جستجوی مقالات مرتبط با کلیدواژه « methylene blue » در نشریات گروه « شیمی »

In this study, acrylamide based graft poly (acrylic acid) hydrogel (AM-g-P(AC)) and its nanocomposite with CdS nanoparticles AM-g-P(AC)/CdS were produced by the free radical method and utilized for methylene blue (MB) dye removal from aqueous solution. The characterization and properties of the adsorbents were studied utilizing FESEM, FTIR, TGA, and XRD analyses, and the results showed that CdS NPs were successfully distributed in the hydrogel structure. CdS NPs were loaded into the hydrogel system and the best adsorption capacity of MB dye was determined at 0.05 g of Cds NPs. Also, the effect of equilibrium time, initial concentration, temperature, and initial pH on the adsorption capacity of MB dye was studied. Behavior of the equilibrium investigation of the adsorption method show that the equilibrium result determined are in the best agreement with the Freundlich isotherm model and the multilayer surfaces play an effective role in the adsorption method. The best multilayer adsorption efficiency (qmax) determined utilizing isotherm Freundlich model for AM-g-P(AC)/CdS. The maximum adsorption capacity (Qe mg/g) determined for CMC-g-P(AAm) and AM-g-P(AC)/CdS were determined as 534.45 mg/g and 467.67 mg/g, respectively. The biological compound activity results were observed before and after the process of loading CdS NPs on it against the types of bacteria tested (Staphylococcus epidermidi and Staphylococcus aureus) and (E. coli and Klebsiella spp.).

This study investigated the adsorption process of methylene blue cationic dye by silver nanoparticles synthesized using extract Tragopogon buphthalmoides. The effectiveness of various parameters, including adsorbent dosage, pH, contact time, and temperature, was evaluated in terms of their effects on the efficiency of dye removal. The study determined that the optimal conditions for dye removal were a pH of 10, an adsorbent dosage of 0.2 g, a contact time of 60 min, and a temperature of 25°C. Then, Ten different isotherm models including Langmuir, Dubinin-Radushkevich (DR), Harkins-Jura, Freundlich, Jovanovic, Temkin, Fowler-Guggenheim, Halsey, Flory-Huggins, and Hill-de Boer were performed based on the optimal conditions. The calculations were fully presented to obtain the constants of each isotherm, and for greater accuracy in selecting the dominant isotherm, some other error functions, such as SSE (sum of squared errors), MSE (mean squared error), and RMSE (root mean square error) were also used. The Freundlich and Halsey isotherms were identified as the dominant models with the highest degree of correlation coefficient (R2= 0.9913) and least error values (SSE= 0.0229, MSE= 0.00229, RMSE= 0.0047). According to the values of the isotherm constants of Freundlich, n= 1.5087 and Kf = 27.0287, it is quite clear that the adsorption process has occurred physically and there is weak interaction between the adsorbate and adsorbent due to the heterogeneous adsorption of multiple layers on the surface of the adsorbent. The Langmuir isotherm determined the qmax (maximum adsorption capacity) to be 181.8182 mg/g, and the RL (separation factor) was found to be 0.5677, indicating favorable adsorption. The results of this study showed that the order of dye adsorption conformity in the studied isotherms was Temkin<Jovanovic<Dubinin-Radushkevich<Harkins-Jura<Langmuir<Flory-Huggins<Fowler-Guggenheim<Hill-de Boer<Halsey, and Freundlich. It is clearly shown from the plots that there was adsorption of methylene blue in more than a monolayer, and this exhibits heterogeneity of the surface.

