Fluoride sorption by soil components: calcium carbonate, humic acid, manganese dioxide and ailica

Soil Research ◽  
1985 ◽  
Vol 23 (3) ◽  
pp. 429 ◽  
Author(s):  
H Farrah ◽  
J Slavek ◽  
WF Pickering
Keyword(s):  
Calcium Carbonate ◽  
Humic Acid ◽  
Ash Content ◽  
Fluoride Ions ◽  
Ph Values ◽  
Counter Ions ◽  
Soil Components ◽  
Significant Uptake ◽  
Ph Range ◽  
Calcium Compounds

The ability of individual soil components to adsorb fluoride ions from dilute solutions (1-12 mg L-1 F-), at different pH values, has been investigated. No significant uptake was detected using substrates such as calcite, hydrous manganese(1v) oxide, cryptomelane, �-MnO2, pyrolusite, silica or silica gel, over the pH range 3-8 (for calcite, 6-9). The sorption of F- by calcite and humic acids at higher solution levels (up to 200 mg L-1) was also examined. Uptake by CaCO3 was observed when [F-] was >7 x 10-4 mol L-1, with the moles retained (pH -8.5) being approximately 1.6[F-]2. The amount of F removed increased on lowering the pH or on adding Ca2+, and it is proposed that the overall reaction is described by the equation CaCO3(S) + 2F- <=>CaF2(S) + CO23-. Two humic acid samples adsorbed increasing amounts of F- as the pH was lowered below 6.5, and increasing amounts of A1 and fluorocomplexes were detected in solution. The amount sorbed (mol kg-', at pH 5.5-6) varied with ash content and equalled either 16[F-]0.64 or 60[F-1. The major interaction appears to be HF attack on aluminosilicates in the ash fraction, with lesser contributions from sorption on calcium compounds and interaction with the counter-ions associated with the humic acid functional groups (e.g. Ca2+, Al3+, Fe3+).

Interaction of Hg(II) with kaolin-humic acid complexes

Clay Minerals ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 35-45 ◽  
Author(s):  
M. Arias ◽  
M.T. Barral ◽  
J . Da Silva–Carvalhal ◽  
J .C. Mejuto ◽  
D. Rubinos
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Dissolved Organic Matter ◽  
Equilibrium Concentration ◽  
Soluble Complex ◽  
Ph Values ◽  
Subsurface Waters ◽  
Ph Range ◽  
Surface And Subsurface Waters ◽  
Reduced Risk

AbstractThe adsorption and desorption of Hg(II) by humic acid (HA) previously adsorbed on kaolin was studied. In the range of HA concentration investigated (0.0 –26.9 mg g–1), the Hg(II) adsorption capacity of kaolin at pH 4 is enhanced by the presence of HA. For the complexes with the highest HA concentration and for low Hg(II) initial concentrations, adsorption was lower, i.e. as HA concentration on the complexes increases, Hg(II) equilibrium concentration also increases. This behaviour is due to the increasing presence of dissolved organic matter as the HA concentration on the complexes increases. The dissolved organic matter is able to form a soluble complex with Hg, thus decreasing adsorption. Hg(II) adsorption from a 2.5×10–5 MHg(II) solution was influenced by pH. For kaolin, a pHmax (pH where maximum adsorption occurs) of 4.5 was observed. At pH values >pHmax retention decreased with increasing pH. This same behaviour was observed for the kaolin- HA complex containing the lowest HA concentration (6.6 mg g –1). For the other kaolin-HA complexes there was little effect of pH on Hg(II) adsorption between pH 2.5 and pH 6.5. The presence of HA increased the adsorption of Hg(II) on kaolin all along the pH range studied. Desorption experiments showed that the amount of Hg(II) desorbed was quite low (<1%) for all the HA and Hg(II) concentration range studied, except for the kaolin at acid pH (pH 2.5) where the Hg(II) released was >50% of Hg(II) previously adsorbed. The presence of HA dramatically reduced this percentage of desorption to values of <3%, indicating reduced risk of toxicity problems in surface and subsurface waters. The addition of Cu(II) did not favour any Hg(II) desorption, even though Cu exhibits a strong affinity for organic matter.

