Contact Time Research Articles

Impacts of Wearable Resistance Placement on Running Efficiency Assessed by Wearable Sensors: A Pilot Study.

Wearable resistance training is widely applied to enhance running performance, but how different placements of wearable resistance across various body parts influence running efficiency remains unclear. This study aimed to explore the impacts of wearable resistance placement on running efficiency by comparing five running conditions: no load, and an additional 10% load of individual body mass on the trunk, forearms, lower legs, and a combination of these areas. Running efficiency was assessed through biomechanical (spatiotemporal, kinematic, and kinetic) variables using acceleration-based wearable sensors placed on the shoes of 15 recreational male runners (20.3 ± 1.23 years) during treadmill running in a randomized order. The main findings indicate distinct effects of different load distributions on specific spatiotemporal variables (contact time, flight time, and flight ratio, p ≤ 0.001) and kinematic variables (footstrike type, p < 0.001). Specifically, adding loads to the lower legs produces effects similar to running with no load: shorter contact time, longer flight time, and a higher flight ratio compared to other load conditions. Moreover, lower leg loads result in a forefoot strike, unlike the midfoot strike seen in other conditions. These findings suggest that lower leg loads enhance running efficiency more than loads on other parts of the body.

Synthesis of chitosan-graphene oxide (GO) composite using the sol-gel method and its application in the adsorption of methylene blue dye

Synthesis of chitosan-GO composites using the sol-gel method and its application to methylene blue adsorption has been carried out. This study aims to determine the ability of chitosan-GO composites to adsorb methylene blue. Chitosan-GO composites were made with mass ratios (1:1), (1:3), and (1:5) and characterized by XRD. Material with a ratio (1:1) was chosen to be characterized using BET, SEM-EDS, and used as methylene blue adsorption. Methylene blue adsorption process with several variables including contact time, concentration, and temperature of methylene blue dye. The results of the XRD characterization of the chitosan-GO composite (1:1), (1:3), and (1:5) showed a diffraction peak at an angle of 2θ, namely 25.1°; 26.29° and 19.54°. The surface area of the chitosan-GO composite (1:1) with BET was 145.3505 m2/g. Characterization using SEM showed that the chitosan-GO (1:1) composite had a porous structure and was not homogeneous. Optimum conditions for the adsorption of the chitosan-GO composite on methylene blue were obtained at 50 minutes contact time, concentration of 60 ppm, and at 50°C. The adsorption process of the chitosan-GO composite on methylene blue followed the Freundlich adsorption isotherm with an adsorption capacity of 2.47 mg/g.

Impacts of Wearable Resistance Placement on Running Efficiency Assessed by Wearable Sensors: A Pilot Study

Wearable resistance training is widely applied to enhance running performance, but how different placements of wearable resistance across various body parts influence running efficiency remains unclear. This study aimed to explore the impacts of wearable resistance placement on running efficiency by comparing five running conditions: no load, and an additional 10% load of individual body mass on the trunk, forearms, lower legs, and a combination of these areas. Running efficiency was assessed through biomechanical (spatiotemporal, kinematic, and kinetic) variables using acceleration-based wearable sensors placed on the shoes of 15 recreational male runners (20.3 ± 1.23 years) during treadmill running in a randomized order. The main findings indicate distinct effects of different load distributions on specific spatiotemporal variables (contact time, flight time, and flight ratio, p ≤ 0.001) and kinematic variables (footstrike type, p &lt; 0.001). Specifically, adding loads to the lower legs produces effects similar to running with no load: shorter contact time, longer flight time, and a higher flight ratio compared to other load conditions. Moreover, lower leg loads result in a forefoot strike, unlike the midfoot strike seen in other conditions. These findings suggest that lower leg loads enhance running efficiency more than loads on other parts of the body.