In this research, the photocatalytic removal of Methylene Blue (MB) dye was investigated using ZSM-5@ZnO nanoflowers. Facile synthesis of ZSM-5@ZnO nanoparticles was performed using a sol-gel procedure. Moreover, crystal structure, functional groups, and morphology of the synthesized nanoparticles were confirmed by applying X-Ray Diffraction (XRD) analysis, Fourier Transform InfraRed (FT-IR), Energy Dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET), and Scanning Electron Microscope (SEM) approaches. Experiments on the initial concentration of MB, catalyst dosage, pH of the medium, light source power, amount of H2O2, and kinetic studies were carried out to achieve the maximum amount of MB removal. The highest removal rate of MB dye was achieved under optimum circumstances, i.e., dye concentration of 5 mg/L, pH of 9, 0.2 ml of H2O2, 50 mg of ZSM-5@ZnO nanocatalyst dosage, and 120 min under 50 W light-emitting diode (LED) lamp irradiation. Regarding the mentioned conditions, the maximum dye removal rate was 94.09%. The Kinetic study also expresses that the removal process follows the first-order model with the equation y=0.024x, R2=0.985, and AARD = 4.269%. Besides, the optimal time for the photocatalytic removal process is 120 min. Notably, the reusability of the nanocatalyst during 5 cycles was promising, and only 4.59% of dye removal efficiency decreased.

This study aimed to investigate alterations in the physical and chemical properties resulting from hydrothermal carbonization process applied to dried coconut pulp samples. The samples were passed through a 50-mesh sieve, immersed in demineralized water, and subjected to heating in an autoclave soaked in silicone oil at 200 °C for 5 hours. Hydrochar product (HTC-coconut pulp) of the treatment is a black powder characterized using several instruments. The results of X-ray diffraction (XRD) analysis showed that the peaks in coconut pulp occurred at 2θ: 16.1°, 20.3°, and in the corresponding HTC-coconut pulp at 2θ: 20.2°, 21.2°. Meanwhile, analysis using FTIR showed a significant change where the peaks were at wavenumber (cm-1) 3603, 2926, 2855, 1746, 1462, 1372, and 1155. The peaks detected in HTC-coconut pulp were at wavenumber (cm-1) 2929, 2849, 1713, 1468, 1290, 1117, and 1057. The results of X-ray fluorescence (XRF) analysis showed several elements such as Al, P, S, Cl, K, and Ca, while HTC-coconut pulp showed Al, Si, P, S, Cl, K, and Ca. A simple application of the two types of materials was as an adsorbent for a simulated methylene blue (MB) solution. According to UV-Vis spectrophotometry absorbance before and after treatment, HTC-coconut pulp showed a slightly higher absorbency compared to normal coconut pulp.

This paper uses a one-step synthesis method to prepare NH2-ZIF-8/NCDs porous materials. A series of composite photocatalysts were obtained by adjusting the additional amount of nitrogen-doped carbon quantum dots (NCDs). The structural characteristics of the nanocomposites were characterized using XRD, FTIR, FESEM, TEM, and BET. The photocatalytic activity of NH2-ZIF-8/NCDs nanocomposites was investigated through the photocatalytic degradation of methylene blue (MB). The results show that when the addition amount of ethylenediamine and NCDs is 1:5, the prepared NH2-ZIF-8/NCDs catalyst can degrade 76.2% of the 20 mg/L methylene blue (MB) solution within 5 minutes of illumination. 97.1% of MB was degraded after 60 minutes. The photocatalytic activity of NH2-ZIF-8/NCDs photocatalyst is higher than that of ZIF-8 and ZIF-8/NCDs photocatalyst. Free radical capture experiments showed that hydroxyl radicals (·OH) were the main active species responsible for removing MB under light illumination.  Highlights  ü NH2-ZIF-8/NCDs prepared by the one-step synthesis method.ü Adding ethylenediamine for amine modification changed the structure of ZIF-8 to a porous structure and increased the reaction sites of the catalyst.ü Adding NCDs can achieve good charge separation efficiency.ü NH2-ZIF-8/NCDs catalyst exhibits excellent photocatalytic performance.

