Search

The description of electronic properties of low bandgap molecular system is often performed by using density functional theory (DFT) and time dependent (TD) DFT calculations with the optimally tuned range-separated hybrid (OT-RSH) functional, as it contains the necessary ingredients to reliably predict charge transfer excitations. However, the range separating parameter (ω) is system-dependent and its optimization, including the chemical environment, is intricate. Refaely-Abramson et al. demonstrated that the gap renormalization in molecular crystals, a ground state property, can be represented by an OT-RSH functional screened by ɛstatic [Phys. Rev. B 88, 081204(R) (2013)], the zero frequency scalar dielectric constant. In this study, we propose the use of an OT-RSH functional screened by the scalar dielectric constant in the high frequency limit (OT-sRSH), ɛ∞, an appropriate constraint for vertical ionization energies or excitations in a dielectric environment. We have performed calculations for S,N-heteroacene derivatives in tetrahydrofuran and dichloromethane. The "unscreened" OT-RSH functional tends to underestimate experimental ionization potentials (IPs) and optical gaps (Egs) by up to 1.5 and 0.5 eV, respectively. In contrast, OT-sRSH functional calculations underestimate IPs and Egs by only 0.4 and 0.2 eV. We also compared the OT-sRSH results to explicitly solvated OT-RSH functional calculations for oligothiophenes in dioxane, benzene in ammonia, and methylene blue in water. We observe that both the approaches perform similarly for weakly interacting intermolecular systems and deviate for solvent–solute interacting systems, as expected. In conclusion, the OT-sRSH functional can describe molecular systems with environmental polarization effects accurately, a step toward describing realistic molecular systems. [ABSTRACT FROM AUTHOR]

In this work, pure and S–N/WO3 (1%–7%) nanoparticles (NPs) have been developed for the degradation of MB dye. Optical properties, vibrational analysis, morphology, structural analysis, and photocatalytic activity of the samples have been evaluated using a variety of characterization techniques, including UV–vis, PL, FTIR, SEM, and x-ray diffraction (XRD). The XRD patterns showed that the stability of the orthorhombic phase of WO3 was affected by the concentrations of S and N. In SEM, nanospheres with an average size of 80 nm of NPs have been observed. The PL results showed that the e−, h+ recombination rate for the S–N7%/WO3 sample was the lowest. The degradation of MB dye has also been investigated in order to investigate the photocatalytic performance. Remarkably, S–N7%/WO3 shows the best results, with a maximum degradation of 90% in 120 min. The stability of the improved catalyst was tested using recycling and trapping studies. S–N7%/WO3 catalyst's exceptional photocatalytic activity highlights its potential use in wastewater treatment. This study will be helpful for manufacturing innovation. [ABSTRACT FROM AUTHOR]

Nanomaterials have excellent adsorption performance due to nano-effect and have been widely used in many fields. The adsorption performance of nanomaterials depends on their adsorption thermodynamics and kinetics. Here, the thermodynamic and kinetic equations of adsorption for spherical nanoparticles are first derived in theory. The mechanisms and regularities of influences of nano-effect on thermodynamics and kinetics, using nano-CdS adsorption of methylene blue as a probe, were investigated. The results show that there are significant influences of nano-effect (i.e., interface area effect and interface tension effect) on the thermodynamics and kinetics of nanoparticle adsorption. When the particle radius is larger and beyond the nanometer scale (∼100 nm), the nano-effect can be neglected. When the radius of the nanoparticle is within 10–50 nm, the nano-effect of adsorption is mainly the interface area effect. When the radius is less than 10 nm, the influences of both the interface area effect and the interface tension effect on adsorption thermodynamics and kinetics become more significant. The theoretic equations and experimental insights in the present work could provide a significant basis and reference for improving and perfecting the adsorption theory involving nanomaterials and provide guidelines for the explanations of adsorption mechanisms as well as the selection of adsorbents. [ABSTRACT FROM AUTHOR]

