Sorption of Lead and Cadmium on Ostsorb P and Ostsorb SA-5 Cellulose Sorbents

1992 ◽  
Vol 57 (10) ◽  
pp. 2089-2094 ◽  
Author(s):  
Ladislav Svoboda ◽  
Leona Čáňová
Keyword(s):  
Ionic Strength ◽  
Functional Groups ◽  
Cation Exchanger ◽  
Exchange Capacity ◽  
Low Ph ◽  
The Other ◽  
Ph Values ◽  
Lead And Cadmium ◽  
Acid Fragment ◽  
Bead Cellulose

The effect of pH and ionic strength on the exchange capacity of sorbents based on modified bead cellulose was examined for the sorption of Pb2+ and Cd2+ ions. Ion exchange of these cations in aqueous solutions is nonselective on Ostsorb SA-5, which is cellulose containing functional groups based on H-acid. The medium acidic Ostsorb P cation exchanger with functional groups formed by the phosphoric acid fragment, on the other hand, sorbs lead, and to a lesser extent also cadmium, also at high ionic strengths of the medium even at low pH values.

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

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
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.

Effect of pH on Glycolate and Ammonia Excretion in L-MSO Treated Chlorella Cells

1987 ◽  
Vol 42 (5) ◽  
pp. 525-529
Author(s):  
Yoshihiro Shiraiwa ◽  
Georg H. Schmid
Keyword(s):  
Chlorella Vulgaris ◽  
Major Part ◽  
Ammonia Excretion ◽  
Low Ph ◽  
Final Concentration ◽  
The Other ◽  
Effect Of Ph ◽  
Photosynthetic Rates ◽  
Ph Values ◽  
Glycolate Metabolism

Abstract The effect of pH changes on the excretion of ammonia and glycolate from algal cells into the medium was investigated in L-MSO (final concentration, 0.5 mм) -treated High-and Low CO2-cells of Chlorella vulgaris 211-11 h. The excretion was analyzed in the condition in which the cells were continuously gassed with air at 25 °C. At the values tested, generally more ammonia was excreted in L-MSO-treated Low CO2-cells than in L-MSO treated High CO2-cells. In both kinds of algal cells more ammonia was excreted at low pH-values and absolutely no ammonia was excreted at pH 8. In the dark, no or only slight ammonia excretion was observed in both L-MSO-treated High and Low CO2-cells. Under all these conditions no or only very low glycolate excretion was observed in both L-MSO treated High and Low CO2-cells. In High CO2-cells rates of photosynthesis were high at pH 6 and lower at higher pH values. On the other hand Low CO2-cells showed practically little dependence of photosynthetic rates on the pH. This result might indicate that the major part of the ammonia excretion observed, was not due to the inhibition of photosynthesis at acid pH values. It is known that ammonia excretion in L-MSO treated algal cells is due to the inhibition of the refixation of ammonia which originates from the glycine-serine aminotransferase reaction in the glycolate pathway. Our results demonstrate that glycolate production and glycolate metabolism are more intense at low pH values when compared to high pH values. This is valid for both High and Low CO2-cells. Low CO2-cells in Chlorella vulgaris 211-11 h exhibit a more active glycolate metabolism than High CO2-cells.

REACTIONS OF IRON HYDROUS OXIDE WITH WYOMING BENTONITE

1968 ◽  
Vol 48 (2) ◽  
pp. 173-183 ◽  
Author(s):  
J. S. Clark ◽  
W. E. Nichol
Keyword(s):  
Exchange Capacity ◽  
Oxide System ◽  
Low Ph ◽  
Exchangeable Cations ◽  
Hydrous Oxide ◽  
Excess Iron ◽  
Ph Values ◽  
Hydrous Oxides ◽  
Fe Complexes ◽  
Wyoming Bentonite