In this study, the bark of scotch pine, a common tree species that can easily grow in different weather conditions, was chosen as a biomass source. Firstly, Bio-Carbon (BC) was produced by hydrothermal pretreatment from the milled and sieved Scotch Pine Bark (SPB). Then, the final Activated Carbon (AC) was obtained from the BC by chemical activation (KCl and Na2S2O3). The produced samples were characterized by SEM, FT-IR, BET, and pHzpc analyses. The adsorption studies of samples were carried out over the removal of methylene blue (MB). The optimum conditions were determined for the parameters of pH (8), temperature (25°C), dye concentration (200 mg/L), adsorbent amount (0.08 g), and contact time (60 min). The Langmuir was determined as the fittest model with the highest R2 value (≈0.9988) with nonlinear regression in the isotherm studies. In addition, the max adsorption capacity and the surface area were found to be 374.183 mg/g and 1258.25 m2/g, respectively. In the kinetic studies, the pseudo-second-order model was determined as the most suitable model with the highest R2 value (≈0,9999) by the nonlinear regression method. It was also determined by the calculated activation energy that the adsorption is a physical sorption process. As a result, it was found that the modified AC obtained from the SPB biomass is a highly effective adsorbent in the removal of MB.

The fabrication of sustainable and efficient metal oxide-based semiconductor materials for effective degradation of environmental pollutants and other applications are currently attracting major interest from researchers. For this reason, magnetic iron oxide (Fe3O4) and zinc incorporated magnetic iron oxide (Zn@Fe3O4) nanoparticles were successfully synthesized by a co-precipitation method and tested for their physical properties and also as a photocatalysts for the degradation of toxic dye from the environment. The photocatalyst were analyzed by the use of scanning electron microscopy (SEM), x-ray diffraction (XRD) and Ultra-Violet Visible spectrophotometer to evaluate their morphology, crystallinity and band gap properties, respectively. The photocatalytic degradation performance of synthesized Fe3O4 and Zn@Fe3O4 was studied for their degradation efficiency on methylene blue (MB) dye. The photocatalytic activity of Fe3O4 was affected by doping with Zn ion. The highest methylene blue degradation (83.80 % and 70.50 %) for Fe3O4 and Zn@Fe3O4 were obtained at 0.5 g dose. The XRD and SEM results approved the existence of Fe3O4 and Zn@Fe3O4, and also highlighted the successful entrance of zinc ion onto Fe3O4. The introduction of zinc dopant into Fe3O4 lattices increases the band gap from 2.77 eV to 2.80 eV. The study of electronic structure of methylene blue was examined through quantum chemical calculations using density functional theory method (DFT) in order to give an insight on the nature of MB interaction with synthesized photocatalyst. The DFT results revealed that the nitrogen atom of the MB molecule is the favorite sites of interaction with the metal oxide surface. Furthermore, the experimental findings showed that magnetic iron oxide demonstrated a good photocatalyst in degradation of methylene blue as compared to the zinc doped magnetic iron oxide particle.

This paper deals with an electrochemical method for the determination of methylene blue (MB) by fabrication of an electrode based on a carbon paste modified with nano-nickel oxide and nitrogen carbon quantum dots (NiO-NCQD), graphene-carbon nitride (g-C3N4), reduced graphene oxide (rGO), and graphite powder and paraffin oil are as a plasticizer. This electrode is used as a working electrode. The analytical method used is cyclic voltammetry (CV), The oxidation-reduction curve of methylene blue was shown using this electrode. It is a quasi-reversible curve, and it works at (pH =1) and the best acid used is HCl a concentration of (0.1M). It was also found that the linear range is within the range of (7.99-31.98 mg L-1). The standard deviation (SD) and relative standard deviation (RSD%) were obtained at (0.361 mg L-1 and 0.294 mg L-1) and (4.52% and 3.68%) for both oxidation and reduction respectively. Retrospective, the limit of quantitative (LOQ) and limit of detection (LOD) were achieved at (99.65%; 99.70%), (0.24 mg L-1; 0.13 mg L-1), and (0.071 mg L-1; 0.039 mg L-1) for both oxidation and reduction respectively. Methylene blue was analyzed by UV-Vis spectrophotometry at (663 nm).