Semiconductor-based photocatalysts have become increasingly used in the removal of pollutants from wastewater, especially antibiotics. A series of composite-based cuprous oxide and bismuth vanadate (Cu2O/BiVO4) composite-based photocatalysts were synthesized by using the chemical method. The structure of the Cu2O/BiVO4 composite was verified by using x-ray diffraction, scanning electron microscopy, photoluminescence, Fourier transform infrared spectroscopy, and UV–visible spectra. The degradation of methylene blue (MB) and tetracycline (TC) was investigated to check the photocatalytic activity of the Cu2O/BiVO4 composite series. The quantity of Cu2O was varied from 1% to 7% by weight to prepare the series of Cu2O/BiVO4 composites. The analysis of results verified that 5% Cu2O/BiVO4 exhibits an outstanding photocatalytic activity as compared to 1%, 3%, and 7% Cu2O/BiVO4, pure Cu2O, and pure BiVO4 under visible light irradiation. The optimum value of photocatalytic degradation achieved with 5% Cu2O/BiVO4 was 97% for MB dye and 95% for TC in 120 min, which is greater than the photocatalytic degradation of pure BiVO4 (MB 45% and TC 72%), pure Cu2O (MB 57% and TC 80%), 1% Cu2O/BiVO4 (MB 72% and TC 85%), 3% Cu2O/BiVO4 (MB 83% and TC 88%), and 7% Cu2O/BiVO4 (MB 87% and TC 91%). The stability and reusability of Cu2O/BiVO4 were also investigated. To check the major role of trapping in degradation, a trapping experiment was also performed by using three trapping agents: BQ, EDTA, and tBuOH. The results showed that Cu2O/BiVO4 exhibits an improved photocatalytic activity in the degradation of antibiotics in polluted water because the recombination rate of the electron–hole pair decreased and the surface area increased, which increased the active sites for redox reactions. Such a photocatalytic composite with high efficiency has various applications, such as energy production, environmental remediation, and water remediation. [ABSTRACT FROM AUTHOR]

Purpose: To determine the optimal implant diameter under limited bone width by comparing the effects of implants with different diameters on implant stability, peri-implant bone stability, and osseointegration. In addition, to evaluate the reliability of resonance frequency analysis (RFA) in detecting osseointegration and marginal bone level (MBL). Materials and Methods: Mandibular premolars and first molars of seven beagle dogs were extracted. After 8 weeks, their mandibular models and radiographic information were collected to fabricate implant templates. Implant sites were randomly divided into three groups according to diameter: Ø3.3, Ø4.1, and Ø4.8 mm. Implant stability quotient (ISQ) measurement and radiographic evaluation were performed after surgery (baseline) and at 4, 8, and 12 weeks. Three dogs were euthanized at 4 weeks to observe osteogenesis and implant-tissue interface biology. Four dogs were euthanized at 12 weeks to observe osseointegration. Hard tissue sections were prepared to analyze osteogenesis (fluorescence double labeling) and osseointegration (methylene blue-acid fuchsin staining). Results: At baseline and at 4, 8, and 12 weeks, the ISQ values of Ø4.1- and Ø4.8-mm implants did not differ (P > .05), but both had higher values than the Ø3.3-mm implants (P < .05). The mean marginal bone resorption (MBR) associated with Ø3.3-, Ø4.1-, and Ø4.8-mm implants was 0.65 ± 0.58 mm, 0.37 ± 0.28 mm, and 0.73 ± 0.37 mm, respectively. The buccal MBR of Ø4.8-mm implants was significantly higher than that of Ø4.1-mm implants (P < .05). The bone-to-implant contact (BIC) percentage at 12 weeks did not differ for any group (P > .05). The correlation coefficients between the ISQ and MBL of the Ø3.3-, Ø4.1-, and Ø4.8-mm implants were -0.84 (P < .01), -0.90 (P < .001), and -0.93 (P < .001), respectively, while that between the ISQ and BIC was 0.15 (P > .05). Conclusions: During the early healing stage, the performance of Ø4.1- and Ø4.8-mm implants in terms of implant stability was better than that of Ø3.3-mm implants. Implant diameter may not influence BIC percentage. RFA can be used to evaluate implant stability and MBL but is not suitable to assess the degree of osseointegration. [ABSTRACT FROM AUTHOR]

In advanced oxidation processes (AOPs), the degradation of organic pollutants by the oxidation of reactive oxygen species (ROS) generated from the interaction between H2O2 and active species Fe2+/Fe3+ has gained significant attention. The cycle of Fe2+/Fe3+ in the catalytic oxidation plays a key role. Herein, a kind of N-doped carbon encapsulated FeMoxOy nanocrystalline material (FeMo@NC) was fabricated using a precipitation–calcination approach and applied to degrade organic pollutants in AOPs. The composite catalyst presents efficient catalytic activity for removing rhodamine B (RhB), methylene blue (MB), congo red (CR) and methyl orange (MO). The facilitating effect of Mo on the Fe2+/Fe3+ cycle and the phase structure and composition of the catalyst on the degradation was explored. Meanwhile, the recovery and reusability of the catalyst were assessed, proving its excellent stability in the degradation process. Quenching experiments demonstrate that the catalyst can activate H2O2 to generate singlet oxygen (1O2) that serves as the main ROS to degrade RhB, and the degradation pathway and mechanism are then proposed. [ABSTRACT FROM AUTHOR]

