Impact Of Contact Time Research Articles

Effect of surface charge on mechano-bactericidal activity of cellulose nanocrystals constructed chevaux-de-frise and meat preservation

The nanostructured insect wings have inspired the development of antimicrobial surfaces with mechano-bactericidal activity. For the first time, a chevaux-de-frise-like nanostructure was fabricated through the coating of cellulose nanocrystals (CNC) onto regenerated cellulose (RC) films via vacuum filtration and the impact of contact time, temperature, and surface topography on eliminating foodborne bacteria was examined. Herein, our focus is to explore in more detail how the surface charge of CNC affects the mechano-bactericidal activity and the performance of chevaux-de-frise-like nanostructure in meat preservation. CNC with neutral (weak), negative, and positive charges were prepared by hydrochloric acid hydrolysis (HCNC), TEMPO oxidation (TCNC), and amination (ACNC), respectively, and showed similar reinforcing effects on the tensile strength (increased from 74.23 ± 1.20 to about 100 MPa) and water vapor barrier property (reduced from 1.83 ± 0.08 to about 1.20 × 10−7 g m−1 h−1 Pa−1). Among them, RC-ACNC showed the highest log reduction against Escherichia coli (0.83 ± 0.06) and Staphylococcus aureus (0.69 ± 0.04) after 5 min contact, respectively, indicating the important role of attractive force in fast eliminating bacteria upon contact. It was worth noting that, during the meat preservation test, all three CNC-coated RC films exhibited a similar 0.4 log reduction of bacteria after day 4, likely due to the same physical attachment with an extended contact time. Therefore, the construction of chevaux-de-frise nanostructure from CNC on food packaging provides a sustainable strategy to contribute to preventing bacterial growth.

Simultaneous removal of diclofenac sodium, cadmium and bacterial inactivation from aqueous solutions by activated MgO nanoparticles

This study investigated whether MgO nanoparticles (NPs) produced via the sol–gel process can simultaneously remove the pharmaceutical diclofenac sodium (DCF) and cadmium ions (Cd2+) from water. The UV spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX) were used to confirm the composition, morphology and particle size of the MgO NPs. The adsorption performance of MgO NPs was compared to that of bentonite-nano zero valent iron (B-nZVI) and activated carbon (AC). The impact of contact time, adsorbate concentration, pH, and temperature on the removal efficacy of DCF and Cd2+ via MgO NPs in aqueous solutions were investigated, and the removal data was best described by the kinetic model of pseudo-second-order and the Langmuir isotherm model (R 2 > 0.996). The maximum removal capacity of MgO for DCF and Cd2+ at pH 7 was 66.2 mg.g−1 (%R = 90) and 50.8 mg.g−1 (%R = 80), respectively. The average adsorption enthalpy for DCF and Cd2+ (ΔH° 50 kJ. mol−1) demonstrates the occurrence of physical adsorption process, while the negative value of ΔG° reveals the spontaneous nature of DCF and Cd2+ adsorption on the surface of MgO NPs. The DCF and Cd2+ adsorbed MgO surfaces were reused against various gram-positive bacteria. Finally, it was shown that MgO and sand column were more effective for removal of persistent substances and heavy metal residues than a column packed by a mixture of B-nZVI and sand.

Synthesis of bimetallic Mn@ZIF–8 nanostructure for the adsorption removal of methyl orange dye from water

In this research, manganese-based Mn@ZIF-8 nanocomposite was prepared using solvothermal strategy. The resultant Mn@ZIF-8 nanostructure was assessed for the adsorption of methyl orange (MO) dye from water. The pristine ZIF-8 and Mn@ZIF-8 nanocomposite have demonstrated a rhombic dodecahedral morphology having a reasonable microporous structure. Besides, they have also displayed an outstanding specific surface area and porosity. The impact of contact time, concentration and variation in pH were analyzed in detail for the investigation of adsorption capacity. From the interpretation of the adsorption isotherms, it has been discovered that adsorption of MO over Mn@ZIF-8 follows the monolayer mechanism (Langmuir isotherm). Remarkable maximum adsorption capacity (qmax, 406 mg.g−1) has been recorded for the Mn@ZIF-8 which is sufficiently high as compared to pristine ZIF-8. The kinetic study explored that experimental data best fitted to the pseudo second order kinetics with relatively high R2 values (0.997) of Mn@ZIF-8. Thermodynamic study reconnoitered the adsorption process is spontaneous in nature. The synthesized Mn@ZIF-8 material also displays exceptional reusability capability of up to 92 % at 4th cycle compared to 1st cycle. Overall, the Mn@ZIF-8 could be a good contestant for the treatment of MO containing wastewater of industries.

