Methylene Blue Absorption Research Articles

Simultaneous photodegradation of two textile dyes using TiO2 as a catalyst

The simultaneous photocatalytic degradation of two dyes: methylene blue (MB), a cationic dye, and arylazo pyridone dye (SD), an anionic dye was investigated using sol–gel prepared TiO2 particles. The paper shows the main difference in degradation kinetics between single dye solution and binary dye solutions. The effects of competitive adsorption and the concentration of the dyes on degradation rate were analyzed. The preferential adsorption capacity of TiO2 toward MB was attributed to electrostatic interactions between the cationic dye and negatively charged TiO2 surface, while repulsion between the negatively charged surface of the catalyst and SD dye results in its lower adsorption capacity. The TiO2 surface charge and accordingly adsorption affinity of investigated dyes were found to be the main factors affecting degradation rate of the dyes. In the single dye system, the catalyst showed considerably higher degradation activity toward MB than to SD. In binary dye systems, the presence of SD did not affect the degradation of MB. On the other hand, the degradation efficiency of SD was found to be highly influenced by initial MB concentration and absorption ability of MB. In addition, higher MB concentration induces the production of a higher amount of reaction products, which also determine the SD degradation rate. Three kinetic regimes for the photodegradation of SD in binary mixtures were observed, used as a starting point to elucidate most influencing parameters for SD reaction kinetics.

Enhancement for Photocatalytic Activity of TiO<sub>2 </sub> Combined with Activated Carbon under Surface Fluorination (F-TiO<sub>2</sub>/AC)

The prepared TiO2 and commercial grade of TiO2 with anatase and rutile phase combined with bulk and powder of activated carbon (TiO2/AC) observed the photocatalytic activity under weak UV. The surface fluorination was applied for all photocatalysts (F-TiO2/AC) to enhance photocatalytic activity. The decolorization of methylene blue (MB) was used to indicate the efficiency of adsorption and degradation of the samples. The prepared TiO2 was prepared by Sol-Gel method under condition of the titanium tetraisopropoxide (TTIP) to 2-propanol (2-PP) ratio of 1:30 and adjusts pH of 2 by HCl acid. Under surface fluorination, the samples of TiO2/AC were immersed of 2 hours under NaF solution of 30 mmol. Surface morphology was observed by field-emission scanning electron microscopy (FE-SEM). MB absorption was recorded by UV-VIS spectrophotometer to indicate MB decolorization. The results showed that, MB were under photocatalytic test of the rich porosities of AC and prepared TiO2/AC were the highest decolorization due to AC showed high adsorption and prepared TiO2/AC showed high decomposition of MB. Both of TiO2/AC and F-TiO2/AC, pure anatase phase showed higher photocatalytic activity than pure rutile phase. Under the same crystalline phase, F-TiO2/AC showed higher photocatalytic activity than TiO2/AC. Prepared TiO2 showed higher photocatalytic activity than TiO2 of commercial grade. Moreover, under the same TiO2, AC powder showed higher adsorption than AC bulk due to AC powder has surface area greater than AC bulk. The best sample for MB-decolorization was F-prepared TiO2/AC powder. Under the sample to MB solution (0.05 mmol) ratio of 0.15g: 400 ml, the MB solution changed to be the colorless solution after treatment of 5 min.

Adsorptive Removal of Methylene Blue from Aqueous Solution using a Ni-Metal Organic Framework Material

A specific metal organic framework (MOF) material was synthesized based on Ni(Ac)2 · 4H2O and 1-H-benzimidazole-5-carboxylic acid through hydrothermal method. It was a promising candidate as adsorbent due to its large surface areas, porous structure, ordering and controllable properties. In this paper, it was characterized by XRD, SEM, FTIR, TGA and N2 adsorption isotherm. Meanwhile MOF was treated as adsorbent for absorption of methylene blue. Using this material to remove methylene blue, which is low cost, simple and high efficiency. It shows great potential in removing other dyes and the adsorption rate could reach 85.08%.

Spectrophotometric determination of bromide in water using the multisyringe flow injection analysis technique coupled to a gas-diffusion unit

Spectrophotometric determination of bromide in water using a gas-diffusion unit.

