Trapping Capacity Research Articles

CO2 geological sequestration in multiscale heterogeneous aquifers: Effects of heterogeneity, connectivity, impurity, and hysteresis

Fundamental understanding of processes controlling geological carbon sequestration (GCS) requires flow and transport modeling in well-characterized aquifer sedimentary deposits. We use three-dimensional, heterogeneous models based on new field studies which incorporate the most important aspects of multiscale architecture in fluvial aquifers. In addition, we use the associated facies-dependent constitutive relations for both relative permeability and capillary pressure curves and their hysteresis. The novelty of this work is to evaluate how CO2 fate and transport is controlled by (1) the spatial organization, volume proportions, and connectivity of sedimentary facies types, (2) facies-dependent constitutive relations and their hysteretic behavior, and (3) presence and/or absence of dissolved components such as methane (CH4) in brine. Model results suggest that the amounts of snap-off and solubility trapping are enhanced by increasing the volume proportion and degree of connectivity of high-permeability facies types. Results also demonstrate that ignoring relative permeability hysteresis leads to underestimation of snap-off trapping and overestimation of solubility trapping. In contrast, neglecting capillary pressure hysteresis (i.e., non-hysteretic Pc) results in overestimation of snap-off trapping and underestimation of solubility trapping. If capillary pressure is totally neglected (i.e., Pc = 0), the amount of trapped CO2 by snap-off and dissolution are, respectively, overestimated and underestimated. Competitive CO2 and CH4 dissolution in brine results in exsolution of CH4 from the aqueous phase into the gaseous phase. Facies connectivity and constitutive relations are also critical for the transport of exsolved CH4. However, disregarding dissolved CH4 leads to overestimation of CO2 trapping capacities.

The effect of quench cracks and retained austenite on the hydrogen trapping capacity of high carbon martensitic steels

Hypereutectoid martensitic steels possess excellent hardness levels which make them attractive materials for specific industrial applications. However, they can contain cracks and/or retained austenite after quenching which show a particular interaction with hydrogen (H). Hence, this work evaluates the interaction between H and a martensitic Fe-1.1C alloy by combining a wide variety of (H) characterization techniques with a systematic approach for specially designed H charged and heat treated samples. A detailed analysis of the microstructure for every condition serves as the basis for the interpretation. The results show that the presence of H leads to additional cracking and branching or growth of pre-existing quench cracks. Moreover, it is shown that when the temperature exceeds the retained austenite decomposition temperature while the austenitic grains contain H, additional cracking occurs which increases the amount of reversible H trapping sites thus raising the HE susceptibility.

The effects of chemical composition of fines and nanoparticles on inhibition of formation damage caused by fines migration: Insights through a simplex-centroid mixture design of experiments

Fines migration in the reservoir can leads to damage associated with the mobilization of particles and their posterior accumulation in throat pores, producing obstructions in the flow of fluids, resulting in a decrease of reservoir permeability. An emergent alternative to solve this issue is the use of nanoparticles/nanofluids due to their physicochemical properties that can favor the trapping capacity of fines. Hence, this experimental work aims to evaluate the chemical nature effect of different fines and their respective interaction with three kinds of nanoparticles used in specialized literature for formation damage. In this work was emulated experimentally the retention phenomena through a packed sand bed treated with the different nanofluids and then assessed with the suspension of the fines. The sand beds were prepared with Ottawa sand in two ways: water-wet and sand restored to reservoir wettability (oil-wet). The sand beds were soaked with the specific nanofluids which were with deionized water as carrier fluid for the nanoparticles of iron, silica, and alumina at a dosage of 0.01% in a mass fraction respectively. The suspension of fines was constituted by quartz, kaolinite, illite, at a dosage of 0.2 wt%; the chemical nature was based on an average composition of a Colombian field. The Adams-Bohart, Thomas, and Wolborska models were used for describing the results of breakthrough curves. The beds treated with alumina nanoparticles at 0.01 wt% presented a higher capacity to retain and stabilize the Kaolinite fines, increasing the retention capacity up to 50%. The results agree with the total energy interaction of the fines-nanoparticles system reported for alumina nanofluids. Additionally, critical rate tests at reservoir conditions were performed, obtaining successful results by the increasing of critical rate by more than 50% for water and oil flow velocities in comparison to the untreated system. In this sense, this work presents a comprehensive analysis of selectivity of fines-nanoparticles couples through the design of the optimized experiment, focused on selecting select the best nanofluid treatment for the problem of fines migration.

