Photocatalytic degradation of methylene blue over MIL-100(Fe)/GO composites: a performance and kinetic study

Adsorption coupled with photocatalytic degradation is proposed to fulfill the removal and thorough elimination of organic dyes.Herein,we report a facile hydrothermal synthesis of MIL-100(Fe)/GO photocatalysts.The adsorption and photocatalytic degradation process of methylene blue(MB)on MIL‐100(Fe)/GO composites were systematically studied from performance and kinetic perspectives.A possible adsorption‐photocatalytic degradation mechanism is proposed.The optimized 1M8G composite achieves 95%MB removal(60.8 mg/g)in 210 min and displays well recyclability over ten cycles.The obtained MB adsorption and degradation results are well fitted onto Langmuir isotherm and pseudo‐second order kinetic model.This study shed light on the design of MOFs based composites for water treatment.

Isotherm,kinetic and thermodynamic investigations of boron phosphide to remove methylene blue from aqueous solution

In this work,the boron phosphide(BP)was synthesized and used for the adsorptive removal of methylene blue(MB)dye from aqueous solutions.To determine the optimum adsorption conditions,studies were performed by varying parameters of temperature(298–328 K),pH(2–12),contact time(0–120 min),adsorbent dose(0.01–0.20 g/50 mL),and dye concentration(10–50 mg/L).Different isotherm and kinetic models were applied to the adsorption data.The linear correlations coefficient showed that the Langmuir isotherm best fits(R^(2)=0.9996).The maximum adsorption capacity of BP was obtained as 555.56 mg/g at 55℃and the removal rate reached up to 84.11%.Additionally,the pseudo-second-order kinetic model described the adsorption process best(R^(2)=0.9998).The thermodynamic studies represented that the adsorption occurred spontaneously(ΔG_(A)^(Θ)=−24.90 kJ/mol)and endothermically(ΔH_(A)^(Θ)=16.67 kJ/mol).The results showed that BP is an efficient adsorbent for removing cationic dyes from aqueous solutions.

Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption

A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions.The core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calcium ions(Ca^(2+)).The shell,composed of a chitosan/activated carbon mixture,was then coated onto the core.Fourier transform infrared spectroscopy confirmed the grafting polymerization of acrylamide onto sodium alginate.Scanning electron microscopy images showed the core-shell structure.The core exhibited a high water uptake ratio,facilitating the diffusion of methylene blue into the core.During the diffusion process,the methylene blue was first adsorbed by the shell and then further adsorbed by the core.Adsorption tests showed that the coreshell structure had a larger adsorption capacity than the core alone.The shell effectively enhanced the adsorption capacity to methylene blue compared to the single core.Methylene blue was adsorbed by activated carbon and chitosan in the shell,and the residual methylene blue diffused into the core and was further adsorbed.

Study of the Influence of Clay in the Degradation of Methylene Blue by Photo-Fenton Process

Industrial effluents from textile, tannery or printing activities often have a significant pollutant load composed of dyes that are difficult to biodegrade. These dyes pose a threat to the environment. To overcome this problem, various processes have been developed to eliminate these dyes in wastewater before their release into nature. Conventional biological or physical processes most often prove to be ineffective and expensive. It is therefore necessary to resort to other processes such as advanced oxidation processes (POA). This work therefore focuses on the study of the influence of clay in the degradation of Methylene Blue by the photo-Fenton process which is one of the advanced oxidation processes (POA), with the source of irradiation, natural light. To do this, two clays from Côte d’Ivoire referenced AB and Aga were the subject of a physicochemical and mineralogical characterization. The results showed that Aga clay is composed of 75.43% quartz, 12.72% kaolinite, 8.75% illite and 3.12% goethite and AB clay consists of 61, 36% kaolinite, 28.6% quartz and 10.10% illite. Under natural light irradiation the optimal amounts of Fenton reagents (iron: 10 mg;H2O2: 0.1 mL) were determined. Finally, the addition of clay to the photo-Fenton process made it possible to improve the degradation of the pollutant (Methylene Blue). Indeed, the yield increased from 92% for the photo-Fenton process to 98.43% with the addition of AB clay and 98.13% for the addition of Aga clay. The results of the degradation kinetics clearly show that the degradation follows the pseudo-second order kinetics with correlation coefficients greater than 0.99.

