scholarly journals Organic acids in the rhizosphere and phytoavailability of sewage sludge-borne trace elements

2007 ◽  
Vol 42 (7) ◽  
pp. 917-924 ◽  
Author(s):  
Adriana Marlene Moreno Pires ◽  
Giuliano Marchi ◽  
Maria Emília Mattiazzo ◽  
Luiz Roberto Guimarães Guilherme
Keyword(s):  
Trace Elements ◽  
Sewage Sludge ◽  
Organic Acids ◽  
High Performance ◽  
Low Molecular Weight ◽  
Average Composition ◽  
Tukey Test ◽  
Linear Correlation Analysis ◽  
Treatment Concentration ◽  
Oxalic Acids

The aim of this work was to quantify low molecular weight organic acids in the rhizosphere of plants grown in a sewage sludge-treated media, and to assess the correlation between the release of the acids and the concentrations of trace-elements in the shoots of the plants. The species utilized in the experiment were cultivated in sand and sewage sludge-treated sand. The acetic, citric, lactic, and oxalic acids, were identified and quantified by high performance liquid chromatography in samples collected from a hydroponics system. Averages obtained from each treatment, concentration of trace elements in shoots and concentration of organic acids in the rhizosphere, were compared by Tukey test, at 5% of probability. Linear correlation analysis was applied to verify an association between the concentrations of organic acids and of trace elements. The average composition of organic acids for all plants was: 43.2, 31.1, 20.4 and 5.3% for acetic, citric, lactic, and oxalic acids, respectively. All organic acids evaluated, except for the citric acid, showed a close statistical agreement with the concentrations of Cd, Cu, Ni, and Zn found in the shoots. There is a positive relationship between organic acids present in the rhizosphere and trace element phytoavailability.

scholarly journals Dynamics of Fe, Mn, and Al Liberated from Contaminated Soil by Low-Molecular-Weight Organic Acids and Their Effects on the Release of Soil-Borne Trace Elements

2018 ◽  
Vol 8 (12) ◽  
pp. 2444 ◽  
Author(s):  
Junhao Qin ◽  
Osim Enya ◽  
Chuxia Lin
Keyword(s):  
Molecular Weight ◽  
Trace Elements ◽  
Organic Acids ◽  
Organic Acid ◽  
Contaminated Soil ◽  
Manganese Oxides ◽  
Low Molecular Weight ◽  
Variation Pattern ◽  
Organic Complexes ◽  
Oxalic Acids

A 15-day batch experiment was conducted to investigate the behaviours of Fe, Mn, and Al oxides upon attack by three common low-molecular-weight organic acids, and their effects on liberation of trace elements from a multi-contaminated soil. While the capacity of malic acid to mobilize soil-borne Fe, Mn, and Al was weaker compared to citric and oxalic acids, a similar trend was observed, showing that the concentration of dissolved Fe, Mn, and Al increased with increasing duration of the experiment. Marked increase in metal concentrations only took place after 5 or 7 days of the experiment. For the same organic acid treatment, Fe, Mn, and Al all showed a very similar temporal variation pattern. The concentration of dissolved Fe, Mn, and Al was markedly controlled by the total Fe, Mn, and Al contained in the soil, respectively. It appears that manganese oxides were more reactive to the organic acids, as compared to their Fe and Al counterparts. However, when multiple organic acids were present, the soil-borne Fe, Mn, and Al were mobilized rapidly within the first 5 or 7 days of the experiment and then tended to decrease. The formation of insoluble Fe, Mn, and Al organic complexes tended to be enhanced due to co-existence of multiple organic acids, resulting in the re-immobilization of the dissolved Fe, Mn, and Al. The organic acid-driven dissolution of Fe, Mn, or Al had a major control on the mobilization of As, Cr, Zn, Ni, Cu, and Cd that were bound to these oxides with a correlation coefficient being frequently greater than 0.9 for As, Cr, Zn, and Ni.

scholarly journals Organic acids effects on desorption of heavy metals from a contaminated soil

