Treatment Strategy for Cr(VI)-Bearing Wastes

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2301-2304 ◽  
Author(s):  
C. F. Lin ◽  
W. Rou ◽  
K. S. Lo
Keyword(s):  
Compressive Strength ◽  
Specific Resistance ◽  
Synthetic Wastewater ◽  
Redox Titration ◽  
Treatment Processes ◽  
Optimum Ph ◽  
Ph Range ◽  
Chromium Wastes ◽  
Optimum Ph Range ◽  
Additional Dosage

The effects of reductants and alkali on the sludge quantity of chromium wastes and the teachability and physical properties of solidified chromium matrix are investigated in this study. FeSO4 and NaHSO3 are model reductants, and NaOH and Ca(OH)2 serve as bases, respectively. Portland cement was used to solidify Cr sludges generated from real wastes. Results from potentiometric redox titration showed that a 99.9% destruction of Cr(VI) at equivalence point is not achievable unless additional dosage is imposed. The extra amounts of reducing agent necessary for 99.9% conversion of Cr(VI) to Cr(III) is dependent on system parameters such as pH and type of reductants applied. An increase in operating pH where redox proceeds may acquire much more reducing chemicals than lower pH does. The optimum pH range for maximum precipitation is from 8.5 to 9.0. Chromium sludges generated from synthetic wastewater have a specific resistance from 8.7×l011 to 1.28×l013 m/kg. The use of Ca(OH)2 as base to precipitate Cr(III) produces sludge with lower specific resistance and larger particle size (near 20 to 60 µm). When examined with TCLP test, the chromium leachated out to the solution from matrix is generally less than 1 mg/L. Compressive strength of solidified sludge can reach near 10 kg/cm2 in 3 days based on 1:1 sludge/cement ratio. The compressive strength is affected by the type of reductants as well as the bases employed in the wastewater treatment processes. To producc a matrix with better compressive strength, it is recommended to use FeSO4 along with Ca(OH)2; however, if NaOH is used to control system pH, NaHSO3 is suggested to serve as reductant.

scholarly journals Haem disorder in modified myoglobins. Effect of reconstitution procedures

1983 ◽  
Vol 215 (1) ◽  
pp. 117-122 ◽  
Author(s):  
M B Ahmad ◽  
J R Kincaid
Keyword(s):  
Selective Oxidation ◽  
High Spin ◽  
Chromatographic Purification ◽  
Optimum Ph ◽  
Ph Range ◽  
Optimum Ph Range

Apomyoglobin was reconstituted with deuterohaem derivatives under various conditions. The fraction of disordered component, which is characterized by a 180 degree rotation of the haem group, for the various preparations was determined by n.m.r. spectroscopy. By using the procedures described, it was shown that the fraction of disordered component is minimized if the reconstitution is carried out with high-spin ferric haem derivatives within an experimentally determined optimum pH range of 8-9.5. Use of low-spin derivatives in either the ferrous or ferric forms leads to substantial increases in the fraction of disordered form. Attempted removal of the disordered form by selective oxidation and chromatographic purification was not effective.

CHARACTERISTICS OF FOUR RHIZOBIOPHAGES ACTIVE AGAINST RHIZOBIUM MELILOTI

1957 ◽  
Vol 3 (4) ◽  
pp. 651-668 ◽  
Author(s):  
D. T. Parker ◽  
O. N. Allen
Keyword(s):  
Rhizobium Meliloti ◽  
The Other ◽  
Cross Reactions ◽  
Thermal Death ◽  
Optimum Ph ◽  
Ph Range ◽  
Optimum Ph Range ◽  
Standard Techniques

Four phage isolates for strains of Rhizobium meliloti were obtained from sewage and held soil and purified by standard techniques. Plaque sizes ranged from 1.0 to 4.0 mm. The titers of these phages remained unchanged after 24 months' storage at 0° and 4 °C. None of the phages lysed all of the 38 strains of R. meliloti tested, although 29 of these strains were lysed by one of the phages. Of 292 other strains of rhizobia isolated from 108 species of 50 leguminous genera, one of the phages lysed six strains, another, five strains, while the other two phages did not lyse any. None of the phages lysed any of the 40 strains of Agrobaderium and Chromobaderium species tested. Inactivation rates of the four phages by their homologous antisera were linear up to 90% inactivation. Cross-reactions with heterologous antisera showed weak serological relationships between some of the phages. The latent periods of growth ranged from 80 to 90 minutes to 170–180 minutes. Burst sizes of rhizobia infected by the four phages ranged from 80 to 317 particles per bacterium after an adsorption period of 60 minutes at 30 °C. The optimum pH range was 6.4–7.8. Thermal death points in broth were 51 °C, 53 °C, 61 °C, and 70 °C, respectively, for the four phages.

