57Fe Mössbauer, FT-IR and FE SEM investigation of the formation of hematite and goethite at high pH values

2007 ◽  
Vol 834-836 ◽  
pp. 141-149 ◽  
Author(s):  
Mark Žic ◽  
Mira Ristić ◽  
Svetozar Musić
Keyword(s):  
High Ph ◽  
57Fe Mössbauer ◽  
Ph Values ◽  
Ft Ir ◽  
Sem Investigation

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

2012 ◽  
Vol 2 (2) ◽  
pp. 79-86 ◽  
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.

Resistance of Spirulina platensis to Ammonia at High pH Values

1991 ◽  
Vol 32 (7) ◽  
pp. 953-958 ◽  
Author(s):  
Shimshon Belkin ◽  
Sammy Boussiba
Keyword(s):  
Spirulina Platensis ◽  
High Ph ◽  
Ph Values

Chemisorption of methylene blue by kaolinite

Clay Minerals ◽  
1967 ◽  
Vol 7 (1) ◽  
pp. 19-31 ◽  
Author(s):  
F. A. Faruqi ◽  
Susumu Okuda ◽  
W. O. Williamson
Keyword(s):  
Methylene Blue ◽  
Special Reference ◽  
Cation Exchange ◽  
High Ph ◽  
Inorganic Cations ◽  
Ph Values ◽  
Aqueous Suspensions ◽  
Exchange Site

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.

Synthesis of water-soluble conducting polypyrrole with transition-metal tetrasulfonated porphyrins

2010 ◽  
Vol 14 (02) ◽  
pp. 128-132 ◽  
Author(s):  
Mohammad Reza Nabid ◽  
Mitra Shamsianpour ◽  
Roya Sedghi ◽  
Samira Osati ◽  
Nasser Safari
Keyword(s):  
Transition Metal ◽  
Water Solubility ◽  
Water Soluble ◽  
Sulfonated Polystyrene ◽  
Salting Out ◽  
Electrically Conducting ◽  
Ph Values ◽  
Ft Ir ◽  
A Charge ◽  
Conducting Polypyrrole

A novel catalytic route for the synthesis of a water-soluble and electrically conducting polypyrrole (PPy) in the presence of sulfonated polystyrene (SPS) is presented. Anionic water-soluble transition-metal tetrasulfonated porphyrins (TSPP) were used to catalyze the polymerization. The reactions were carried out with different monomer, catalyst, template and initiator concentrations and the optimum conditions are reported. Also various pH values ranging from 1 to 4 were investigated. The absorbance of the polaron bands at different pH values demonstrates that pH 2 is the best condition for polymerization. Precipitation or "salting out" phenomenon was highly dependent on the mentioned factors. The formation of PPy was confirmed by UV-vis and FT-IR spectroscopy. Cyclic voltammetry (CV) showed that the synthesized polymer has convenient electroactivity. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility.

Bentonite Interaction with Saline High-pH Solutions

2012 ◽  
Vol 1475 ◽  
Author(s):  
Heikola Tiina ◽  
Vuorinen Ulla
Keyword(s):  
Cementitious Materials ◽  
Buffering Capacity ◽  
Ongoing Research ◽  
High Ph ◽  
Ph Values ◽  
Safety Function ◽  
Bentonite Buffer ◽  
Different Temperatures ◽  
Leaching Solution ◽  
In The Beginning