Synthesis of chitosan-graphene oxide (GO) composite using the sol-gel method and its application in the adsorption of methylene blue dye

Synthesis of chitosan-GO composites using the sol-gel method and its application to methylene blue adsorption has been carried out. This study aims to determine the ability of chitosan-GO composites to adsorb methylene blue. Chitosan-GO composites were made with mass ratios (1:1), (1:3), and (1:5) and characterized by XRD. Material with a ratio (1:1) was chosen to be characterized using BET, SEM-EDS, and used as methylene blue adsorption. Methylene blue adsorption process with several variables including contact time, concentration, and temperature of methylene blue dye. The results of the XRD characterization of the chitosan-GO composite (1:1), (1:3), and (1:5) showed a diffraction peak at an angle of 2θ, namely 25.1°; 26.29° and 19.54°. The surface area of the chitosan-GO composite (1:1) with BET was 145.3505 m2/g. Characterization using SEM showed that the chitosan-GO (1:1) composite had a porous structure and was not homogeneous. Optimum conditions for the adsorption of the chitosan-GO composite on methylene blue were obtained at 50 minutes contact time, concentration of 60 ppm, and at 50°C. The adsorption process of the chitosan-GO composite on methylene blue followed the Freundlich adsorption isotherm with an adsorption capacity of 2.47 mg/g.

Sustainable and efficient recovery of lithium from rubidium raffinate via solvent extraction

In recent years, with the increasing prevalence of rechargeable lithium-ion batteries in the burgeoning markets of electric vehicles and portable electronic devices, the consumption of lithium batteries has significantly surged. Hence, the efficient development and utilization of associated lithium resources bear paramount significance. This study aims to recover lithium from rubidium raffinate via solvent extraction. A systematic investigation was conducted to examine the effects of various parameters such as organic phase concentration, contact time, and phase ratio (O/A) during the separation process. The results indicated that the organic phase composed of 0.1 mol/L 4,4,4-Trifluoro-1-phenyl-1,3-butanedione (HBTA) and 0.1 mol/L Trioctylphosphine oxide (TOPO) could efficiently extract lithium from the rubidium raffinate. The optimal conditions were observed at a temperature of 20℃, O/A=1, and a contact time of 5 min. After three-stage countercurrent extraction, a lithium extraction rate of 99.24 % could be achieved, with over 95 % of the sodium easily scrubbed by 0.1 mol/L HCl at an O/A=10. With the use of 3 mol/L HCl, stripping efficiency exceeding 99 % could be attained at an O/A=10, consequently a successful preparation of battery-grade lithium carbonate product was achieved. Regeneration experiments confirmed the organic phase's excellent reproducibility efficiency. Slope analysis and density function theory (DFT) simulations indicated that optimal lithium extraction is achieved when HBTA and TOPO are at equal molar concentrations. The proposed process is expected to provide a green and sustainable route for the recovery of associated lithium resources.

Removal of acetaminophen from wastewater using a novel bimetallic La/Th metal-organic framework: Kinetics, thermodynamics, isotherms, and optimization through Box-Behnken design

Acetaminophen (ACT), a common drug pollutant, has been effectively removed from wastewater by a novel adsorbent called La/Th-MOF. This adsorbent is made of stacked nanorods of 2-methyl imidazole with lanthanum and thorium. La/Th-MOF, which is characterized by sophisticated techniques including SEM, XRD, and BET analysis, has a mesoporous assembly with a 1.23 nm pore size and a capacious surface area of 2226.93 m2/g, which facilitates effectual adsorption. The adsorption tests, which were impacted by factors such as pH levels, ACT concentration, and contact time, fit into a pseudo-second-order chemisorption kinetic model and with the Langmuir isotherm, suggesting homogenous monolayer adsorption. The material in question demonstrated a noteworthy maximum adsorption capability of 339.75 mg/g for ACT, indicating its probable as a feasible and economical adsorbent for the mitigation of pharmaceutical contamination in wastewater. Our results designate that pH levels have an important influence on the efficacy of ACT absorption by La/Th-MOF, with an acidic pH 5 environment being most favorable for maximal adsorption at a material dosage of 0.02 g. It was discovered that the adsorption procedure was endothermic. Using pseudo-second-order kinetic models and the Langmuir isotherm, which both fit the experimental data very well, to explain the adsorption kinetics. A chemisorption mechanism was found to be predominant throughout the process, as specified by the predicted adsorption energy of 22.62 kJ/mol. In addition, optimized the influencing parameters by using the Box-Behnken design (BBD) and response surface methodology (RSM), which improved process efficiency. La/Th-MOF, has a remarkable half-life, as demonstrated by six rounds of adsorption and desorption without a discernible decline in performance. Research endeavors aimed at elucidating the interplay between La/Th-MOF and ACT hint to several plausible points of contact that could contribute to the adsorption procedure, such as hydrogen bonding, π-π interactions, pore filling or electrostatic forces. This study, which is innovative in its use, reveals the exceptional efficacy of La/Th-MOF in wastewater purification using ACT extraction. An astounding 339.75 mg/g of optimal adsorption capability was attained at an acidic pH of 5. This highlights how the La/Th-MOF can be used in practice to treat pharmaceutical pollutants found in water sources.

