Methylene Blue Concentration Research Articles

A novel biosorbent material from waste fish scales (Cyprinus carpio) for biosorption of toxic dyes in aquatic environments

AbstractPolluted water sources are a growing concern in our world today, with more and more of our precious freshwater sources becoming contaminated. Pollution can come from a variety of sources, such as industrial discharge, agricultural runoff, and even urban runoff. Several treatment technologies have been investigated, mainly for dye pollution from textile and industrial wastes. In this study, the biosorption of methylene blue dye from the water environment was examined utilizing a low-cost and biodegradable biomaterial. Waste fish scales modified with NaOH were used as biomaterial. The biosorption effect of methylene blue concentration and pH variables was optimized. SEM for the surface morphology of the biomaterial and FT-IR analyses for the detection of functional groups were performed. The characterization of methylene blue biosorption was conducted to fully understand its nature, including its kinetics, equilibrium, and thermodynamic works. It has been determined that the biosorption process conforms most closely to the pseudo-second-order kinetic model for its kinetic results and to the Langmuir isotherm for its equilibrium results. Based on the Langmuir isotherm data, the maximum capacity for biosorption (qmax) was found to be 344.82 mg g−1. The thermodynamic results showed that the process of biosorption of methylene blue on various surfaces is spontaneous and occurs via physisorption. Additionally, the experimental design method was utilized to determine the optimum conditions of the methylene blue biosorption process under various conditions. The maximum biosorption capacity was determined to be 102.367 mg g−1 at the optimal conditions. The potential of biosorbent derived from the waste fish scales is promising as a novel biosorbent material due to its unique surface morphology and high biosorption capacity.

Computational modelling of scleral photocrosslinking: from rat to minipig to human.

Selective scleral crosslinking has been proposed as a novel treatment to increase scleral stiffness to counteract biomechanical changes associated with glaucoma and high myopia. Scleral stiffening has been shown by transpupillary peripapillary scleral photocrosslinking in rats, where the photosensitizer, methylene blue (MB), was injected retrobulbarly and red light initiated crosslinking reactions with collagen. Here, we adapted a computational model previously developed to model this treatment in rat eyes to additionally model MB photocrosslinking in minipigs and humans. Increased tissue length and subsequent diffusion and light penetration limitations were found to be barriers to achieving the same extent of crosslinking as in rats. Per cent inspired O2, injected MB concentration and laser fluence were simultaneously varied to overcome these limitations and used to determine optimal combinations of treatment parameters in rats, minipigs and humans. Increasing these three treatment parameters simultaneously resulted in maximum crosslinking, except in rats, where the highest MB concentrations decreased crosslinking. Additionally, the kinetics and diffusion of photocrosslinking reaction intermediates and unproductive side products were modelled across space and time. The model provides a mechanistic understanding of MB photocrosslinking in scleral tissue and a basis for adapting and screening treatment parameters in larger animal models and, eventually, human eyes.

Magnetic hybrid spheres of glauconite/calcium alginate interface for methylene blue adsorption: Synthesis, characterization, and novel physicochemical insights through theoretical treatment

Fe3O4 nanoparticles were embedded within a glauconite‑calcium alginate (G/CA) matrix to create magnetic hybrid spheres (MNPs-G/CA), with the aim of purifying water from methylene blue (MB) at temperatures of 25, 40, and 50 °C. MNPs-G/CA adsorbent was characterized using numerous techniques, including elemental mapping, zeta potential, FTIR, FESEM, XRD, EDX, and TEM. The greatest amount of the removed MB was achieved under definite conditions of solution pH 8.0, MNPs-G/CA mass (25 mg), interaction time (2 h), and 200 mg/L of MB concentration. The MB uptake process kinetic followed a pseudo-second-order equation (R2 > 0.99) at all tested temperatures. The equilibrium data were fitted to a statistical physics multilayer model in conjunction with the Langmuir and Freundlich equations. The steric n parameter reveals that MNPs-G/CA adsorbent possesses a mixed adsorption orientation (i.e., ranging from 0.69 to 0.93) across various temperatures. The amount of MNPs-G/CA active positions (the NM parameter) was progressively increased from 245 mg/g to 419 mg/g. The measured adsorption capacities (Qsat) ranged from 466.49 to 664.37 mg/g, and the removal of MB molecules was consistent with an endothermic interaction. The interface between the MNPs-G/CA-MB was principally dictated by electrostatic attractions, as evidenced by the values of adsorption energies (∆E), which varied from 16.75 to 21.52 kJ/mol. The regenerated MNPs-G/CA offered over 80 % of its adsorption strength after the fourth adsorption–desorption cycle. This study contributes to our understanding of the physicochemical parameters controlling the MB adsorption mechanism on multifunctional hybrid adsorbents, like the interface between glauconite, alginate, and MNPs.