Conditions and processes controlling carbon mineral trapping in intraformational baffles

Carbon mineral trapping is commonly believed to be insignificant relative to other trapping mechanisms, yet, the role of cm-scale intraformational baffles is rarely considered in reservoir scale assessments. The present study aims to reveal conditions governing carbon mineral trapping and its quantification for a range of rock compositions in intraformational baffles. A series of 2-D multiphase reactive transport simulations were set-up to model the geochemical processes occurring at the interface of a baffle and a reservoir rock for a period of 1000 years. The study shows that the presence of baffles with certain rock properties within the reservoir rock can enhance or reduce carbon mineral trapping capacity relative to homogeneous reservoir rocks depending on clay and carbonate mineral content in baffles. The analysis shows that the precipitation of secondary carbonates occurs at the interface of the two rock types. Furthermore, it was found that higher clay and lower carbonate content of the baffle contribute towards enhancing mineral trapping while the mineralogy of reservoir rock does not have an important influence. The results are further utilized to derive averaged mineral composition for the integration of fine scale processes in coarser scale simulations.

Livestock grazing reduces sediment deposition and accretion rates on a highly anthropogenically altered marsh island in the Wadden Sea

Coastal salt marshes and their provided ecosystem services are threatened by rising sea levels all over the world. In the Northern Wadden Sea region, a sea-level rise of 4 mm y−1 was recorded for recent years. Identifying and understanding factors that affect sediment deposition and determine vertical accretion of salt marshes is crucial for the management of these ecosystems. Even though major processes contributing to sedimentation and accretion have already been identified, the influence of reduced canopy heights due to livestock grazing is still debated. On a highly anthropogenically altered marsh island in the Wadden Sea, sediment deposition, accretion and suspended sediment concentration was analyzed on grazed and adjacent ungrazed plots both at the marsh edge and at the marsh interior. Due to a low seawall (a so-called ‘summer dike’), flooding frequency on the island is reduced and flooding mainly takes place during storm surges. After five flooding events within a year, mean sediment deposition and accretion were found to be up to seven times higher on ungrazed plots compared to grazed plots, but only at the marsh edges. This result was not explained by the overmarsh suspended sediment concentration (SSC), which was found to be twice as high on grazed plots compared to ungrazed plots. It is concluded that grazing has a negative effect on sediment deposition and accretion on Wadden Sea marsh islands and areas with similar conditions (e.g. presence of a summer dike) by reducing the sediment trapping capacity of those marshes. Overall, vertical marsh accretion ranged from 0.11 ± 0.09 mm y−1 on a grazed plot at the marsh edge to 1.12 ± 0.71 mm y−1 on an ungrazed plot at the marsh edge. By increasing the discrepancy between accretion and sea-level rise, livestock grazing can lead to higher inundation levels and in turn to increased hydrodynamic forces acting on these anthropogenically altered marshes.