Auto ignition assisted synthesis of magnetic CaFe2O4: Exploring role of fuel molecule and amplest dye dismissal

The present work explores the pioneering use of different fuels for the synthesis of CaFe2O4 (CF) nanopowder through auto-ignition synthesis (AIS) with potential application in the acid fuchsine (AF) dye removal. The results showed significant alternation in structure, morphology, and magnetic properties depending on fuel type. The morphology of the CaFe2O4 nanopowders changed from a rock-like appearance for dextrose to a porous, thick-walled network structure for sucrose. All synthesized particles showed superparamagnetic behavior, with a crystallite size of 9 nm to 16 nm. The different adsorption process parameters, including the solution pH, adsorbent amount, and contact time, were studied and optimized. The Langmuir isotherm well explains the adsorption of AF, and the maximum monolayer capacity of CF-dextrose, CF-xylitol, CF-sorbitol, and CF-sucrose was found to be 788, 1024, 1125, and 1297 mg/g, respectively. The pseudo-second-order (PSO) kinetic model describes the adsorption data and the value of rate constant (k2 = 2.36E-05 for CF-dextrose, 3.11E-05 for CF-xylitol, 2.70E-05 for CF-sorbitol, and 5.36E-05 for CF-sucrose) explain fast adsorption process. Furthermore, the CF nanopowder exhibits better regeneration and reusability capacity after multiple consecutive cycles, and magnetic separation aptitude makes it more convenient to isolate the adsorbent after the adsorption process.

Secondary attack rate following on-site isolation of patients with suspected COVID-19 in multiple-bed rooms

The implementation of isolation precautions for patients with suspected Coronavirus Disease 2019 (COVID-19) and pending test results is resource intensive. Due to the limited availability of single-bed rooms at our institution, we isolated patients with suspected COVID-19 together with patients without suspected COVID-19 on-site in multiple-bed rooms until SARS-CoV-2-test results were available. We evaluated the likelihood of SARS-CoV-2 transmission to individuals sharing the room with patients isolated on-site. This observational study was performed at the University Hospital Basel, Switzerland, from 03/20 − 11/20. Secondary attack rates were compared between patients hospitalized in multiple-bed rooms and exposed to individuals subjected to on-site isolation precautions (on-site isolation group), and patients exposed to individuals initially not identified as having COVID-19, and not placed under isolation precautions until the diagnosis was suspected (control group). Transmission events were confirmed by whole-genome sequencing. Among 1,218 patients with suspected COVID-19, 67 (5.5%) tested positive for SARS-CoV-2. Of these, 21 were isolated on-site potentially exposing 27 patients sharing the same room. Median contact time was 12 h (interquartile range 7–18 h). SARS-CoV-2 transmission was identified in none of the patients in the on-site isolation group vs. 10/63 (15.9%) in the control group (p = 0.03). Isolation on-site of suspected COVID-19-patients in multiple-bed rooms avoided single-room occupancy and subsequent in-hospital relocation for many patients without confirmed SARS-CoV-2-infection. The absence of secondary transmission among the exposed patients in the on-site isolation group allows for assessment of the risk/benefit ratio of this strategy given the limitation of a small sample size.