Photodegradation, kinetics and non-linear error functions of methylene blue dye using SrZrO3 perovskite photocatalyst

The degradation of methylene blue dye-contaminated wastewater via photocatalysis is an efficient approach towards environmental remediation. The SrZrO3 perovskite photocatalyst was synthesized using the modified Pechini sol-gel method, and characterized using XRD, FESEM, FTIR, and UV–visible spectrophotometer. Crystallite size obtained by the Scherrer and Williamson-Hall methods were 45.56 and 44.50 nm, respectively. The sample exhibited an orthorhombic crystal structure. The optical bandgap was estimated to be 5.31 eV. Kinetic study for the degradation of methylene blue dye using SrZrO3 in the presence of H2O2 showed complete decontamination of the methylene blue dye in the time interval of 90–120 min under visible light irradiation. The degradation efficiency was above 80.1 % under illumination and less than 40.1 % in dark. Kinetic studies were performed by varying the dose of photocatalyst and initial concentration of methylene blue. It was observed that higher dose of the photocatalyst and lower concentration of the contaminant produced higher rate of degradation. The solution pH 3 and catalysts dosage of 200 mg yielded the highest rate of degradation. The experimental data fitted best into the Psuedosecond order kinetic model with the highest R2 value, indicating a strong linear relationship. The experimental data was subjected into nonlinear error functions, where the Psuedo-second order kinetic model demonstrated lower values of error functions. The results suggest that the prepared SrZrO3 photocatalyst coupled H2O2 is a promising photocatalyst for the decontamination of methylene blue dye under visible light irradiation.

Sodium lignosulfonate as an extracting agent of methylene blue dye using a polymer-enhanced ultrafiltration technique

The purpose of this research was to evaluate the efficacy of sodium lignosulfonate (LS) as a dye adsorbent in the removal of methylene blue (MB) from water by polymer-enhanced ultrafiltration. Various parameters were evaluated, such as membrane molecular weight cut-off, pH, LS dose, MB concentration, applied pressure, and the effect of interfering ions. The results showed that the use of LS generated a significant increase in MB removal, reaching an elimination of up to 98.0 % with 50.0 mg LS and 100 mg L−1 MB. The maximum MB removal capacity was 21 g g−1 using the enrichment method. In addition, LS was reusable for up to four consecutive cycles of dye removal-elution. The removal test in a simulated liquid industrial waste from the textile industry was also effective, with a MB removal of 97.2 %. These findings indicate that LS is highly effective in removing high concentrations of MB dye, suggesting new prospects for its application in water treatment processes.