Spinach assisted green reduction of graphene oxide and its antioxidant and dye absorption properties

Spinach (Spinacia oleracea) leaves mediated efficient green reduction of graphene oxide (GO) was achieved to produce multifunctional reduced graphene oxide (rGO). GO was mixed with spinach juice and refluxed for 30min at 100°C. Powder XRD, TEM and UV–visible techniques demonstrate the formation of well-organized layered rGO. Industrially important carcinogenic Methylene blue (MB) and Malachite green (MG) dyes absorption experiments with rGO were performed under dark condition. Complete removal of MB and MG occurs in spans of 60 and 40min respectively in the presence of 20mg rGO. Potential antioxidant activity was exhibited by the rGO with 50% inhibitory concentration of 1590µg/mL against the scavenging of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radicals. Environment friendly, economical and facile reduction method is suggested for the efficient reduction of GO.

Enhanced photocatalytic activity of graphene oxide/titania nanosheets composites for methylene blue degradation

In the present work, we report enhanced photocatalytic degradation of methylene blue dye in aqueous solution by using ultra-thin anatase TiO2 nanosheets (NSs) combined with graphene oxide (GO) as a photocatalyst. The two-dimensional ultra-thin anatase TiO2 NSs are fabricated via chemical exfoliation. By completely delaminating a lepidocrocite-type layered protonic titanate HxTi2−x/4□x/4O4·H2O (x=0.7, □: vacancy) into individual layers through ion exchange with tetrabutylammonium (TBA+) cations, well-dispersed ultra-thin colloidal Ti0.91O2 NSs with a lateral size up to a few micrometers are obtained. Subsequent acid treatment induces colloidal Ti0.91O2 to reassemble and precipitate into a gelation form, followed by thermal annealing to convert the Ti0.91O2 gelation into anatase TiO2 nanosheets as photocatalyst for methylene blue degradation. TiO2 NSs show a high photocatalytic degradation efficiency of 53.2% due to the ultra-thin thickness for facile electron transfering and large surface area for methylene blue absorption. Moreover, photocatalytic effect can be further improved by simply adding GO suspension to achieve colloidal self-assembly of GO and TiO2 NSs. An optimal GO content of 3wt% further increases the photocatalytic degradation efficiency to 91.2% due to faster electron–hole seperation and improved surface area provided by GO. This work provides a simple but effective approach by combing graphene oxide with TiO2 nanosheets synthesized via the exfoliation method for methylene blue degradation.

Corneal-protective effects of an artificial tear containing sodium hyaluronate and castor oil on a porcine short-term dry eye model.

ABSTRACTThe corneal-protective effects of an artificial tear containing sodium hyaluronate (SH) and castor oil (CO) were evaluated on a porcine short-term dry eye model. Fresh porcine eyes with an intact cornea were treated with an artificial tear of saline, SH solution (0.1%, 0.5% or 1%), CO solution (0.5%, 1% or 5%) or a mixture solution containing 0.5% SH and 1% CO and then desiccated for 60, 90 or 180 min. To assess corneal damage, the eyes were stained with methylene blue (MB) or lissamine green (LG). The staining score of MB, absorbance of MB extracted from the cornea and staining density of LG increased significantly with increasing desiccation time in untreated and all artificial tear-treated eyes, although there were no significant differences in staining scores and absorbance of MB between eyes treated continuously with saline and 1% SH-treated ones at 60 and 90 min of desiccation or the mixture-treated eyes at 60 min of desiccation. No significant differences in the staining density of LG were also found between continuous saline-treated eyes and ones desiccated for 60 min and treated with 1% SH and the mixture. Mild cytoplasmic vacuolations were histopathologically observed in the basal and wing cells in eyes desiccated for 60 min and treated with 1% SH and the mixture. The mixture solution containing 0.5% SH and 1% CO has protective effects against corneal desiccation similar to those of 1% SH and would be helpful as an artificial tear.