The interaction of a humic acid with heavy metals

Soil Research ◽  
1997 ◽  
Vol 35 (1) ◽  
pp. 89 ◽  
Author(s):  
K. M. Spark ◽  
J. D. Wells ◽  
B. B. Johnson
Keyword(s):  
Heavy Metals ◽  
Humic Acid ◽  
Functional Group ◽  
Electrolyte Concentration ◽  
Background Electrolyte ◽  
Metal Hydroxides ◽  
Step Process ◽  
Ph Values ◽  
Major Functional Group ◽  
Ph Range

The solubility of a coal humic acid and the sorption of heavy metals (Cu(II), Zn(II), Co(II), and Cd(II)) in the absence and presence of the humic acid were determined as a function of pH and concentration of background electrolyte. The solubility of the humic acid at low electrolyte concentration increases in a 2-step process with increase in pH. About 80% dissolves in the pH region 3–8·5, and the remainder in the region pH >8·5. The sorption of metals occurs at pH values significantly lower than those associated with the formation of insoluble metal hydroxides, with a maximum occurring in the pH region 5·5–7·5, and involves the solid state fraction of the humic acid. At the higher electrolyte concentration, the solubility of the humic acid is again a 2-step process but the increase in acid solution occurs over a relatively narrow pH range (5–6). At high pH, the presence of the humic acid significantly reduces the precipitation of the metals at both low and high salt concentration, probably due to the formation of soluble metal–humate species. There is evidence to suggest that the major functional group of the humic acid with which the metal cations interact is the carboxyl group.

PRODUCTION AND PROPERTIES OF 2,3-BUTANEDIOL: VIII. pH CONTROL IN AEROBACILLUS POLYMYXA FERMENTATIONS AND ITS EFFECTS ON PRODUCTS AND THEIR RECOVERY

1946 ◽  
Vol 24f (1) ◽  
pp. 12-28 ◽  
Author(s):  
G. A. Adams ◽  
J. D. Leslie
Keyword(s):  
Carbon Dioxide ◽  
Heat Treatment ◽  
Calcium Carbonate ◽  
Nicotinic Acid ◽  
Acid Production ◽  
Ammonium Hydroxide ◽  
Ph Control ◽  
Ash Content ◽  
Carbon Balances ◽  
Ph Range

Comparative studies have shown that the pH of 15% wheat mashes fermented by Aerobacillus polymyxa can be as satisfactorily controlled by ammonium hydroxide as by calcium carbonate. The formation of 2,3-butanediol and ethanol was unaffected by all pH levels tested (5.8, 6.0, 6.5, 7.0) with the possible exception of pH 7.0, where a slight diminution of diol formation appeared at 96 hr. Over the pH range 5.8 to 6.0, the amount of ammonium hydroxide required, the escape of ammonia from the mash, and the production of acid were all minimized. The consumption of ammonia was greatest in the first 36 hr. of the fermentation owing to rapid acid production. Fermentation at the different pH levels did not affect the butanediol–ethanol ratio, which was approximately 1.5.Replacement of calcium carbonate by ammonium hydroxide reduced the ash content of the unfermented residue from approximately 20 to 4%. Protein contents (N × 5.7) of insoluble residues from carbonate and ammonia treated washes were 25 and 32%, respectively. In both mashes approximately 50% of the unfermented solids were soluble.Calculation of carbon balances on fermentables showed that increased acid production was accompanied by a decrease in carbon dioxide formation.Riboflavin and nicotinic acid contents per 100 gm. of fermented mash averaged 19.2 and 1270 μgm., respectively and were unaffected by pH of fermenting mash and heat treatment at 100 °C. for 10 hr. The riboflavin showed an 80% increase over that present in the original wheat; nicotinic acid showed a 40% decrease.

The Malachite Green Biodegradation in Bioreactors on Various pH Domains

2019 ◽  
Vol 70 (8) ◽  
pp. 2996-2999
Author(s):  
Viorel Gheorghe ◽  
Catalina Gabriela Gheorghe ◽  
Andreea Bondarev ◽  
Vasile Matei ◽  
Mihaela Bombos
Keyword(s):  
Malachite Green ◽  
Contact Time ◽  
Dominant Species ◽  
Wastewater Treatment Plants ◽  
Organic Substances ◽  
Biological Degradation ◽  
Growth Promoters ◽  
Ph Values ◽  
Biological Sludge ◽  
Ph Range

In the experimental study was studied the malachite green colorant biodegradation in biological sludge with biological activity. The biodegradability tests were carried out in laboratory bioreactors, on aqueous solutions of green malachite contacted with microorganisms in which the dominant species is Paramecium caudatum, in a pH range between 8 and 12, temperatures in the ranges 25-350C, using pH neutralizing substances and biomass growth promoters. The colorant initial concentrations and those obtained after biological degradation depending on the contact time, at certain pH values, were established through UV-Vis spectrometry. The studies have shown the measure of possible biological degradation of some organic substances with extended uses, with largely aromatic structure, resistance to biodegradation of microorganisms, commonly used in wastewater treatment plants.