Superabsorbent ZnO/rubber-based hydrogel composite for removal and photocatalytic degradation of methylene blue

A superabsorbent hydrogel was prepared by the free-radical copolymerization of natural rubber (NR) latex with poly(acrylic acid) (PAA) at NR loadings up to 50 wt%. An NR/PAA hydrogel containing 40 wt% of NR (NR-40) had a water absorption capacity of 214 g/g (21,400 %) of its dry weight. The compressive modulus increased 512 % and sample integrity was improved due to the physical entanglement of NR chains. NR-40 hydrogel removed 97 % of methylene blue (MB) from the aqueous solution in 1 h (at initial concentrations of 10–1000 mg/L) and produced a maximum removal of 1191 mg MB/g of hydrogel at an initial MB concentration of 4500 mg/L. The adsorption of MB was an endothermic process. Fourier transform infrared spectroscopy indicated that hydrogen bonding and electrostatic interaction drove the process. After the in-situ incorporation of ZnO into NR-40, absorbed energy from sunlight generated active species that could photocatalytically degrade adsorbed MB in the hydrogel matrix. The scavenger tests indicated that superoxide radical anions and hydroxyl radicals were the main species for this process. The hydrogel composite material showed good stability and could be regenerated and reused over 10 cycles, degrading >80 % of the adsorbed dye. This novel natural-based hydrogel provides double functions of adsorption and photodegradation of toxic dyes without the requirement of chemicals and a separation process.

Exploring the sustainable elimination of dye using cellulose nanofibrils- vinyl resin based nanofiltration membranes

This study focuses on the development of a novel self-cleaning nanofiltration membrane for the efficient removal of the cationic dye methylene blue (MB) from industrial wastewater. The membrane is composed of vinyl resin (VR), cellulose nanofibrils (CNF), and titanium alpha aluminate (TAAL) nanoparticles.The TAAL loading ranged from 1 to 5 wt%, the pH varied from 5 to 10, and the initial MB concentration ranged from 10 to 50 ppm. Using a dead-end filtration system, the (VR/CNF@TAAL) membrane with 5 wt% TAAL at pH 10 demonstrated excellent performances. It achieved a remarkable 98.6% removal efficiency for 30 ppm MB dye, with a maximum adsorption capacity of 125.8 mg/g. The adsorption kinetics analysis revealed that the process followed the pseudo-second-order model, indicating a chemisorption mechanism. The rate constant was determined to be 1.2732 × 10–3 g mg−1 min−1. The Freundlich isotherm model provided a better fit (R2 = 0.996) than the Langmuir model, suggesting multilayer adsorption on the nanocomposite membrane surface. In addition to its high adsorption and filtration capabilities, the (VR/CNF@TAAL) nanocomposite membrane exhibited cost-effectiveness and environmental friendliness as an adsorbent for MB removal from industrial wastewater. The membrane’s self-cleaning property further contributes to sustainability by reducing the need for additional chemical treatments.

Studying the kinetics and removal mechanism of the methylene blue dye in a continuous adsorption process using prepared mesoporous materials

ABSTRACT This study investigated the removal of a typical organic pollutant methylene blue (MB) dye from wastewater by a prepared mesoporous SBA-15 adsorbent in a continuous adsorption system (fixed-bed column). The structural and textural properties of the SBA-15 adsorbent were determined using different characterization techniques. The adsorption of continuous system experiments assessed the bed height effect, initial concentration, and flow rate on a breakthrough curve. The kinetic constants and breakthrough curves were obtained using the Thomas and Yan models. The breakthrough results revealed that SBA-15 has an excellent adsorption efficiency for use in the continuous adsorption system. The findings explain that MB removal achieved the maximum uptake (84 mg/g) at 6 cm of bed height, 0.5 mL/min of flow rate, and 30 mg/L initial concentration of MB. SBA-15 can be efficiently regenerated by calcination and re-employed 5 times in a fixed-bed system without a significant loss in its adsorption capacity of MB from MB solutions. As a result, SBA-15 was determined as the appropriate media to be adsorbent for MB. This study suggests that the prepared SBA-15 is feasible to use effectively for MB removal from the wastewater.

Chitosan extraction from Amanita phalloides: yield, crystallinity, degree of deacetylation, azo dye removal and antibacterial properties.