Improvement of the sorption capacity of methylene blue dye using slag, a steel by product

A steel by-product, the slag collected from the blast furnace, was exploited as an adsorbent to remove methylene blue dye in solution by batch adsorption under the impact of contact time, mass of solid, agitation speed, pH, temperature, particles size, and initial concentration. The slag is mainly composed of silica, alumina and lime with a considerable specific surface (320.46 m2/g), which increased its adsorbent power. The experimental data revealed that the methylene blue (MB) dye adsorption on the slag is favorable (R = 93.3%) and the maximum adsorbed capacity after 50 min of contact amounts to 140.44 mg/g. The adsorption isotherms revealed that the adsorption of methylene blue dye was performed on a homogeneous monolayer surface, and their parameters confirmed that the process is favorable and physically achievable. The kinetic study specified that the methylene blue dye sorption is more adapted to the pseudo-second-order kinetic model (R2 = 0.99). In accordance to the diffusion investigation, exterior diffusion under the diffusional and kinetic regimes and internal diffusion under the diffusional regime alone successively controlled the passage of the pollutant from solution to adsorbent. According to the values of free energy, enthalpy, and entropy, the MB dye adsorption is spontaneous, exothermic, and less entropic. Additionally, the free energy and enthalpy values suggest that this process was performed physically (physical adsorption) under the influence of electrostatic interactions. Based on the results of the desorption investigation, the slag could potentially be recycled four times in a row using hydrochloric acid (0.5 M) as a desorbent.

Kinetic and Theoretical Study of Removal Gentian Violet from Aqueous Solution Using Stachy Plant

The main parameters and methods influencing the removal of Gentian Violet (GV) dye from aqueous media were investigated using a stachy plant in this study. The surface of the stachy plant was determined using FTIR spectra. Adsorption is influenced by the adsorbent's characteristic groups. The research took into account the usual conditions for GV dye adsorption by the stachy plant, such as the impact of contact time. Mass dosage , after 0.3 g the amount of adsorbed dye declines. Study pH and ionic strength, the results obtained showed that at pH 3 the largest adsorption of (GV) was seen, while at pH 9, the lowest adsorption was observed at 298 K, the adsorption kinetics and equilibrium constants were achieved, and the equilibrium data was fitted using the Langmuir, Freundlich, and Temkin models. The pseudo-first-order and pseudo-second-order kinetic models were used to investigate the adsorption process of gentian violet. The adsorption kinetics was discovered to be governed by a pseudo-second-order kinetic model with a determination coefficient (R2) of 0. 0.9943. Study the theoretical electrostatics of Gentian Violet dye was measured and plotted as a 2D and 3D contour and the program hyperchem-8.07 was used for semi-empirical and molecular mechanic calculations in the gas phase to estimate the total energy.

Surface-modified magnetite nanoparticles using polyethylene terephthalate waste derivatives for oil spill remediation.

This work aims at synthesizing new cross-linked poly ionic liquids, CPILs, VIMDE-Cl and CPIL, VIMDE-TFA, utilizing polyethylene terephthalate waste as a precursor and applying them to magnetite nanoparticles surface modification, producing surface-modified magnetite nanoparticles, SMNPs, VDCL/MNPs, and VDTA/MNPs, respectively. The structures of VIMDE-Cl and VIMDE-TFA, VDCL/MNPs, and VDTA/MNPs, were verified using different techniques. The particle sizes of SMNPs, VDCL/MNPs, and VDTA/MNPs, were evaluated with a transmission electron microscope and dynamic light scattering. The compatibility of VDCL/MNPs and VDTA/MNPs with crude oil components and their response to an external magnet were also measured using contact angle measurements and a vibrating sample magnetometer. The data confirmed the formation of SMNPs, nanosized structure, compatibility with oil components, and response to an external magnet. For that, VDCL/MNPs and VDTA/MNPs were applied for oil spill recovery using different SMNP : crude oil weight ratios. The impact of contact time on SMNPs' performance was also evaluated. The data indicated increased performance with an increase in SMNPs ratio, reaching maximum values of 99% and 96% for VDCL/MNPs and VDTA/MNPs, respectively, at SMNPs : crude oil ratio of 1 : 1. According to the results, the optimal contact time was 6 min, resulting in 89% and 97% performance for VDCL/MNPs and VDTA/MNPs at 1 : 4 SMNPs : crude oil ratio.