scholarly journals Stabilization and Release of Palm Tocotrienol Emulsion Fabricated Using pH-Sensitive Calcium Carbonate

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 358
Author(s):  
Phui Yee Tan ◽  
Beng Ti Tey ◽  
Eng Seng Chan ◽  
Oi Ming Lai ◽  
Hon Weng Chang ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Droplet Size ◽  
Entrapment Efficiency ◽  
Ph Sensitive ◽  
Emulsion System ◽  
Ph Responsive ◽  
Small Droplet ◽  
Homogenization Time ◽  
Oil In Water ◽  
Ph Range

Calcium carbonate (CaCO3) has been utilized as a pH-responsive component in various products. In this present work, palm tocotrienols-rich fraction (TRF) was successfully entrapped in a self-assembled oil-in-water (O/W) emulsion system by using CaCO3 as the stabilizer. The emulsion droplet size, viscosity and tocotrienols entrapment efficiency (EE) were strongly affected by varying the processing (homogenization speed and time) and formulation (CaCO3 and TRF concentrations) parameters. Our findings indicated that the combination of 5000 rpm homogenization speed, 15 min homogenization time, 0.75% CaCO3 concentration and 2% TRF concentration resulted in a high EE of tocotrienols (92.59–99.16%) and small droplet size (18.83 ± 1.36 µm). The resulting emulsion system readily released the entrapped tocotrienols across the pH range tested (pH 1–9); with relatively the highest release observed at pH 3. The current study presents a potential pH-sensitive emulsion system for the entrapment and delivery of palm tocotrienols.

scholarly journals Mechanism of Coagulation of Humic Acid in Presence of Metal Ion Coagulants at Low pH Values

1970 ◽  
Vol 73 (5) ◽  
pp. 874-878 ◽  
Author(s):  
Takao YOTSUYANAGI ◽  
Katsumi GOTO ◽  
Masaichi NAGAYAMA
Keyword(s):  
Humic Acid ◽  
Metal Ion ◽  
Low Ph ◽  
Ph Values

Study on desorption of Mn, Fe, and Mg from TMP and evaluation of the complexing strength of different chelating agents using side reaction coefficients 10th EWLP, Stockholm, Sweden, August 25–28, 2008

Holzforschung ◽  
2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Kim Granholm ◽  
Pingping Su ◽  
Leo Harju ◽  
Ari Ivaska
Keyword(s):  
Citric Acid ◽  
Metal Ions ◽  
Chelating Agents ◽  
Side Reaction ◽  
Sodium Dithionite ◽  
Thermomechanical Pulp ◽  
Peroxide Bleaching ◽  
Ph Values ◽  
Reducing Environment ◽  
Ph Range

Abstract Chelation of thermomechanical pulp (TMP) was studied in this work. The desorption of Mn, Fe, and Mg due to their impact on peroxide bleaching was investigated. The desorption experiments were performed with EDTA, citric acid, oxalic acid, and formic acid as chelating agents at different pH. Chelation experiments with EDTA were carried out at pH 3–11. Sodium dithionite was used as the reducing agent in studying chelation with EDTA in a reducing environment. Mn was very effectively desorbed with EDTA from TMP at pH <10 and the reducing environment further improved the removal of all the studied metal ions from TMP with EDTA. Citric acid also removed Mn effectively from TMP at pH 5. The thermodynamic stability constants of different metal chelates do not present the correct picture of how strongly the metal ions are bound by the chelating agents in different conditions. But by means of the side reaction coefficients (α M(L)-coefficients) it is also theoretically possible to evaluate and compare the real binding strengths between the metal ions and different chelating agents at varying pH values and other solution conditions. In this study, a theory is given for the calculation of side reaction coefficients. Values of the α M(L)-coefficients, for the pH range 0–14, are presented for EDTA, DTPA, and also for some other new potential environmentally friendly chelating agents.

Properties of hymatomelanic acid peat and its influence on the growth processes of spring wheat varieties Iren

2020 ◽  
Author(s):  
A.O. Smirnova ◽  
◽  
O.V. Rybachuk ◽  
Keyword(s):  
Humic Acid ◽  
Spring Wheat ◽  
Biological Action ◽  
Ash Content ◽  
Economic Feasibility ◽  
Acid Extraction ◽  
Growth Processes ◽  
Wheat Varieties ◽  
Similarities And Differences ◽  
Hymatomelanic Acid