Eco-Friendly Synthesis of Al2O3 Nanoparticles: Comprehensive Characterization Properties, Mechanics, and Photocatalytic Dye Adsorption Study

Metal and metal oxide nanoparticles are gaining traction in inorganic catalysis and photocatalysis, driving the development of eco-friendly methods. This study introduces an eco-friendly and cost-effective approach for synthesizing Al2O3 nanoparticles (NPs) using extracts derived from the leaves of Calligonum comosum L. The primary objective of this investigation is to assess the photocatalytic efficacy of the synthesized catalyst in addressing organic pollutants. The Al2O3 NPs exhibit a spherical morphology with crystalline arrangements, as evidenced by an average crystallite size of 25.1 nm in the XRD analysis. The band gap energy of the Al2O3 NPs is determined to be 2.86 eV. In terms of mechanical properties, the Al2O3 NPs show significant potential in enhancing both flexural and compressive properties, thereby making them a viable choice for improving the mechanical performance of composites. Notably, the Young’s modulus of the hybrid composite (comprising plant material and Al2O3 NPs) exhibits a remarkable increase of 34.4% in flexion and 78.3% in compression compared to the plant material alone. The catalytic performance of the Al2O3 NPs is evaluated using methylene blue (MB) as a cationic dye and Rose Bengal (RB) as an anionic dye. Impressively, the Al2O3 NPs demonstrate degradation efficiencies of 98.2% for MB and 90.5% for RB. The degradation processes occur under solar light irradiation, with a contact time of 120 m, a maintained pH of 7, and a temperature of 25 °C. This study found that Al2O3 nanoparticles are a promising, cost-effective, and environmentally friendly option for water treatment.

Nanostructured Glass-Ceramic Materials from Glass Waste with Antimicrobial Activity

Modern consumption patterns have led to a surge in waste glass accumulating in municipal landfills, contributing to environmental pollution, especially in countries that do not have well-established recycling standards. While glass itself is 100% recyclable, the logistics and handling involved present significant challenges. Flint and amber-colored glass, often found in high quantities in municipal waste, can serve as valuable sources of raw materials. We propose an affordable route that requires just a thermal treatment of glass waste to obtain glass-based antimicrobial materials. The thermal treatment induces crystallized nanoregions, which are the primary factor responsible for the bactericidal effect of waste glass. As a result, coarse particles of flint waste glass that undergo thermal treatment at 720 °C show superior antimicrobial activity than amber waste glass. Glass-ceramic materials from flint waste glass, obtained by thermal treatment at 720 °C during 2 h, show antimicrobial activity against Escherichia coli after just 30 min of contact time. Laser-induced breakdown spectroscopy (LIBS) was employed to monitor the elemental composition of the glass waste. The obtained glass-ceramic material was structurally characterized by transmission electron microscopy, enabling the confirmation of the presence of nanocrystals embedded within the glass matrix.

Nanostructured Glass-Ceramic Materials from Glass Waste with Antimicrobial Activity.

Modern consumption patterns have led to a surge in waste glass accumulating in municipal landfills, contributing to environmental pollution, especially in countries that do not have well-established recycling standards. While glass itself is 100% recyclable, the logistics and handling involved present significant challenges. Flint and amber-colored glass, often found in high quantities in municipal waste, can serve as valuable sources of raw materials. We propose an affordable route that requires just a thermal treatment of glass waste to obtain glass-based antimicrobial materials. The thermal treatment induces crystallized nanoregions, which are the primary factor responsible for the bactericidal effect of waste glass. As a result, coarse particles of flint waste glass that undergo thermal treatment at 720 °C show superior antimicrobial activity than amber waste glass. Glass-ceramic materials from flint waste glass, obtained by thermal treatment at 720 °C during 2 h, show antimicrobial activity against Escherichia coli after just 30 min of contact time. Laser-induced breakdown spectroscopy (LIBS) was employed to monitor the elemental composition of the glass waste. The obtained glass-ceramic material was structurally characterized by transmission electron microscopy, enabling the confirmation of the presence of nanocrystals embedded within the glass matrix.

