Methylene Blue Uptake Research Articles

Investigation of Chitosan-PVA Composite Films and Their Adsorption Properties

Viscous aqueous solutions of chitosan and polyvinyl alcohol (PVA) were blended to enhance miscibility and avoid polymer phase separation. The mixtures were drop-casted and air dried to yield composite film materials that were characterized by equilibrium water uptake, physical stability in aqueous solution, and thermal stability. Chitosan/PVA blends have greater thermal stability, unique morphology, and reduced solubility in acidic solution, thus extending the useful pH range for chitosan as a sorbent material. The uptake properties of the films was investigated using methylene blue (MB) and a p-nitrophenol (PNP) dyes, where it was found that each single component polymer has greater uptake toward MB than PNP. A direct relationship between film composition (chitosan:PVA) with solution pH and the uptake of MB was observed. The results are in agreement with electrostatic interactions and contributions due to the hydrophobic effect for such composite materials.

Evaluation of Red Marine Alga Kappaphycus alvarezii as Biosorbent for Methylene Blue: Isotherm, Kinetic, and Mechanism Studies

In this work, non-living red seaweed (Kappaphycus alvarezii) biomass was investigated as a new biosorbent of methylene blue from aqueous solution. The effect of operational parameters such as equilibrium pH, agitation time, initial dye concentrations, and biosorbent dosage on the biosorption capacity of Kappaphycus alvarezii was studied. The equilibrium solution pH was found to profoundly affect methylene blue sorption capacity of Kappaphycus alvarezii with pH 8 found to be optimum. Evidence from Fourier-transform infrared spectroscopy and scanning electron microscopy pictures confirmed the dye biosorption mechanism as electrostatic interaction between the negatively charged seaweed surface and positively charged methylene blue. Biosorption isotherms indicated that Kappaphycus alvarezii exhibited methylene blue uptake of 74.4 mg/g, according to the Langmuir model. The equilibrium isotherm data were evaluated using the Freundlich, Langmuir, Redlich-Peterson, and Toth models. Kinetic studies revealed that methylene blue uptake was fast with 97% or more of the uptake occurred within 60 min of contact time. The pseudo first and second order models were applied to describe kinetic data, of which the pseudo-first order described experimental data better with high correlation coefficient and low percentage of error values.

Optimization of Activated Carbon Preparation from Date Stones by Microwave Assisted K2CO3 Activation

The preparation of activated carbon (AC) from date stones by using microwave assisted K2CO3 activation was investigated in this paper. The influence of radiation time, radiation power, and impregnation ratio on the yield and methylene blue (MB) uptake of such carbon were studied. Based on Box-Wilson central composite design, two second order polynomial models were developed to correlate the process variables to the two responses. From the analysis of variance the significant variables on each response were identified. Optimum coditions of 8 min radiation time, 660 W radiation power and 1.5 g/g impregnation ratio gave 460.123 mg/g MB uptake and 19.99 % yield. The characteristics of the AC were examined by pore structure analysis, and scanning electron microscopy (SEM).The BET surface area and total pore volume were indentified to be 1144.25 m²/g and 0.656 m³/g, respectively.

Adsorption of Methylene Blue from Aqueous Solution Using Steam-Activated Carbon Produced from <i>Lantana camara</i> Stem

This study investigated the adsorption of Methylene Blue (MB) present in wastewater onto the activated carbon produce from Lantana camara stem. The agricultural material (Lantana camara stem) was carbonized at 300°C for 2 h, ground and steam-activated. The Steam-Activated Lantana camara (SALC) stem carbon was characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR) Spectrophotometry before and after adsorption. Batch model experiments were conducted at 20°C to study the effects of pH, agitation time, adsorbent dosage and initial concentration of methylene blue. The equilibrium adsorption isotherms and kinetics were investigated. The FTIR bands at 3500, 2500, 2196 and 1682 cm-1 were shifted to 3646.3, 3030, 2822, 1709.05 cm-1 after MB adsorption. Similarly, the Scanning Electron Microscopy (SEM) analysis showed that the average pore size on the activated carbon was 20 μm. The Methylene Blue (MB) uptake increased with the increase in pH. Similarly, the dye adsorption increased as contact time increased, and reached equilibrium at 60 minutes. The removal of the dye increased when the dosage was increased from 0.5 - 2.0 g·L-1, at different dye concentrations (50 - 200 mg·L-1). The percentage removal decreased with increasing initial dye concentration for SALC. The adsorption isotherm data fitted well to the Freundlich isotherm (R2 = 0.989) while the experimental data fitted very well to the pseudo-second-order kinetic model (R2 = 0.99). This study suggests that adsorbent prepared from Lantana camara stem can be used effectively for the adsorption of methylene blue in wastewater.