Prussian Blue Analogue‑Templated Nanocomposites for Alkali‑Ion Batteries:Progress and Perspective

Lithium-ion batteries(LIBs)have dominated the portable electronic and electrochemical energy markets since their commercialisation,whose high cost and lithium scarcity have prompted the development of other alkali-ion batteries(AIBs)including sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).Owing to larger ion sizes of Na^(+)and K^(+)compared with Li^(+),nanocomposites with excellent crystallinity orientation and well-developed porosity show unprecedented potential for advanced lithium/sodium/potassium storage.With enticing open rigid framework structures,Prussian blue analogues(PBAs)remain promising self-sacrificial templates for the preparation of various nanocomposites,whose appeal originates from the well-retained porous structures and exceptional electrochemical activities after thermal decomposition.This review focuses on the recent progress of PBA-derived nanocomposites from their fabrication,lithium/sodium/potassium storage mechanism,and applications in AIBs(LIBs,SIBs,and PIBs).To distinguish various PBA derivatives,the working mechanism and applications of PBA-templated metal oxides,metal chalcogenides,metal phosphides,and other nanocomposites are systematically evaluated,facilitating the establishment of a structure–activity correlation for these materials.Based on the fruitful achievements of PBA-derived nanocomposites,perspectives for their future development are envisioned,aiming to narrow down the gap between laboratory study and industrial reality.

Steam Methane Reforming(SMR)Combined with Ship Based Carbon Capture(SBCC)for an Efficient Blue Hydrogen Production on Board Liquefied Natural Gas(LNG)Carriers

The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint.

Enhanced adsorption of Methylene Blue from aqueous solution by chitosan-g-poly(acrylic acid)/vermiculite hydrogel composites

A series of chitosan-g-poly （acrylic acid）/vermiculite hydrogel composites were synthesized and used as adsorbents for the investigation of the effect of process parameters such as vermiculite content, pH of dye solution, contact time, initial concentration of dye solution, temperature, ionic strength and concentration of surfactant sodium dodecyl sulfate on the removal of Methylene Blue （MB） from aqueous solution. The results showed that the adsorption capacity for dye increased with increasing pH, contact time and initial dye concentration, but decreased with increasing temperature, ionic strength and sodium dodecyl sulfate concentration in the present of the surfactant. The adsorption kinetics of MB onto the hydrogel composite followed pseudo second-order kinetics and the adsorption equilibrium data obeyed Langmuir isotherm. By introducing 10 wt.% vermiculite into chitosan-g-poly （acrylic acid） polymeric network, the obtaining hydrogel composite showed the highest adsorption capacity for MB, and then could be regarded as a potential adsorbent for cationic dye removal in a wastewater treatment process.

Colorectal cancer lymph node staining by activated carbon nanoparticles suspension in vivo or methylene blue in vitro

AIM:To investigate whether activated carbon nanoparticles suspension(ACNS) or methylene blue(MB) can increase the detected number of lymph nodes in colorectal cancer.METHODS:Sixty-seven of 72 colorectal cancer patients treated at our hospital fulfilled the inclusion criteria of the study which was conducted from December 2010 to February 2012.Seven patients refused to participate.Eventually,60 patients were included,and randomly assigned to three groups(20 in each group):ACNS group(group A),MB group(group B) and non-stained conventional surgical group(group C).In group A,patients received subserosal injection of 1 mL ACNS in a 4-quadrant region around the mass.In group B,the main artery of specimen was identified and isolated after the specimen was removed,and 2 mL MB was slowly injected into the isolated,stretched and fixed vessel.In group C,no ACNS and MB were injected.All the mesentery lymph nodes were isolated and removed systematically by visually inspecting and palpating the adipose tissue.RESULTS:No difference was observed among the three groups in age,gender,tumor location,tumor diameter,T-stage,degree of differentiation,postoperative complications and peritoneal drainage retention time.The total number of detected lymph nodes was 535,476 and 223 in the three groups,respectively.The mean number of detected lymph nodes per patient was significantly higher in group A than in group C(26.8 ± 8.4 vs 12.2 ± 3.2,P < 0.001).Similarly,there were significantly more lymph nodes detected in group B than in group C(23.8 ± 6.9 vs 12.2 ± 3.2,P < 0.001).However,there was no significant difference between group A and group B.There were 50,46 and 32 metastatic lymph nodes dissected in 13 patients of group A,10 patients of group B and 11 patients of group C,without significant differences among the three groups.Eleven of the 60 patients had insufficient number of detected lymph nodes(< 12).Only one patient with T 4a rectal cancer had 10 lymph nodes detected in group B,the other 10 patients were all from group C.Based on the different diameter categories,the number of detected lymph nodes in groups A and B was significantly higher than in group C.However,there was no statistically significant difference between group A and group B.The metastatic lymph nodes were not significant different among the three groups.Similarly,tumor location,T stage and tumor differentiation did not affect the staining results.Body mass index was a minor influencing factor in the two different staining methods.The stained lymph nodes can easily be identified from the mesenteric adipose tissues,and the staining time for lymph nodes was not significantly different compared with unstained group.None of the patients in groups A and B had drug-related complications.CONCLUSION:Both activated carbon nanoparticles suspension in vivo and methylene blue in vitro can be used as tracers to increase the detected number of lymph nodes in colorectal cancer.