Insoluble dietary fibre scavenges reactive carbonyl species under simulated physiological conditions: The key role of fibre-bound polyphenols

Polyphenols bound to insoluble fibre may scavenge reactive carbonyl species by surface chemical reactions. In the present study, this hypothesis was tested by investigating the ability of bound-polyphenol rich insoluble dietary fibre (BP-IDF) isolated from blackberry pomace, red cabbage, and wheat bran in scavenging carbonyl compounds. Three BP-IDF showed high scavenging efficacy for glyoxal, methylglyoxal, acrolein and malondialdehyde. Upon in vitro digestion, trapping capacity was retained by the insoluble fraction suggesting that carbonyl trapping activity and physiological relevance needs to be extended to undigestible materials. The removal of bound polyphenols from the polysaccharide backbones through alkaline and acidic treatment reduced by up to 90% of trapping capacity of BP-IDF. Moreover, methylglyoxal-polyphenol adducts were detected bound to blackberry pomace BP-IDF after hydrolysis. These findings demonstrated that polyphenols bound to IDF scavenged reactive carbonyl species and highlighted the physiological relevance of BP-IDF in limiting carbonyl stress along all the gastrointestinal tract.

Secondary Metabolites and Antioxidant Activity of Different Parts of the Baobab Fruit (<i>Adansonia digitata</i> L.)

The objective of this study was to determine the polyphenol, flavonoid and tannin content and the antioxidant power of methanolic extracts from the different parts of the Senegalese baobab fruit. Phytochemical screening revealed the presence of saponosides, tannins, alkaloids, sterols, flavonoids, coumarins and total sugars in all extracts from the fruit parts. The total polyphenol content was determined by the folin-ciocalteu method. This method is based on the quantification of the total concentration of hydroxyl groups present in the extract. In an alkaline medium, the reagent of folin-ciocalteu, oxidizes the phenols to ion phenolates and partially reduces its hetero-polyacids, hence the formation of a blue complex. The absorbance is read at 765 nm against a control. The Flavonoids vere determined using aluminum trichloride and sodium hydroxide. Aluminum trichloride forms a yellow complex with flavonoids and sodium hydroxyde forms a pink complex absorbing in the visible range at 510 nm. The alternative colorimetric method based on reactions with vanillin in an acidic medium made it possible to determine the tannin content. Absorbances were measured at 500 nm. The results show that the methanolic extracts of the fibers and shell have very high polyphenol, flavonoid and tannin contents. In fact, the polyphenol contents of the fiber (159.00 ± 0.93 μg EAG/mg extract) and shell (155.39 ± 0.89 μg EAG/mg extract) were much higher than those of the pulp (27.21 ± 0.26 μg EAG/mg extract) and seeds (18.36 ± 0.07 μg EAG/mg extract). In addition, the flavonoid contents of the fibers (97.64 ± 0.40 μg EQ/mg) and of the shell (86.18 ± 0.46 μg EQ/mg) were higher than those of the seeds (12.82 ± 0.04 μg EQ/mg) and pulp (5.66 ± 0.18 μg EQ/mg). The tannin contents of the fibers (256.65 ± 1.45 μg EC/mg) and of the shell (196.05 ± 25 μg EC/mg) are higher than those of the pulp (103.09 ± 0.62 μg EC/mg extract) and seeds (1.09 ± 0.04 μg EC/mg extract). The antioxidant activity of extracts from different parts of the baobab fruit has Also been achieved using two different methods (DPPH and FRAP). The trapping capacity of the DPPH radical is very advantageous for the fibers (IC50 = 2.27 μg/mL) and the shell (IC50 = 1.52 μg/mL). The FRAP test has shown that the extracts from the shell (18.47 μg/mL) and fibers (20.00 μg/mL) have a greater iron reduction capacity than that of the standard ascorbic acid (45.64 μg/mL).

Influence of Humic acids on CO2-quartz wettability: Implications for CO2 storage

Carbon Geo Sequestration (CGS) is considered an effective way to reduce anthropogenic greenhouse gas emission into the atmosphere. The storage of captured CO2 is mainly geological. Several researchers confirmed Humic Acid (HA) concentration in the deep aquifer at high temperature and high-pressure conditions, which may affect the rock wettability and reduce storage capacities and containment security. One key parameter which affects the wettability of formation in the presence of humic acid is pH. However, there is a lack of information on the relationship of pH, humic acid and wettability of CO2 in storage formation. We measured the effect of pH on the CO2 wettability of storage formation in the presence of humic acid. Advancing and receding contact angles were measured at HPHT conditions (pressure of 12 MPa and temperature of 323 K), using the pendant drop tilted-plate method for various pH (2 to 12) at the humic acid concentration (25 mg/L) and brine salinities (0 and 0.2 M NaCl). We concluded that decreasing pH significantly impacts rock wettability; and shifts water-wet to CO2-wet, thus reducing structural and residual trapping capacities. Therefore, presence of organic acids in reservoir geochemical conditions should be considered to de-risk the development of CGS projects.