3D-printed red mud/metakaolin-based geopolymers as water pollutant sorbents of methylene blue

This work reports a novel management strategy for a hazardous waste derived from the alumina industry, known as bauxite residue or red mud (RM). Herein, and for the first time, RM-containing porous structures were prepared by direct ink writing (DIW) and then used directly to extract methylene blue (MB) from synthetic wastewater. The lattices were prepared using a 50:50 wt% blend between RM and metakaolin (MK). The incorporation of RM was evaluated by comparing with the MK-based printed structure. Despite the high residue amount, the lattices showed high compressive strength (10.7 MPa), high open porosity (62.40%), very high specific surface area (55 m2/g), and excellent stability throughout the tests (leaching, sorption, and thermal regeneration). In the batch adsorption tests, the impact of contact time, and dye concentration was evaluated. At the optimized conditions ([MB]0 = 50 mg/g; contact time: 48 h) the RM/MK-based structures showed a MB uptake of 19.96 mg/g, ranking them amongst the best performing bulk-type (not powders) geopolymer adsorbents. Furthermore, lattices were successfully regenerated and reused (up to ten cycles) without compromising their performance. Their excellent performance was also corroborated under continuous-flow column experiments. These promising results demonstrate the potential valorisation of a hazardous waste in wastewater treatment.

Polystyrene electrospun nanofibers as effective sorbents for the removal of atypical antipsychotics: Kinetic and thermodynamic studies

In this study, polystyrene nanofibers were prepared by electrospinning for the adsorption of olanzapine, risperidone, and clozapine from aqueous solution. The properties of polystyrene nanofibers were characterized via FTIR, SEM, TEM, TG, and XRD analyses. In addition, the impact of contact time, initial ion concentration, adsorbent dosage, temperature, and pH on the adsorption was studied. The adsorption kinetics and thermodynamic evaluation of three analytes on PS nanofibers were performed. The adsorption of the three analytes by polystyrene nanofibers followed the first-order kinetics with constant rates of 0.02348, 0.02683, and 0.03024 mg/g min for olanzapine, risperidone, and clozapine, respectively. Further, the adsorption conformed to Redlich-Peterson isotherm model and the maximum adsorption capacities for olanzapine, risperidone, and clozapine were 12.33, 8.36, and 12.96 mg/g, respectively. The adsorption process was characterized by spontaneous, exothermic, and physical reaction. The regeneration of nanofiber adsorbent showed that the adsorption capacity did not significantly change after 5 cycles of desorption. The selectivity of different analytes followed the order of clozapine > risperidone > olanzapine. Thus, the polystyrene electrospun nanofibers exhibit good potential as novel adsorbents for the isolation and purification of antipsychotic drugs from biological samples.

Porous zinc-discs as nanocatalysts for methylene blue dye treatment in water: sensing, adsorption and photocatalytic degradation.

This paper reports a zinc derived (ZD) porous nanosystem that has been used for selective sensing, adsorption, and photocatalytic degradation of the known hazardous dye, Methylene blue (MB). Using zinc nitrate and 2-aminoterphthalic acid as precursors, the synthesis has been optimized to yield disc-shaped nanoparticles. This luminescent ZD nanoparticles exhibit absorption and emission wavelengths of 328 nm and 427 nm, respectively at an excitation wavelength of 330 nm. In the presence of MB, there is a sharp decrease in the photoluminescence emission intensity of ZD nanoparticles. The detection limit, quenching constant and the binding constant of ZD nanoparticles with MB are found to be 0.31 × 10-9 M, 3.30 × 106 M-1 and 2.27 × 106 M-1 respectively. The impact of contact time, initial MB concentration, and pH on the adsorption process were investigated. The equilibrium data fit well with the Langmuir adsorption isotherm model (R 2 = 0.989) and superlatively fitted to the pseudo-second-order rate model (rate constant: 0.00011 g mg-1 min-1; adsorption capacity (q e, calc.): 386.1 mg g-1; R 2: 0.990). Further, the MB dye degradation was performed under ultra-violet irradiation and ∼95% MB degradation was achieved within 70 min. The experimental data are well fitted to the pseudo-first order kinetics (R 2: 0.99; rate constant: 0.015 min-1). These disc shaped ZD nanoparticles can not only facilitate the detection, but also the adsorption and photocatalytic degradation of MB, which can be further processed for environmental remediation applications.