Removal of microcystin-LR from aqueous solutions using % burn-off activated carbon of waste wood material

The activated carbon (AC), prepared at different burn-off rates, showed a high uptake of methylene blue. At 93% burn-off, methylene blue uptake was 620 mg/g. Adsorption capacity of microcystin-LR onto rubber wood AC was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH and temperature. Microcystin-LR removal is pH dependent and found to be highest at pH 2.5. Increases in adsorption capacity with increase in temperature indicate that the adsorption reaction is endothermic. Based on this study, the thermodynamic parameters like standard Gibb9s free energy (Δ G °), standard enthalpy (Δ H °) and standard entropy (Δ S °) were evaluated. A pseudo second order model was found to explain the kinetics of microcystin-LR adsorption most effectively. The rate of intraparticle diffusion was also evaluated. The Langmuir and Freundlich isotherms were used to describe the adsorption equilibrium studies of rubber wood AC at different temperatures. The Langmuir isotherm shows better fit than Freundlich isotherms in the temperature range studied. The results show that the rubber wood AC can be efficiently used for the removal of microcystin-LR from water. In order to investigate the possibility of regeneration and reuse of exhausted adsorbent, desorption studies were also performed.

Effectiveness of Carboxymethyl Cellulose for the Removal of Methylene Blue from Aqueous Solution

The adsorptive properties of carboxymethyl cellulose (CMC) prepared from sugarcane bagasse (SB) for the removal of methylene blue (MB) from aqueous solution was investigated. Two batches of CMC, CTSB-CMC-B1 and CTSB-CMC-B2, were prepared from chlorite treated sugarcane bagasse (CTSB). The prepared CMCs were characterized by FT-IR spectral analysis. Degree of substitution (DS) value of prepared CMCs was estimated. Batch adsorption experiments show that the adsorption of MB on CMCs reaches equilibrium within 30 minutes. The MB adsorption capacity of CTSB-CMC-B1 and CTSB-CMC-B2 were found to be 652.0 and 369.0 mg g?1, respectively. CMC with the higher DS value (CTSBCMC- B1) shows higher adsorption capacity than the CMC having lower DS value (CTSB-CMC-B2). The uptake of MB was minimum at pH 2 and gradually increases with the increase of pH. From the desorption studies, it was found that large amount of MB was released in strong acidic (pH 3.0) conditions. DOI: http://dx.doi.org/10.3329/dujs.v61i2.17069 Dhaka Univ. J. Sci. 61(2): 193-198, 2013 (July)

Optimization of microwave preparation conditions for activated carbon from Albizia lebbeck seed pods for methylene blue dye adsorption

Microwave assisted KOH activation has been utilized for preparation of activated carbon from agricultural wastes, Albizia lebbeck seed pods. The surface area, micropores volume, and mesopores volume of this carbon (KAC) were 1824.88m2/g, 0.645cm3/g, and 0.137cm3/g, respectively. The effects of process variables represented by radiation time, radiation power, and impregnation ratio on the yield and methylene blue (MB) uptake of such carbon were studied. Box-Wilson central composite design was adopted to arrange the experiments and two second order polynomial models were developed to correlate the process variables to the two responses. MB uptake of 220.83mg/g and 22.48% carbon yield were reported at optimum preparation conditions. The best fitting for MB experimental equilibrium data was achieved with the Langmuir isotherm, giving a maximum MB adsorption capacity of 381.22mg/g. The experimental kinetic data were well described by the pseudo-second order model.