Defective MOF-801 (Zirconium-fumarate metal-organic framework) was de novo synthesized using environmentally friendly ultrasound-assisted synthesis. The effect of the modulator on the crystallinity, morphology, density of missing linkers, pore volume, and the specific surface area (BET) of synthesized MOF-801 was studied using two modulators, acetic acid, and formic acid, in different quantities. The MOF-801 sample (MOF-801-100FA) was applied to investigate the adsorptive removal of two cationic dyes viz Crystal Violet (CV) and Methylene Blue (MB) from an aqueous solution in a single system. MOF-801-100FA was found to be more effective in removing MB dye than CV dye. The maximum equilibrium adsorption capacity was 30.4 mg/g and 18.9 mg/g with MB and CV dyes having an initial concentration of 50 mg/L. Langmuir and Freundlich isotherm models were the best fit for adsorption data based on linear regression analysis. The best kinetic model for the adsorption was pseudo-second-order kinetics (R2 = 0.9975 for CV dye and 0.9998 for MB dye). The effect of dye concentration, contact time, MOF dose, and pH of dye solution on the adsorption of dyes was also investigated. The study showed that defective MOF-801-100FA is an efficient adsorbent for the removal of CV and MB dyes from aqueous solution.

The surface of bio-synthesized TiO2 nanoparticles was modified with a silane agent to generate the chemical link to the preparation of TiO2/β-cyclodextrin and TiO2/Ag/β-cyclodextrin nanocomposites. The structure of synthesized nanocomposites was identified using different techniques, including FTIR, DRS, XRD, ICP, TGA, FESEM, and EDX MAPPING. The photocatalytic activity of the nanocomposites was investigated in the degradation of methylene blue dye in aqueous solution under sunlight irradiation (400-700 nm). The effective factors in the degradation of methylene blue dye including, nanocomposite dosage, initial methylene blue concentration, and irradiation time were studied. The results revealed that under optimum degradation conditions (0.01 g nanocomposite, initial methylene blue concentration of 10 ppm, and 120 min sunlight exposure time), TiO2/Ag/β-cyclodextrin exhibited the highest photocatalytic activity among the tested nanocomposites. The photocatalytic efficiency of nanocomposites showed the order: TiO2/Ag/β-cyclodextrin (99.38%)> TiO2/β-cyclodextrin (84.1%)> TiO2 nanoparticles (63.76 %). Photocatalytic activity of the synthesized nanocomposites revealed that these materials could be promising candidates for the degradation of various pollutants.

Corn stalk can be used as a potential adsorbent because of its abundance, cost-effectiveness, and accessible functional groups that allow chemical modifications. This study aims to synthesize cellulose xanthate alginate beads (ACX beads) from corn stalks to remove methylene blue from aqueous solutions. ACX beads with various doses of porogen CaCO3 were printed using the ionic gelation method, and then characterized using FTIR, optical microscopy, and SEM-EDX. The results of the FTIR analysis reported changes in the C-S, C=S, and S-C-S vibrations that indicated the xanthate formation. Furthermore, as the porogen dose increased, the OH intensity decreased. The high intensity of the OH group results in a high swelling process. The results of the optical microscopy analysis showed that the porogen made the ACX beads spherical. SEM-EDX analysis showed that the higher the porogen dose, the rougher the surface morphology of the ACX beads and the larger the pore diameter. The maximum adsorption capacity was obtained on ACX beads without porogen with a contact time of 360 hours. The study reveals that the kinetic adsorption followed a pseudo-second-order kinetic model proposed chemical adsorption. The larger the porogen, the more crosslinks between the divalent cations and alginate or cellulose that are formed, inhibiting the bond between the ACX beads and water and methylene blue, thereby reducing the swelling process and the adsorption capacity of the ACX beads. In addition, the pore size that is too large does not match the size of the methylene blue molecule.

