Adsorption Of Cationic Methylene Blue Dye Research Articles

Physicochemical Characterization of Clay and Study of Cationic Methylene Blue Dye Adsorption.

In an attempt to examine novel adsorbents in accessing an ideal adsorption system, this study aimed to help understand the main and secondary characteristics of a Moroccan natural clay. X-ray fluorescence, infrared, and scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis (SEM-EDX) were used for the identification. The findings demonstrate that this Clay is composed of a mixture of quartz, calcite, magnetite, and Rutile in very high proportions. SEM revealed the presence of clay grains in the presence of fine particles and irregularly contoured sticks. The results of semiquantitative detection by EDX also reveal the presence of certain mineral species (Si, Al, Mg, Fe, K, Cl, S, Ca, and Na). The exploited kinetic technique was achieved using two different kinetic models: first- and second-order rate laws. Commensurate to the obtained results, the 2-sec order model better described the adsorption of dye MB onto the natural clay. The results confirmed that the adsorption process followed the Langmuir model with the high coefficient correlation obtained which are very close to 1. In the sequel, DFT results revealed that the HOMO and LUMO surfaces of the methylene blue dye are mostly distributed on all dye parts, reflecting possible strong interactions with the clay. The quantum descriptors investigated in this study identify the most nucleophilic and electrophilic centers that can be used to suggest a suitable mechanism for the adsorption of the dye by the clay. The values of enthalpy ΔH0 and entropy ΔS0 of activation were -15.88 kJ mol-1 and -0.021 J mol-1 K-1, respectively, show that the nature of the adsorption process of MB on clay is exothermic and the order of distribution of the dye molecules on the adsorbent increases with respect to that of the solution so the negative values of ΔG0 (from -9. 62 to -8.99 kJ mol-1) indicate that the adsorption process is spontaneous.

Adsorption of methylene blue dye onto modified activated carbon produced from groundnut shells

In this research work, groundnut shells agricultural byproducts were utilized for the production of modified groundnut shell based activated carbon (MGSAC) through the use of phosphoric acid and ethylene-diamine tetraacetic acid disodium salt (Na2EDTA) as an activating agent and a modifier, respectively. A three factor, two-level full factorial design (FFD) was employed for the exploratory design of experiments (DoE). The independent process variables are temperature, activation time, and activating agent concentration for the production of MGSAC in a muffle furnace. The product yield and methylene blue (MB) dye adsorption were considered as the performance indicators for the process. Regression analysis was conducted to examine the influence of process variables on the responses of the process parameters. From the analysis, it was found that the activation temperature has the most significant effects on the MGSAC product yield and the activation time for the adsorption of MB dye. The results obtained showed that the best operating conditions for production of MGSAC were carbonization temperature of 450°C, activation time of 30 min and activating agent concentration of (35 mmol Na2EDTA; 50% H3PO4) which resulted in the product yield of 55.5% MGSAC, and 99.6% MB dye adsorption. It was also observed that experimental values obtained were in good agreement with the values predicted by the model. Hence, the two-level FFD DoE technique demonstrated worthwhile features in disclosing the dominant factors that affect the production of modified groundnut shell based activated carbon. The products appear to be promising adsorbents for the adsorption of cationic MB dye from wastewaters.

Structural analysis and dye removal behavior of amorphous titania embedded poly(vinyl butyral) hybrid fiber.

This study reports on the efficient methylene blue (MB) dye removal properties of a polyvinyl butyral (PVB)–amorphous titania (amTiO2) hybrid fiber (PVB–amTiO2F) made by air-gap spinning in acetone solvent. The successful fabrication of PVB–amTiO2F was confirmed by employing Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and energy dispersive X-ray measurement. Batch experiments were used to examine the cationic MB dye adsorption performance in the dark. The observed data showed that the developed PVB–amTiO2F exhibited moderate adsorption efficiency (68–70%) which is comparable to other amorphous titania-rich adsorbents. The adsorption kinetics was well fitted with a pseudo-second-order model, suggesting that adsorption is mainly led by chemisorption. In addition, the MB degradation properties under visible light were also studied afterwards. A possible adsorption mechanism is discussed. Moreover, the as-fabricated fiber exhibited average to good reusability after 6 cycles. Only cationic MB dye solution was able to demonstrate such properties.

Improved removal of methylene blue on modified hierarchical zeolite Y: Achieved by a “destructive-constructive” method

Abstract In this study removal of methylene blue (MB) from an aqueous solution by zeolite (NaY) and related modified hierarchical zeolite (MY) has been investigated. The NaY zeolite with a low ratio of Si/Al was synthesized from silica extracted rice husk ash. It was transformed to hierarchical zeolite (MY) by a “destructive-constructive” modification method using tetramethyl ammonium hydroxide (TMAOH) and a cationic surfactant (Cetyltrime-thylammonium bromide, CTAB) as a templating agent. Various characterization method like FT-IR, XRF, XRD, BET, TGA, SEM and BJH confirmed the construction of parent zeolite and also successfulness of the modification process. EDX showed a negligible change of Si/Al ratio during modification which is favorite in adsorption of cationic MB dye. In order to study the interaction between the surface of adsorbent and adsorbate, six common isotherms were used. By Langmuir isotherm, it is clarified that, the maximum adsorption capacity (qm) had improvement from 15.2 mg g-1 to 133.1 mg g-1 for NaY and MY, respectively. The kinetic studies showed that the adsorption obeys the Pseudo-second order model for both NaY and MY zeolites. Also, the usage frequency of the MY was investigated. Results showed that there was not any noticeable change in performance of adsorption after four circles.

Synthesis of magnetic oxidized multiwalled carbon nanotube-κ-carrageenan-Fe3O4 nanocomposite adsorbent and its application in cationic Methylene Blue dye adsorption

In this study, magnetic oxidized multiwalled carbon nanotube (OMWCNT)-Fe3O4 and OMWCNT-κ-carrageenan-Fe3O4 nanocomposites were synthesized and used as adsorbent for the removal of Methylene Blue (MB) from aqueous solution. Magnetic nanocomposites were characterized by using of specific surface area, Fourier transform infrared, X-ray diffraction, vibrating sample magnetometry, thermal gravimetric analysis, scanning electron microscope and transmission electron microscope measurements. The results of characterization analyses exhibited that OMWCNT was successfully modified with κ-carrageenan. Furthermore, OMWCNT-Fe3O4 and OMWCNT-κ-carrageenan-Fe3O4 nanocomposites were of a super-paramagnetic property. Adsorption studies revealed that the data of adsorption kinetics and isotherm were well fitted by the pseudo second-order kinetic model and Langmuir isotherm model, respectively. The adsorption amounts of magnetic adsorbents increased with contact time and initial dye concentration. Compared with magnetic OMWCNT-Fe3O4 nanocomposite, magnetic OMWCNT-κ-carrageenan-Fe3O4 nanocomposite showed a better adsorption performance for the removal of MB from aqueous solution. Therefore, OMWCNT-κ-carrageenan-Fe3O4 nanocomposite may be used as a magnetic adsorbent to remove the cationic dyes from wastewaters.