Synthesis, characterization, and dye sorption ability of carbon nanotube–biochar nanocomposites

Innovative technologies incorporating engineered nanoparticles into biochar production systems could improve the functions of biochar for many applications including soil fertility enhancement, carbon sequestration and wastewater treatment. In this study, hybrid multi-walled carbon nanotube (CNT)-coated biochars were synthesized by dip-coating biomass in varying concentrations of carboxyl-functionalized CNT solutions (0.01% and 1% by weight) prior to slow pyrolysis. Untreated hickory and bagasse biochars (HC and BC, respectively) and CNT–biochar composites (HC–CNT and BC–CNT, respectively) were characterized, and the methylene blue (MB) sorption ability of the resulting chars was evaluated in batch sorption experiments. The addition of CNTs significantly enhanced the physiochemical properties of the biochars with HC–CNT-1% and BC–CNT-1% exhibiting the greatest thermal stabilities, surface areas (351 and 390m2g−1, respectively), and pore volumes (0.14 and 0.22ccg−1, respectively). Sorption kinetic and isotherm data showed that, among the biochars examined, BC–CNT-1% had the highest MB sorption capacity (6.2mgg−1). While increased pH (up to ∼7), promoted the uptake of MB by all the biochars, whether coated or not, increasing ionic strength decreased the uptake of MB by all biochars tested. These findings suggest that electrostatic attraction was the dominant mechanisms for the sorption of MB onto the chars, though diffusion controlled its rate. Hybridized CNT–biochar nanocomposite can thus be considered a promising, inexpensive sorbent material for removing dyes and organic pollutants from aqueous systems.

Adsorption and catalytic ozonation performance of activated carbon and cobalt‐supported activated carbon derived from brewing yeast

AbstractActivated carbon (AC) was prepared from brewing yeast by NaCO activation, and cobalt was supported on activated carbon (Co/AC) by the adsorption–activation method. The XPS test indicated that supported cobalt was Co(II). The total BET surface areas of prepared AC and Co/AC were 957.7 and 847.9 m/g, with total pore volumes of 0.81 and 0.80 cm/g, respectively. The average pore diameters of AC and Co/AC were found to be 3.8 and 3.3 nm. The contact time required for equilibrium of methylene blue (MB) adsorption onto prepared AC and Co/AC was about 120 min. The maximum uptake of MB by AC and Co/AC was estimated to be 372.1 and 213.5 mg/g, respectively. The presence of prepared AC or Co/AC was advantageous for TOC reduction compared with UV/O system, and the greatest TOC removal was obtained in the presence of Co/AC. The kinetics of the degradation of MB fitted the Langmuir‐first‐order model well. The rate constants of Langmuir first‐order were determined to be 0.0096 min−1 for UV/O/AC and 0.0143 min−1 for UV/O/Co/AC, respectively.

Adsorptive removal of methylene blue using the natural adsorbent-banana leaves

In this work, the banana leaf, an agricultural waste, widely used for wrapping of food was utilized as a low-cost adsorbent for removing methylene blue (MB) dye from the aqueous solution. The effects of initial concentration, contact time, and solution pH on the adsorption performance were investigated in a batch mode study at 30°C. The adsorptive uptake of MB increased with increasing the initial MB concentration and solution pH. Equilibrium data were simulated using the Langmuir and Freundlich isotherms, pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The data were well fitted to the Langmuir isotherm model, showing a maximum monolayer adsorption capacity of 109.89 mg/g. Adsorption kinetics were best described by the pseudo-second-order and intraparticle diffusion models. The results illustrated the potential use of waste banana leaves for the removal of colors and dyes from the textile wastewater.