Effect of humic acid on CO2-wettability in sandstone formation

HypothesisMillions of tons of CO2 are stored in CO2 geological storage (CGS) formations (depleted oil reservoirs and deep saline aquifers) every year. These CGS formations naturally contain small concentrations of water-soluble organic components in particular humic acid (HA), which may drastically affect the rock wettability - a significant factor determining storage capacities and containment security. Hence, it is essential to characterise the effect of humic acid concentration on CO2-wettability and its associated impact on storage capacity. ExperimentalTo achieve this, we measured advancing and receding contact angles at reservoir conditions using the pendant drop tilted plate method for various humic acid concentrations (1, 10, and 100 mg/L) as a function of pressure (0.1–25 MPa), temperature (303–333 K), and brine salinity (0–0.3 M NaCl). Further, the influence of humic acid adsorption on the mineral’s surface was examined by several independent techniques. ResultsOur results demonstrate that humic acid significantly changes rock wettability from water-wet (0–50°) towards CO2-wet (90–110°). An increase in pressure, temperature, and salinity had a similar effect. Humic acid adsorption also increased the surface roughness of the substrates. We conclude that even trace amounts of humic acid (i.e. 1 mg/L), which exist in storage aquifers, significantly increase CO2-wettability and thus reduce structural and residual trapping capacities. Therefore, it is pertinent to account for these humic acid concentrations to de-risk CGS projects.

2D square nanosheets of Anatase TiO2: A surfactant free nanofiller for transformer oil nanofluids

Rutile TiO2 nanoparticle with high dielectric constant has already become an automatic choice as a favorable nanofiller for efficacious transformer oil (TO) nanofluids (NFs) development, thanks to their large surface area and splendid electron trapping capacity. In this work, the role of phase and morphology of TiO2 on the properties of TO has been deciphered for the first time. For this, solvothermally prepared ultra-thin, square nanosheets of purely anatase phase TiO2 (a-TiO2) with 50–70 nm dimensions are used for NF preparation in two types of commercial mineral oil. The dielectric breakdown strength and thermo-physical properties of the resultant TO NFs have been investigated thereafter. A significant enhancement (27–30%) in breakdown voltage (BDV) at very low filler fraction (0.005 wt%) due to accelerated charge scavenging capability by virtue of the inherent surface oxygen vacancies, high electronegativity and slightly higher band-gap than rutile phase is observed. Additionally, the thermal conductivity of TO is seen to rise by 13–23% (±5%) at 50C which is facilitated by long phonon lifetime mediated inter-sheet transfer of heat. Further, the electronegativity induced strong repulsive forces among the dispersed nanofillers at ultra-low concentrations leads to a surfactant-free stable liquid insulation over a prolonged time. Besides, the acidity and viscosity, the increment of which with filler fraction causes a serious drawback for NFs, are below par the alarming level of TO due to low filler fraction of a-TiO2. All the above beneficial features along with improved flash and pour points makes the synthesized 2D a-TiO2 a budding candidate for efficient NF development at very low filler fraction without any usage of surfactant.

