Adsorption of methylene blue

A differentiation in the activities of surfaces may likewise be witnessed in a variety of chemical and catalytic processes. Thus we find that charcoal will undergo slow autoxidation when exposed to air it will also cataljrtically accelerate the oxidation of a number of organic subtances such as oxalic acid. By processes of selective poisoning of the charcoal it can be demonstrated quite readily that the portion of the surface which can accelerate the oxidation of, oxalic acid is but a small portion of the surface which is available for say the adsorption of methylene blue and that but a minute fraction of the surface (less than 0 5 % foi a good sugar charcoal) is capable of undergoing autoxidation. 

Table 1 shows the properties of smectite-type materials prepared. Smectite materials prepared at lower pH had fewer sodium ions, higher surface areas, and larger pore volumes for a series of samples containing the same divalent cation species (nickel and cobalt) in the octahedral sheet. The adsorption of methylene blue on all the synthetic smectites shows that the smectite fragments are negatively charged. The Si M ratios of synthetic smectites were about 8 6, indicating that most of divalent cations exist in octahedral layers and small amount of divalent cations would exist as hydroxide or oxide cluster in smectite materials. However, the amounts of the hydroxide or oxide cluster were small, because only smectite structures were observed in XRD patterns and EXAFS Fourier transforms of synthetic smectites calcined at 873 K. 

Here the rate of reaction, r, is expressed in units (mole C02)/m2 hr (specific surface area of carbon being measured by adsorption of methylene blue) pressures are in atmospheres. 

Fig. 3 B. Adsorption of methylene blue at different pH values as dependent on the heating temperature of pholerite.

Selective and efficient adsorption of anthraquinone blue (Acid Blue 25) in the presence of methylene blue on H2N-MCM-41, and, inversely, selective adsorption of methylene blue in the presence of anthraquinone blue with carboxyl-functionalized phases.112... 

ADSORPTION OF METHYLENE BLUE FROM WATER ONTO ACTIVATED CARBON PREPARED FROM COIR PITH,... 

The adsorption of methylene blue by coir pith carbon was carried out by varying the parameters such as agitation time, dye concentration, adsorbent dose, pH and temperature. Equilibrium adsorption data obeyed Langmuir isotherm. Adsorption kinetics followed a second order rate kinetic model. The adsorption capacity was found to be 5.87 mg dye per g of the adsorbent. There was no significant change in the per cent removal with pH. The pH effect and desorption studies suggest that chemisorption might be the major mode of the adsorption process. 

Positive values of AH show the endothermic nature of adsorption. Similar results have been reported for the adsorption of methylene blue by clay [19].The negative values of AG indicate the spontaneous nature of adsorption for mefriylene blue at 35, 40, 50 and 60 C. The positive values of AS suggest the increased randomness at the solid /solution interface during the adsorption of dye on coir pith carbon. Equilibrium data at different temperatures for the adsorption of dye on coir pith carbon do not follow the first order kinetic model but follows the second order kinetic model. The second order rate constants were in the range 0.357-0.879g/mg/min. 

FIG. 20 Effect of pH on the adsorption of methylene blue by two carbon blacks. (Adapted from Ref. 514.)... 

Nechaev, E.A., Adsorption of methylene blue on oxides from aqueous solutions, Kolloid. Zh., 42, 371, 1980. 

Chang, H. et al.. Photodecomposition and surface adsorption of methylene blue on TiOj nanofluid prepared by ASNSS. Mater. Trans., 45, 3334, 2004. 

Fetterolf, M.L., Patel, H.V., and Jennings, J.M., Adsorption of methylene blue and acid blue 40 on titania from aqueous solution, J. Chem. Eng. Data, 48, 831, 2003. 

In this section we shall briefly review three different cases taken from our recent work the adsorption of trichloroethene by clay minerals, the adsorption of methylene blue by clay minerals, and studies dealing with the alkyl ammonium ion method for layer charge determination. 

The methods described above for the study of TCE are representative of the methods we are currently using to study the adsorption of a variety of organic molecules by clay mineral surfaces. We shall briefly summarize the results obtained so far in two other cases, one dealing with the adsorption of methylene blue to clays and the other dealing with a recalibration of the alkyl ammonium ion method for surface charge determination. In both of these studies, essentially the same computational techniques as those described above were used. 