Hidden Relaxation Channels in Aqueous Methylene Blue after Functionalization of Graphene Oxide Probed by Transient Absorption Spectroscopy

The mixture of graphene oxide （GO） and dye molecules may provide some new applications due to unique electronic, optical, and structural properties. Methylene blue （MB）, a typ- ical anionic dye, can attach on GO via π-π stacking and electrostatic interaction, and the molecule removal process on GO has been observed. However, it remains unclear about the ultrafast carrier dynamics and the internal energy transfer pathways of the system which is composed of GO and MB. We have employed ultrafast optical pump-probe spectroscopy to investigate the excited dynamics of the GO-MB system dispersed in water by exciting the samples at 400 nm pump pulse. The pristine MB and GO dynamics are also analyzed in tandem for a direct comparison. Utilizing the global analysis to fit the measured signal via a sequential model, five lifetimes are acquired：（0.61±0.01） ps, （3.52±0.04） ps, （14.1±0.3） ps, （84±2） ps, and （3.66±0.08） ns. The ultrafast dynamics corresponding to these lifetimes was analyzed and the new relaxation processes were found in the GO-MB system, compared with the pristine MB. The results reveal that the functionalization of GO can alter the known decay pathways of MB via the energy transfer from GO to MB in system, the increased intermediate state, and the promoted energy transfer from triplet state MB to ground state oxygen molecules dissolved in aqueous sample.

TiO_2/polyaniline composites:An efficient photocatalyst for the degradation of methylene blue under natural light

Polyaniline （PAn） sensitized nanocrystalline TiO2 composites （TiO2/PAn） were successfully prepared and used as an efficient photocatalyst for the degradation of dye methylene blue （MB）. The results showed that PAn was able to sensitize TiO2 efficiently and the composite photocatalyst could be activated by absorbing both the ultraviolet and visible light （λ： 190 ～ 800 nm）, whereas pure TiO2 absorbed ultraviolet light only （λ 〈 380 nm）. Under the irradiation of natural light, MB could be degraded more efficiently on the TiO2/PAn composites than on the TiO2 Furthermore, it could be easily separated from the solution by simple sedimentation.

High surface area and mesoporous activated carbon from KOH-activated dragon fruit peels for methylene blue dye adsorption:Optimization and mechanism study

In this study,an alternative precursor for production of activated carbon was introduced using dragon fruit(Hylocereus costaricensis)peel(DFP).Moreover,KOH was used as a chemical activator in the thermal carbonization process to convert DFP into activated carbon(DFPAC).In order to accomplish this research,several approaches were employed to examine the elemental composition,surface properties,amorphous and crystalline nature,essential active group,and surface morphology of the DFPAC.The BrunauerEmmettTeller test demonstrated a mesoporous structure of the DFPAC has a high surface area of 756.3 m2g 1.The cationic dye Methylene Blue(MB)was used as a probe to assess the efficiency of DFPAC towards the removal of MB dye from aqueous solution.The effects of adsorption input factors(e.g.DFPAC dose(A:0.040.12 g L 1),pH(B:310),and temperature(C:3050℃))were investigated and optimized using statistical analysis(i.e.BoxBehnken design(BBD)).The adsorption kinetic model can be best categorized as the pseudofirst order(PFO).Whereas,the adsorption isotherm model can be best described by Langmuir model,with maximum adsorption capacity of DFPAC for MB dye was 195.2 mg g 1 at 50℃.The adsorption mechanism of MB by DFPAC surface was attributed to the electrostatic interaction,pp interaction,and Hbonding.Finally,the results support the ability of DFP to be a promising precursor for production of highly porous activated carbon suitable for removal of cationic dyes(e.g.MB).