Effect of magnetic field on tribological performance of laser dimple textured surface

Experiments were performed to examine the friction and wear of laser dimple textured surfaces of medium carbon steel under three conditions: normal, degaussing, and an additional magnetic field. The coefficients of friction and wear volume of the laser dimple textured surfaces were measured, and the hardness of the dimple edge were measured. The worn surfaces of the specimens were examined, and the elemental contents of the wear debris were analysed. The wear debris within the laser dimples was examined at regular intervals to analyse the trapping processes. The experimental results indicated that the coefficients of friction and wear volume mass were reduced by the laser dimple textured surface. Compared with the normal condition, the abrasive wear of the laser dimple textured surface was reduced under both the degaussing and additional magnetic conditions, and the coefficients of friction and wear were reduced. Under the additional magnetic condition, uniform debris attachment to the inner walls of the laser dimples occurred. The distributions of the magnetic domains within the specimens affected the trapping process of wear debris during the wear experiments, and the wear-debris trapping capacity of the laser dimples was improved under the additional magnetic condition. The following phenomena occurred under the additional magnetic condition: hardness improvement of the dimple edge, oxidation of the wear debris, and coverage of the worn surfaces by wear debris. The results indicate that the tribological performance of the laser dimple textured surface of medium carbon steel can be improved under degaussing and additional magnetic conditions.

Local hydrogen accumulation after cold forming and heat treatment in punched advanced high strength steel sheets

Hydrogen embrittlement is one of the most crucial problems in the application of advanced high strength steel (AHSS) sheets for the automotive industry. Especially, the severe plastic deformation in punched edges makes the components susceptible to hydrogen assisted cracking (HAC). While small amounts of hydrogen are measured in the bulk material, hydrogen concentration increases in the micrometer-sized shear affected zone many times, along with severe plastic deformation. To contribute to the understanding of local microstructure and local stress states on the hydrogen accumulation in the shear affected zone, two industrial AHSS were investigated. Both steels had the same ultimate tensile strength of 1200 MPa, but different uniform elongations. High-pressure torsion (HPT) deformed samples were used to represent the material state in the shear affected zone. Thermal desorption spectroscopy (TDS), X-ray diffraction (XRD), magnetic retained austenite measurements and electron backscattering diffraction (EBSD) in a high resolution secondary electron microscopy (SEM) were applied among other techniques to gain more insights with microstructural resolution. The hydrogen analysis results of the HPT samples were correlated with the local hydrogen trapping capacity in punched edges. Finally, a simplified “two-zone” model considering the bulk and punched edge as separate zones was developed in order to estimate the local hydrogen concentration of punched AHSS sheets as a function of hydrogen bulk concentration. In a concluding remark it is shown, that the effect of the hydrostatic stress field as trap site is negligibly small compared to other traps.

Fine-Tuning Pore Dimension in Hybrid Ultramicroporous Materials Boosting Simultaneous Trapping of Trace Alkynes from Alkenes.

Removing trace amounts of alkynes from alkenes is one of the most critical and challenging steps to produce high-purity alkenes, the fundamental raw materials in petrochemical industry. Selective hydrogenation using noble metal catalysts under harsh conditions can convert trace alkynes to alkenes, but suffers from limited selectivity, over-hydrogenation, and energy-intensive consumption. Herein, the simultaneously adsorptive removal of trace propyne (C3 H4 ) and acetylene (C2 H2 ) from quaternary C2 H2 /C2 H4 /C3 H4 /C3 H6 mixture is reported for the first time using an anion-pillared hybrid ultramicroporous material ZU-16-Co (or TIFSIX-3-Co) by finely tuning the pore dimensions and introducing different binding sites to match the shape of alkynes. ZU-16-Co with contracted aperture size and judiciously extended cell dimension simultaneously exhibits superior trapping capacity for propyne under low concentration (2.45mmol g-1 at 5000ppm) and surprisingly high C2 H2 uptake (4.18 and 1.4mmol g-1 at 1.0 and 0.01bar, respectively) through synergistic host-guest and guest-guest interactions. Importantly, the ability of ZU-16-Co to capture trace alkynes (C2 H2 and C3 H4 ) in one step is confirmed by breakthrough experiments for quaternary C3 H4 /C2 H2 /C3 H6 /C2 H4 mixtures, presenting ZU-16-Co as a promising material for alkyne trapping.