Physical, mechanical and petrographic properties of Lesser Himalayan rocks from Kavre area: An assessment of quality for concrete aggregate

With rapidly growing population, development of human civilization and increasing construction of infrastructures, the demand of aggregate is increasing day by day. The quarries of naturally occurring sand and gravel are not sufficient to fulfill the demand, and are disturbing the river environments. Therefore, the crushed-rock aggregates should be used to meet the requirements. The accessible resources, quality and quantity for aggregates play an important role in the durability of roads, buildings, projects, many other infrastructures and sustainable development. Negligence of quality of aggregates would lead to rapid degradation of concrete structures. Therefore, being aware of these things, quality of aggregates should be prioritized. The exploration of outcrops from which suitable aggregates can be exploited is essential. This study aims to explore and evaluate the resources and quality of crushed-rock aggregates from the Lesser Himalayan rocks in the Kavre area.
 Different kinds of rocks were identified from the outcrop in the study area: quartzite, psammitic schist, calc­quartzite, metasandstone and metasiltstone. Thirteen representative samples were taken from different lithological formations. The water absorption value (WAY) of samples ranges from 0.302 to 2.393%. Dry density varies from2.308 to 2.743gm/cm3 and the uniaxial compressive strength value ranges from 23.62 to 217.92 MPa. In general, these values indicate that the aggregates are compact and strong. The aggregate crushing value (ACY) ranges from 19.56 to 35.4% and the aggregate impact value (AIV) ranges from 11.02 to 23.84%showing that the aggregates are resistant against compressive load and strong against impact load. The sodium sulphate soundness value (SSSV) lies between 5.95 to 16.66% and methylene blue absorption values (MBAV) in all samples are <1% indicating that the samples are durable and chemically sound. The alkali silica reactive features, swelling and expanding clay minerals like chert, opal, high-quartz, extremely deformed fractured quartz, smectite, and kaolinite are absent. Though some quartz grains are undulosed and fractured, they are mega and low-quartz. Only the clay mineral illite, IM type is present in very small proportion. All these parameters show that the samples of the Lesser Himalayan rocks from the Kavre area are suitable and acceptable for concrete aggregates of general.

Fabrication of ultra-light graphene-based gels and their adsorption of methylene blue

Porous 3D network, monolithic graphene oxide (GO) gels were fabricated using a simple process of aqueous gel precursor freezing, solvent exchange, and ethanol drying. The randomly oriented GO sheets were consolidated by cross-linked sodium alginate (SA). The obtained GO–SA gel was reduced to RGO–SA gel by glucose. GO–SA and RGO–SA gels had low densities of 16.79 and 12.93mg/cm3, respectively. The effects of contact time and temperature on the adsorption of methylene blue (MB) onto the gels were investigated. The kinetic adsorption fit the pseudo second-order and intra-particle diffusion models. The isotherm data followed the Langmuir and Freundlich models. The maximum adsorption capacity from the Langmuir isotherm equation reached 833.3mg/g for GO–SA indicating that it is a good adsorbent for MB. The MB absorption mechanisms can be different for these two gels. Electrostatic interaction is the main interaction between the negative surface oxygen containing groups of GO and cationic MB, but π–π stacking is the primary interaction between the aromatic rings of RGO–SA and MB molecules.

Photocatalytic degradation of methylene blue and inactivation of Gram-negative bacteria by TiO2 nanoparticles in aqueous suspension

The photocatalytic degradation of methylene blue (MB) and inactivation of Gram-negative bacteria Escherichia coli (generic) and Pseudomonas aeruginosa by TiO2 nanoparticles in aqueous suspension were studied. TiO2 resulted in significant reduction in MB absorption and a shift of MB absorption peak from 664 nm to 658 nm after a short time of irradiation. The maximum degradation of MB was observed when the concentration of TiO2 in the aqueous suspension was 0.5 g L−1. TiO2 was also very effective with inhibiting growth of both Gram-negative bacteria E. coli and P. aeruginosa, although it took more than 60 min to observe the inactivation effects. The photocatalytic inactivation toward E. coli and P. aeruginosa by TiO2 showed a similar trend with much higher effectiveness toward E. coli under the same experimental conditions. The inactivation kinetic behaviors could be explained by the modified Langmuir–Hinshelwood model, and well fitted to a pseudo-first order kinetic equation. The reaction rate constant for E. coli and P. aeruginosa were 7.768 × 106 cfu mL−1 min−1 and 5.655 × 106 cfu mL−1 min−1, respectively. The adsorption equilibrium constant for E. coli was 1.053 × 10−8 mL cfu−1, while it was 1.438 × 10−8 mL cfu−1 for P. aeruginosa. These results further demonstrate that in an aqueous system, TiO2 nanoparticles can effectively both degrade organic compounds and inhibit Gram-negative bacteria under UVA light. Compared with the degradation activity of TiO2 toward organic compounds, its antimicrobial activity against Gram-negative bacteria would be delayed by 60 min. The antimicrobial activity of TiO2 against Gram-negative bacteria could vary with bacterial species.