Chitosan, a biopolymer obtained from chitin, is known for its remarkable adsorption abilities for dyes, drugs, and fats, and its diverse array of antibacterial characteristics. This study explores the extraction and characterization of chitosan from the mycelium of Amanita phalloides. The moisture content, ash content, water binding capacity, fat binding capacity, and degree of deacetylation of the extracted chitosan were determined. The chitosan exhibited a high yield of 70%, crystallinity of 49.07%, a degree of deacetylation of 86%, and potent antimicrobial properties against both Gram-negative and Gram-positive bacteria. The study also examined the adsorption capabilities of chitosan to remove methylene blue (MB) dye by analysing specific factors like pH, reaction time, and MB concentration using the response surface model. The highest degree of MB dye removal was 91.6% at a pH of 6, a reaction time of around 60min and an initial dye concentration of 16ppm. This experimental design can be applied for chitosan adsorption of other organic compounds such as dyes, proteins, drugs, and fats.

Facile Fabrication of Hydroxyapatite and Bentonite Encapsulated Biopolymeric Hybrid Composites for Selective Removal of Methylene Blue

AbstractDyeing industries release their hazardous dyeing effluents into the environment which affects the human health and ecosystem. Hence, the removal of dye from waste‐water is mandatory one. In this present study, focus on the fabrication of bio‐clay‐ceramic hybrid composites by dispersing bentonite (BT) clay and ceramic hydroxyapatite (HA) into alginate (Alg) and gelatin (Gel) polymeric matrixes by in‐situ method which gives BTHAAlg and BTHAGel hybrid composites for methylene blue (MB) removal. The various adsorption influencing parameters such as shaking time, adsorbent dosage, pH and initial MB concentration were optimized under batch method. The highest MB adsorption capacities of BTHAAlg and BTHAGel composites were found to be 43.70 and 47.50 mg/g respectively with optimized conditions of 100 mg/L of initial MB concentration, 40 min shaking time and 0.1 g dosages. In pH studies, the high MB adsorption capacity of bio‐clay‐ceramic composites were noticed at pH 11. The characterization techniques like FTIR, SEM and EDAX analysis were performed to find the physico‐chemical properties of bio‐clay‐ceramic composites. The equilibrium data of hybrid composites towards MB adsorption was well fitted with Langmuir isotherm model than D‐R and Fruendlich models because of higher r and low sd values. The negative values of ▵Go at three different temperatures (303, 313 and 323 K) indicate that the spontaneous nature of MB adsorption, while positive values of ΔHo and ΔSo revealed that the MB adsorption onto hybrid composites was endothermic in nature and more randomness occurred at solid/liquid interfaces. In kinetic studies, the MB adsorption onto hybrid composites was well fitted with pseudo‐second‐order and intra‐particle diffusion models. The electrostatic attraction and hydrogen bonding plays a dominant role in MB adsorption onto BTHAAlg and BTHAGel bio‐clay‐ceramic composites. The regeneration studies proposed that the hybrid composites can be reusable upto five cycles. Hence, the developed bio‐clay‐ceramic hybrid composites were act as best adsorbents for MB removal.

Potassium iodide enhances the killing effect of methylene blue mediated photodynamic therapy against F. monophora

BackgroundChromoblastomycosis (CMB) is a chronic granulomatous fungal infection that affect the skin and subcutaneous tissues. It is clinically problematic due to limited treatment options, low cure rates, and high rates of relapse. This underscores the necessity for innovative treatment approaches. In this study, potassium iodide (KI) combined with Methylene Blue (MB) mediated antimicrobial photodynamic therapy (PDT) were assessed in the treatment of Fonsecaea monophora (F. monophora) both in vitro and in vivo. And the underlying mechanism that contributes to the efficacy of this treatment approach was investigated. MethodsIn vitro experiments were conducted using different combinations and concentrations of MB, KI, and 660 nm light (60 mW/cm2) to inhibit F. monophora. The study was carried out using colony-forming unit (CFU) counts and scanning electron microscopy (SEM). The production of singlet oxygen (1O2), free iodine (I2), hydrogen peroxide (H2O2), and superoxide anion during the KI combined MB-mediated antimicrobial PDT process was also detected. In vivo experiments were developed using a Balb/c mouse paw infection model with F. monophora and treated with PBS, 10 mM KI, 2 mM MB +100 J/cm² and 10 mM KI+2 mM MB +100 J/cm² respectively. Inflammatory swelling, fungal load and histopathological analyses of the mouse footpads were assessed. ResultsKI enhanced the killing effect of MB-mediated antimicrobial PDT on the conidial spores of F. monophora at the cell and infected animal model level. During the process, the main antimicrobial agents in KI combined with MB- mediated antimicrobial PDT could produce stronger toxic active species including free I2 and H2O2. ConclusionKI combined with MB-mediated antimicrobial PDT could be an effective adjunct therapy for treating CBM.

