABSTRACT FROM AUTHOR]