Synergy of the flow behaviour and disperse phase of cellulose nanoparticles in enhancing oil recovery at reservoir condition.
ABSTRACT: Ascorbic acid was used for the first time to synthesize cellulose nanoparticles (CNP) extracted from okra mucilage. The physical properties of the CNP including their size distribution, and crystalline structures were investigated. The rheological properties of the cellulose nanofluid (CNF) were compared with the bulk okra mucilage and commercial polymer xanthan. The interfacial properties of the CNF at the interface of oil-water (O/W) system were investigated at different concentrations and temperatures. The effects of the interaction between the electrolyte and ultrasonic were determined. Core flooding experiment was conducted at reservoir condition to justify the effect of the flow behaviour and disperse phase behaviour of CNF on additional oil recovery. The performance of the CNF was compared to conventional EOR chemical. The combined method of ultrasonic, weak-acid hydrolysis and nanoprecipitation were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm, increased yield of 51% and preserved crystallinity respectively. The zeta potential result shows that the CNF was stable, and the surface charge signifies long term stability of the fluid when injected into oil field reservoirs. The CNF, okra and xanthan exhibited shear-thinning and pseudoplastic behaviour. The IFT decreased with increase in concentration of CNF, electrolyte and temperature. The pressure drop data confirmed the stability of CNF at 120°C and the formation of oil bank was enough to increase the oil recovery by 20%. CNF was found to be very effective in mobilizing residual oil at high-temperature high-pressure (HTHP) reservoir condition. The energy and cost estimations have shown that investing in ultrasonic-assisted weak-acid hydrolysis is easier, cost-effective, and can reduce energy consumption making the method economically advantageous compared to conventional methods.
Project description:The Arabidopsis seed coat is composed of two layers of mucilage, a water-soluble non-adherent outer layer and an adherent inner layer. The non-adherent mucilage can easily be extracted by gentle shaking. However, adherent mucilage is extremely difficult to dissociate from the seed coat. Despite various treatments to extract the adherent mucilage, including EDTA, ammonium oxalate, dilute alkali or acid washes, most of it remains on the seed coat. Here, we show for the first time the extraction of almost all of the adherent mucilage from the Arabidopsis seed coat. Our results demonstrate that ultrasonic treatment was able to extract the adherent mucilage effectively within 20?seconds. Adherent mucilage, like non-adherent mucilage, is mainly composed of rhamnogalacturonan I (RG I). The crystalline cellulose content in adherent mucilage was measured as 3.7?mg?g-1 of dry seed. Compared with non-adherent mucilage, the adherent mucilage exhibits relatively stable levels of sugar under various environmental conditions. In all cases, adherent mucilage showed higher levels of sugar than non-adherent mucilage. The cell wall remnant could associate with the adherent mucilage, which could prevent the extraction of the adherent mucilage. Our results show that ultrasonic treatment is an effective method for the quick extraction of Arabidopsis adherent mucilage with little effort.
Project description:Abstract: Never-dried bacterial cellulose (BC) and crosslinked cellulose nanofibers (CNF) were used for the removal of oil from stabilized and non-stabilized oil-in-water emulsions with droplet sizes less than 1 µm. The CNF membranes were exchanged with isopropyl alcohol before drying. The microscopic structure of the prepared membranes was evaluated using scanning electron microscopy (SEM); the water flux and the rejection of oil were evaluated using a dead-end filtration cell. BC harvested after different incubation time periods (2 to 10 days) did not show a change in the width of the nanofibers, but only the thickness of the membranes was increased. Pure water flux was not affected as a result of increasing thicknesses of BC membranes harvested after 4⁻10 days while BC harvested after two days had significantly higher water flux than the others. BC showed a higher flux and efficiency in removing oil from oil emulsions than CNF membranes. Removal of oil by the different membranes from the non-stabilized oil emulsion was more efficient than from the stabilized one.
Project description:Ionic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water-free topochemical modification of the nanocellulose (a process denoted as "WtF-Nano"). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co-solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non-dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide-angle X-ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1?D and 2?D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters.