De, D.K., J.L. das Kanugo, and S.K. Chakravarty. 1974, Adsorption of methylene blue, crystal violet and malachite green on bentonite, vermiculite, kaolinite, asbestos, and feldspar. Ind. J. Chem. 12 1187-1189. 

The adsorption of Methylene Blue has been thoroughly studied. This dye, when dissolved in water, undergoes hydrolysis ... 

The influence of a salt on adsorption is reported to be specific in some instances. Kruyt27 found considerable specificity in the influence of the anion. The adsorption of Methylene Blue was promoted by anions in the order Cl, S04, P04 Br, N03 whereas for Crystal Violet, the order was P04, S04, Cl, Br, N03 and for auramine, Cl, S04, Br, N03, P04. Kozakevich28 found Br ions more effective than Cl ions for promoting adsorption of benzoic... 

Matthews, R. W., 1989, Photocatalytic oxidation and adsorption of methylene blue on thin films of near-ultraviolet-illuminated Ti02- J. Chem. Soc., Faraday Trans. 1, 85(6) 1291-1302. 

Rafatullah, M., Sulaiman, 0., Hashim, R., and Ahmad, A. (2010). Adsorption of methylene blue on low-cost adsorbents A review, Hazard. Mater. 177, 70-80. 

Single measurements of methylene blue adsorption on pulp fibers gave different results, probably as a result of non-specific binding. The conditions of the assay (volume, sample amount, and use of new glassware and plastic ware) were adjusted so that the adsorption of methylene blue to a pulp sample could be determined reproducibly. The final form of the assay is described m Methds and uses at least three different samples of pulp, all of which adsorb le than half the methylene blue in the assay. The adsorption of methylene blue was determined from the slope of methylene blue adsorbed as a function of weight of the pulp (Figure 1). 

The MnP treatment did not increase the binding of methylene blue above that of the controls. The laccase together with 4-hydroxyphenylacetic acid did increase the adsorption of methylene blue. Both the MnP treatment and laccase treatment together with 4-hydroxyphenylacetic acid increased handsheet strength. Methylene blue adsorption does not appear to correlate with handsheet strength. 

J. He, S. Hong, L. Zhang, E Gan, Y.-S. Ho, Equilibrium and thermodynamic parameters of adsorption of methylene blue onto rectorite. Fresenius Environ Bull 2010,19,2651-2656. 

Table 9.4 Adsorption of methylene blue and metanil yellow on carbon fibers...

ADSORPTION OF METHYLENE BLUE ON PVC-DOP-NATURAL ZEOLITE COMPOSITES... 

ABSTRACT. Rates of methylene blue adsorption from 0.02 gdm aquous solution on composites prepared from 100 phr PVC, 60 phr DOP, 0-40 phr natural zeolite (clinoptillolite) were studied. The adsorption of methylene blue was negligible for composites having no zeolite additive, whereas extensive adsorption was observed for composites having 5-40 phr zeolite. 

Microporous materials from PVC are used as battery seperators, filters, supports for enzymatic catalyts, breathable liners and paper substitutes. While the mechanical properties of PVC composites were studied extensively little work exists on adsorptive properties(2,3). Thus adsorption of methylene blue from aquous solutions was chosen to be studied as the representative of adsorptive properties in this work. 

The degree of fusion of the plastisol and the extent of wetting of the zeolite particles by the plastic matrix affects the rate of diffusion and extent of adsorption of methylene blue whic are preferentially adsorbed on zeolites. Experimental work indicated that addition of zeolites to PVC plastisols created an interface accessible to aquous solutions. 

Aznar AJ, Casal B, Ruiz-Hitzky E, Lopez-Arbeloa I, Lopez-Arbeloa F, Santaren J, Alvarez A (1992) Adsorption of methylene-blue on sepiolite gels - spectroscopic and rheological studies. Clay Miner 27 101-108... 

Adsorption of Methylene Blue and Metanil Yellow in Relation to Surface Area and Surface Acidity... 

FIGURE 3.5 Influence of surface oxidation on the adsorption of methylene blue on ACF-307. (After Goyal, M., Ph.D. dissertation. Panjab Univ., Chandigarh, India, 1997. With... 

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