Eco-Friendly Synthesis of Al2O3 Nanoparticles: Comprehensive Characterization Properties, Mechanics, and Photocatalytic Dye Adsorption Study

Metal and metal oxide nanoparticles are gaining traction in inorganic catalysis and photocatalysis, driving the development of eco-friendly methods. This study introduces an eco-friendly and cost-effective approach for synthesizing Al2O3 nanoparticles (NPs) using extracts derived from the leaves of Calligonum comosum L. The primary objective of this investigation is to assess the photocatalytic efficacy of the synthesized catalyst in addressing organic pollutants. The Al2O3 NPs exhibit a spherical morphology with crystalline arrangements, as evidenced by an average crystallite size of 25.1 nm in the XRD analysis. The band gap energy of the Al2O3 NPs is determined to be 2.86 eV. In terms of mechanical properties, the Al2O3 NPs show significant potential in enhancing both flexural and compressive properties, thereby making them a viable choice for improving the mechanical performance of composites. Notably, the Young’s modulus of the hybrid composite (comprising plant material and Al2O3 NPs) exhibits a remarkable increase of 34.4% in flexion and 78.3% in compression compared to the plant material alone. The catalytic performance of the Al2O3 NPs is evaluated using methylene blue (MB) as a cationic dye and Rose Bengal (RB) as an anionic dye. Impressively, the Al2O3 NPs demonstrate degradation efficiencies of 98.2% for MB and 90.5% for RB. The degradation processes occur under solar light irradiation, with a contact time of 120 m, a maintained pH of 7, and a temperature of 25 °C. This study found that Al2O3 nanoparticles are a promising, cost-effective, and environmentally friendly option for water treatment.

Adsorption characteristics and applications of andesite in removing some pollutants from wastewater

Andesite was employed to effectively extract mercury(II) in an aqueous solution. After evaluating its characteristics, andesite was characterized by applying modern techniques such as BET and TGA methods. The study employed SEM and TEM measurements to analyze the variation in the surface shape and crystallinity of the metal due to adsorption. Using the EDX process, the chemical composition, weight, and atomic percentage of each element of andesite were determined. FTIR techniques were also used to confirm the TEM–EDX findings. Zeta potential was estimated. Cycles of regeneration and desorption have been examined. 99.03% was the highest uptake percentage. Adsorbent quantity (0.0025–0.05) g/L, contact time (5–60) min, pH (2–10), temperature (25–60) °C, and dose (0.0027, 0.0044, 0.0125, 0.0155, and 0.0399) mg/L all affect the amount of removal that increases with the increase in contact time, pH, dose, and temperature but drops as the metal ion concentration rises. The ideal values for contact time, pH, metal ion concentration, dose, and temperature were found to be, respectively, 30 min, 0.0155 mg/l, 0.02 g/l, and 40 °C. The calculation of thermodynamic parameters, including ΔH, ΔG, and ΔS, was imperative in establishing that the mechanism of heavy metal adsorption on andesite was endothermic, exhibiting a physical nature that escalated with temperature rise. The Freundlich adsorption equation's linear form is matched by the adsorption of mercury(II) on andesite; constant n was 1.85, 1.06, 1.1, and 1.1, whereas the Langmuir constant qm was found to be 1.85, 2.41, 3.54, and 2.28 mg/g at 25–60 °C. Furthermore, adsorption follows a pseudo-second-order rate constant of (3.08, 3.24, 3.24, and 13) g/mg/min under identical temperature conditions, as opposed to a first-order rate constant of 4, 3, 2.6, and 2. Hg2+, NH4+, Cl−, Br−, NO3−, SO42−, Na+, K+, H2S, and CH3SH were all extracted from wastewater by this application.

