Chemisorption of methylene blue by kaolinite

AbstractThe chemisorption of methylene blue by kaolinite crystals increased as the aqueous suspensions changed from acid to alkaline because, at high pH values, not only the basal pinacoids but the edge-faces were negatively charged. The inability to calculate acceptable specific surfaces or cation exchange capacities from the chemisorption data is discussed, with special reference to the orientation of adsorbed dye cations, the covering of more than one exchange site by a monomer or polymer, the different concentrations of exchange sites on the basal pinacoids and edge-faces respectively, the possibility that such sites occur on the tetrahedral rather than on the octahedral basal pinacoid, and the incomplete replacement of inorganic cations.

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Uranium(VI) adsorption on surfactant modified heulandite/clinoptilolite rich tuff

Journal of the Serbian Chemical Society ◽

10.2298/jsc0612323m ◽

2006 ◽

Vol 71 (12) ◽

pp. 1323-1331 ◽

Cited By ~ 21

Author(s):

Srdjan Matijasevic ◽

Aleksandra Dakovic ◽

Magdalena Tomasevic-Canovic ◽

Mirjana Stojanovic ◽

Deana Iles

Keyword(s):

Ion Exchange ◽

Cation Exchange ◽

Adsorption Isotherms ◽

Cation Exchange Capacity ◽

Exchange Capacity ◽

Zeolitic Tuff ◽

Zeolite Surface ◽

Inorganic Cations ◽

Maximal Amount ◽

Ph Values

The adsorption of uranium(VI) on heulandite/clinoptilolite rich zeolitic tuff modified with different amounts (2, 5 and 10 meq/100 g) of hexadecyltrimethyl ammonium (HDTMA) ion was investigated. The organozeolites were prepared by ion exchange of inorganic cations at the zeolite surface with HDTMA ions, and the three prepared samples were denoted as OA-2, OA-5 and OA-10. The maximal amount of HDTMAin the organozeolite OA-10 (10 meq/100 g) was equal to the external cation exchange capacity of the starting material. The results showed that uranium( VI) adsorption on unmodified zeolitic tuff was low (0.34 mg uranium(VI)/g adsorbent), while for the organozeolites, the adsorption increased with increasing amount of HDTMA at the zeolitic surface. The highest adsorption indexes were achieved for the organozeolite OA-10, in which all the surface inorganic cations had been replaced with HDTMA. An investigation of the adsorption of uranium(VI) ions onto organozeolite OA-10 at different pH values (3, 6 and 8) showed that the adsorption index increased with increasing amount of adsorbent in the suspension. Since uranium(VI) speciation is highly dependent on pH, from the adsorption isotherms, it can be seen that uranium(VI) adsorption on organozeolite OA-10 at pH 6 and 8 is well described by a Langmuir type of isotherm, while at pH 3, it corresponds to a Type III isotherm. .

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Impact of climate and bulking materials on characteristics of compost from ecological toilets

Journal of Water Sanitation and Hygiene for Development ◽

10.2166/washdev.2012.059 ◽

2012 ◽

Vol 2 (2) ◽

pp. 79-86 ◽

Cited By ~ 3

Author(s):

James W. McKinley ◽

Rebecca E. Parzen ◽

Álvaro Mercado Guzmán

Keyword(s):

Low Carbon ◽

Pathogen Inactivation ◽

High Ph ◽

Moisture Contents ◽

Urine Diversion ◽

Ph Values ◽

Dominant Process ◽

Nitrogen Ratio ◽

Storage Times ◽

Carbon Concentrations

Urine-diversion dehydration toilets (UDDT) are common throughout the developing world, and the toilet product is widely used as compost. There is no comprehensive research to date that characterizes the compost to determine its quality, extent of pathogen inactivation, and the effects of climate and bulking materials on the compost. Compost was collected from 45 UDDT in Bolivia and analyzed for physical, chemical, and biological parameters. Eighty percent and 56% of samples did not meet acceptable compost guidelines for moisture content and pH, respectively, indicating desiccation was the dominant process in UDDT. Bulking materials significantly impacted compost characteristics in terms of pH, carbon, carbon-to-nitrogen ratio, and carbon stability (P < 0.05). Composts with ash exhibited, on average, low carbon concentrations (4.9%) and high pH values (9.7), which can be harmful to plants and composting microorganisms. Composts with sawdust exhibited, on average, high carbon concentrations (40.0%) and carbon-to-nitrogen ratios (31.0). Climate had no significant impact on chemical characteristics, however composts from humid regions had significantly higher moisture contents (34.4%) than those from arid climates (24.8%) (P < 0.05). Viable Ascaris lumbricoides ova were identified in 31% of samples, including samples with high pH, low moisture contents, and long storage times.

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Effects of pH and ionic strength on the cation exchange capacity of soils with variable charge

Soil Research ◽

10.1071/sr9810093 ◽

1981 ◽

Vol 19 (1) ◽

pp. 93 ◽

Cited By ~ 30

Author(s):

GP Gillman

Keyword(s):

Ionic Strength ◽

Cation Exchange ◽

Cation Exchange Capacity ◽

Exchange Capacity ◽

Surface Soils ◽

Ph Values ◽

Variable Charge ◽

Effects Of Ph ◽

Variable Charge Soils

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.