This research focuses on gamma alumina nanoparticles using for the adsorption of the cationic methylene blue dye (MB) from aqueous solutions. Batch adsorption studies carried out to study various parameters included pH, gamma alumina nanoparticles dosage, temperature and contact time. The concentration of methylene blue dye was measured using a UV-vis Spectrophotometer at the wavelength of 620 nm. The optimum adsorption conditions were found to be pH=8, adsorbent dose=0.05 g, temperature=298 K and contact time=40 min. The experimental results of this work were compared with Langmuir, Friendlich and Tamkin's isotherm models. The obtained results from isotherm models showed that the surface adsorption of these dyes on the better adsorbent follows the Langmuir isotherm model. Analysis of thermodynamic data showed that the adsorption process of the studied dyes on the surface adsorbent is spontaneous (The negativ value of ΔG0) and exothermic (The negativ value of ΔH0).

In this work, Zn2(BDC)2(DABCO) metal-organic framework (MOF) was prepared by Zn = zinc acetate dehydrates, BDC = 1,4-benzenedicarboxylate, and DABCO = 1,4-diazabicyclo [2.2.2] octane. The MOF and its polyurethane (PU) nanocomposite were used to remove Methylene Blue (MB) as a harmful and toxic dye from an aqueous solution. Polyurethane polymer has been modified with a zinc-based metal-organic framework by the press method to develop an efficient adsorbent for the first time. Samples were characterized by Fourier Transform InfraRed (FT-IR) spectroscopy to evaluate functional groups, X-Ray Diffraction (XRD) analysis of crystal structure, field emission scanning electron microscope (FESEM) to determine morphology and size, BET analysis for measurement of surface area, and Ultraviolet–Visible (UV–Vis) spectroscopy to study MB adsorption. Methylene blue adsorption was reported by changing the amount of adsorbent, MB concentration, pH, and temperature of the solution over time. According to the results, increasing the amount and percentage of adsorbent, pH, and temperature of the solution increased the percentage of adsorption efficiency. Also, the MOF and its nanocomposite can be a good choice for the adsorption of methylene blue as a cationic dye due to its high level and low material consumption. The results show that Zn2(BDC)2(DABCO) MOF and its PU nanocomposite can have good potential for the development of various adsorbents.

The objective of this study is to characterize the Biosorbent (Atriplex Halimus leaves) and its application in the removal by adsorption of anionic and cationic dyes known for their toxicity such as Bemacid Blue (BB), Bemacid Red (BR), and Methylene Blue (MB) contained in water. The Atriplex Halimus was characterized by Boehm's method, FT-IR, XPS, SEM, pH Zero Charge Point (pHZPC), iodine value, and Methylene Blue value. The tests carried out in this experiment showed that the Biosorbent can remove Bemacid Blue (BB), Bemacid Red (BR), and Methylene Blue (MB). The effect of several parameters such as pH of the solution, biomass dose, contact time, initial concentration of dye used, and the temperature was studied in a batch system. The adsorbate-adsorbent equilibrium times are reached after 60 min for MB and 90 min for BB and BR. The adsorption is maximal for an adsorbent dose of 8 g/L for the three dyes. The best retentions were observed at pH 11, 6.45, and 5.12 for MB, BB, and BR respectively. The maximum adsorption capacities are 289.8, 29.7, and 32.9 mg/g for Methylene Blue (MB), Bemacid Blue (BB), and Bemacid Red (BR) respectively. Modeling of the experimental data showed that the Langmuir and pseudo-second-order models describe, respectively, the adsorption isotherms and the kinetics in a satisfactory way. The study of the thermodynamic aspects showed that the adsorption of the three dyes by the leaf biomass of Atriplex Halimus is a favorable, exothermic, and spontaneous phenomenon.

