Pattern Formation in the Methylene Blue-Fructose-Oxygen System in Aqueous Solution and in Gel Systems

2000 ◽  
Vol 65 (9) ◽  
pp. 1394-1402 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Mária Hupková ◽  
Peter Ševčík

Spatial patterns in methylene blue-catalyzed oxidation of fructose at alkaline pH were found in aqueous solution and in gel systems. In a thin liquid layer (thickness >2.4 mm) a mixture of spots and stripes was formed by interaction of a nonlinear reaction and the Rayleigh or Maragoni instabilities. The pattern formation was affected by initial reactant concentrations and by the thickness of the reaction mixture layer. Long-lasting structures were formed in gel systems (polyacrylamide, agar, gelatin). These patterns also arise primarily from hydrodynamic processes.

2013 ◽  
Vol 12 (24) ◽  
pp. 34-41
Author(s):  
Caroline CASTANHETTI ◽  
Ana Paula FIGUEIREDO ◽  
Lucas DOMINGUINI

This study examined the potential for adsorption of methylene blue, in solution of 50 mg.L-1, by banana fiber spray, to 2 g/L of solution. We carried out variations in temperature and pH of the solution. The results indicate that it is possible to use the banana fiber as adsorbent methylene blue in ambient temperature and alkaline pH values with high efficiency. The FT-IR spectrum showed the presence of carboxylic acid and hydroxyl groups on the fiber. Such groups are capable of forming hydrogen bonds with methylene blue and removing it from the aqueous solution. It was concluded that for the conditions tested, the best temperature for adsorption was 25 °C and pH to better efficiency of better temperature was 11.


Author(s):  
Saraa Muwafaq Ibrahim ◽  
Ziad T. Abd Ali

Batch experiments have been studied to remove methylene blue dye (MB) from aqueous solution using modified bentonite. The modified bentonite was synthesized by replacing exchangeable calcium cations in natural bentonite with cationic surfactant cetyl trimethyl ammonium bromide (CTAB). The characteristics of modified bentonite were studied using different analysis such as Scanning electronic microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and surface area. Where SEM shows the natural bentonite has a porous structure, a rough and uneven appearance with scattered and different block structure sizes, while the modified bentonite surface morphology was smooth and supplemented by a limited number of holes. On other hand, (FTIR) analysis that proved NH group aliphatic and aromatic group of MB and silanol group are responsible for the sorption of contaminate. The organic matter peaks at 2848 and 2930 cm-1 in the spectra of modified bentonite which are sharper than those of the natural bentonite were assigned to the CH2 scissor vibration band and the symmetrical CH3 stretching absorption band, respectively, also the 2930 cm-1 peak is assigned to CH stretching band. The batch study was provided the maximum removal efficiency (99.99 % MB) with a sorption capacity of 129.87 mg/g at specified conditions (100 mg/L, 25℃, pH 11 and 250rpm). The sorption isotherm data fitted well with the Freundlich isotherm model. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.


Author(s):  
Arun Kumar Sharma ◽  
Pradeep Parasher ◽  
Rashmi Sharma ◽  
Davarakonda S.N. Prasad

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 208
Author(s):  
Ramona B. J. Ihlenburg ◽  
Anne-Catherine Lehnen ◽  
Joachim Koetz ◽  
Andreas Taubert

New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N’,N’-tetramethyl-N,N’-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further.


2021 ◽  
pp. 50655
Author(s):  
Aafia Tehrim ◽  
Min Dai ◽  
Xiange Wu ◽  
Malik Muhammad Umair ◽  
Imran Ali ◽  
...  

2021 ◽  
Vol 232 (6) ◽  
Author(s):  
Shoomaila Latif ◽  
Shamaila Iram ◽  
Muhammad Imran ◽  
Farah Kanwal ◽  
Zafar Iqbal ◽  
...  

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