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Effects of Surface Properties and Solvent PH Values on the Adsorption/Desorption Abilities of Mesoporous SBA-15 to Methylene Blue Molecules

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.352 ◽

2012 ◽

Vol 518-523 ◽

pp. 352-355

Author(s):

Hui Liu ◽

Hong Liang Li ◽

Meng Xue Wang ◽

Jing Jing Sang ◽

Xiu Song Zhao

Keyword(s):

Aqueous Solution ◽

Methylene Blue ◽

Pore Size Distribution ◽

Pore Size ◽

Surface Properties ◽

Weak Base ◽

Adsorption Ability ◽

Ph Values ◽

Model Molecule ◽

Adsorption Desorption

Methylene blue (MB) was used as model molecule to investigate the effects of surface properties and solvent pH values on the adsorption and desorption (or release) behaviors of mesoporous SBA-15 materials. It was found that the treatment of SBA-15 with a pH 7.8 aqueous solution can enhance the adsorption rate and capacity in comparison with the pristine SBA-15. The effect of pH values on MB releasing from the weak base treated SBA-15 and the pristine one have been studied and been compared in pH values range from 0.5 to 7.0. Both of them showed a maximum releasing rate at about pH 2 and all of the treated SBA-15 samples showed a higher releasing quantity than the pristine ones. The influence mechanisms of base treatment on the adsorption ability and that of pH values on the releasing properties of SBA-15 samples have been analyzed and been discussed based on the composition, the morphology, the surface area and pore size distribution and adsorption/desorption measurements.

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Simultaneous adsorptive removal of methylene blue and copper ions from aqueous solution by ferrocene-modified cation exchange resin

Journal of Applied Polymer Science ◽

10.1002/app.41029 ◽

2014 ◽

Vol 131 (21) ◽

Cited By ~ 231

Author(s):

Qian Wang ◽

Dehua Zhang ◽

Senlin Tian ◽

Ping Ning

Keyword(s):

Aqueous Solution ◽

Methylene Blue ◽

Cation Exchange ◽

Exchange Resin ◽

Copper Ions ◽

Cation Exchange Resin ◽

Adsorptive Removal

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Study of photocatalytic activity of TiO2 fluorinated by thermal shock method for the degradation of different dyes

Science and Technology Development Journal ◽

10.32508/stdj.v18i2.1173 ◽

2015 ◽

Vol 18 (2) ◽

pp. 121-131

Author(s):

Khoa Tien Le ◽

Ngoc Chau Hoang ◽

Tien Thuy Thai ◽

Anh Trung Le ◽

Thinh Nguyen Huu Pham ◽

...

Keyword(s):

Methylene Blue ◽

Photocatalytic Activity ◽

Methyl Orange ◽

Thermal Shock ◽

Photocatalytic Oxidation ◽

Organic Dyes ◽

Cationic Dye ◽

Solution Ph ◽

Ph Values ◽

Methylene Blue Cationic Dye

TiO2 P25 was fluorinated by thermal shock method in order to study the influence of thermal shock fluorination on the surface properties and the photocatalytic activity for the degradation of cationic and anionic organic dyes at different pH values. The surface charge of catalysts was characterized by the pHPZC measurement. The photocatalytic activity of catalysts was evaluated via the degradation of methylene blue (cationic dye) and methyl orange (anionic dye). The results showed that the thermal shock fluorination and the rise of solution pH can increase the surface negative charge of TiO2, which enhanced the adsorption of methylene blue and then improved the photocatalytic degradation of this cationic dye under UV and visible light. On the other hand, after the fluorination, the adsorption of methyl orange on TiO2 was strongly reduced, which limited the photocatalytic oxidation of this anion dye.

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Visible absorption spectroscopy study of the adsorption of Congo Red by montmorillonite

Clay Minerals ◽

10.1180/0009855033840110 ◽

2003 ◽

Vol 38 (4) ◽

pp. 483-500 ◽

Cited By ~ 35

Author(s):

Z. Yermiyahu ◽

I . Lapides ◽

S. Yariv

Keyword(s):

Congo Red ◽

Surface Acidity ◽

Electronic Spectroscopy ◽

Visible Absorption ◽

Ph Values ◽

Aqueous Suspensions ◽

Metallic Cation ◽

Dark Violet ◽

Effects Of Aging ◽

Dark Blue

AbstractThe adsorption of the anionic dye Congo Red (CR) by Na-, Cs-, Mg-, Cu-, Al- and Fe-montmorillonite was investigated by electronic spectroscopy. Spectra of the aqueous suspensions of different clay concentrations and different loadings were recorded. The spectra were curve fitted and were compared to spectra of aqueous solutions of CR at different pH values. Four bands representing anionic varieties and two representing protonated varieties of CR were identified in spectra of CR-treated Na-, Cs-, Mg-, Cu- and Al-montmorillonite. Spectra of CR-treated Femontmorillonite were slightly different, showing three bands representing anionic varieties and four representing protonated CR. The ratio between areas of bands, which represent the protonated varieties, and those representing the anionic varieties were determined showing correlation with the acidity of the metallic cation. The clay in the aqueous suspensions became coloured after the adsorption of CR. The following stainings were obtained, Na- and Mg-clay, red, Cs-clay, violet-red, Cu-clay, reddish-violet, Al-clay, dark violet and Fe-clay, dark blue. It appears that CR can serve as an indicator of the surface acidity of montmorillonite. The effects of aging on the sorption of the dye and on the surface-acidity of the CR-clay complex were investigated.

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