جستجوی مقالات مرتبط با کلیدواژه "methylene blue" در نشریات گروه "شیمی"

CuS/ZrS2 nanocomposites were prepared by precipitation method. A number of techniques for nanoparticle characterization were used, including X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV-Vis, and FTIR techniques. The characterization revealed the presence of CuS /ZrS2 composite. The field emission scanning electron microscopy (FESEM) and the manufactured product was examined CuS/ZrS2 -30, CuS/ZrS2-90 particle sizes have been found 27.64 nm and 24.96 nm, respectively. The XRD patterns of CuS/ZrS2 nanocomposite, it was discovered that ZrS2/CuS-30, CuS/ZrS2-90 nanoparticles had a pattern of 8.92 nm and 10.04 nm, respectively. The band gap energy value for the nanoparticles was estimated to be (1.7 eV and 2.1 eV). Finally, the removal of methylene blue by CuS/ZrS2 nanocomposite from aqueous solution was investigated in the present study. The adsorption kinetics was examined using pseudo-first-order, pseudo-second-order and intra-particle diffusion model. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherm models. The results revealed that the pseudo-second-order model and Langmuir isotherm fit the kinetics and equilibrium data, respectively. In addition, various thermodynamic parameters, such as change in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS), were also calculated. The thermodynamic analysis showed that the adsorption of MB was spontaneous and exothermic.

Herein, we report visible light active, efficient, simple, bi-phasic photocatalyst composed ofanatase-brookite mixed phase, crystalline TiO2nanoparticles synthesized through a simple sol-gelapproach. The physicochemical characteristics of the nanoparticles were established throughcharacterization tools such as XRD, FESEM, EDS, TEM, DRS, FT-IR, XPS, Raman, PL, andTGA. Visible light-driven degradation of methylene blue (MB) dye was observed, which wasconfirmed through the improvement in the rate constant compared to that in UV exposure. Thiscan be attributed to the prolonged charge separation resulting from the anatase-brookite junctioneffect. The free radicals generated (superoxide anions and hydroxyl radicals) after the incidence oflight are responsible for the photocatalytic degradation of the MB, whose influence was validatedthrough the scavenger method. The generation of degradation intermediates were verified throughLC-MS-MS analysis. The nanoparticles showed maximum photocatalytic performance in the basicpH conditions. The recyclability of the photocatalyst was also established. The enhanced activityresulting from the combined effect of anatase-brookite phases of TiO2in the nanoformulationwill enable its potential use as a vital, visible light active, eco-friendly bi-phasic photo catalystoffering low-cost environment remediation in a short period of time using the minimum quantityof photocatalyst.

This study utilized Semecarpus Anacardium (SA) and Quercus Infectoria (QI) nutshells as raw materials to manufacture Activated Carbon (AC) which is both inexpensive and possesses a large surface area. All materials were examined using Fourier Transform InfraRed (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM/EDX), X-Ray powder Diffraction (XRD), and Brunauer, Emmett, and Teller (BET) surface area methods. The effective synthesis of AC was validated by surface functional groups in FT-IR spectra and XRD diffractograms, which showed a broad peak in the region of 2θ=15-28° and a faint and wide peak in the range of 2θ=40-48°. The BET results indicated that the AC synthesized from SA and activated with KOH (ACSAK) had the greatest surface area (717 m2/g), the most enormous pore volume (0.286 cm3/g), and mean pore diameters (<2nm). The synthesized AC in this research can be classified into micro-pore adsorbents entirely. Finally, the resulting ACSAK was applied to Methylene Blue (MB) adsorption. Adsorption studies demonstrate that the Langmuir isotherm (R2=0.996) matches somewhat more accurately than the Freundlich and Temkin isotherms. Our adsorption kinetics findings show that the pseudo-second-order model has the maximum fitness and accuracy on MB adsorption data in AC (R2 = 0.999).

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.

A novel metal–organic framework (MOF), with the formula [Cu(II)L]n (L= 4, 4′-diamino diphenyl sulfone), has been synthesized conventionally and hydrothermally methods and characterized by FT-IR, PXRD, EDX, and SEM techniques. The results MOFs were applied for photodegradation of Methylene Blue (MB). The influence of affecting variables, such as initial MB dye concentration (2–8mg L−1), Cu(II)-MOF mass (0.01–0.03 mg), pH (3.0–9.0), and time of irradiation (30–90 min). The photocatalytic degradation efficiency was investigated by the central composite design (CCD) methodology. The results of CCD analysis for optimum values of variables revealed that Cu(II)-MOF mass was 0.025g, the initial concentration of MB was 3.51 mg L−1, pH was 4.50 and irradiation time was 75 min.Under the optimum conditions, the photocatalytic MB degradation percentage at the desirability function value of 1.0 was found to be 70%. In addition, the obtained R2 value of 0.97 in the regression analysis showed a high photocatalytic efficiency of the proposed method for MB degradation.

The adsorption of methylene blue dye on modified mesoporous silica based on palm oil boiler ash (MS-POBA) as an adsorbent with a methyl ester sulfonate (MES) was investigated. MS-POBA and MES as a template improved the adsorption capacity of methylene blue by increasing the pore size of boiler ash silica. The characteristics of the material were determined using FTIR, XRD, BET, and SEM-EDX analyzers. The adsorption of methylene blue on the MS-POBA adsorbent was determined using a UV-Vis spectrophotometer. The MES as a template pasted to MS-POBA, could be increased surface area, pore diameter, and volume. In optimized conditions, pH, the adsorbent mass, the adsorption time, the methylene blue concentration, the adsorption capacity, and recovery were obtained at 7.0, 0.03 g, 45 minutes, 20 mg L–1, 15.578 mg g–1, and 96.9%, respectively. The adsorption of methylene blue on boiler ash silica with an MES template follows the pseudo-second-order kinetic model with a value of R2 = 0.999 and Langmuir isotherm adsorption model.

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.

Organic dyes such as methylene blue (MB) are known as important water and environment pollutants. Several techniques have been employed for removing this dye from contaminated aqueous solutions. In this study, polymer inclusion membranes composed of polyvinyl chloride (PVC) and bis(2-ethylhexyl)phosphoric acid (DEHPA), respectively as the base polymer and extractant, without requiring to additional plasticizing reagent are prepared and assessed for the removal of methylene blue from aqueous solutions. The membrane with a composition of 50 wt.% of PVC and 50 wt.% of DEHPA is found to be flexible, physically stable. This PIM shows the best performance for the MB elimination from the solutions. Various techniques including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy SEM), atomic force microscopy (AFM), contact angle measurements, thermogravimetric analysis (TGA), and stress-strain analysis are employed for characterizing the optimized PIM. The parameters affecting the removal of MB from the solutions are optimized. It is found that a circular disc PIM with 3.5 cm diameter, an average mass of 0.0890±0.0046 g, with a thickness of 72.0±0.8 m removes quantitatively MB from 50 mL aqueous solution adjusted to pH 3, after 120 min orbital shaking. The PIM is stable for 6 times consecutive cycles. The kinetics of process is obeyed pseudo second-order model, while the Langmuir model interpret well the isotherm of the MB removal.

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.