Effective adsorption of dye pollutants is essential to preserving human health and life before they are released into the environment. Ionic coordination polymers are considered good candidates for the effective elimination of dye pollutants. In this research, an anionic coordination polymer, {[NH2(CH3)2]2[Cd(μ4-L)]·1.5H2O·0.75DMF}n (1), [L4−: (E)-5,5′-(fumaroylbis(azanediyl))diisophthalate], was prepared and characterized. Structural analysis revealed that each Cd(II) ion was linked to four L4− ligands forming a 3D framework. A 2-fold interpenetrated 3D architecture of the compound was observed with a dia topology due to the large pore of a single framework. Owing to its water stability and anionic skeleton, the removal ability of four dyes with different charges and sizes by the compound was investigated. The compound, maintaining the negative charge density, effectively adsorbed the cationic methylene blue (MB) dye, while the elimination of anionic methyl orange (MO) and Congo red (CR) dyes was not observed owing to electrostatic repulsion. Additionally, the compound displayed size-dependent adsorption as evidenced by its non-adsorption of the cationic rhodamine B (RhB) dye. The compound exhibited a high MB adsorption capacity with a maximum of 689.93 mg g−1. The experimental data agreed well with the Langmuir isotherm model, and the adsorption process could be marked as a pseudo-second-order kinetic model. The MB adsorption of the compound could be attributed to electrostatic interactions due to its anionic framework and weak interactions. [ABSTRACT FROM AUTHOR]

In advanced oxidation processes (AOPs), the degradation of organic pollutants by the oxidation of reactive oxygen species (ROS) generated from the interaction between H2O2 and active species Fe2+/Fe3+ has gained significant attention. The cycle of Fe2+/Fe3+ in the catalytic oxidation plays a key role. Herein, a kind of N-doped carbon encapsulated FeMoxOy nanocrystalline material (FeMo@NC) was fabricated using a precipitation–calcination approach and applied to degrade organic pollutants in AOPs. The composite catalyst presents efficient catalytic activity for removing rhodamine B (RhB), methylene blue (MB), congo red (CR) and methyl orange (MO). The facilitating effect of Mo on the Fe2+/Fe3+ cycle and the phase structure and composition of the catalyst on the degradation was explored. Meanwhile, the recovery and reusability of the catalyst were assessed, proving its excellent stability in the degradation process. Quenching experiments demonstrate that the catalyst can activate H2O2 to generate singlet oxygen (1O2) that serves as the main ROS to degrade RhB, and the degradation pathway and mechanism are then proposed. [ABSTRACT FROM AUTHOR]

Background: Intraoperative use of methylene blue has been shown to reduce postoperative complications and recurrence rates in adults. It has however not been assessed if these beneficial effects would also apply to pediatric pilonidal sinus disease with its high recurrence rates. We, therefore, aimed to assess its effects on complications and recurrences in our retrospective exploratory cohort study. Methods: Of 55 consecutive children treated in our centre between January 2009 and December 2020, 48 were retrospectively included. We used logistic regression with a priori chosen predictors of intraoperative use of blue dyes, previous surgery for pilonidal sinus disease, and the presence of comorbidities on the composite outcome of complications and recurrence. Cramér's V was used to explore associations between the use of blue dyes and the extent of resection. Results: The median age in our cohort was 15.3 years. Five patients were below 2 years of age, and 24 (50%) of them were males. Chronic diseases were present in 13 (27%) patients, eight had previously been operated on for pilonidal sinus disease, and blue dyes were used in 34 patients (71%). Their intraoperative use was linked to the composite outcome with an odds ratio of 5.41 (95% confidence interval (CI) 1.52–25.34, P = 0.017) as were comorbidities with an odds ratio of 1.86 (95% CI 1.18–3.25, P = 0.014), but not re-do surgery (odds ratio 2.94 (95% CI 0.37 23.42, P = 0.3)). The use of blue dyes was associated with larger resections (Cramér's V 0.556 (95% CI 0.329–0.74)). Conclusion: The intraoperative use of blue dyes was negatively associated with complications and recurrences in pediatric pilonidal sinus disease. However, if blue dyes were used, the extent of resection was also larger. Larger resections had been shown before to be associated with complications and recurrences, too. This potential interaction requires further elucidation in future studies. [ABSTRACT FROM AUTHOR]