ABSTRACTDegradation of cementitious materials produces leachates of high pH. Such an alkaline plume, if reaching the bentonite buffer, is likely to induce mineralogical and chemical changes in bentonite over long times and may jeopardise the set safety function of the buffer.The objective of this ongoing research is to study the possible alterations of two bentonites, MX-80 and Deponit CA-N, in alkaline leachates at two different temperatures. Also the buffering capacity of the bentonites against high pH will be evaluated.The ongoing batch experiments are carried out in an anaerobic glove-box (Ar atmosphere, low CO2) at two temperatures (25/60 °C) with three types of simulated cement waters (pH 9.7/9,3, 11.3/10.2 and 12.0/10.9) at 25/0 °C) and one saline groundwater simulate (pH 8.3/7.9) as reference. The solid to liquid ratio used is 1/10. For each set of experiments there are three parallels so that bentonite alteration can be analysed after three different time periods. In the experiment each bentonite sample is leached with several batches of leaching solution. For each renewal of the leaching solution the phases are separated by centrifugation, the reacted solution withdrawn and the chemical composition analysed.The high-pH experiments (11.3 and 12.0, at 25°C) have continuously shown an initial decrease in the pH-values after each leachate renewal, albeit less dramatic than in the beginning, indicating remaining buffering capacity of the bentonites. The other two experiments (pH 8.3 and 9.7 at 25°C) have shown rather unaltered pH-values. In general, slightly lower pH-values were observed in the Deponit CA-N samples than in those of MX-80. The main cations (Na and Ca) analysed in the leachates have shown a rather expected trends as a result of ion-exchange occurring in the bentonites. The analysed Si concentrations indicate possible dissolution of smectite. More conclusions are possible after the bentonites have been characterized. One experimental set of the 25 °C experiments has been finished and the bentonite phases are being characterized. Other experiment sets are still continued.

Aggregation, Isomerization and Thermo-Optic Property of Azobenzene Polyelectrolyte

2010 ◽  
Vol 123-125 ◽  
pp. 851-854 ◽  
Author(s):  
Feng Xian Qiu ◽  
Dong Ya Yang ◽  
Qing Zhang ◽  
Guo Rong Cao
Keyword(s):  
Thin Film ◽  
Optical Storage ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Inorganic Materials ◽  
Ph Values ◽  
Vis Spectroscopy ◽  
Optic Property ◽  
Ft Ir ◽  
Aggregation Behaviors

A novel azobenzene polyelectrolyte (ABAPE) was synthesized based on chromophore 4-(4’-nitrophenylazo) naphthol (NPAN), epoxychloropropane and α-methacrylic acid. The ABAPE was characterized by FT-IR and UV-vis spectroscopy. The aggregation behaviors of ABAPE were investigated based on different pH values by the UV-vis spectroscopy. The isomerization behavior of the ABAPE in DMAC solution was studied by 256 nm UV irradiation light. Attenuated total reflection (ATR) method was adopted and carried out the measurement of refractive index of the thin film. The thermo-optic coefficient (dn/dT) was -2.9228×10-4°C-1 and was bigger than inorganic materials such as silica glass, zinc silicate glass, borosilicate glass and the organic materials of polystyrene and PMMA. These results showed that the polyelectrolyte could be used to carry out optical storage and thermo-optic switch.

Role of nickel and chrome in the active-passive transition in low-strength steels in media with high pH values

1989 ◽  
Vol 25 (1) ◽  
pp. 35-39
Author(s):  
A. V. Vasilik ◽  
S. I. Girnyi ◽  
R. K. Melekhov
Keyword(s):  
High Ph ◽  
Ph Values ◽  
Passive Transition ◽  
Low Strength

Adsorptive Removal of Ni(II) Ions from Aqueous Solution by Polyacrylic Acid/Attapulgite Composite Hydrogels

2017 ◽  
Vol 727 ◽  
pp. 859-865 ◽  
Author(s):  
Yi Wei Zheng ◽  
Wen Wen Tao ◽  
Gui Fang Zhang ◽  
Chao Lv ◽  
Yi Ping Zhao ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Polyacrylic Acid ◽  
Swelling Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorptive Removal ◽  
Composite Hydrogels ◽  
Ph Values ◽  
Ft Ir

Polyacrylic acid/attapulgite (PAA/ATP) composite hydrogels used for removal of heavy metal ions from aqueous solution was synthesized via radical polymerization with acrylic acid (AA) and attapulgite (ATP) modified by hydrochloric acid as adsorbent. Chemical composition of the modified ATP was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) and the morphology of the PAA/ATP hydrogels was characterized by scanning electron microscope (SEM), respectively. The swelling ratio, pH-sensitivity and adsorption performance of Ni (II) ions of the composite hydrogels were studied. The results showed the swelling ratio of the PAA/ATP composite hydrogels was higher than that of PAA hydrogels and the composite hydrogels displayed sensitivity to pH values with a sharp increase of swelling ratio when the pH values increased from 4 to 6. Comparing with PAA hydrogels, the composite hydrogels obtained a larger adsorption capacity of Ni (II) ions, the average adsorption capacity could reach 72.8 mg/g and adsorption ratio could reach 84%.

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