Synthesis and characterization of mesoporous caged silica for efficient adsorption of methylene blue from aqueous solution

Addressing the challenge of removing dyes from textile industry wastewater is crucial for wastewater treatment. Adsorption, utilizing suitable materials, emerges as a promising solution. This work introduces caged silica as an effective adsorption material for wastewater treatment in the textile industry. The proposed caged silica was synthesized via the hard template synthesis method, commonly used in various applications such as catalysts and wastewater treatment. Caged silica exhibited an amorphous structure with notable BET surface area (448m2/g), pore volume (0.325cm3/g), and average pore size (2.4nm), confirmed through detailed characterization. Evaluation of its adsorption capacity for methylene blue (MB) revealed an impressive removal efficiency of approximately 95% within the initial 20 min. The adsorption process followed the pseudo-second-order model and adhered more closely to the Freundlich isotherm model than the Langmuir model. Additionally, the study investigates the effects of pH, percent removal efficiency, cyclic stability, and initial MB concentration on the adsorption procedure. Consequently, the synthesized caged silica stands out as a promising mesoporous material for efficiently removing MB from aqueous solutions, offering practical application potential in wastewater treatment.

Surface enriched ternary hybrid via interfacial polymerization as an effective adsorbent for dye removal

Methylene blue (MB) is a carcinogenic pollutant that can negatively affect both human health and marine life. Developing effective adsorbents for MB removal is therefore crucial for ensuring safe human life and mitigating environmental issues. Herein, we present an interfacial polymerization to synthesize polydopamine assisted multi-walled carbon nanotubes stitched graphene oxide (PDA@MWNTs/GO) as an effective adsorbent for MB removal. Stitching the PDA layer interfacially onto MWNTs/GO effectively prevents disintegration, diminishes agglomeration/restacking issues, and maximizes adsorption sites. The inherent catecholamine functionality within the PDA layer significantly enhances hydrophilicity. These distinctive characteristics endowed the PDA@MWNTs/GO composite with exceptional adsorption capacity for the cationic MB. The effects of MB concentration, pH, and temperature on the dye solution were thoroughly investigated. The results of the adsorption isotherm and kinetics analysis revealed conformity with the Langmuir isotherm model and adherence to the pseudo-second-order kinetic model. Moreover, PDA@MWNTs/GO demonstrated removal efficiency, exceeding 90% after three consecutive cycles of reuse. The adsorption mechanism was driven by electrostatic attraction and π–π stacking. The superior adsorption performance, attributable to the diverse functionalities and high removal efficiency, demonstrates the potential of PDA@MWNTs/GO as an efficient adsorbent for MB and can also function for other cationic dye impurities.

The Influence of the Methylene Blue Dye on the Rate and the Mechanism of the Oxidative Polymerization of Aniline

AbstractIt 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.