Two new uranium complexes [UO2L2(H2O)] (where L2=diacetyl bis‐isonicotinoyl hydrazone) complex 1, and [UO2(L1)2] (where L1=diacetylmonoxime isonicotinoylhydrazone) complex 2, have been synthesized by precisely adjusting the pH values of the reaction system. Complex 1 was formed in an acidic ethanolic solution (pH=3) through an in‐situ acid catalytic reaction of diacetylmonoxime isonicotinoylhydrazone and UO2(NO3)2.6H2O, while complex 2 was acquired in a neutral medium (pH=7) through self‐assembly of two ligands and one uranium (VI) metal centre. Both complexes were thoroughly characterized by elemental analysis, UV‐Visible spectroscopy, IR spectroscopy, NMR, TGA, cyclic voltammetry, and powder X‐ray diffraction. The studies indicate that the bis‐hydrazone in complex 1 is a dianionic tetradentate N2O2 donor, whereas in complex 2 it is a monoanionic tridendate N2O donor. The formation of complex 1 was further confirmed by a single‐crystal X‐ray diffraction study, which revealed the role of a water molecule in forming a pentagonal bipyramidal geometry of [UO2L2(H2O)]. Photophysical studies revealed that complexes 1 and 2 exhibited low band gap values of 2.07 and 2.12 eV, respectively, indicating their semiconducting nature. From the CV measurements, the higher negative potentials of the complexes 1 & 2 {1, −0.6 V and 2, −0.5 V vs. ferrocenium/ferrocene (Fc+/Fc)} in DMSO are assigned to the presence of {UO2}2+/{UO2}+ couple signifying their redox active nature. Dye adsorption studies show that both the complexes were able to remove 90 % of Methylene blue (MB) and Rhodamine B (RhB) from the solutions with the concentration of 10−5 M. The structural insights and electronic properties of Ligand HL1 and complex 1 were further explored by density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

In this study, a series of submicron‐sized functional polymer particles poly(Sty‐co‐MAA) with variable methacrylic acid (MAA) content were prepared by soap‐free emulsion polymerization of styrene (Sty), methacrylic acid (MAA), and ethylene glycol dimethacrylate (EGDMA). The number‐average diameters of polymer particles (Dn) were in the range of 0.11 to 0.19 μm. A decrease in particle size was observed with increasing the molar ratio of MAA comonomer in the recipe. ZnO/poly(Sty‐co‐MAA) hybrid polymer particles were prepared by seeded emulsion copolymerization in presence of zinc oxide nanoparticles (ZnO NPs) as seed particles synthesized using Citrus lemon aqueous leaf extract. Scanning electron microscopy (SEM), transmission electron microsphere (TEM), X‐Ray Diffraction (XRD), and Fourier transformed infra‐red (FT‐IR) analysis were performed to characterize polymer particles. The crystalline size of ZnO NPs and ZnO/poly(Sty‐co‐MAA) hybrid polymer particles calculated from XRD analysis were 20.75 and 29.85 nm, respectively. These hybrid polymer particles were applied as photocatalyst in the photodegradation of methylene blue (MB) dye under UV irradiation, which showed high catalytic activity with degradation efficiency of 85.70 % at room temperature compared to bare ZnO NPs. [ABSTRACT FROM AUTHOR]

ABSTRACT The versatile application of metal‐based nanoparticles has led to a recent rise in interest in the low‐cost and eco‐friendly green chemistry‐based development of metal oxide nanoparticles. This work focuses on the photocatalytic and antibacterial uses of the zinc oxide nanoparticles (ZnONPs) that were produced based on a green approach employing stem extract of Piper chaba. The formation of ZnONPs was preliminary validated by the appearance of an absorption band at 373 nm and a stretching band due to ZnO at 480 cm−1 in UV–Vis and FTIR spectrum, respectively. The crystalline nature of ZnONPs with a hexagonal wurtzite phase and an average crystallite size of 25 nm was validated by XRD analysis. ZnONPs' crystalline nature was further supported by TEM, which further showed that they were mostly cubic in form and had an average length of 30 nm. Synthesized ZnONPs demonstrated significant antibacterial activity against Salmonella typhi, Vibrio cholerae, Escherichia coli, and Staphylococcus aureus and lucrative photocatalytic activity with the rate constant value of 0.0273 min−1 towards the degradation of methylene blue under sunlight exposure. Therefore, a facile, affordable, and ecologically sustainable method like this might be used for the large‐scale synthesis of ZnONPs. [ABSTRACT FROM AUTHOR]