Food cannery effluent, pineapple peel as an effective low-cost biosorbent for removing cationic dye from aqueous solutions

The present research explores the viability of pineapple peel, an agricultural effluent discharged from the food can processing industries for removing methylene blue (MB) dye from the aqueous solution. The effects of contact time, initial concentration, and solution pH on the adsorptive uptake of MB were investigated in a batch mode study. The morphological and functional characterization of the adsorbent was performed using the scanning electron microscopy and Fourier transform infrared analysis. The adsorption equilibrium was simulated using the Langmuir, Freundlich and Temkin isotherm models. Kinetic modeling was fitted to the pseudo-first-order and pseudo-second-order kinetic equations, while the adsorption mechanism was determined using the intraparticle diffusion model. Equilibrium data were favorably described by the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 97.09 mg/g. The results provide a strong evidence to support the potential use of pineapple waste as an effective adsorbent for the treatment of textile wastewater.

Unusual dye adsorption behavior of κ-carrageenan coated superparamagnetic nanoparticles

κ-Carrageenan coated magnetic iron oxide nanoparticles (NPs) were synthesized and tested as adsorbents for the magnetically assisted removal of methylene blue (MB) from aqueous solutions, a cationic dye commonly present in wastes from the textile industry. The resulting composite NPs were superparamagnetic and contained ca. 12wt% carrageenan. The MB uptake ability was found to vary with the pH solution and was larger in alkaline conditions. Both pseudo-first-order and pseudo-second-order equations predicted well the kinetics with the maximum adsorption achieved very fast, within 5min. The MB adsorption has shown an unusual Z-type isotherm which suggests the generation of new adsorbing sites with increasing MB initial concentration. Under the experimental conditions used (23°C, pH 9) the materials presented here displayed MB adsorption capacity (185.3mg/g) higher than other magnetic sorbents previously reported. Thus κ-carrageenan coated magnetic NPs are very promising eco-friendly materials for removing MB from wastewater using magnetic separation.

Removal of methylene blue by adsorption onto activated carbon developed from Ficus carica bast

In this study, activated carbon was developed from Ficus carica bast (FCBAC). The experiments were carried out to explore methylene blue (MB) uptake by FCBAC. The influence of various experimental factors such as contact time, initial dye concentration, adsorbent dosage, temperature and pH of dye solution was investigated. The adsorption equilibrium was represented with Langmuir, Freundlich and Temkin isotherm models. Langmuir and Tempkin equations were found to have the correlation coefficient value in good agreement. Adsorption of MB onto FCBAC followed pseudo second order kinetics. The calculated values of ΔH°, ΔS° and ΔG° were found to be 21.55kJ/mol, 76.24J/molK and −1.55kJ/mol, respectably. Adsorption process was spontaneous and endothermic in nature.

Abstract 3923: Photoacoustic image guided photodynamic therapy of glioblastoma.

Abstract Introduction: Glioblastoma multiforme(GBM) is an aggressive cancer with bleak survival rates and limited new treatment options. Fluorescence guided resection of GBM followed by photodynamic therapy (PDT) has shown promise in several chemo-or radiotherapy non-responsive GBM treatments clinically. PDT causes cytotoxicity with a combination of specific wavelength of light and photosensitizer (PS). Fluorescence is used in PDT research for detection of tumors, as the PS is also fluorescent. However, typically these molecules have low fluorescence quantum yields but good singlet oxygen yields to cause photodynamic damage. Also, in-vivo florescence images are surface-weighted and donot provide 3D image of the tumoral drug accumulation. In this study we utilize photoacoustic imaging (PA), a non-invasive, non-ionizing technique that provides contrast based on optical absorption properties of the tissue, to obtain 3D biodistribution of different fluorophores and PDT agents such as methylene blue (MB) free or encapsulated in liposomes in orthotopic brain tumors. We encapsulated verteporfin and MB in liposomes to increase its circulation half-life in-vivo and tumoral accumulation due to the enhanced-permeation and retention effect. Moreover, PA imaging can also be used to monitor tumoral blood oxygen saturation and this information is critical in PDT as oxygen plays a major role in creation of singlet oxygen cytotoxic species. Methods and Results: In this study, U87 glioma cells and patient derived GBM6 glioma cells were implanted orthotopically in the brain in 4-6 weeks old nude mice. 10 days post implantation, a burr hole was made in the skull to image intravenously injected liposomal methylene blue (10 mg/kg) uptake in the tumor. The liposomes were ∼110 nm in diameter evaluated using dynamic light scattering. A methylene blue loading efficiency of ∼50% was obtained in these liposomes. We observed that 2 hours post I.V. injection, the photoacoustic signal in brain tumor region increased ∼2.3 times and remained the same in non-tumor regions within the brain. We performed pilot studies in orthotopic glioma models that demonstrated: i) the efficacy of the photosensitizer encapsulated liposomes to accumulate in the glioma tumors, ii) ability of PA imaging technique to monitor the 3D heterogeneous uptake of the liposome constructs and iii) monitor PDT-induced changes in tumor vascular oxygen saturation non-invasively in real time. Conclusions: Taken together, we anticipate significant tumor burden reduction in our on-going in-vivo studies where the PDT light dose will be compensated based on the photoacoustic image information of the PDT agents uptake in the tumor. The findings of this study will form the basis for customized photodynamic therapy for glioblastoma and have the potential to serve as a platform for treatment of other cancers. Citation Format: Srivalleesha Mallidi, Huang-Chiao Huang, Joyce Y. Liu, Lawrence Mensah, Zhiming Mai, Tayyaba Hasan. Photoacoustic image guided photodynamic therapy of glioblastoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3923. doi:10.1158/1538-7445.AM2013-3923