Removal of Copper from Industrial Wastewater and its Relationship with Wilson's Disease

Background:Wilson’s illness, or hepatolenticular degeneration, is an autosomal passive issue that outcomes from an accumulation of copper prevalently in the liver and brain. The aggregation is happen because of imperfect biliary discharge of copper. Current information demonstrates that grown-up people need to ingest about 0.75 mg of copper every day to continue a parity. Because of a hereditary imperfection, people with Wilson’s ailment can't discharge the abundance copper, bringing about a progressive develop of copper in the body. Substantial metals are the most hurtful of the concoction toxins and are of specific worry because of their poison levels to people. From this poisonous metal copper, which has impacts in drinking water on the gastrointestinal tract, yet there is some with respect to the drawn out impacts of copper on delicate populaces, for example, bearers of the quality for Wilson’smalady and other metabolic issue of copper homeostasis. Method:We picked as a characteristic adsorbent in this work the Moringa Oleifera Seeds (MOSs) from Mali assortment, which could be a practical and earth safe strategy for water sanitization. All examinations were directed at room temperature, andafter being permitted to represent two hours, the examples were broke down utilizing the Atomic Absorption Spectrophotometer (AAS). The seeds of Moringawere set up by taking around 1 g of the seed squashed and blending it in with around 20 cm3 of water to be decontaminated in three distinct measuring utensils. Result:The different arrangements after filtration, indicated an expanded thickness in the amount of copper, which demonstrates the viability of the cleansing intensity of the seeds of MO. The best consequences of adsorption were for 30 min of contact time. We had half copper evacuation. The impact of contact time is significant in biosorption investigations to decide the harmony time required for the take-up of metal particles by the MOSs. Conclusion:In this investigation, the MOS from Mali were demonstrated to be a proficient regular adsorbent material of copper from fluid arrangements. The limit of the MOS to evacuate copper relies upon numerous models as; plant assortment and states of examinations. Our examination is going on the investigation of evacuation parameters, for example, contact time, pH, temperature, molecule size, sorbent portion, and introductory metal fixation.

Removal of Copper from Industrial Wastewater and its Relationship with Wilson's disease

Background:Wilson’s illness, or hepatolenticular degeneration, is an autosomal passive issue that outcomes from an accumulation of copper prevalently in the liver and brain. The aggregation is happen because of imperfect biliary discharge of copper. Current information demonstrates that grown-up people need to ingest about 0.75 mg of copper every day to continue a parity. Because of a hereditary imperfection, people with Wilson’s ailment can't discharge the abundance copper, bringing about a progressive develop of copper in the body. Substantial metals are the most hurtful of the concoction toxins and are of specific worry because of their poison levels to people. From this poisonous metal copper, which has impacts in drinking water on the gastrointestinal tract, yet there is some with respect to the drawn out impacts of copper on delicate populaces, for example, bearers of the quality for Wilson’smalady and other metabolic issue of copper homeostasis.
 Method:We picked as a characteristic adsorbent in this work the Moringa Oleifera Seeds (MOSs) from Mali assortment, which could be a practical and earth safe strategy for water sanitization. All examinations were directed at room temperature, andafter being permitted to represent two hours, the examples were broke down utilizing the Atomic Absorption Spectrophotometer (AAS). The seeds of Moringawere set up by taking around 1 g of the seed squashed and blending it in with around 20 cm3 of water to be decontaminated in three distinct measuring utensils.
 Result:The different arrangements after filtration, indicated an expanded thickness in the amount of copper, which demonstrates the viability of the cleansing intensity of the seeds of MO. The best consequences of adsorption were for 30 min of contact time. We had half copper evacuation. The impact of contact time is significant in biosorption investigations to decide the harmony time required for the take-up of metal particles by the MOSs.
 Conclusion:In this investigation, the MOS from Mali were demonstrated to be a proficient regular adsorbent material of copper from fluid arrangements. The limit of the MOS to evacuate copper relies upon numerous models as; plant assortment and states of examinations. Our examination is going on the investigation of evacuation parameters, for example, contact time, pH, temperature, molecule size, sorbent portion, and introductory metal fixation.