Pharmaceutical Removal from Synthetic Wastewater Using Heterogeneous - Photocatalyst

2015 ◽  
Vol 802 ◽  
pp. 507-512 ◽  
Author(s):  
Chee Mei Lee ◽  
Puganeshwary Palaniandy ◽  
Nastaein Qamaruz Zaman ◽  
Mohd Nordin Adlan
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Treatment Process ◽  
Treatment Method ◽  
Synthetic Wastewater ◽  
Optimum Ph ◽  
Pharmaceutical Removal ◽  
Ph Range ◽  
Very High

Compound Parabolic Collecting Reactor (CPCR) was designed and used for the heterogeneous-photocatalytic treatment process. Sunray was act as an economically and ecologically sensible light source. The photocatalytic degradation of paracetamol in the synthetic wastewater by using titanium dioxide (TiO2) was investigated. The experimental results show that the paracetamol removal rates were very high and nearly equal (97.2% to 99.7%) at pH 4-7 and TiO2 concentration of 0.5-1 g/L. This implies that the photocatalytic degradation rate of paracetamol is not affected by pH range in this study as the electrostatic interaction between the TiO2 and paracetamol is not able to be developed unless a wider range of pH is set. Furthermore, the concentration of TiO2 of 0.5 g/L is too high to treat the concentration of 10 mg/L of paracetamol. Further research is needed in order to identify the optimum pH condition and a suitable correlation of concentration between TiO2 and paracetamol. Finally, the results proved that the heterogeneous-photocatalyst treatment method which associated with the application of CPCR and solar energy is able to eliminate the paracetamol from the synthetic wastewater.

scholarly journals The subcellular distribution of triphosphoinositide phosphomonoesterase in guinea-pig brain

1972 ◽  
Vol 128 (3) ◽  
pp. 579-586 ◽  
Author(s):  
A. Sheltawy ◽  
M. Brammer ◽  
D. Borrill
Keyword(s):  
Guinea Pig ◽  
Subcellular Fractions ◽  
Assay System ◽  
Acid Phosphatases ◽  
Alkaline Phosphatases ◽  
Pig Brain ◽  
Optimum Ph ◽  
Ph Range ◽  
Guinea Pig Brain ◽  
Optimum Ph Range

1. Some properties of the triphosphoinositide phosphomonoesterase from the homogenates of guinea-pig brain were studied. The enzyme has an optimum pH range 6.7–7.3, is stimulated with KCl at a concentration of 0.1m, and under these conditions has Km1.43×10-4m. 2. A factor from the ‘pH5 supernatant’ of guinea-pig brain stimulates the enzyme activity over and above the stimulation produced by KCl. Subcellular fractions of guinea-pig brain varied in their response to the ‘pH5 supernatant’. Maximum stimulation was observed with the P1 fraction, containing myelin and nuclei. 3. An assay system for the enzyme was developed that contained optimum concentrations of both KCl and the ‘pH5 supernatant’. Acid phosphatases were inhibited by NaF, but, in contrast with previous work, no EDTA was added to the assay system to inhibit the alkaline phosphatases. This reagent inhibited the triphosphoinositide phosphomonoesterase. It was estimated that the remaining fraction of non-specific phosphatases can account for only 14% of the observed triphosphoinositide phosphomonoesterase activity. 4. Subcellular fractions of guinea-pig brain were characterized by electron microscopy and subcellular markers. The triphosphoinositide phosphomonoesterase exhibited a distribution between the fractions similar to that of 5′-nucleotidase, but different from that of alkaline phosphatase.