Green hybrid coagulants for water treatment: An innovative approach using alum and bentonite clay combined with eco-friendly plant materials for batch and column adsorption

Textile industries contribute to water pollution through synthetic dye discharge. This study explores the use of natural bio-coagulants to remove acid dyes from wastewater, investigating factors like pH, coagulant dose, dye concentration, contact time, and temperature for optimal results. The optimum pH and coagulants capabilities of (CAAPP, CAAPH, CBAGL, CBAPP and CBAPH) were 3 (49.6 mg/g), 3 (42.5 mg/g), 3 (38.9 mg/g), 4 (35.7 mg/g), 4 (34.1 mg/g), and 4 (29.4 mg/g) respectively, while treating of selected BRF-221 dyes from water solution. The acidic range (3–4) was found to have the best pH for the maximal coagulation, and the optimal dose were found to be 0.05 g/50 mL. The equilibrium was attained within 45–60 min for all coagulants. After 60 min of shaking, the maximum coagulation capacities (21.9, 21.02, 16.5, 27.9, 25.3, and 23.4 mg/g) of several coagulant composites (CAAGL, CAAPP, CAAPH, CBAGL, CBAPP, CBAPH) were determined. The initial BRF-221 dye concentration in the range of 10–200 mg/L was considered as optimum for gaiting maximum elimination of dye using different coagulants. At a dye value of 100 mg/L of BRF-221, maximal coagulation capacities CAAGL (179.19 mg/g), CAAPP (166.06 mg/g), CAAPH (141.60 mg/g), and CBAGL (126.49 mg/g), CBAPP (113.9 mg/g), CBAPH (93.08 mg/g) were attained. The study found 35 °C to be the optimal temperature for maximum acid dye removal using bio-coagulants. Increasing temperature reduced coagulation capacity, indicating an exothermic process. Freundlich and Langmuir isotherms showed suitability for pseudo-first-order and pseudo-second-order kinetics in biosorption. Thermodynamic parameters were assessed for process feasibility. Effective coagulants demonstrated sensitivity to electrolyte variations. In column studies, adjusting parameters achieved maximum coagulation efficiency for removing BRF-221 dyes. The study successfully applied optimal parameters to remove real textile effluents at a practical scale. SEM, FT-IR, BET and XRD characterized coagulants, providing insights into stability and morphology.

Recycling polyolefin plastic waste at short contact times via rapid joule heating

The chemical deconstruction of polyolefins to fuels, lubricants, and waxes offers a promising strategy for mitigating their accumulation in landfills and the environment. Yet, achieving true recyclability of polyolefins into C2-C4 monomers with high yields, low energy demand, and low carbon dioxide emissions under realistic polymer-to-catalyst ratios remains elusive. Here, we demonstrate a single-step electrified approach utilizing Rapid Joule Heating over an H-ZSM-5 catalyst to efficiently deconstruct polyolefin plastic waste into light olefins (C2-C4) in milliseconds, with high productivity at much higher polymer-to-catalyst ratio than prior work. The catalyst is essential in producing a narrow distribution of light olefins. Pulsed operation and steam co-feeding enable highly selective deconstruction (product fraction of >90% towards C2-C4 hydrocarbons) with minimal catalyst deactivation compared to Continuous Joule Heating. This laboratory-scale approach demonstrates effective deconstruction of real-life waste materials, resilience to additives and impurities, and versatility for circular polyolefin plastic waste management.

Preparation magnetic graphene oxide/diethylenetriamine composite for removal of methylene blue from aqueous solutions