Project description:Hybrid aerogels consisting of cellulose nanofibers (CNF) and modified few-walled carbon nanotubes (FWCNT) are investigated under cyclic mechanical compression to explore "electrical fatigue". For this purpose the FWCNTs were hydrophilized, thus promoting their aqueous dispersibility to allow FWCNT/CNF hybrid hydrogels, followed by freeze-drying to obtain hybrid aerogels. The optimized composition consisting of FWCNT/CNF 20/80 wt/wt showed conductivity of 10-5 S cm-1 as promoted due to double percolation, and showed only small changes in electrical and mechanical behaviour upon cycling 100 times. The electrical behaviour under cycled compression shows good stability and reversibility.
Project description:Cellulose nanocrystals (CNCs) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (T-CNFs) were tested as enhanced oil recovery (EOR) agents through core floods and microfluidic experiments. Both particles were mixed with low salinity water (LSW). The core floods were grouped into three parts based on the research objectives. In Part 1, secondary core flood using CNCs was compared to regular water flooding at fixed conditions, by reusing the same core plug to maintain the same pore structure. CNCs produced 5.8% of original oil in place (OOIP) more oil than LSW. For Part 2, the effect of injection scheme, temperature, and rock wettability was investigated using CNCs. The same trend was observed for the secondary floods, with CNCs performing better than their parallel experiment using LSW. Furthermore, the particles seemed to perform better under mixed-wet conditions. Additional oil (2.9-15.7% of OOIP) was produced when CNCs were injected as a tertiary EOR agent, with more incremental oil produced at high temperature. In the final part, the effect of particle type was studied. T-CNFs produced significantly more oil compared to CNCs. However, the injection of T-CNF particles resulted in a steep increase in pressure, which never stabilized. Furthermore, a filter cake was observed at the core face after the experiment was completed. Microfluidic experiments showed that both T-CNF and CNC nanofluids led to a better sweep efficiency compared to low salinity water flooding. T-CNF particles showed the ability to enhance the oil recovery by breaking up events and reducing the trapping efficiency of the porous medium. A higher flow rate resulted in lower oil recovery factors and higher remaining oil connectivity. Contact angle and interfacial tension measurements were conducted to understand the oil recovery mechanisms. CNCs altered the interfacial tension the most, while T-CNFs had the largest effect on the contact angle. However, the changes were not significant enough for them to be considered primary EOR mechanisms.
Project description:The seed coat mucilage envelope is formed just after hydration and surrounds the seed as a gel-like, transparent capsule. The mucilage envelope represents a special type of modified cell wall with all of the typical polysaccharides i.e. cellulose, pectins and hemicelluloses. The chemical composition of the mucilage is well-recognized but its structural organization remains unclear. In the presented study, we visualized the spatial architecture of the seed mucilage envelope of selected taxa which produce cellulose mucilage. Using critical point drying (CPD) and scanning electron microscopy (SEM) imaging, we demonstrated the structural details of the mucilage from the micro- down to the nanoscale. The mucilage, after CPD, had a visibly spatial structure which differed between the studied taxa; for example, a tangled organization in Arabidopsis thaliana and a more ordered arrangement in Ocimum basilicum were revealed. In general, the mucilaginous fibrillary components formed network made of long, unbranched, thicker cellulose fibrils together with shorter, thinner and, often branched other polysaccharides. Cellulose fibrils built a kind of scaffold for the rest of the components which were spread between them and/or covered their surface. The cellulose fibrils were attached to the seed surface, and therefore prevent the loss of the mucilage envelope during mechanical impacts. The loose architecture and special chemical composition of the mucilaginous cell wall is important for water binding and storage, which are crucial for the proper functioning of the seed mucilage envelope.
Project description:The fabrication of smart biocomposites from sustainable resources that could replace today's petroleum-derived polymer materials is a growing field of research. Here, we report preparation of novel biocomposites using nanocellulose networks extracted from food residue (onion skin) and a vegetable oil-based bioresin. The resin was synthesized via the Diels-Alder reaction between furfuryl methacrylate and tung oil at various ratios of the components. The onion-skin-extracted cellulose nanofiber and cellulose nanocrystal networks were then impregnated with the resins yielding biocomposites that exhibited improved mechanical strength and higher storage modulus values. The properties of the resins, as well as biocomposites, were affected by the resin compositions. A 190-240-fold increase in mechanical strength was observed in the cellulose nanofiber (CNF) and cellulose nanocrystal (CNC)-reinforced biocomposites with low furfuryl methacrylate content. The biocomposites exhibited interesting shape-memory behavior with 80-96% shape recovery being observed after 7 creep cycles.