Adsorption Kinetics of Methylene Blue from Aqueous Solutions onto Palygorskite

The adsorption kinetics of methylene blue from aqueous solutions on purified palygorskite was investigated. The kinetics data related to the adsorption of methylene blue from aqueous solutions are in good agreement with the pseudo-second order equation in ranges of initial concentration of 120-210 mg/L, oscillation speed of 100-200 r/min and temperature of 298-328K. The experimental results show that methylene blue is only adsorbed onto the external surface of purified palygorskite, and the apparent adsorption activation energy is 13.92 kJ/mol. The relatively low apparent adsorption activation energy suggests that the adsorption of methylene blue involves in not only a chemical, but also a physical adsorption process, and it is controlled by the combination of chemical adsorption and fiquid-film diffusion.

Effect of Methylene Blue (MB)-value of Manufactured Sand on the Durability of Concretes

The relation between the methylene blue （MB） value of MS and its limestone powder content and clay content was investigated. The effects of MB values ranging from 0.35 to 2.5 on the workability of fresh concrete, the mechanical properties, the resistance to freezing as well as the resistance to chlorine ion permeation of the hardened concrete were all investigated. The experimental results showed that the MB value had no correlation with the limestone powder content of MS, while it was directly related to the clay content. With an increase of MB value, concrete workability decreased, as did the flexural and 7-day compressive strengths, however, the 28-day compressive strength was not affected. Furthermore, influence of MB value on concretes of different strength levels was different. For low-strength concretes, an increase of MB value could improve its impermeability, but this was not the case for high-strength concretes. Instead, their resistance to chloride ion permeability decreased slightly. However, even a slight increase in MB value remarkably accelerated freeze-thaw damage of MS concrete. It was thus concluded that the critical MB value of 1.4 would not cause significant deterioration in the performance of MS concretes.

Three modes of a direct-current plasma jet operated underwater to degrade methylene blue

A direct-current air plasma jet operated underwater presents three stable modes including an intermittently-pulsed discharge, a periodically-pulsed discharge and a continuous discharge with increasing the power voltage. The three discharge modes have different appearances for the plasma plumes. Moreover, gap voltage-current characteristics indicate that the continuous discharge is in a normal glow regime. Spectral lines from reactive species（OH, N2, N2^＋, Hα,and O） have been revealed in the emission spectrum of the plasma jet operated underwater.Spectral intensities emitted from OH radical and oxygen atom increase with increasing the power voltage or the gas flow rate, indicating that reactive species are abundant. These reactive species cause the degradation of the methylene blue dye in solution. Effects of the experimental parameters such as the power voltage, the gas flow rate and the treatment time are investigated on the degradation efficiency. Results indicate that the degradation efficiency increases with increasing the power voltage, the gas flow rate or the treatment time. Compared with degradation in the intermittently-pulsed mode or the periodically-pulsed one, it is more efficient in the continuous mode, reaching 98% after 21 min treatment.

Methylene blue enhances polyethylene glycol-fusion repair of completely severed rat sciatic nerves

Complete transection of peripheral mixed nerves immediately produces loss of sensory perception,muscle contractions and voluntary behavior mediated by the severed distal axons.In contrast to natural regeneration(~1 mm/d)of proximal axons that may eventually reinnervate denervated targets,re-innervation is restored within minutes by PEG-fusion that consists of neurorrhaphy and a sequence of well specified hypo-and isotonic calcium-free or calcium-containing solutions,the anti-oxidant methylene blue(MB)and the membrane fusogen polyethylene glycol(PEG).In this study,we examined the relative efficacy of PEG-fusion with no MB(0%),0.5%MB,or 1%MB on the recovery of voluntary behaviors by female Sprague-Dawley rats with a complete mid-thigh severance of their sciatic nerve bathed in extracellular fluid or calcium-containing isotonic saline.The recovery of voluntary behaviors is the most relevant measure of success of any technique to repair peripheral nerve injuries.We assessed recovery by the sciatic functional index,a commonly used measure of voluntary hindlimb behaviors following complete sciatic transections.We reported that both 1%MB and 0.5%MB in sterile distilled water in our PEG-fusion protocol with neurorrhaphy significantly increased the rate and extent of behavioral recovery compared to PEG plus neurorrhaphy alone.Furthermore,0.5%MB was as effective as 1%MB in voluntary behavioral recovery as assessed by the sciatic functional index.Since sterile 1%MB is no longer clinically available,we therefore recommend that 0.5%MB be included in upcoming human clinical trials to evaluate the safety and efficacy of PEG-fusion.All animal procedures were approved by the University of Texas Institutional Animal Care and Use Committee(AUP-2019-00225)on September 9,2020.