Zebrafish as an in vivo screening tool to establish PARP inhibitor efficacy

Double strand break (DSB) repair through Homologous Recombination (HR) is essential in maintaining genomic stability of the cell. Mutations in the HR pathway confer an increased risk for breast, ovarian, pancreatic and prostate cancer. PARP inhibitors (PARPi) are compounds that specifically target tumours deficient in HR. Novel PARPi are constantly being developed, but research is still heavily focussed on in vitro data, with mouse xenografts only being used in late stages of development. There is a need for assays that can: 1) provide in vivo data, 2) early in the development process of novel PARPi, 3) provide fast results and 4) at an affordable cost. Here we propose a combination of in vivo zebrafish assays to accurately quantify PARP inhibitor efficacy. We showed that PARPi display functional effects in zebrafish, generally correlating with their PARP trapping capacities. Furthermore, we displayed how olaparib mediated radiosensitization is conserved in our zebrafish model. These assays could aid the development of novel PARPi by providing early in vivo data. In addition, using zebrafish allows for high-throughput testing of combination therapies in search of novel treatment strategies.

Quantification of the turning point saturation for cross bedded CO2 storage reservoirs

Cross bedding is a prominent sedimentary structure commonly found in fluvial and coastal to shallow-marine sedimentary sequences, which are often considered for the geological CO2 storage. A millimeter-thick silt- or mudstone lamina draped over a lens of sandstone is characteristic for cross bedding. This type of sedimentary structure gives rise to a greater capillary heterogeneity trapping capacity compared to other sedimentary structures such as planar bedding. The estimation of capillary trapping depends on turning point CO2 saturation. However, turning point saturations for a range of rock type combinations in cross bedded structures have not been quantified. This study uses field data to build 120 multiphase flow realizations to quantify the range of turning point saturation. The results show that maximum turning point saturation can vary between 40–95 % of end-point CO2 saturation depending on rock type properties. Statistical analysis is used to quantify the impact of different rock properties and their associated heterogeneity on turning point saturation. Results show that heterogeneity in entry pressure contributes about 69 % of the total variability in the maximum CO2 saturation under drainage. The results are used to derive multivariable linear regression models for the direct estimation of turning point CO2 saturations using intrinsic rock properties.

Simultaneous effect of nitrogen, trifluoromethyl and dimethyl amino group on the radical trapping capacity of diphenylamine: a quantum chemical study

In order to maximize the peroxyl radical trapping capacity of diphenynlamines, the substituents such as N, NMe2, and CF3 are suggested to add to their phenolic rings. The reasonable combination of these substituents at right position can reduce the bond strength of the N-H bond, but still keep the derivatives stable in air.

Advanced glycation end-products (AGE) trapping agents: Design and synthesis of nature inspired indeno[2,1-c]pyridinones

Advanced glycation end products (AGEs) are implicated to be the key players in most of the diabetic complications. The AGE’s interfere with the proteins heterogeneously, thereby rendering denaturation and the consequent loss of function and accumulation. Thus, a novel natural product inspired indeno[2,1-c]pyridinone (4a-4ad) molecular templates with AGE’s trapping potential was designed through scaffold hopping approach and synthesized via facile two-step synthetic route. Amongst the tested indeno[2,1-c]pyridinone hybrids, 4i, 4x and 4aa exhibited excellent efficiency in trapping the AGE’s. The percentage of antiglycation is measured by the analytical model system, i.e. via MG trapping capacity; here the compounds 4i, 4x and 4aa with 50.03%, 69.58%, and 93.37% respectively has displayed promising efficiency. In particular, 4aa demonstrated better activity than the positive control aminoguanidine (79.82%). The in-vitro toxicity of compounds was tested on L6 rat skeletal muscle cell lines revealed that none of the compounds showed any significant toxicity at concentrations up to 1000 μM.