In this work, Au/Bi2O3 was synthesized by loading Au nanoparticles (NPs) onto β-Bi2O3 by a simple solution reduction method. β-Bi2O3 was synthesized by a precipitation-thermal decomposition procedure, which results in significantly improved SERS detection limits down to 10−9 M for methylene blue (MB) and 10−7 M for methyl orange (MO) as probe molecules, comparable to those reported for the best semiconductor SERS substrates. In particular, further deposition of Au NPs (5.20% wt%) onto β-Bi2O3 results in a two-order-of-magnitude enhancement in detection sensitivity, achieving a detection limit of 10−11 M for MB and 10−9 M for MO. Under ultraviolet/visible irradiation, the Au/Bi2O3 hybrids substrate exhibits superior self-cleaning ability due to its photocatalytic degradation ability which can be applied repeatedly to the detection of pollutants. The advanced composite substrate simultaneously achieved ultra-low mass loading of Au NPs, outstanding detection performance, good reproducibility, high stability and self-cleaning ability. The development strategy of low load noble metal coupled high performance semiconductor β-Bi2O3 to obtain nano-hybrid materials provides a method to balance SERS sensitivity, cost effectiveness and operational stability, and can be synthesized in large quantities, which is a key step towards commercialization and has good reliability prospects. [ABSTRACT FROM AUTHOR]

In this work, we report a facile fabrication of an interface-induced piezoelectric PVDF-ZnSnO3-MoS2 (PZM) device for the rapid degradation of organic dyes, namely, crystal violet (CV) and methylene blue (MB) in wastewater. The piezocatalyst composite mold is fabricated with PVDF as a binder matrix and ZnSnO3/MoS2 as piezoelectric cocatalysts to increase the selectivity and efficiency of the device. SEM micrographs display the formation of aggregated nanoparticle structures with a large number of active sites for superior catalytic activity. The structural studies reveal the increase in the β-phase of PVDF with the increased concentration of ZnSnO3 and MoS2 nanoparticles in the PZM mold. The optimized composite mold displays the superior performance of both CV and MB with 100% degradation in 14 and 6 min, respectively. Further, the superior performance of alkaline pH solution with an ultrasonic power of 50 W and a weight percentage of 20% was optimized to achieve maximum catalytic efficiency, selectivity, and stability to minimize the environmental impact. The fabricated piezocatalyst is found to be efficient and reusable after 7 degradation studies displaying high repeatability. The approach presented in this work can inspire a new strategy for designing efficient and scalable piezocatalytic materials for sustainable wastewater treatment. [ABSTRACT FROM AUTHOR]

Herein we have reported a fluorescent probe (MB-M) based on MB derivative for Cu2+ ions detection. The probe was well characterized by 1H NMR, 13C NMR and HR-MS spectrum. Probe MB-M showed naked-eyes recognition to Cu2+ as color change from colorless to indigo. The probe exhibited promising features such as high fluorescence and UV–vis selectivity, fast response (5 mint), workable at pH 2–7, and low limit of detection (LOD = 0.33 µM). Probe MB-M was also used for Cu2+ ions imaging in HepG-2 cells and detection in daily life (Test Strip and lake water). Moreover, non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analysis were used to study the interaction between MB-M and Cu2+ ions. By examining the electronic characteristics of the complex using natural bond orbital (NBO), electron density difference (EDD), and frontier molecular orbital (FMO) analysis, the sensitivity of MB-M towards Cu2+ ions were investigated. The results illustrated that the interactions between MB-M and Cu2+ ions involved chemisorption. [ABSTRACT FROM AUTHOR]

Water coloring has the properties of resistance to mutagenic, toxic, aggressive, carcinogenic, destructive, strong light and unstable oxidation and air pollution and has serious effects on environmental systems and human health. Because of its severe toxicity, methylene blue (MB) can cause cancer, mutagenesis, and teratogenic consequences in people as well as enter the food chain. The main objective of this investigation is to study the modeling and the optimization parameters of MB adsorption using a low‐cost adsorbent Fe3O4. The parameters evaluated for adsorption are the adsorbent dosage, pH, contact time, and temperature using the response surface methodology. The principal variables affecting MB removal were pH (3–11), catalyst dosage (0.01–0.3 g), contact duration (10–180 min), and temperature (25–55 °C). To select an experimental domain, a preliminary study was performed first. The results showed that at pH 10, 1.4 g L−1 Fe3O4‐nanoparticles (NPs) had the highest removal efficiency of cationic dye MB (20 ppm) from aqueous solutions by batch adsorption technique. The pseudo‐second‐order (PSO) kinetic models and the Langmuir isotherm provided the best fit for the adoption of MB. The adsorption process was exothermic and spontaneous, according to thermodynamics studies. To determine the effect of the investigated variables and their interaction on the adsorption process, a Box–Behnken design was used. A second‐order polynomial equation was used to model the experimental results. The experimental findings were consistent with the suggested model as demonstrated by the high value of the determination coefficient. The performance of the model equation verified the experimental observation with just a slight divergence, and the values acquired from the experiment and model predictions were found to be in suitable agreement. According to the numerical optimization, 98.61 % is the optimal elimination efficiency for MB adsorption. These results suggest that an adsorption process utilizing Fe3O4 NPs is efficient in environmental remediation. [ABSTRACT FROM AUTHOR]