Relationships between Modified Methylene Blue Value of Microfines in Manufactured Sand and Concrete Properties

To better understand and assess the effect of microfines on concrete properties, the synergetic effect of methylene blue value and content of microfines on properties of low and high strength concrete was studied and then the relationships between the index of modified methylene blue value （MMBV） and concrete properties were investigated. The results show that relationships between MMBV and fresh and hardened properties of concrete can be fully established, and the correlation between MMBV and C60 concrete property is higher than the correlation between MMBV and C30 concrete. With the increase of MMBV, concrete workability and frost resistance decrease while drying shrinkage decreases; however, compressive strength and chloride-ion penetration resistance of C30 concrete have not been negatively affected whereas those of C60 concrete are significantly deteriorated when MMBV exceeds 100. To make use of microfines without remarkably damaging concrete quality, it is suggested that MMBV of microfines in MS used in C30 and C60 concrete be no more than 100.

Near-infrared fluorescence imaging of a solitary fibrous tumor of the pancreas using methylene blue

A 67-year-old female presented with unexplained abdominal pain. A contrast-enhanced computed tomography scan of the abdomen incidentally revealed a mass in the uncinate process of the pancreas. This mass was resected and based on histopathological findings, diagnosed as a solitary fibrous tumor (SFT) of the pancreas. A SFT is an extremely rare benign mesenchymal tumor that in 65% of cases affects the visceral pleura but can also affect extra-pleural sites. The intraoperative demarcation of pancreatic tumors, such as SFTs, can bechallenging. In this report, the first clear intraoperative identification of a SFT of the pancreas in a human was shown using near-infrared fluorescence and methylene blue.

Kinetics and mechanism of the adsorption of methylene blue onto ACFs

The kinetics and mechanism of methylene blue (MB) adsorption onto activated carbon fibers (ACFs) have been studied. The effects of various experimental parameters, such as the initial MB concentration and the ACF mass, on the adsorption rate were investigated. Equilibrium data were fit well by a Freundlich isotherm equation. Adsorption measurements show that the process is very fast. The adsorption data were modeled using first- and second-order kinetic equations and intra–particle diffusion models. It was found that the first-order kinetic equation could best describe the adsorption kinetics. The adsorption process was found to be complex and controlled by both surface and pore diffusion with surface diffusion at the earlier stages, followed by pore diffusion at the later stages. The thermodynamic parameters △G0, △S0 and △H0, have been calculated. The thermodynamics of the MB-ACF system indicate that the adsorption process is spontaneous.

Microstructure and Photocatalytic Decomposition of Methylene Blue by TiO2-Mounted Halloysite, a Natural Tubular Mineral

On the basis of analysis of structure and properties, halloysite, a natural tubular mineral, was developed for an environmental treatment. TiO2 was mounted into halloysite by using hydrolysis of tetrabutyl titanate at room temperature. The adsorption and photocatalytic performance of halloysite and TiO2-mounted halloysite have been examined in methylene blue aqueous solution in the dark and under ultraviolet ray irradiation, respectively. Their performance of adsorption and photodecomposition was evaluated from the adsorbed and degraded amounts of methylene blue （MB）. Due to the mixture of adsorption and photodecomposition, the concentration of MB, organic pollution, in water decreased rapidly with TiO2-mounted halloysite powder, which is a faster reaction than that with halloysite-only adsorption. This new use of halloysite is leading to many interesting applications in the decomposition and elimination of various pollutants in air and water.

Photodegradation of Methylene Blue in Natural Seawater

This paper reports the photochemical degradation of Methylene Blue(MB)in natural seawater(NSW).The photode-gradation reaction conformed to the first-order reaction kinetics with the rate constant 0.0158 min-1.MB was photochemically de-gradated faster under high-pressure mercury lamp(HPML)than under sunlight.When MB was in lower concentrations,salinitycould inhibit the photoreaction whereas MB in higher concentration,salinity could accelerate the photoreaction.Humid acid couldalso inhibit the photoreactions.Toxicity tests with marine phytoplankton Skeletonema costatum(Sk)and Heterosigma akashiwo Hada(Ha)showed decreased acute toxicity after photodegradation.