Revealing the theoretical assumptions of the trap-depth distribution model in the thermoluminescence theory

The theoretical assumptions of the analytical expressions characterizing the thermoluminescence glow-peak arising from a continuous trap-depth distribution have been investigated. The sets of the differential equations governing the electrons’ transitions within a continuous trap-depth distribution during the irradiation and heating stages have been numerically solved. The analytical expressions are essentially based on a theoretical assumption that correlates the concentrations of the trapped electrons with the distribution of the trap depths in the bandgap. This correlation could not be considered in the numerical solution, since the irradiation stage is entirely independent of the trap depth. Thus, the final values of the instantaneous trap-filling functions of the irradiation stage do not depend on the trap depth, but rather on the trap capacity and the trapping probability coefficient. Consequently, in the numerical solution, the distribution of the trap depths and the distribution of the trapped electrons are independent. This inconsistency between the numerical solution and the analytical expression has led to differences in the shape of the thermoluminescence glow peaks resulting from the same trap-depth spectrum.

Mineral dissolution and precipitation reactions and their net balance controlled by mineral surface area: An experimental study on the interactions between continental flood basalts and CO2-saturated water at 80 bars and 60 °C

Continental flood basalts are currently considered as unconventional CO2 storage reservoirs given several knowledge gaps remain. This study addresses the question whether subvertical fractures and joints in the storage complex and its overburden may lead to long-term CO2 leakage or whether commencement of self-sealing can be expected at an early stage of geochemical reactions. The latter occurs when mineral precipitation outcompetes mineral dissolution. The nature of secondary mineral precipitation and the change of ion concentrations over time were studied in a batch reactor experiment where basalt wafers with a low surface area were exposed to CO2-saturated formation water at a pressure of 80 bars and 60 °C. Primarily stilbite (a zeolite) and montmorillionite (a smectite) were observed in suspension and kaolinite, Fe-oxide and Na-nontronite were additionally identified as authigenic minerals on the surface of the basalt wafers at the end of the incubation. These observations are in agreement with the state of mineral saturation based on the water composition throughout the incubation. Carbonate minerals were undersaturated throughout the incubation suggesting limited carbon mineral trapping capacity under the given conditions. A mineral nucleation phase (day 1 to 6) dominated by cation release due to dissolution and a mineral growth phase (day 8 to 44) dominated by cation uptake due to precipitation were identified. The latter resulted in the formation of considerable mineral mass, which was deposited almost completely on the wafer surface.

Carboxymethyl cellulose supported green synthetic features of gold nanoparticles: Antioxidant, cell viability, and antibacterial effectiveness

Gold nanoparticles (AuNPs) are widely used in the diagnosis and treatment of diseases owing to their environmental friendliness and controllability due to their compatibility and high potency in drug delivery. Here, AuNPs were prepared from carboxymethyl cellulose (CMC) and showed an extensive absorption peak at 528 nm owing to the characterized Plasmon Surface Resonance. TEM measurement affirms that the Au particles had spherical shapes accompanied by a uniform distribution and a size of approximately 12-20 nm. Otherwise, SEM images showed that the AuNPs were configured in agglomerated spherical shapes and the crystalline phase was evident from SAED images and spikes in the XRD model. Vigorous antioxidant was tested using the DPPH scavenger analysis and the produced maximum trapping capacity (241.1 ± 13.22 mg/g) was reached at an AuNPs content of 106.25 mg/mL. The ratio of viable cells for AuNPs by HEK 293 T cell lines was reduced to 75.1 ± 3.8% at an approximated concentration of 500 μg / mL. Besides, the antibacterial potency was examined after one day of exposure to (E. coli and P. aeruginosa) and (S. aureus and B. subtilis). AuNPs were toxic against all selected bacteria. P. aeruginosa was the most susceptible bacterium to AuNPs with maximum inhibition zones of 50% whereas B. subtilis at 2 mg/L concentration of AuNPs takes the lowest percentages of inhibition zone with 30% compared to 25% for antibiotic standard. These extraordinary behaviors of AuNPs exhibits the manipulation of nanoparticles is highly recommended for universal use in the treatment of skin and wounds.