Methylene blue as an early diagnostic marker for oral precancer and cancer

Oral cancer is one of the most common neoplasm’s and is ranked eighth in the cancer incidence worldwide. Early detection is of critical importance because survival rates markedly improve. In vivo staining is a simple, inexpensive, and fairly sensitive method. Involved 120 patients (50 with Premalignant Lesion, 50 with OSCC and 20 controls) stained by Methylene Blue (MB). The results of MB uptake were compared with a simultaneous biopsy of these lesions. Pathologically confirmed precancers and cancers were the positive targets of this screening, while hyperkeratosis without dysplasia and no evidence of malignancy were sorted as negative subjects of screening. The results revealed sensitivity of 91.4%, specificity of 66.6%, positive predictive value 97.7% and negative predictive value 33% leading to diagnostic accuracy of MB stain to 90%. We state that MB staining is useful diagnostic tool in community oral cancer screening programmes for high-risk individuals.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-95) contains supplementary material, which is available to authorized users.

Methylene Blue Adsorption by Synthetic Nano-Carbon-Hydroxylapatite

Synthetic nano-carbon-hydroxylapatite was used to remove methylene blue (MB) from aqueous solution. The influence of various parameters such as reaction time, initial dye concentration and pH on the adsorption was investigated in batch mode and the adsorption mechanism was briefly discussed. The experimental results show that the uptake of MB was rapid and equilibrium could be reached in 30 minutes, and the uptake of MB increased with increasing initial dye concentration and pH. The pseudo-second-order model fits well to the kinetics and Henry adsorption isotherm can be used to describe the experimental data. The adsorption mechanism can be explained mainly by electrostatic attraction.

Thermally processed sewage sludge for methylene blue uptake

Sewage sludge, with zero recycling rate, poses landfill problems as Semakau island, the dumping site, is rapidly occupied in within a short period of time. Dried sewage sludge was heated at different temperatures ranging from 200 °C to 700 °C over various heating times of 2–5 h. The heated dried sludge (DS) was equilibrated with methylene blue (MB) solutions at different concentration to determine the optimum adsorption time, effect of different heating temperatures of sludge, effect of pH and effect of adsorbent concentration on the percentage of MB adsorbed. The results were compared to a commercial activated carbon (AC) in adsorbing the same MB concentration. The higher heating temperatures the more the DS was able to adsorb MB. DS, which was heated at 700 °C, showed the highest percentage of MB adsorbed of 95%, compared to that of AC, which were 91.20% (Grade 17) and 97.99% (Grade 19), when adsorbing the same initial MB concentration of 10 μmol l−1. However, DS heated at 200 °C for 5 h (DS-200-5) was found to have a ratio of MB adsorbed per power consumption of 21.568 (μmol l−1 kW), the highest ratio among the other sludge samples, making it the most cost effective type of sludge. Overall, DS was able to adsorb MB between 90% and 98% at a wide pH range of 3 < pH < 12, showing the potentiality of DS to remove contaminant from industrial discharge. In addition the reuse of sludge for other environmental application can help to prolong the lifespan of landfill dumping site.