Wet-Purification of a Sodium-Based Bentonite

Bentonite mainly consists of montmorillonite, but is always associated with other impure minerals. In order to increase the montmorillonite content in raw bentonite from Xinjiang, this paper adopts wet-purification process which integrates the scrubbing process with streamlined centrifugalization. The optimum experiment condition is solid - liquid ratio (wv) 130, macerating time 20h, scrubbing time 10min, centrifugation time 13min, centrifugation velocity 1260r/min, ZHL dosage 0.4% and ZHC dosage 0.4%. According to the amount of methylene blue absorption raising from 64.5mmol/100g to 110mmol/100g and X-ray diffraction analysis, the montmorillonite content raises from 48% to 82%.

A facile synthesis of 1D nano structured selenium and Au decorated nano selenium: catalysts for the clock reaction

Elemental selenium nanowires (Se NWs) are obtained from the easily available, less-toxic, low-cost reagents sodium selenite and ethylenediamine (en) through a modified hydrothermal reaction (MHT). The reaction supports the habitual growth of selenium nanowires and the amine molecules act as a reducing agent. Then, an interesting galvanic exchange reaction deposits Au nanoparticles on the as-synthesized Se evolving an Au decorated composite material. But a similar galvanic exchange produces Ag2Se because of the lower diffusion activation energy of Ag. Selenium nanowires, even as metalloids, have been found to catalyze the reduction of methylene blue (MB) using NaBH4 as a reducing agent. The blue colour of MB vanishes due to the formation of leucomethylene blue (LMB). On shaking the reaction mixture, the blue colour reappears by aerial oxidation. This oscillation of reversible colour change is taken as a clock reaction. The reversible reaction is monitored by a UV-visible spectrophotometer with respect to the absorbance of MB at λmax = 663 nm. Common reducing agents such as hydrazine hydrate, ammonium thiocyanate and glucose do not show this stunning phenomenon. Sodium borohydride fails to assist the reduction process in the presence of bulk selenium. The reduction process proceeds through two steps. Initially, the rate is slower due to an ‘induction period’ and then it becomes facile. A higher catalyst dose reduces the time lag, i.e., the induction period. The Se NWs performed well for about 30–50 cycles for a clock reaction set up. Finally, the composite materials have been found to exhibit a faster clock reaction cycle in comparison to neat Se NWs.

Drug Delivery Stimulation by Alternating Current Using Methylene Blue Dye Absorption by Pig?s Skin as a Model

Pig skin has been studied as administration site of drug for its systemic effects, since systemic therapeutic agents can be delivered for long time with a controlled ratio, escaping from the first pass effect by liver through the transdermal delivery, which can decrease the drug dose. The low permeability of drug molecules through stratum corneum(SC) has been the limiting factor for developing transdermal delivery system of therapeutic agents. The aim of the present work is to study the enhancement of drug absorption by the skin using stimulating alternating current (AC).In our study stimulated voltage over range 6.5 V to 200 V had been used to enhancement the absorption of methylene blue (MB) with pig’s skin. Our results showed that the highest MB concentration in tissue was (0.239± 0.011) mg/g and lowest ohmic resistances (kΩ/cm) (3.15±0.223) for skin were obtained after skin stimulation with 12.5 V; these results had been confirmed using histochemistry study. Dielectric properties of skin in the range of 10 Hz- 100 KHz revealed change in the dielectric dispersion curves immediately after skin stimulation.