Coagulation/flocculation of dye-containing solutions using polyaluminium chloride and alum

2009 ◽  
Vol 59 (7) ◽  
pp. 1343-1351 ◽  
Author(s):  
M. Hasani Zonoozi ◽  
M. R. Alavi Moghaddam ◽  
M. Arami
Keyword(s):  
Dye Removal ◽  
Coagulant Dosage ◽  
Optimum Ph ◽  
Ph Range ◽  
Influence Of Ph ◽  
Acid Blue ◽  
Ph Variations ◽  
Optimum Ph Range ◽  
Low Dosage ◽  
Polyaluminium Chloride

This study aims to compare the performance of Polyaluminium Chloride (PAC) and alum as coagulants to remove a specific type of dye (Acid Blue 292 (AB292)) from dye-containing solution. For this purpose, the influence of pH, coagulant dosage, coagulant aids (kaolinite and bentonite), and initial dye concentration on dye removal efficiency were examined. According to the results, removal of AB292 was absolutely dependent on the pH variations. The maximum dye removal occurred when pH was 7 and 5 for PAC and alum, respectively. Both coagulants efficiently removed the dye (about 85%) with a relatively low dosage (40 mg/l) in their optimum pH range. By adding kaolinite as a coagulant aid, the removal efficiencies tended to increase, especially for lower dosages of PAC and alum. With the increase of initial dye concentration, PAC and alum represented different behaviors. In the case of PAC, Q (the amount of the removed dye per unit mass of coagulant) increased at first and reached to a maximum value, 2.1 mg dye/mg PAC, and then decreased rapidly. While for alum, Q steadily increased with the increase of dye concentration and reached to 2.8 mg dye/mg alum. No reduction of Q occurred for alum with the increase of dye concentration in the range of 25–250 mg/l.

Catechol functionalized aminopropyl silica gel: synthesis, characterization and preconcentrative separation of uranium(VI) from thorium(IV)

2005 ◽  
Vol 93 (4) ◽  
Author(s):  
P. Metilda ◽  
J. Mary Gladis ◽  
T. Prasada Rao
Keyword(s):  
Silica Gel ◽  
Solid Phase ◽  
Inorganic Ions ◽  
Functionalized Silica ◽  
Selective Enrichment ◽  
Optimum Ph ◽  
Maximum Sorption ◽  
Solid Phase Extractant ◽  
Ph Range ◽  
Optimum Ph Range

SummaryA novel solid phase extractant is prepared by chemically immobilizing catechol with diazotized aminopropyl silica gel. The resulting catechol functionalized silica gel (CASG) was characterized by FTIR, and microanalysis and was used for selective enrichment of uranium(VI) from other inorganic ions. The optimum pH range for maximum sorption of uranium(VI) and thorium(IV) was found to be in the range 3.5–6.0. The above actinides were eluted with 10 cm

THE ESTIMATION OF LACTATE DEHYDROGENASE ACTIVITY OF HUMAN ERYTHROCYTES

1961 ◽  
Vol 39 (2) ◽  
pp. 257-265 ◽  
Author(s):  
J. A. Birkbeck ◽  
A. G. Stewart
Keyword(s):  
Whole Blood ◽  
Enzyme Stability ◽  
Enzyme Concentration ◽  
Human Erythrocytes ◽  
Lactate Dehydrogenase Activity ◽  
Ldh Activity ◽  
Optimum Ph ◽  
Ph Range ◽  
Influence Of Ph ◽  
Optimum Ph Range

The influence of pH, temperature, and the concentrations of substrate, coenzyme, and enzyme on the estimation of the LDH activity of human erythrocytes have been examined. The activity had a broad optimum pH range of 7.0 to 7.8 and was markedly influenced by temperature. The optimum concentrations of pyruvate and DPNH were found to be 1.7 × 10−6and 0.8 × 10−7mole/ml of incubation mixture respectively. A method for the measurement of LDH activity at optimum conditions (except for temperature) is described. The method was satisfactory over a 10-fold range of enzyme concentration. Of the anticoagulants commonly used in clinical laboratories for collecting blood, oxalate was inhibitory and heparin, fluoride, versene, and citrate had no influence on LDH activity. Enzyme stability studies indicated that whole blood at 4 °C and dilute hemolyzate frozen at −10 °C could be kept for 4 weeks without loss of LDH activity. Dilute hemolyzate was less stable than whole blood at the same temperature.