It is shown that one‐electron oxidation of aniline with methylene blue is possible only at low temperatures under UV radiation. The kinetics of aniline polymerization under the action of ammonium persulfate in the presence of catalytic amounts of methylene blue is studied. Kinetic curves are obtained by electron paramagnetic resonance (EPR) spectroscopy at various temperatures and concentrations of methylene blue. The catalytic action of the unassociated form of methylene blue and the deactivation of reactive complexes by the dye dimers are shown to compete. In the context of the obtained results the autocatalysis mechanism of oxidative polymerization is considered, which suggests the formation of complexes of aniline and polyaniline that are subject to subsequent rapid oxidation by the persulfate anion. [ABSTRACT FROM AUTHOR]

Radix Paeoniae Alba is an important plant resource and valuable tonic in traditional Chinese medicine. The radix of Radix Paeoniae Alba is rich in starch. There are few reports of Radix Paeoniae Alba starch. In present study, the Radix Paeoniae Alba starch is extracted, citrate esterified starches are prepared, the starch‐based hydrogels are synthesized, and adsorptive properties are investigated. The investigation suggests that Radix Paeoniae Alba starch‐based adsorbent is promising as an efficient and sustainable adsorbent for copper ions and methylene blue removal; therefore, Radix Paeoniae Alba starch has an appealing application prospect in adsorption for scavenging metal ions and dyes from real complex waste liquid. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTThis research examined the effectiveness of using Albizia lebbeck seed pods (ALB) as an adsorbent to remove dye effluents and clean up wastewater. More specifically, the binding capacity of methylene blue (MB) and Congo red (CR) dyes from aqueous solution using unmodified Albizia lebbeck seed pods (UALB) and citric acid modified Albizia lebbeck seed pods (CALB) were compared. The adsorbents underwent characterization via the use of Fourier transform infrared spectroscopy and scanning electron microscopy. Several operational factors were investigated using batch tests to ascertain their effects. These parameters included pH, adsorbent dose, interaction duration, and initial dye concentration. The residual dye concentrations were determined, and the data generated were fitted to equilibrium and kinetic models. In CALB and UALB, MB adsorption ideal pH values were 10 and 12, whereas CR optimal pH values were 3 and 2. Also, MB and CR equilibrium durations were 360 and 240 min, respectively. Temkin model best described the adsorption in CALB (r2 = 0.9916, 0.9484) whereas Freundlich worked well for UALB in MB and CR (r2 = 0.9626, 0.9871). Kinetic modeling of the adsorption data showed that the pseudo-second-order kinetic model provided the best fit (r2 = 0.9998, 0.9999) for CALB and (r2 = 1, 0.9992) for UALB for both MB and CR dyes. Maximum adsorption for MB was 9.499 mg/g and for CR it was 8.628 mg/g, and the findings showed a positive linear correlation between the concentration of dye-ions and their adsorption ability. The CALB also demonstrated superior efficacy in the removal of MB (4.661 mg/g) dye relative to CR (4.113 mg/g). The results of this study demonstrate that the use of ALB, in both modified and unmodified forms, is a cost-effective and efficient approach for the removal of MB and CR from the aqueous environment.In this study, Albizia lebbeck seed pod (ALB), an agricultural waste, was used in both its unmodified (UALB) and modified (CALB) forms to remove cationic MB and anionic CR dyes from aqueous solution. The study showed that ALB proved to be an excellent low-cost alternative adsorbent for the removal of MB and CR dyes from an aqueous solution. However, the adsorption capacity was higher for MB (9.499 mg/g) compared to CR (8.628 mg/g). According to the results, CALB also proved to be more efficient in the removal of MB dye (4.661 mg/g) compared to CR (4.113 mg/g). [ABSTRACT FROM AUTHOR]