Iron hydrous oxides were precipitated in Wyoming bentonite suspensions. With these preparations, close agreement was obtained between experimental corrected lime-potential and base saturation values and the titration curve calculated for the Wyoming bentonite-Fe hydrous oxide system, if (a) the exchangeable cations were extracted with NaNO3, (b) titration was used to determine the sum of trivalent ions extracted and (c) Fe and Al were considered to be equivalent exchangeable cations. The sum of cations extracted with NaNO3, therefore, was used as a measure of the effective cation exchange capacity (CEC) of the clay preparations containing excess iron oxides.The effective CEC's were low after short reaction intervals, but increased rapidly with time and were approaching the original CEC of the clay. The extent to which the CEC may have been reduced initially could not be determined because charged polynuclear hydroxy Fe complexes were present on the exchange complex. The fact that these complexes disappeared by 2 weeks and that the CEC values were approaching the original value clearly show that the Fe hydrous oxide clay complexes were not stable. Because of this and the low pH values at which the complexes were formed, the existence of Fe hydrous oxide-clay complexes in most natural soils was considered unlikely.

scholarly journals pH-dependent interconversion of two forms of tyrosinase in human skin

1988 ◽  
Vol 252 (2) ◽  
pp. 481-487 ◽  
Author(s):  
R K Tripathi ◽  
C Chaya Devi ◽  
A Ramaiah
Keyword(s):  
Human Skin ◽  
Sodium Phosphate ◽  
Inhibitory Concentration ◽  
Low Ph ◽  
The Other ◽  
Gradual Change ◽  
Ph Values ◽  
Sodium Phosphate Buffer ◽  
Solubilized Enzyme ◽  
Ph Dependent

1. We have shown that the characteristic lag in cresolase activity of human skin tyrosinase at inhibitory concentration of tyrosine was absent at all pH values studied, i.e. pH 5.2, 5.7, 6.2 and 6.8, if the enzyme solubilized at low pH was used as the source of enzyme, but the same enzyme when dialysed against buffers of various pH values showed linear activity only at pH 5.2 and was not inhibited by excess tyrosine, whereas at higher pH values it exhibited a lag and inhibition by excess tyrosine. 2. However, the enzyme solubilized in buffer/detergent, pH 6.8, when dialysed against buffer of the same pH showed linear activity at pH 5.2 and non-linear activity at pH 6.8. 3. The water/detergent-solubilized enzyme from human skin melanosomes showed linear activity even at inhibitory concentrations of tyrosine at pH 5.2 and 6.8 up to 2 h, but acceleration of rate was observed after 2 h for the enzyme measured at pH 6.8. 4. After dialysis of the water/detergent-solubilized enzyme against double-glass-distilled water, it still exhibits linear activity at inhibitory concentration of tyrosines at pH 6.8 for the first 2 h, but the same enzyme when dialysed against 0.02 M-sodium phosphate buffer, pH 6.8, exhibits negligible activity up to 1/2 h, in contrast with considerable activity before dialysis during the same interval of time, but without any loss of activity at later intervals of incubation time. 5. On the basis of these results, it is concluded that the enzyme exists in at least two interconvertible forms, one without lag and inhibition by excess tyrosine and the other with lag and inhibition by excess tyrosine. These two forms are interconvertible only by gradual change in pH over a period of hours.

scholarly journals SOIL pH MEASUREMENT AND ITS APPLICATION TO ORGANIC SOILS

1977 ◽  
Vol 57 (1) ◽  
pp. 55-64 ◽  
Author(s):  
WM. van LIEROP ◽  
A. F. MacKENZIE
Keyword(s):  
Ionic Strength ◽  
Soil Ph ◽  
Growing Season ◽  
Application Rate ◽  
The Other ◽  
Organic Soils ◽  
Significant Treatment ◽  
Hydrogen Saturation ◽  
Ph Values ◽  
Exchangeable Hydrogen

The average soil pH of 10 organic soils was significantly influenced by drying and the salt concentration of the suspending media. Accordingly, mean soil pH of field-moist and oven-dried soils was pH 5.0 and 4.5, 4.1 and 3.9, and 3.8 and 3.6 for soils suspended in water, 0.015 M CaCl2 and 1 M KCl. A significant treatment–soil interaction indicated that the soils responded differently to the treatments. No junction potentials were found when the ionic strength of the solution was 0.01 M CaCl2 equivalent or greater. Milli-equivalents exchangeable hydrogen (−0.984**), percent hydrogen saturation (−0.966**) milli-equivalents extractable bases (0.937**) and percent base saturation (0.957**) were more closely correlated with 1 M KCl pH values than with values in the other media. Liming influenced soil pH significantly on all field sites and within 8 h after application on two field sites. The influence of liming on soil pH tended to diminish the year after applications were made. Measured soil pH variability among treatments and replicates at various sampling dates ranged up to 1 pH unit during the growing season. However, it was about 0.2 pH unit on the control treatments with undetectable quantities of residual limestone. The quantity of reacted limestone was established at 25 and 40%, between 23 May and 31 July, on two sites (J.I.V. and S.B.). The reacted limestone was found to be proportional to the application rate.