In this study, eco-friendly composite material polyacrylamide/cellulose hydrogel reinforced with fuller’s earth (PAAm/CG/FE), has been synthesized and used for the effective adsorption of the Methylene Blue (MB) dye. The synthesis of PAA/CG/FE composite followed the free radical polymerization method. Chemical compositions and morphology of the synthesized composite have been characterized by Fourier Transform InfraRed (FT-IR) Spectroscopy and Scanning Electron Microscope (SEM). Thermal stability has been determined by TGA analysis. Batch adsorption experiments have been carried out by varying different parameters viz. contact time, pH of the solution, and temperature in order to determine the maximum dye adsorption capacity of the composite. Introducing cellulose and fuller earth into the polyacrylamide eventually enhanced the structural stability, thermal stability, and MB adsorption capacity. Based on the experimental data, adsorption kinetics has been found to be well correlated with the pseudo-second-order kinetic model. It has been found that the equilibrium adsorption isotherm data perfectly followed the Langmuir isotherm model and maximum adsorption capacities were found to be 48.30 and 56.17 mg/g for PAAm and PAAm/CG/FE composite, respectively. Furthermore, the prepared composite exhibits good reusability, and it is economic, eco-friendly, and nontoxic material.

this project, keggin-type polyoxometalate, cationic exchange Q5PMoV2O40 (denoted as TBA-PMoV) was synthesized to produce a recoverable catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Field Emission scanning electron microscopy (FESEM) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The synthesized catalyst showed high photocatalytic activity in the degradation of methylene blue as a pollutant under UV light irradiation. The effect of various factors such as catalyst amount, contact time and pH on degradation of methylene blue (denoted as MB) were investigated. Formal batch adsorption studies was applied for investigation of effects of various parameters, such as initial solution pH, initial dye concentration, catalyst amount, temperature, etc. Optimization results for 20 mg/L methylene blue showed that maximum degradation efficiency 96.8 % at the optimum conditions was found to be: catalyst amount 25 mg, pH= 7.6 and time 60 min at ambient pressure and temperature.

In this study, the Liquid-Liquid Extraction (LLE) method was used to demonstrate the extraction of Methylene Blue (MB) from aqueous solutions using 4.48 ´10(-1) mol/L Phenyl Propiolic acid benzene. The operating parameters like the changes brought by varying pH (liquefied solution pH), diluents, the concentration of extractant, and stripping reagents were evaluated with fixed reaction conditions. A maximum recovery of MB was obtained at pH 7±0.1. Similarly, the maximum stripping efficiency of MB was achieved by the use of 1 N H2SO4. The optimized parameter obtained for the recovery of MB from the LLE process was implemented in the Bbulk Liquid Membrane (BLM) technique. The separation and procurement of MB were performed in a single step is called the protraction process. The role of pH in the aqueous donor phase, the effect of phenyl propiolic acid concentration in the membrane phase, and the effect of stripping reagents concentration were evaluated in detail to understand the transport mechanism of MB from the aqueous phase to interface and interface to stripping solution.

The adsorption capacity of activated carbon powder prepared from Ananas comosus peels for the removal of methylene blue dye as a contaminant was investigated. These adsorbents were prepared by carbonization at 500 oC with activating agents (K2CO3, H3PO4 and NaOH) and characterized using Fourier Transform Infrared. Plackett-Burman Design was used to analyze the various factors affecting adsorption. Response surface methodology techniques was employed to determine the optimal condition of pH=12.6569 and adsorbent dosage of 1.1864. At the optimal condition, the activated carbon yielded the highest removal of methylene blue (99.4 %). The experimental data best fitted the pseudo-second order kinetic model, except for acid activation (ACP-A) which agreed with inter-particle diffusion model with the determination coefficient of 0.9939. The adsorption isotherms for all the prepared carbons were highly consistent with Langmuir adsorption isotherm. This study demonstrates that the activated carbon prepared from Ananas comosus peels can be efficient in removing methylene blue dye contaminants from aqueous solution.