Graphene oxide (GO) and its derivatives have several applications in many areas such as environmental and energy materials, water treatment and biomedical technologies. Because of having various polar groups on its surface, GO is considered as an excellent adsorbent. However, for many applications such as adsorption of pollution from aqueous solutions, chemical functionalization of graphene oxide is often a necessary requirement. In the present study, a new composite from graphene oxide, diethylenetriamine (DETA) and silica coated MnFe2O4 nanoparticles (GO/DETA/MnFe2O4@SiO2) was prepared. The structure, thermal stability and magnetic properties of the composite were studied by FT-IR, XRD, SEM, EDS, VSM and TGA spectroscopic methods. The prepared composite showed magnetic property with a saturation magnetization of 3.0 emu/g. The adsorption properties of GO/DETA/MnFe2O4@SiO2 composite for methylene blue (MB) in aqueous solution were studied using batch method. The effects of important parameters on the surface adsorption process of MB, including pH, contact time, adsorbent dosage and initial dye concentration were investigated. The adsorption isotherm was in accordance with Langmuir model showing surface homogeneity of the adsorbent. According to the Langmuir analysis, the maximum adsorption capacity (qm) of GO/DETA/MnFe2O4@SiO2 composite for MB was found to be 243.91 mg/g. The kinetic studies showed that the adsorption was pseudo first-order process. In addition, the thermodynamic studies indicated the adsorption was spontaneous and endothermic process.

Olive leaf extract-assisted preparation of nanoferrite for adsorptive removal of cationic dye

In this work, magnetic Fe3O4 nanoparticles synthesized with olive leaf extract were used to investigate the adsorption of Basic violet 16 from aqueous solutions. The physicochemical characteristics of Fe3O4 nanoparticles were evaluated by DLS, zeta potential, XRD, FTIR SEM, EDX, N2 adsorption-desorption, TEM, and VSM analyses. Using DLS analysis, the average size of the Fe3O4 nanoparticles was found to be 231.2 nm. Zeta potential studies indicated that the synthesized nanoparticles were moderately stable, and zeta potential was calculated as −14.9 mV. According to TEM analysis, the synthesized nanoparticles ranged in size from 6.28 to 17.3 nm. The optimum parameters for the adsorption of basic violet 16 with Fe3O4 nanoparticles were determined as pH: 9.0, adsorbent dose: 0.8 g, contact time: 210 min, stirring speed: 250 rpm. Langmuir, Freundlich, Dubinin Radushkevich (D-R) and Temkin isotherm models were used to characterize the basic violet 16 sorption data onto Fe3O4 nanoparticles and it was seen that Basic violet 16 adsorption onto the Fe3O4 nanoparticles followed Langmuir isotherm model at all temperatures. The maximum adsorption capacity of Basic violet 16 with Fe3O4 nanoparticles was determined as 117.64 mg/g at 318 K. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to describe the adsorption kinetics at 298–318 K. The adsorption followed the pseudo-second-order kinetic model. Adsorption of Basic violet 16 onto Fe3O4 nanoparticles occurred spontaneously and endothermically. Characteristic peaks Fe3O4 nanoparticles were visible in the XRD analysis. The SBET surface area dropped from 110.42 m2/g to 91.27 m2/g after dye adsorption. Peaks in the FTIR analysis showed that Basic violet 16 had been successfully adsorbed on Fe3O4 nanoparticles.

High efficiency of treated-phengite clay by sodium hydroxide for the Congo red dye adsorption: Optimization, cost estimation, and mechanism study

Wastewater textile dye treatment is a challenge that requires the development of eco-friendly technology to avoid the alarming problems associated with water scarcity and health-environment. This study investigated the potential of phengite clay as naturally low-cost abundant clay from Tamgroute, Morocco (TMG) that was activated with a 0.1 M NaOH base (TMGB) after calcination at 850 °C for 3 h (TMGC) before its application in the Congo red (CR) anionic dye from the aqueous solution. The effect of various key operational parameters: adsorbent dose, contact time, dye concentration, pH, temperature, and the effect of salts, was studied by a series of adsorption experiments in a batch system, which affected the adsorption performance of TMG, TMGC, and TMGB for CR dye removal. In addition, the properties of adsorption kinetics, isotherms, and thermodynamics were also studied. Experimental results showed that optimal adsorption occurred at an acidic pH. At a CR concentration of 100 mg L−1, equilibrium elimination rates were 68%, 38%, and 92% for TMG, TMGC, and TMGB, respectively. The adsorption process is rapid, follows pseudo-second-order kinetics, and is best described by a Temkin and Langmuir isotherm. The thermodynamic parameters indicated that the adsorption of CR onto TMGB is endothermic and spontaneous. The experimental values of CR adsorption on TMGB are consistent with the predictions of the response surface methodology. These led to a maximum removal rate of 99.97% under the following conditions: pH = 2, TMGB dose of 7 g L−1, and CR concentration of 50 mg L−1. The adsorbent TMGB's relatively low preparation cost of around $2.629 g-1 and its ability to regenerate in more than 6 thermal calcination cycles with a CR removal rate of around 56.98%, stimulate its use for textile effluent treatment on a pilot industrial scale.