Synthesis and characterization of high efficiency and stable Ag3PO4/TiO2 visible light photocatalyst for the degradation of methylene blue and rhodamine B solutions

A facile and reproducible method for the synthesis of Ag3PO4/TiO2 visible light photocatalyst has been developed to improve the photocatalytic activity and stability of Ag3PO4. The innovation of this method is to in situ deposit Ag3PO4 nanoparticles onto the TiO2 (P25) surface forming a heterostructure. The improved activity of the Ag3PO4/TiO2 heterostructured photocatalyst for the degradation of methylene blue (MB) and rhodamine B (RhB) under visible light irradiation is attributed to the increased surface area and enhanced absorption of MB and RhB. Furthermore, depositing Ag3PO4 onto the surface of TiO2 facilitates electron–hole separation that leads to the elevated photocatalytic activity. The heterostructured Ag3PO4/TiO2 photocatalyst significantly decreases the loading of noble metal Ag from 77 wt% to 47 wt%, thereby significantly reducing the cost for the practical application of Ag3PO4 photocatalyst.

Modal Analysis of Montmorillonite in Bentonites Using Phase Mixing Equation

Based on the mass balance principle, mineral contents of the bentonites from Yangxian of Shaanxi province, Queshan of Henan province, and Chifeng of the Inner Mongolia Autonomous Region were estimated by resolving the Phase Mixing Equation constructed from the data of X-ray diffraction, microprobe analysis of montmorillonite grains, and chemical anaysis of the bentonites. The crystal formulas of montmorillonite in the bentonites were calculated based on the anion hydrogen equivalent method. The cell lattice constants of the principal minerals in the bentonites were calculated with a FORTRAN90 program CELLSR. When compared with both methods of the methylene blue absorption and XRD Rietveld quantitative phase analysis, the Phase Mixing Equation was confirmed to be the most effective modal analysis method for determing content of montmorillonite in bentonites with several minerals coexisted.

Thermodynamic studies of methylene blue adsorption onto Fe-doped sulfated titania

Adsorption equilibrium of methylene blue onto Fe-doped sulfated titania (FST) samples was studied at different temperatures (298, 303, and 308 K). Based on the wavelength scanning from 580 to 760 nm, the wavelength of maximum absorbance of methylene blue was determined to be 666 nm and the corresponding calibration curve can be described by the equation of A = 0.0068 + 0.1514C. The adsorption of methylene blue onto FST samples was conformed to the Langmuir isotherms. The absorption capacity of each FST sample for methylene blue increases with increasing temperature. The increase in the adsorption parameters (q m, b, and K 0) and the positive ΔH θ reveal the endothermic feature of this adsorption process. The negative ΔG θ shows the adsorption of methylene blue onto FST samples can be carried out spontaneously at the examined temperatures. Furthermore, with the calcination temperature increases, the variation in crystallization degree, the surface and the sulfur species will obviously influence the adsorption properties of FST samples and the thermodynamic parameters of this adsorption process.

콜라겐을 첨가한 퍼머넌트웨이브제의 개발

본 연구에서는 콜라겐의 처방이 퍼머넌트웨이브 시술시 미치는 영향을 알아보기 위하여 정상모에 콜라겐을 농도별 처방한 퍼머넌트웨이브제로 퍼머넌트웨이브를 시술한 후 모발에 컬의 형성력, 굵기 관찰, 인장 강도, 메틸렌블루 흡광도, 수분 감소량 등의 변화를 측정하여 비교분석하였다. 결론적으로 퍼머넌트웨이브제의 콜라겐 처방 여부에 따라 모발의 굵기, 모발의 인장강도, 모발의 수분 감소량, 흡광도가 처방하지 않은 환원제에 대비하여 감소하였으며, 처방된 콜라겐의 농도가 증가할수록 모발의 손상도가 줄어드는 결과를 보였다. 그러나 콜라겐의 농도의 크기가 커질수록 퍼머넌트웨이브 시술시 컬의 형성력이 떨어지는 결과가 나타났다. 그러므로 퍼머넌트웨이브 시술시 모발의 손상도를 줄이기 위한 콜라겐 처방 농도는 2%가 적당하였다. In this study, in order to find effects of collagen manipulation on hair in permanent wave treatment, it was conducted measurement and analysis on hair curl formation, thickness, tensile strength, methylene blue absorbance, and moisture loss after manipulating concentration proportion of collagen in permanent wave treatment on normal hair. As a result, it was found that by contrast with applying the reductant, hair thickness, tensile strength, methylene blue absorbance, and moisture loss were decreased when applied collagen in permanent wave treatment the higher concentration proportion of collagen was applied, the less damage was occurred on hair However curl formation capacity was decreased in permanent wave treatment as concentration proportion of collagen was increased. Therefore, the appropriate concentration proportion of collagen was 2% in order to reduce hair damage in permanent wave treatment.