scholarly journals Shelf life of minimally processed pineapples treated with ascorbic and citric acids

Bragantia ◽  
2012 ◽  
Vol 71 (3) ◽  
pp. 447-453 ◽  
Author(s):  
Lucimara Rogéria Antoniolli ◽  
Benedito Carlos Benedetti ◽  
Men de Sá Moreira de Souza Filho ◽  
Deborah dos Santos Garruti ◽  
Maria de Fátima Borges
Keyword(s):  
Ascorbic Acid ◽  
Shelf Life ◽  
Respiratory Activity ◽  
Low Ph ◽  
The Other ◽  
Water Control ◽  
Minimally Processed ◽  
Ph Values ◽  
Physical Chemical ◽  
Polyethylene Terephtalate

The purpose of this research was to determine the shelf life of minimally processed (MP) 'Pérola' pineapples treated with ascorbic acid (AA) and citric acid (CA) based on physical, chemical, sensorial and microbiological attributes. Slices were dipped into drinking water (control) or combined solutions of AA:CA (%) (1.0:0.5 and 1.0:1.0) with sodium hypochlorite (NaClO 20 mg L-1) for 30 seconds. The samples were conditioned in polyethylene terephtalate packages and stored at 4±1 °C per 13 days. The low peroxidase activity in the slices treated with antioxidant combinations was related to low pH values observed in these samples. The treatments 1.0:0.5 and 1.0:1.0 (AA:CA, %) favored maintenance of the initial a* values and avoided the pulp browning. The ascorbic acid increased more than double on the 2nd day in the treated slices. By the 4th day the CO2 values suggested a higher respiratory activity in the slices treated with anti-browning compounds. The antioxidant treatments did not produce detectable residual flavors in the MP pineapple. Regardless of microbiological safety during the 13 days of cold storage, the control slices can be kept by 6 days, afterwards the color and dehydration become strong enough to affect the appearance. On the other hand, MP 'Pérola' pineapples treated with 1.0:0.5 (AA:CA, %) and NaClO (20 mg L-1) can be stored for 8 days at 4±1 ºC, which represents the extension of the shelf life in 2 days. After this period the overripe odor starts to develop.

THE EFFECT OF NITROGEN AND PHOSPHORUS NUTRITION ON pH OF TOMATO

1966 ◽  
Vol 46 (6) ◽  
pp. 681-684 ◽  
Author(s):  
J. S. Matthews ◽  
L. G. Denby
Keyword(s):  
Low Ph ◽  
The Other ◽  
Phosphorus Nutrition ◽  
Nitrogen And Phosphorus ◽  
Tomato Fruits ◽  
High Ph ◽  
Ph Values ◽  
Low Levels ◽  
Nutrient Solutions

Tomato fruits, grown under glass in inert media, and supplied with nutrient solutions containing high and low levels of N and P, varied in pH from 4.21 to 4.61. Fruits from plants receiving low levels of both nutrients consistently had low pH values. Those from plants fed high levels of P or N had high pH whenever the level of the other element was not limiting.

scholarly journals Sorption of 137Cs and 90Sr on Organic Sorbents

2021 ◽  
Vol 11 (23) ◽  
pp. 11531
Author(s):  
Petr Belousov ◽  
Anna Semenkova ◽  
Yulia Izosimova ◽  
Inna Tolpeshta ◽  
Anna Romanchuk ◽  
...  
Keyword(s):  
Functional Groups ◽  
Brown Coal ◽  
Exchange Capacity ◽  
Buffering Capacity ◽  
Hard Coal ◽  
Ph Values ◽  
High Moor ◽  
Brown Coals ◽  
Ph Range ◽  
High Moor Peat