Project description:The plant cell wall is held together by the interactions between four major components: cellulose, pectin, hemicellulose, and proteins. Mucilage is a powerful model system to study the interactions between these components as it is formed of polysaccharides that are deposited in the apoplast of seed coat epidermal cells during seed development. When seeds are hydrated, these polysaccharides expand rapidly out of the apoplastic pocket, and form an adherent halo of mucilage around the seed. In Arabidopsis, mutations in multiple genes have similar loss of mucilage adherence phenotypes including CELLULOSE SYNTHASE 5 (CESA5)/MUCILAGE-MODIFIED 3 (MUM3), MUM5/MUCI21, SALT-OVERLY SENSITIVE 5 (SOS5), and FEI2. Here, we examine the interactions between these factors to better understand how they participate to control mucilage adherence. Double mutant phenotypes indicated that MUM5 and CESA5 function in a common mechanism that adheres pectin to the seed through the biosynthesis of cellulose and xylan, whereas SOS5 and FEI2, encoding a fasciclin-like arabinogalactan protein or a receptor-like kinase, respectively, function through an independent pathway. Cytological analyses of mucilage indicates that heteromannans are associated with cellulose, and not in the pathway involving SOS5 or FEI2. A SOS5 fluorescent protein fusion (SOS5-mCITRINE) was localized throughout the mucilage pocket, consistent with a structural role in pectin adhesion. The relationship between SOS5 and FEI2 mediated mucilage adherence was examined in more detail and while sos5 and fei2 mutants show similar phenotypes, key differences in the macromolecular characteristics and amounts of mucilage polymers were observed. FEI2 thus appears to have additional, as well as overlapping functions, with SOS5. Given that FEI2 is required for SOS5 function, we propose that FEI2 serves to localize SOS5 at the plasma membrane where it establishes interactions with mucilage polysaccharides, notably pectins, required for mucilage adherence prior to SOS5 being released into the apoplast.
Project description:Environmental and health concerns are driving the need for new materials in food packaging to replace poly- or perfluorinated compounds, aluminum layers, and petroleum-based polymers. Cellulose nanofibrils (CNF) have been shown by a number of groups to form excellent barrier layers to oxygen and grease. However, the influence of lignin-containing cellulose nanofibrils (LCNF) on film barrier properties has not been well reported. Herein, thin films (16 g/m2) from LCNF and CNF were formed on paper substrates through a filtration technique that should mimic the addition of material at the wet end of a paper machine. Surface, barrier and mechanical attributes of these samples were characterized. The analysis on the surface free energy and water contact angle pointed to the positive role of lignin distribution in inducing a certain degree of water repellency. The observed oxygen transmission rate (OTR) and water vapor permeability (WVP) values of LCNF-coated samples were nearly similar to those with CNF. However, the presence of lignin improved the oil proof performance; these layered designs exhibited an excellent resistance to grease (kit No. 12). The attained papers with LCNF coat were formed into bowl-like containers using metal molds and a facile oven drying protocol to evaluate their resistance to oil penetration over a longer period. The results confirmed the capability of LCNF layer in holding commercially available cooking oils with no evidence of leakage for over five months. Also, an improvement in the tensile strength and elongation at break was observed in the studied papers. Overall, the proposed packaging material possesses viable architecture and can be considered as a fully wood-based alternative for the current fluorocarbon systems.
Project description:The influence of nanocellulose on oil well cement (OWC) properties is not known in detail, despite recent advances in nanocellulose technology and its related composite materials. The effect of cellulose nanofibers (CNFs) on flow, hydration, morphology, and strength of OWC was investigated using a range of spectroscopic methods coupled with rheological modelling and strength analysis. The Vom-Berg model showed the best fitting result of the rheology data. The addition of CNFs increased the yield stress of OWC slurry and degree of hydration value of hydrated CNF-OWC composites. The flexural strength of hydrated OWC samples was increased by 20.7% at the CNF/OWC ratio of 0.04?wt%. Excessive addition of CNFs into OWC matrix had a detrimental effect on the mechanical properties of hydrated CNF-OWC composites. This phenomenon was attributed to the aggregation of CNFs as observed through coupled morphological and elemental analysis. This study demonstrates a sustainable reinforcing nano-material for use in cement-based formulations.