Self‐Assembling TiO2 Nanorods on Large Graphene Oxide Sheets at a Two‐Phase Interface and Their Anti‐Recombination in Photocatalytic Applications

AbstractTiO2 nanorods are self‐assembled on the graphene oxide (GO) sheets at the water/toluene interface. The self‐assembled GO–TiO2 nanorod composites (GO–TiO2 NRCs) can be dispersed in water. The effective anchoring of TiO2 nanorods on the whole GO sheets is confirmed by transmission electron microscopy (TEM), X‐ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), and thermogravimetric analysis (TGA). The significant increase of photocatalytic activity is confirmed by the degradation of methylene blue (MB) under UV light irridiation. The large enhancement of photocatalytic activity is caused by the effective charge anti‐recombination and the effective absorption of MB on GO. The effective charge transfer from TiO2 to GO sheets is confirmed by the significant photoluminescence quenching of TiO2 nanorods, which can effectively prevent the charge recombination during photocatalytic process. The effective absorption of MB on GO is confirmed by the UV‐vis spectra. The degradation rate of MB in the second cycle is faster than that in the first cycle because of the reduction of GO under UV light irradiation.

Antibacterial and absorbent acrylonitrile-vinylidene chloride copolymer fibres

A series of antibacterial and absorbent acrylonitrile (AN)-vinylidene chloride (VDC) copolymer fibres were fabricated by adding micro- or nano-sized silver-impregnated activated carbon (Ag-AC) powders in AN-VDC copolymer-dimethylformamide (DMF) solution, and then extruded through a spinneret into a coagulation bath of DMF-water. The fibres containing less than 25 wt% of Ag-AC were spun smoothly. The structure and properties of the fibres were characterized using differential scanning calorimeter (DSC), scanning electron microscopy (SEM), wide-angle X-ray diffraction, and other universal test methods. The BET specific surface areas of the fibres were determined from nitrogen adsorption isotherms, and the absorbability was measured by methylene blue (MB) absorption. The results show that the tensile strength and strain of the fibre containing 20 wt% Ag-AC are 1.3 cN/dtexs and 30%. The BET specific surface area of this fibre is 198 m2/g. The antibacterial activity of the fibres containing 0.10 wt% silver is excellent, the bactericide efficiency of Escherichia coli and Staphylococcus aureus is above 99%.

Real-time, near-infrared, fluorescence-guided identification of the ureters using methylene blue

The aim of this study was to determine whether the invisible near-infrared (NIR) fluorescence properties of methylene blue (MB), a dye already approved by the U.S. Food and Drug Administration for other indications, could be exploited for real-time, intra-operative identification of the ureters. The optical properties of MB were quantified in vitro. Open surgery and laparoscopic NIR fluorescence imaging systems were employed. Yorkshire pigs were injected intravenously with 0.1-mg/kg MB (n = 8), 10-mg furosemide followed by 0.1-mg/kg MB (n = 6), or 0.5-mg/kg MB (n = 6). The contrast-to-background ratio (CBR) of the kidney and ureters, and the MB concentration in the urine, were quantified. Peak MB absorbance, emission, and intensity in urine occurred at 668 nm, 688 nm, and 20 mumol/L, respectively. After intravenous injection, doses as low as 0.1-mg/kg MB provided prolonged imaging of the ureters, and a dose of 0.5 mg/kg provided statistically significant improvement of CBR. The preinjection of furosemide increased urine volume but did not improve CBR. Laparoscopic identification of the ureter using MB NIR fluorescence was demonstrated. Ureteral imaging using MB NIR fluorescence provides sensitive, real-time, intra-operative identification of the ureters during open and laparoscopic surgeries.