Computational intelligence for empirical modelling and optimization of methylene blue adsorption phenomena utilizing an activated carbon‐supported [Co(NH3)6]Cl3 complex

AbstractThe study focuses on the efficiency of hexaamminecobalt (III) chloride (HACo, [Co(NH3)6]Cl3) immobilized on activated carbon for removing methylene blue (MB) from water solutions. The primary objective of this study was to assess the sorption performance of HACo immobilized on activated carbon in removing MB from water solutions. Additionally, predictive models were developed to optimize the MB removal percentage. Lastly, the study aimed to determine the optimal conditions for achieving maximum MB removal. Samples were characterized using scanning electron microscopy. Batch sorption experiments were conducted to analyze the impact of MB concentration, adsorbent mass, pH, temperature, and contact time. Predictive models were built using multiple linear regression and neural network techniques, specifically artificial neural networks (ANN) and hybrid ANN–particle swarm optimization (ANN‐PSO). The PSO‐ANN model with a single hidden layer of eight neurons trained using the Levenberg–Marquardt algorithm demonstrated high accuracy in predicting MB removal percentage, with mean absolute percentage error (MAPE) = 0.083788, root mean square error (RMSE) = 0.11441, and R2 = 0.99693. The MB adsorption process followed a mono‐layer with one energy model and a pseudo‐first‐order kinetic model. Optimization using the genetic algorithm revealed that the maximum MB removal percentage of 99.56% is achievable at an MB concentration of 9.36 mg/L, adsorbent mass of 15.72 mg, and temperature of 311.2 K. The study confirms the effectiveness of HACo immobilized on activated carbon for MB removal. The PSO‐ANN predictive model proved superior in accuracy compared to empirical models. Optimization results provide the optimal conditions for maximizing MB removal, offering valuable insights for practical applications.

Optimization of Fe/Ni, Fe/Cu bimetallic nanoparticle synthesis process utilizing concentrated Camellia sinensis extract solution and activity evaluation through methylene blue removal reaction

In this study, we introduce a synthesis process of bimetallic nanoparticles (BNPs) Fe/Ni and Fe/Cu utilizing concentrated Camellia sinenis extract that was optimized with a solvent ratio of ethanol/H2O 4/1 (v/v), a metal ratio of 5/1 (w/w), a total polyphenol content (TPC) in the solution of 12.5 g.l−1, pH = 3–4, 25 °C, and the reaction time ranging from 30 min to 50 min. The structural and morphological characteristics of the resulting materials were determined using several techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The maximum removal efficiency of methylene blue (MB) by BNPs Fe/Ni and Fe/Cu materials was found to be 88.60% and 91.06%, respectively, at a concentration of MB = 25 mg.l−1 and 25 °C. According to the results of the kinetic modeling study, the adsorption process of MB on the two BNPs materials followed second-order kinetics, with the maximum adsorption capacities of MB on Fe/Ni and Fe/Cu BNPs being 26.94 mg.g−1and 28.00 mg.g−1, respectively.

Catalytic Activity of CuO-bentonite Bead for the Removal of Methylene Blue by Fenton like Process

Non-biodegradable dyes, potentially contaminate the water and poses serious risk to the environment. So their removal requires alarming attention. The formation of CuO-bentonite bead and their dye removal application is the main focus of the current investigation. X-ray diffraction spectroscopy (XRD), Field emission scanning electron microscopy (FESEM), and Energy dispersive X-ray spectroscopy (EDS) analysis were implemented to evaluate the crystalline structure and morphology of the prepared sample. The catalytic activity of the CuO-bentonite bead was studied against the dye methylene blue (MB) by an advanced oxidation process like Fenton. The experimental data shows a maximum 94.08 % of the dye removal capacity of the beads in just 20 minutes. Further, for the detail dye removal study optimum environments such as initial MB concentration, pH range, and oxidant dosage were altered during the reaction. Additionally, the CuO-bentonite bead showed 89.03 % dye removal even after five reuse cycles; which exhibits the heightened stability and robustness of the CuO-bentonite bead as a catalyst. Therefore, this simply prepared CuO-bentonite bead revealed a new approach to wastewater treatment.