The Approximate Bayesian Computing (ABC) was used in this work to perform the selection and calibration of models in reactor dynamics. Five phenomenologically based hydrodynamic models on dead volume, flow deviation and retro-mix anomalies were evaluated and classified into two groups. The inverse problems were solved from experimental data obtained by the technique of residence time distribution (RTD) in positive step, using the methylene blue tracer in a stirred-tank reactor. The experiments evaluated the influence of volumetric flow, effluent outlet position, agitation position and rotation on the hydrodynamic characterization of the reactor. The results revealed that the most influential parameter in the first group was the dead volume, while in the second group, the retro-mix anomaly was highly sensitive to rotation. The ABC algorithm applied in this work used the Morozov discrepancy principle to select the tolerance in the final population. Tolerances for other intermediate populations were obtained from the median distance of each particle accepted in the previous population. The application of the Bayesian approach in RTD problems was excellent for the hydrodynamic characterization of reactors. The ABC SMC algorithm proved to be efficient for the calibration and selection of hydrodynamic models of reactors. The most influential anomaly in the flow was the dead volume. [ABSTRACT FROM AUTHOR]

In this study, Sorel cement (SC) was doped with Mn7+ to develop a cost-effective adsorbent that can quickly remove methylene blue (MB) dye from aqueous solutions. The characteristics of the prepared adsorbents were examined using X-ray diffraction, atomic force microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The examinations confirmed the formation of SC and the successful doping of manganese. Batch adsorption experiments were also performed to investigate and to optimise the operational parameters such as Mn7+ ion concentration, contact time, dosage, MB concentration, pH, and temperature. The modified adsorbent revealed a significant adsorption improvement when compared with pure SC. A small addition of 0.01 g of Mn7+ exhibited 100% removal efficiency up to a dye concentration of about 100 mg/L, whereas about 64% removal efficiency was obtained with pure SC using 36.5 mg/L of the MB solution. Furthermore, the modified adsorbent revealed rapid equilibrium times of around 1 and 3 minutes using 36.5 and 100 mg/L of the MB solution, respectively. An experimental adsorption capacity of up to 246 mg/g was obtained, and the equilibrium data were consistent with the Freundlich isotherm and were well fitted with a pseudo-second-order kinetic model. The thermodynamic values indicated a physisorption, exothermic (ΔH° = −7.7 kJ/mol), and spontaneous (ΔG° = −9.4 kJ/mol) nature of the adsorption process with enhanced feasibility and comparable regeneration efficiency for up to five cycles. Therefore, the results indicate that the modified sorbent can possibly be utilised as a potential fast method for the removal of MB dye from wastewater. [ABSTRACT FROM AUTHOR]

In this study, catalytic-degradation of dyes such as methylene blue (MB) and malachite green (MG) was carried out by using silver nanoparticles (AgNPs), obtained by adopting the flower extract of Luffa acutangula (LA). The biogenic synthesised LA-AgNPs were characterised by using UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), DLS (dynamic light scattering) with zeta potential analysis, X-ray diffraction (XRD) and high-resolution transmission electron microscopic(HR-TEM) analyses. The typical surface plasmon resonance peak of LA-AgNPs was observed at 428 nm, as confirmed from UV-Vis spectrum. The formation of LA-AgNPs was observed through colour transformation from pale yellow to dark-brown due to the reduction of Ag+. Synthesised LA-AgNPs displayed spherical shape and face-centred cubic structure with an average size of 10–30 nm. The effects of various parameters such as initial extract concentration, time and time process were studied. The degradation reactions of MB and MG are found to follow the Langmuir–Hinshelwood mechanism with a pseudo-first-order kinetic model. Biogenic synthesised LA-AgNPs showed good degradation ability to reduce the MG and MB with NaBH4. [ABSTRACT FROM AUTHOR]

Purpose: Leaks after sleeve gastrectomy remain a deadly complication significantly affecting outcomes and medical costs. The aim of the present review is to provide an updated decalogue on leak prevention. Methods: Risk factors of leakage after LSG were examined based on an extensive review of literature (in period time 2016–2024) and summary of evidence was provided using Oxford levels of evidence scale. Results: Pathogenesis of leakage after LSG still remain related to ischemic and mechanical factors and, therefore, no new evidence has been reported. Conversely, some technical aspect of the procedure has changed: bougie size, antrum resection, staple line reinforcement, and intraoperative leak testing. Conclusions: Bougie size 36 F is effective and safe achieving similar leakage rate compared to larger bougie sizes (EL:2) 2024 UPDATE; There is no significant difference in the leak rate between restrictive (< 6 cm) and conservative (6 cm) antrum resection (EL: 1) 2024 UPDATE; Surgical experience and case volume affect the leak rate more consistently than every kind of SLR (EL: 2) 2024 UPDATE; Intraoperative leak test after LSG represents a decision based on surgeon preference in absence of standardization (endoscopy, bubble test, methylene blue, indocyanine green.) and strong detection/prevention rate (EL: 3) 2024 UPDATE. [ABSTRACT FROM AUTHOR]