The present study examines the sorption of Cs (I) and Sr (II) on organic sorbents in the pH range from 2 to 10, as well as the mechanisms of their binding. In order to determine the influence of the physical properties and the quantity of functional groups of the organic sorbents on sorption, experiments were carried out on organic materials of varying degrees of metamorphism: high-moor peat, hard and brown coals and shungite. A detailed description of their mineral composition, cation exchange capacity, buffering capacity and elemental composition of sorbents is provided. XRD, XRF, SEM and BET adsorption methods were used for assaying. As a result of the conducted research, it can be concluded that Sr (II) showed a higher sorption per unit specific surface area than Cs (I) in the studied range of concentrations and pH values. Sr (II) sorption decreases in the following order: high-moor peat > brown coal > shungite > hard coal. The sorption of Cs (I) is highest on brown coal and lesser for high-moor peat, shungite and hard coal. It is suggested that Cs (I) and Sr (II) can be fixed on carboxyl functional groups and Cs (I), possibly, in insignificant amounts on phenolic hydroxyls of all four studied organic sorbents.

scholarly journals Mechanisms of Heat-induced Antigen Retrieval: Does pH or Ionic Strength of the Solution Play a Role for Refolding Antigens?

2005 ◽  
Vol 53 (11) ◽  
pp. 1311-1321 ◽  
Author(s):  
Katsura Emoto ◽  
Shuji Yamashita ◽  
Yasunori Okada
Keyword(s):  
Ionic Strength ◽  
The Other ◽  
Antigen Retrieval ◽  
Antigenic Determinants ◽  
Acidic Ph ◽  
Cooling Process ◽  
Ph Values ◽  
Ph Dependency ◽  
Nacl Concentration ◽  
Effects Of Ph

We investigated the effects of pH and ionic strength of solutions used for antigen retrieval to elucidate the mechanism of heat-induced antigen retrieval (HIAR) in immunohistochemistry. The immunostaining intensity of nuclear, cytoplasmic, cell membrane, and extracellular matrix antigens with 17 different antibodies was evaluated in formaldehyde-fixed and paraffin-embedded mouse and human tissues. Deparaffinized sections were autoclaved for 10 min in buffers with different pH values ranging from 3.0 to 10.5. To test the influence of ionic strength on immunoreactions, the sections were autoclaved for 10 min in 20 mM Tris-HCl buffers (TB) at pH 9.0 and 10.5 with or without 25, 50, and 100 mM NaCl. There were two immunostaining patterns for pH dependency of HIAR. First, the majority of antibodies recovered their antigenicity when heated in the buffers with both acidic pH (pH 3.0) and basic pH (pH 9.0 and 10.5). Second, some antibodies showed strong immunostaining only at basic pH values (pH 9.0 and 10.5). When the sections were autoclaved in TB at pH 9.0, immunostaining of all eight antibodies examined decreased as the NaCl concentration increased. On the other hand, when the sections were treated with TB at pH 10.5, all antibodies yielded stronger reactions in the buffer containing NaCl than in the buffer without NaCl; five antibodies exhibited the strongest immunoreaction at concentrations from 25 to 50 mM. These results suggest that the extended polypeptides by heating are charged negatively or positively at basic or acidic pH, and that an electrostatic repulsion force acts to prevent random entangling of polypeptides caused by hydrophobic attractive force and to expose antigenic determinants, during cooling process of HIAR solution.

Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb DITHIZON and Ostsorb SALICYL

1994 ◽  
Vol 59 (6) ◽  
pp. 1319-1325 ◽  
Author(s):  
Ladislav Svoboda ◽  
Stanislav Jech
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Exchange Capacity ◽  
Ion Exchanger ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Metal Concentrations ◽  
Cadmium And Lead

The pH and I (ionic strength) dependences of exchange capacity of chelating ion exchangers Ostsorb based on spherical cellulose modified with functional groups of dithizone and salicylic acid have been studied in the sorption of Pb(II) and Cd(II) ions. The cellulosic selective sorbents Ostsorb DITHIZON and Ostsorb SALICYL can be used for sorption of Pb(II) and Cd(II) ions from aqueous solutions of I = 0 - 1 mol l-1 (Pb) and I = 0 - 5 mol l-1 (Cd); the dithizone ion exchanger retains both metals most effectively at pH 7 - 8, the salicyl ion exchanger at pH 5.5 - 6.5 (Pb) or pH 4 - 9 (Cd). Because of the formation of precipitates of hydrolytic products of the two metals in neutral and alkaline media, it is suitable to carry out the sorption in media of mild acidity if possible, particularly so at the metal concentrations above 1 mg l-1. Increasing ionic strength affects the exchange capacity for both metals in a negative way.

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