In this paper, we consider two ways for obtaining hymatomelanic acid extraction into conventional Soxhlet extractions: directly from the peat and from the dry product of humic acid. The results of the study of the elemental composition of humic and hymatomelanic acids are presented, their similarities and differences are analyzed. In order to study the effect of humic and hymatomelanic acid preparations on the growth processes of spring wheat, a vegetation experiment was conducted. Peculiarities of biological action of the solutions and hymatomelanic and humic acids of different concentrations in spring wheat varieties “IREN” were investigated. The paper presents a method for determining the ash content of the studied peat, as well as, calculations of the economic feasibility of using preparations based on the hymatomelanic acids.

scholarly journals Effects of pH and Aeration on Sclerotium rolfsii sacc. Mycelial Growth, Sclerotial Production and Germination

2018 ◽  
Vol 7 (3) ◽  
pp. 123-129 ◽  
Author(s):  
Fakher Ayed ◽  
Hayfa Jabnoun-Khiareddine ◽  
Rania Aydi-Ben-Abdallah ◽  
Mejda Daami-Remadi
Keyword(s):  
Mycelial Growth ◽  
Sclerotium Rolfsii ◽  
Dry Weight ◽  
Ph Values ◽  
Effects Of Ph ◽  
Ph Range ◽  
Sclerotial Development ◽  
Sclerotial Germination

Sclerotium rolfsii is one of the devastating soilborne fungus responsible for significant plant losses. The effects of pH and aeration on pathogen mycelial growth, sclerotial production and germination were investigated for three Tunisian isolates. Optimal mycelial growth occurred at pH 6 for Sr2 and Sr3 isolates and at pH 6-7 for Sr1. Dry mycelial growth was optimum at pH values ranging between 4 and 7. Sclerotial initiation started on the 3rd day of incubation at all pH values tested and mature sclerotia were formed after 6 to 12 days. Optimal sclerotial production was noted at pH 5. The dry weight of 100 sclerotia varied depending on isolates and pH and occurred at pH range 4-7. At pH 9, mycelial growth, sclerotial production and dry weight of 100 sclerotia were restricted. The optimum sclerotial germination, noted after 24 h of incubation, varied depending on isolates and pH and occurred at pH 4-9. Mycelial growth was optimum in aerated plates with a significant isolates x aeration treatments interaction. Sclerotial initiation occurred at the 3rd day of incubation and mature sclerotia were observed after 6-9 days. Sclerotial development was very slow in completely sealed plates and dark sclerotia were produced only after 15 days of incubation. The highest sclerotial yields were noted in aerated plates. The highest dry weight of 100 sclerotia for Sr1 isolate was recorded in ½ sealed, no sealed and completely sealed plates, while for Sr2, it was noted in ½ and ⅔ sealed plates. For Sr3, the maximum dry weight of 100 sclerotia was recorded in ½, ⅔ and completely sealed plates. Germination of S. rolfsii sclerotia, after 24 h of incubation, did not vary significantly depending on aeration treatments and ranged from 90 to 100% for all isolates.

Decline of Mysis relicta During the Acidification of Lake 223

1983 ◽  
Vol 40 (11) ◽  
pp. 1905-1911 ◽  
Author(s):  
R. W. Nero ◽  
D. W. Schindler
Keyword(s):  
Confidence Limits ◽  
Experimental Lakes Area ◽  
Mysis Relicta ◽  
Ph Values ◽  
Northwestern Ontario ◽  
Population Comparisons ◽  
Acidification Of Lake ◽  
Ph Range ◽  
Shield Lakes ◽  
Direct Toxicity

The population size of Mysis relicta in Lake 223 of the Experimental Lakes Area, northwestern Ontario, decreased from 6 700 000 ± 1 330 000 (± 95% confidence limits) during August of 1978, to 270 000 ± 75 000 during August of 1979, a 96% decrease. Because Mysis, a cold stenotherm, is restricted to the metalimnion and hypolimnion of lakes during summer, the pH range encountered by the population was 5.51 to 6.32 in 1978 and 5.23 to 6.10 in 1979, even though mean pH values in epilimnion waters for the 2 yr were 5.84 and 5.60. A decrease in pH of its habitat from 6.2 to 5.6 during fall overturn in 1979 caused the elimination of the remaining 4% of the population. Comparisons with four control lakes suggested that the decline and disappearance were not normal occurrences in unstressed lakes. Concentrations of Zn, Al, Mn, Fe, Cd, Cu, Ni, and Hg in Lake 223 water were low, and concentrations in Mysis were less than or equal to those in animals from five control lakes, suggesting that the decline in this species was not due to the toxic effects of metals. All size classes were affected, so that direct toxicity of hydrogen ion may be responsible for this abrupt population collapse. These results suggest that Mysis may be a useful early indicator of acidification damage to Precambrian Shield lakes.

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