NiTiO3 nanoparticles: An environmental game changer in electro-Fenton wastewater remediation

BackgroundIn the face of escalating water pollution challenges, the study explores the efficacy of Electro-Fenton (EF) treatment using NiTiO3 perovskite-modified cathodes for methylene blue (MB) removal from wastewater. MethodsEmploying a Central Composite Design (CCD) methodology, significant factors influencing the EF process, including initial MB concentration, pH, applied current, and reaction time, were optimized. The NiTiO3 catalyst was meticulously characterized, revealing its rhombohedral crystal structure, uniform particle distribution, and efficient charge transfer properties. FindingsElectrochemical analyses demonstrated the superior performance of the NiTiO3/Graphite electrode, emphasizing its increased electroactive sites, enhanced oxygen reduction capability, and reduced charge transfer resistance compared to the bare Graphite electrode. The EF process was finely tuned, demonstrating a 95.38 % removal efficiency of MB at optimal conditions (initial concentration: 25 mg L−1, pH: 4.5, current: 40 mA, time: 110 min). This study underscores the promising potential of NiTiO3-modified cathodes in advanced water treatment applications, highlighting their robust efficiency and environmental significance in combating persistent organic pollutants.

Methylene blue dose-dependently induces cutaneous inflammation and heat hyperalgesia in a novel rat model.

Methylene blue (MB) has been shown to reduce mortality and morbidity in vasoplegic patients after cardiac surgery. Though MB is considered to be safe, extravasation of MB leading to cutaneous toxicity has been reported. In this study, we sought to characterize MB-induced cutaneous toxicity and investigate the underlying mechanisms. To induce MB-induced cutaneous toxicity, we injected 64 adult male Sprague-Dawley rates with 200 µL saline (vehicle) or 1%, 0.1%, or 0.01% MB in the plantar hind paws. Paw swelling, skin histologic changes, and heat and mechanical hyperalgesia were measured. Injection of 1%, but not 0.1% or 0.01% MB, produced significant paw swelling compared to saline. Injection of 1% MB produced heat hyperalgesia but not mechanical hyperalgesia. Pain behaviors were unchanged following injections of 0.1% or 0.01% MB. Global transcriptomic analysis by RNAseq identified 117 differentially expressed genes (111 upregulated, 6 downregulated). Ingenuity Pathway Analysis showed an increased quantity of leukocytes, increased lipids, and decreased apoptosis of myeloid cells and phagocytes with activation of IL-1β and Fos as the two major regulatory hubs. qPCR showed a 16-fold increase in IL-6 mRNA. Thus, using a novel rat model of MB-induced cutaneous toxicity, we show that infiltration of 1% MB into cutaneous tissue causes a dose-dependent pro-inflammatory response, highlighting potential roles of IL-6, IL-1β, and Fos. Thus, anesthesiologists should administer dilute MB intravenously through peripheral venous catheters. Higher concentrations of MB (1%) should be administered through a central venous catheter to minimize the risk of cutaneous toxicity.

Carrageenan/calcium alginate composite hydrogel filtration membranes for efficient cationic dye separation

The development of biopolymer-based filtration systems for water remediation applications is an extremely fascinating area of research. In this paper, we developed a biopolymer-based filtration system using sodium alginate (NaAlg) and carrageenan (Car) for the removal of the toxic cationic dye, methylene blue (MB). The membrane's properties were assessed using FTIR, TGA, UTM, FESEM, EDS, XRD, and water uptake, revealing commendable thermomechanical stability (5.79 MPa), good hydrophilicity, and compatibility. The experimental results further revealed that lambda Car/calcium alginate (λ-Car/CaAlg) exhibited superior dye rejection (100%) and flux (11.67 L m−2 h−1) compared to kappa Car/CaAlg (κ-Car/CaAlg) (99.22% and 11.19 L m−2 h−1) and plain alginate (CaAlg) (99.63% and 9.79 L m−2 h−1). The high MB rejection rate was attributed to the sieving mechanism and electrostatic interaction. A rejection rate of 100% was achieved at an initial MB concentration of 10 mg/L, pressure of 0.1 MPa, pH of 7, and temperature of 25°C. Furthermore, the hydrogel membranes demonstrated excellent recyclability over nine cycles, indicating their potential for water treatment applications.