Biosorption of pb(II) from aqueous solution by citrus reticulate: adsorption studies, and modeling

Removing toxic Pb(II) ions from aqueous solution by the peels of citrus reticulate (mandarin orange), a fruit industry waste, presents suitable scale-up possibilities. The Scanning Electron Microscope (SEM) and Brunauer-Emmett-Teller (BET) studies reflected that the mandarin orange peel powder had a porous surface area (32.46 m2g−1), average pore size and pore volume was 38.6 Å and 0.402 cm3g−1, respectively, favorable for binding Pb(II) ions. Fourier-transform infrared spectroscopy (FTIR) showed C-Br stretching, primary alcohol (C-O), phenolic O-H, and carbodimide N = C = N bands primarily helped to bind Pb(II) ions. The study evaluated and optimized the parametric influences of pH, adsorbate and biosorbent concentration, contact time and temperature on the removal efficiency of Pb(II) ions. A maximum of 97.08% Pb(II) was removed from 20 mg L−1 solution when 2.5 g L−1 adsorbent was present. The reaction obeyed the pseudo-second-order kinetic model. The intra-particle diffusion was involved in lead sorption. The Langmuir isotherm model resulted in an adsorption capacity of 23.04 mg g−1. 35.28% Pb(II) was removed in the 3rd adsorption-desorption cycle with 0.4 M HCl. The adsorption process was natural, impulsive and endothermic. The statistical investigation used Multiple Polynomial Regression (MPR) and Genetic Algorithm (GA). The analysis effectively forecasted the percentage removal at the optimized condition.

Antiviral and antibacterial efficacy of nanocomposite amorphous carbon films with copper nanoparticleswe

Copper compound-rich films and coatings are effective against widespread viruses and bacteria. Even though the killing mechanisms are still debated, it is agreed that the metal ion, nanoparticle release, and surface effects are of paramount importance to the antiviral and antibacterial efficacy of the surfaces. In this work we have investigated the behavior of the reactive magnetron sputtered nanocomposite diamond-like carbon thin films with copper nanoparticles (DLC:Cu). The films were etched employing oxygen plasma and/or exposed to ultra-pure water, aiming to investigate the differences of the Cu release in the medium and changes in film morphology. The presence of metallic copper and Cu2O phases was confirmed by multiple analytical methods. Pristine films were more effective in the Cu release reaching up to 1.3 mg/L/cm2 concentration. Plasma processing resulted in the oxidation of the films which released less Cu, but after exposure to water, their average roughness increased more, up to 5.5 nm. Pristine and O2 plasma processed DLC:Cu films were effective against both model coronavirus and herpesvirus after 1-hour contact time and reached virus reductions of up to 2.23 and 1.63 log10, respectively. Pristine DLC:Cu films were more effective than plasma-processed ones against herpesvirus, while less expressed difference was found for coronavirus. The virucidal efficacy over up to 24 h exposures in the aqueous medium was validated. A bactericidal study confirmed that pristine DLC:Cu films were effective against gram-negative E. coli and gram-positive E. faecalis bacteria. After 3 h, 100 % antibacterial efficiency (ABE) was obtained for E. coli and 99.97 % for E. faecalis. After 8 h and longer exposures, 100 % ABE was reached. The half-life inactivation of viruses was 8.10–11.08 min and for E. faecalis 15.1–72.2 min.