2006 ◽  
Vol 63 (3) ◽  
pp. 276-280 ◽  
Author(s):  
Clístenes Williams Araújo do Nascimento
Keyword(s):  
Heavy Metals ◽  
Molecular Weight ◽  
Citric Acid ◽  
Organic Acids ◽  
Low Molecular Weight ◽  
High Biomass ◽  
High Concentration ◽  
Accumulation Of Metals ◽  
Pb Concentration ◽  
Oxalic Acids

Phytoremediation of heavy metals is a biotechnology that extracts metals from soils and transfer them to plant. As hyperaccumulator species have demonstrated low potential for commercial phytoextraction, synthetic chelates have been successfully used to induce accumulation of metals by high-biomass plants. However, they pose serious environmental drawbacks regarding excessive amount of metals solubilized. In search for synthetic chelate-alternatives, this paper evaluate the performance of DTPA, EDTA, citric acid, oxalic acid, vanillic acid, and gallic acid in desorbing Cd, Pb, Zn, Cu, and Ni from soil. DTPA and EDTA were highly effective in desorbing Cd, Pb, Zn, Cu, and Ni from soil. However, the excessively high concentration of metals brought in solution by such chelates limits their application in the field. Citric and oxalic acids desorbed substantial quantities of Zn, Cu, and Ni if applied at 10 or 20 mmol kg-1. At the 20 mmol kg-1 dose, vanillic and gallic acids solubilized significant amounts of Zn, Ni, and Cd from soil. None of the tested low molecular weight organic acids substantially increased the Pb concentration in soil solution.

Optimization of Fe2 + /solids content ratio for a novel sludge heavy metal bioleaching process

2008 ◽  
Vol 57 (3) ◽  
pp. 445-450 ◽  
Author(s):  
J. W. C. Wong ◽  
X. Y. Gu
Keyword(s):  
Heavy Metal ◽  
Sewage Sludge ◽  
Organic Acids ◽  
No Reduction ◽  
Iron Oxidation ◽  
Low Molecular Weight ◽  
Nutrient Contents ◽  
Content Ratio ◽  
Solids Content ◽  
High Solids Content

A novel bioleaching process, preincubation bioleaching (PB) has been recently developed in our laboratory for decontamination of heavy-metal-laden sewage sludge by removing the toxic low molecular weight organic acids using an isolated degradative yeast species. The objective of the present study was to optimize Fe2 + /solids content ratio required for removing heavy metals from sewage sludge by using this novel process at high solids content. Results from the present study showed that regardless of the Fe2 + /solids content ratio iron oxidation and sludge acidification could be achieved within 2 days confirming the effectiveness of PB in reducing the inhibitory organic acids. When PB was conducted at an elevated solids content of 3%, Fe2 + /solids content ratio could be reduced to 0.75:1, 1:1 and 1.25:1 for solubilization of Zn, Cu and Cr respectively. Under this optimized bioleaching conditions, the following solubilization efficiencies were obtained after 8 days of bioleaching: 100% Zn, 96% Cu, 60% Cr with no reduction in nutrient contents. Hence, bioleaching at elevated solids contents represents a more economical way for decontamination of heavy-metal-laden sewage sludge while preserving its fertility values.

scholarly journals The role of low molecular weight organic acids in the release of phosphorus from sewage sludge-based biochar

All Life ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 599-609
Author(s):  
Chandra Sekhar Paul ◽  
Filip Mercl ◽  
Jiřina Száková ◽  
Václav Tejnecký ◽  
Pavel Tlustoš
Keyword(s):  
Molecular Weight ◽  
Sewage Sludge ◽  
Organic Acids ◽  
Low Molecular Weight

scholarly journals COPPER MOBILITY IN SOILS AS AFFECTED BY SEWAGE SLUDGE AND LOW MOLECULAR WEIGHT ORGANIC ACIDS

Soil Science ◽  
2006 ◽  
Vol 171 (1) ◽  
pp. 29-38 ◽  
Author(s):  
L. Bahaminyakamwe ◽  
J. Simunek ◽  
J. H. Dane ◽  
J. F. Adams ◽  
J. W. Odom
Keyword(s):  
Molecular Weight ◽  
Sewage Sludge ◽  
Organic Acids ◽  
Low Molecular Weight

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

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