Effectiveness of Several Antimicrobials and the Effect of Contact Time in Reducing Salmonella and Campylobacter on Poultry Drumsticks

Salmonella and Campylobacter are the two pathogens commonly associated with raw poultry meat, as poultry products are frequent vehicles of these bacteria. The objective of the current research was to determine the optimal contact time for 6 antimicrobial treatments, including water, 0.003% chlorine, 0.07% peracetic acid (PAA), 0.1% PAA, 0.35% cetylpyridinium chloride (CPC), and 0.6% CPC. Drumsticks (n = 192) were inoculated with Salmonella Typhimurium and Campylobacter jejuni, and allowing some bacterial attachment time, drumsticks were treated with the 6 antimicrobials mentioned above for 10, 20, and 30 s contact time. The recoveries of Salmonella Typhimurium and Campylobacter jejuni were determined after plating. The results of this study indicated the antimicrobial effect on reducing Salmonella and Campylobacter on poultry parts, and the impact of contact time on the efficacy. This could be a guide for industrial application of which antimicrobial to use and how to control the contact time.

Impact of the contact time of different oak wood chips on red wine phenolic composition evolution after bottling

The main object of the present work was to evaluate the potential influence of the oak wood chips-wines contact time (30 and 60 days) on the evolution of the red wine phenolic composition during storage in bottle. Thus, global phenolic composition, color parameters, and individual anthocyanins of bottled red wines that had previously been in contact with oak wood chips during different times were analyzed. The results obtained demonstrates that in general, after 6 months of bottle storage, red wines with a previous oak wood chips contact time showed a more evident decrease on anthocyanin content, independently of the oak wood chips species used and toasting level. This tendency was also confirmed by the decrease in the values obtained for color intensity anda∗(redness) CIELab coordinate value. However, a positive impact of oak wood chips contact time on wine hue color andb∗(yellowness) CIELab coordinate values, was detected. Thus, after 6 months of bottle storage, red wines that were in a previous contact with oak wood chips (particularly during 60 aging days), exhibited lower color hue andb∗values compared with control wine (without any oak wood chips contact).

Release behavior of uranium in uranium mill tailings under environmental conditions

Uranium contamination is observed in sedimentary geochemical environments, but the geochemical and mineralogical processes that control uranium release from sediment are not fully appreciated. Identification of how sediments and water influence the release and migration of uranium is critical to improve the prevention of uranium contamination in soil and groundwater. To understand the process of uranium release and migration from uranium mill tailings under water chemistry conditions, uranium mill tailing samples from northwest China were investigated with batch leaching experiments. Results showed that water played an important role in uranium release from the tailing minerals. The uranium release was clearly influenced by contact time, liquid-solid ratio, particle size, and pH under water chemistry conditions. Longer contact time, higher liquid content, and extreme pH were all not conducive to the stabilization of uranium and accelerated the uranium release from the tailing mineral to the solution. The values of pH were found to significantly influence the extent and mechanisms of uranium release from minerals to water. Uranium release was monitored by a number of interactive processes, including dissolution of uranium-bearing minerals, uranium desorption from mineral surfaces, and formation of aqueous uranium complexes. Considering the impact of contact time, liquid-solid ratio, particle size, and pH on uranium release from uranium mill tailings, reducing the water content, decreasing the porosity of tailing dumps and controlling the pH of tailings were the key factors for prevention and management of environmental pollution in areas near uranium mines.