Till date it is a great challenge to synthesize CdS photocatalyst with a high stability. In this study, a stable CdS photocatalyst was successfully synthesized by a simple, cost‐effective hydrothermal route via cadmium acetate and thiourea as Cd and S precursors, respectively. The effect of different processing times (8 h and 24 h) and molar ratios on the photocatalytic activity and stability were mainly investigated. The samples were characterized in detail by XRD, FT‐IR, XPS, UV‐vis DRS, Photolummiscence spectroscopy and Surface photovoltage. The photocatalytic activity of the as‐obtained nanostructures was examined for methylene blue (MB) dye degradation under visible light irradiation (λ≥420 nm). After 70 min of irradiation, nearly 82 % of MB was degraded by CdS nanostructures, display an improved photocatalytic activity for MB degradation with an apparent rate constant (k) of 0.019 min−1. Additionally, CdS nanostructures sustained a good photostability after five consecutive cycles. The higher photocatalytic activity of CdS nanostructure is attributed to an efficient separation of photogenerated electron‐hole pairs stimulated by its optimal molar ratio, optimal temperature and surface morphology. Our synthesized stable nanostructures have potential for dye contaminated waste‐water treatment. [ABSTRACT FROM AUTHOR]

A new imidazole‐modified reduced graphene oxide was synthesized through a substitution reaction between amino imidazole and chlorographene. Functional groups and material composition were characterized by using several methods. The N content of product is high, it possesses more ligands. These ligands still combine metal ions under acidic conditions. Adsorption for methylene blue can be fitted by quasi‐second‐order kinetics and Langmuir isotherm model, physical adsorption is the predominant adsorption mechanism. Adsorption capacity (350.7 mg/g) of product for Cr (III) is about fourfold higher than that (74.7 mg/g) of reduced graphene oxide. [ABSTRACT FROM AUTHOR]

Zirconium dioxide nanomaterials doped with samarium were produced through a bio-template method, utilizing citric acid as a fuel. Various advanced methods, for instance, XRD, TEM, EDX, PL, XPS, and UV–Vis spectrophotometry, were employed to characterize the compositions. XRD analysis confirmed that all peaks corresponded to the tetragonal phase of ZrO2, with no presence of impurities from other phases. The elemental composition was analyzed using EDX, verifying the presence of Zr, Sm, and O. The energy gap widening concerning the pure ZrO2 may be the well-known Moss–Burstein shift. This shift was linked to an increase in the bandgap (from 5.25eV to 5.54eV) with increasing concentrations of Sm. This observation was made during the analysis of the photocatalysis of pure ZrO2 and various concentrations of Sm-doped ZrO2 for Methylene Blue. The augmentation of Sm doping resulted in an improvement in the efficiency of removing Methylene Blue, increasing the removal rate from 35% to 80%. [ABSTRACT FROM AUTHOR]

Activated carbon (ACcs) from chili straw was prepared by sequential carbonization and K2CO3 activation and applied for adsorption of cationic (methylene blue (MB)) and anionic (methyl orange (MO)) dyes with similar molecular sizes from aqueous solution. The physicochemical properties of chili straw char (Charcs) and ACcs were compared based on N2-adsorption/desorption, SEM, XRD, Raman spectroscopy, and FTIR. Activation mechanism was revealed with the aid of TG-FTIR. Batch experiments were performed to determine the isotherm models for adsorption of dyes. Results showed that ACcs possessed a large specific surface area of 1868 m2 g−1. The formation of pores was attributed to the reactions between oxygen-containing functional groups in Charcs and K2CO3 at temperatures of 670 to 850 °C. Sips model was applicable for the adsorption isotherm data for both MO and MB with outstanding maximum adsorption capacities of 1542 and 989 mg g−1, respectively. Thermodynamic analysis revealed that the adsorption processes of MO and MB were endothermic and spontaneous, and the adsorption was more spontaneous in the case of MO. Zeta potential analysis revealed that electrostatic interactions were responsible for the significant difference between the adsorption capacities for MO and MB. Thermal desorption MO from ACcs was investigated by TG-FTIR, and thermal regeneration of MO-saturated ACcs was carried out at 650 °C for 30 min, and the regeneration efficiency remained higher than 60% after five cycles. [ABSTRACT FROM AUTHOR]