The calculation of the optimum pH range for synthesizing BST nanopowders by sol–gel auto-combustion process

2008 ◽  
Vol 49 (2) ◽  
pp. 166-169 ◽  
Author(s):  
Shun Hua Xiao ◽  
Jin Hu ◽  
Hai Jun Xu ◽  
Wei Fen Jiang ◽  
Xin Jian Li
Keyword(s):  
Sol Gel ◽  
Combustion Process ◽  
Auto Combustion ◽  
Optimum Ph ◽  
Ph Range ◽  
Optimum Ph Range

scholarly journals Phosphorated Calix[6]arene Derivatives as an Ionophore for Atropine-Selective Membrane Electrodes

2007 ◽  
Vol 90 (1) ◽  
pp. 147-152 ◽  
Author(s):  
Mohsen M Zareh ◽  
Elizabeita Malinowska
Keyword(s):  
Selectivity Coefficient ◽  
Atropine Sulfate ◽  
Eye Drops ◽  
Membrane Electrodes ◽  
Relative Standard ◽  
Optimum Ph ◽  
Selective Membrane ◽  
Ph Range ◽  
Polyvinyl Chloride Membrane ◽  
Optimum Ph Range

Abstract 37,40-bis-(diethoxy-thiophosphoryl)oxy-5,11,17, 23,29,35-hexakis(1,1-dimethyl-ethyl)-calix[6]arene-8,39,41,42-tetrol; 37,38,39,40,41-pentakis-(diethoxythiophosphoryl)-oxy-5,11,17,23,29,35-hexakis (1,1-dimethylethyl)-calix[6]-arene-42-ol; and 37-(diethoxythiophosphoryl)oxy-5,11,17,23,29,35-hexakis-(1,1dimethylethyl)-calix[6]arene-38,39,40, 41,42-pentol were introduced as neutral ionophores for atropine-selective electrodes. Practical Nernstian responses were found (54.3, 49.1, and 50.8 mV/decade) for polyvinyl chloride membrane electrodes incorporating these compounds. They exhibited practical linear ranges of 1.9 10-6-7.9 10-3,7.9 10-6-7.9 10-3, and 6.3 10-6-7.9 10-3 M, respectively. The optimum pH range was 2.58.5. The selectivity coefficient values were estimated and interpreted. The electrode performance was correlated to the calixarene structure. Then, the electrode was applied to an actual analysis of pharmaceutical atropine preparations. The recovery values of 18.7 g/mL-5.5193 mg/mL atropine sulfate were 97.599.1%. The corresponding relative standard deviation values ranged between 0.39-0.72% for 5 determinations. The first electrode was applied successfully for analyzing atropine sulfate in injection solution and eye drops.

Removal of arsenic(V) ion from aqueous solutions by lanthanum compounds

1997 ◽  
Vol 35 (7) ◽  
pp. 71-78 ◽  
Author(s):  
Shuzo Tokunaga ◽  
Syed A. Wasay ◽  
Sang-Won Park
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Process ◽  
Lanthanum Carbonate ◽  
Lanthanum Hydroxide ◽  
First Order ◽  
Optimum Ph ◽  
Initial Ph ◽  
Ph Range ◽  
Removal Of Arsenic ◽  
Optimum Ph Range

A new adsorption process for the removal of As(V) ion from aqueous solutions has been studied using lanthanum hydroxide (LH), lanthanum carbonate (LC) and basic lanthanum carbonate (BLC). These La compounds were effective in removing As ion to decrease the concentration down to < 0.001 mM. Dissolution of these La compounds was measured in the pH range of 2 to 12. The dissolution was appreciable at initial pH <4.3, <4.3 and <4.0 for LH, LC and BLC, respectively. Kinetic study showed that the As removal was a first-order reaction in the neutral pH range and the rate constants were in the order of LH > LC > BLC. The As removal was highly pH-dependent. The optimum pH range was 3-8, 4-7 and 2-4 for LH, LC and BLC, respectively. The following two mechanisms are proposed: (i) adsorption by exchange of CO3 and/or OH group with As ions in the neutral to alkaline pH range where La does not dissolve and (ii) precipitation of insoluble lanthanum arsenate, LaAsO4, in the acid pH range.

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