Impact of contact time, pH, ionic strength, soil humic substances, and temperature on the uptake of Pb(II) onto graphene oxide

ABSTRACTThe uptake of Pb(II) from wastewaters onto graphene oxide was studied as a function of various water quality parameters. The results indicated that uptake was fast and kinetic uptake could be well fitted by a pseudo-second-order model. The uptake was strongly dependent on pH and independent of ionic strength. Namely, inner-sphere surface complexation was the main uptake mechanism. The presence of humic acid or fulvic acid enhanced the uptake at low pH values, while reduced at high pH. The Langmuir, Freundlich, and Dubinin–Redushkevich (D-R) isotherm models were used to simulate the uptake. Thermodynamics indicated that the uptake was endothermic and spontaneous.

Nonideal transport of contaminants in heterogeneous porous media: 9 – Impact of contact time on desorption and elution tailing

A series of miscible-displacement experiments was conducted to examine the impact of sorption contact time on desorption and elution of trichloroethene from a well-characterized soil. A large number of contact times were examined, spanning 1h to 4years (∼2×106h). Effluent trichloroethene concentrations were monitored over a range of greater than six orders of magnitude, allowing characterization of potential asymptotic tailing. The results of the column experiments showed that trichloroethene exhibited extensive elution tailing for all experiments. Each increase in contact time resulted in a successive increase in the extent of tailing. In total, the number of pore volumes of water flushing required to reach the analytical detection limit increased from approximately 1000 for the 1-h contact time to almost 9000 for the 4-year contact time. These results indicate that a contact time of less than 1h produced a sorbed phase that is relatively resistant to desorption, and that a progressive increase in resistance to desorption occurred with increased contact time. A mathematical model incorporating nonlinear, rate-limited sorption/desorption described by a continuous-distribution reaction function was used to successfully simulate the measured data. The nonlinear sorption, the apparent rapid development of desorption resistance, and the progressive increase in resistance with increasing contact time are consistent with behavior anticipated for sorbate interactions with hard-carbon components of the soil.

Stress Relaxation During Bond Formation and Adhesion of Pressure-Sensitive Adhesives

Relaxation properties and adhesion of pressure-sensitive adhesives (PSAs) have been studied with the Probe Tack method under the conditions corresponding to the adhesive bond formation. Typical representatives of various PSA classes are examined: adhesives based on the styrene-isoprene-styrene (SIS) block copolymer, polyisobutylene of two molecular weights, acrylic and silicone PSAs. By comparison of the adhesive and relaxation behaviors of different PSAs it has been established that the PSA relaxation contributes appreciably to the strength of the adhesive bond and underlies the impact of contact time on adhesion. Direct correlation has been established between the compressive stress relaxation in the course of bond formation and the mechanism of debonding. All the examined PSAs can be classified into two groups: 1) the fluid-like PSAs that are capable of relaxing fully under compression (PIB, silicone adhesives) and 2) the PSAs, which reveal a residual unrelaxed stress. Physically crosslinked SIS and chemically crosslinked acrylic adhesives exemplify the PSAs of the second group. The occurrence of two peaks on the debonding stress–strain curves is typical of the PSAs of the second group. High adhesive strength requires the contribution of the longer relaxation times that vary for different PSAs in the range from 150 to 800 s. Minimum values of the longer relaxation times are featured for fluid adhesives, whereas the maximum values are found for crosslinked, network, and entangled adhesives. The adhesive strength achieves its maximum when the slow relaxation processes become dominating. Relative contributions of viscous and elastic deformations to relaxation properties of PSAs are assessed in terms of the Deborah number.

The impact of contact time on pyrene sorptive behavior by a sandy-loam soil

Batch experiments with pyrene (PYR) were conducted to quantify the effect of contact time on its sorption and desorption behavior by a sandy-loam soil. Twenty-four and 48 h contact times were chosen for the nonequilibrium conditions and 240 h for the pseudoequilibrium study. All times was selected based on the kinetic results. The nonlinear, pseudoequilibrium sorption isotherm was fit to a two-stage Freundlich model: 3–7 mg/l for the first stage and 7–15 mg/l for the second stage. A substantial fraction of the sorbed PYR was not desorbed within the given desorption time. The reason of hysteresis was found to be a sorption enhancement due to soil hydration which provided more sorption sites. A desorption enhancement at 240-h desorption steps was attributed to the increased dissolved organic matter evolution. This study also found that both soil organic matter and clay materials had an equal role in PYR sorption enhancement and desorption resistance.