Adsorption of methylene blue onto carbons made of residues from the biodiesel industry

The performance of carbons produced from the cold-pressed cake of Raphanus sativus (L. var.), a residue from the biodiesel industry, was evaluated for the adsorption of methylene blue (MB) from synthetic aqueous solutions. The study has focused on the following three topics: (i) physical and textural characterization of the carbon, (ii) batch investigation of equilibrium and kinetics of MB adsorption at room temperature, and (iii) analysis of MB adsorption mechanism onto such carbonaceous structures. Regarding the fi rst topic, carbon was characterized using several methods such as Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH), scanning electron microscopy (SEM), and Raman spectroscopy. A microporous carbon was found thus indicating that MB adsorption may occur predominantly at the surface of the carbon. Regarding the second topic, equilibrium tests revealed that Langmuir-based maximum MB uptake capacity was 19.8 mg g –1 and that MB kinetics onto carbon was best described by a pseudo second-order model. Data fi tting analysis confi rmed that MB adsorption onto such carbons was predominantly superfi cial. And fi nally, regarding the third topic, MB adsorption may probably occur by bonding of monomer MB through the central nitrogen atom of its molecule and through sulfur atom while MB bonding through amino nitrogen atom does not seem probable. The study reveals that carbons made of R. sativus are suitable materials for the removal of dyes from aqueous solutions, mainly if fifraction of carbons is used, because MB adsorption was found to be predominantly superfi cial.

Electrically-responsive anti-adherent hydrogels for photodynamic antimicrobial chemotherapy

The loading of the photosensitisers meso-Tetra (N-methyl-4-pyridyl) porphine tetra tosylate (TMP), methylene blue (MB) and TMP with sodium dodecyl sulphate (SDS) into and release from hydrogels composed of the polyelectrolyte poly(methyl vinyl ether-co-maleic acid) crosslinked in a 2:1 ratio with PEG 10,000 were investigated as a potential rapid photodynamic antimicrobial chemotherapy (PACT) treatment for infected wounds using iontophoresis as a novel delivery method. Photosensitiser uptake was very high; (% TMP uptake; 95.53–96.72%) (% MB uptake; 90.58–93.26%) and was PMVE/MA concentration independent, whilst SDS severely limited TMP uptake (5.93–8.75%). Hydrogel hardness, compressibility and adhesiveness on the dermal surface of neonate porcine skin increased with PMVE/MA concentration and were significantly increased with SDS.The ionic conductivities of the hydrogels increased with PMVE/MA concentration. Drug release was PMVE/MA concentration independent, except for drug release under iontophoteric conditions for MB and TMP (without SDS). In just 15min, the mean% drug concentrations released of TMP, TMP (with SDS) and MB using an electric current ranged from 22.30 to 64.72μgml−1, 6.37–4.59μgml−1 and 11.73–36.57μgml−1 respectively. These concentrations were in excess of those required to induce complete kill of clinical strains of meticillin-resistant Staphylococcus aureus and Burkholderia cepacia. Thus these results support our contention that the iontophoteric delivery of TMP and MB using anti-adherent, electrically-responsive, PEG-crosslinked PMVE/MA hydrogels are a potential option in the rapid PACT treatment of infected wounds.

Adsorption of Methylene Blue from Solution by Natural Zeolite in Fixed-Bed Column: Effect of Bed Depth

The effect of bed depth on adsorption ability of natural zeolite to removal methylene blue (MB) from aqueous solution in the fixed-bed column was studied. The results showed that the increase in column height favored the MB removal form solution. The equilibrium uptake of MB onto unit mass zeolite increased with the bed depth growth. The experimental data were fitted to Yan model using linear and nonlinear regression analysis, respectively. The experimental points and the predicted curves using the Yan model were compared and the error analysis was performed. The results indicated that Yan model were good to predict the breakthrough curves and both two methods can be used to obtain the parameters of Yan model and to predict the breakthrough curves.