scholarly journals Phosphate Sorption Speciation and Precipitation Mechanisms on Amorphous Aluminum Hydroxide

Soil Systems ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 20 ◽  
Author(s):  
Xiaoming Wang ◽  
Brian Phillips ◽  
Jean-François Boily ◽  
Yongfeng Hu ◽  
Zhen Hu ◽  
...  
Keyword(s):  
Solubility Product ◽  
Bulk Solution ◽  
Phosphate Adsorption ◽  
Phosphate Sorption ◽  
Surface Precipitation ◽  
P Sorption ◽  
P Concentration ◽  
Soils And Sediments ◽  
High Phosphate ◽  
Amorphous Alpo4

Aluminum (Al) oxides are important adsorbents for phosphate in soils and sediments, and significantly limit Phosphate (P) mobility and bioavailability, but the speciation of surface-adsorbed phosphate on Al oxides remains poorly understood. Here, phosphate sorption speciation on amorphous Al hydroxide (AAH) was determined under pH 3–8 and P concentration of 0.03 mM–15 mM using various spectroscopic approaches, and phosphate precipitation mechanisms were discussed as well. AAH exhibits an extremely high phosphate sorption capacity, increasing from 3.80 mmol/g at pH 7 to 4.63 mmol/g at pH 3. Regardless of reaction pH, with increasing P sorption loading, the sorption mechanism transits from bidentate binuclear (BB) surface complexation with dP-Al of 3.12 Å to surface precipitation of analogous amorphous AlPO4 (AAP), possibly with ternary complexes, such as (≡Al-O)2-PO2-Al, as intermediate products. Additionally, the percentage of precipitated phosphate occurring in AAP linearly and positively correlates with P sorption loading. Compared to phosphate reaction with ferrihydrite, phosphate adsorbs and precipitates more readily on AAH due to the higher solubility product (Ksp) of AAH. The formation of AAP particles involves AlIII release, which is promoted by phosphate adsorption, and its subsequent precipitation with phosphate at AAH surfaces or in the bulk solution.

Influence of soil water content on the supply of phosphate to plants

Soil Research ◽  
1986 ◽  
Vol 24 (3) ◽  
pp. 435 ◽  
Author(s):  
MCH Mouat ◽  
P Nes
Keyword(s):  
Water Treatment ◽  
P Uptake ◽  
The Other ◽  
Water Volume ◽  
Phosphate Adsorption ◽  
Lolium Perenne L ◽  
Water Treatments ◽  
Water Holding ◽  
P Supply ◽  
High Phosphate

Ryegrass (Lolium perenne L.) was grown in a pot trial in soil of high phosphate adsorption capacity at 10 levels of P-supply and at two water regimes, one regularly adjusted to the water-holding capacity of the pots corresponding to a water potential of -2 to -3 kPa, and the other at 20% less water volume corresponding to - 20 kPa. P uptake was lower in the lower water treatment at all P-supply levels, even when the P-supply was severely limiting P uptake. This reduction in P uptake at all P levels was equivalent to the reduction in water volume between the two water treatments, and is apparently a result of a lower supply of solution phosphate in the lower water treatment in the highly buffered soil.

LABILE RESIDUAL FERTILIZER PHOSPHORUS IN CHERNOZEMIC SOILS. I. SOLUBILITY AND QUANTITY/INTENSITY STUDIES

1977 ◽  
Vol 57 (1) ◽  
pp. 65-73 ◽  
Author(s):  
J. M. SADLER ◽  
J. W. B. STEWART
Keyword(s):  
Solubility Product ◽  
Monoammonium Phosphate ◽  
Inorganic P ◽  
Residual P ◽  
Phosphate Dihydrate ◽  
P Concentration ◽  
Aluminum Iron ◽  
Labile P ◽  
P Addition ◽  
Soil Interface

Granular monoammonium phosphate (500 μg P/g soil) was applied in the field to three soils of an Oxbow catena. Changes in the inorganic P forms controlling P concentration or intensity (Ie) in soil solution during the ensuing 2½ yr were determined by equilibrium solubility product and related quantity/intensity analyses. In the Calcareous and Orthic control soils, Ie was controlled by impure hydroxyapatite. After P addition, it was controlled by dicalcium phosphate dihydrate and octocalcium phosphate. Marked changes in the quantity of labile P caused negligible changes in values for Ie. Therefore, in these and similar Chernozemic soils, Ie should adequately reflect the availability of residual P to plants. In the Gleysol after P addition, Ie was determined by adsorbed P or by the solubility of aluminum/iron-bound P forms. For this and similar Chernozemic soils, the quantity/intensity data indicated that estimates of the availability of residual P will require a measurement of its capacity to maintain Ie at the root–soil interface against depletion by plant uptake rather than a measurement of Ie alone.

Solubility and retention of phosphate in soils of the northwestern Canadian prairie

1991 ◽  
Vol 71 (4) ◽  
pp. 453-463 ◽  
Author(s):  
Y. K. Soon
Keyword(s):  
Organic Matter ◽  
Sorption Capacity ◽  
Agricultural Soils ◽  
Clay Content ◽  
Phosphorus Concentration ◽  
Canadian Prairie ◽  
P Sorption ◽  
P Sorption Capacity ◽  
P Concentration ◽  
Order Of Magnitude

Phosphate solubility and sorption characteristics of 39 agricultural soils in the northwestern Canadian Prairie were studied to gain insights into the retention of fertilizer P added to soil. The soils were mostly acidic with base saturation of 59–95%. The solubility of P as determined by the equilibrium P concentration and phosphoric acid potential was low and appeared to be controlled by sorption of phosphate by soil components. The mean equilibrium solution P concentration was 0.03 mg L−1. Phosphorus concentration in saturation extracts was about one order of magnitude higher, but would have included organic and colloidal P since P analysis in these extracts was done by ICP. Sorption capacity of P as determined by Langmuir isotherm was greater for the Dark Gray and Black soils and gleysols, i.e., soils with higher amounts of organic matter, than the Gray Luvisolic and Solodic soils by about 30%. Partial correlation showed that clay content, Al-organic matter complexes (AlOM) and amorphous iron oxide (FeOX) were significantly correlated with P sorption capacity. When both topsoils and subsoils were considered, clay content was the most important soil property influencing P sorption capacity, followed by AlOM and FeOX (standard partial regression coefficients, b′, of 0.47, 0.39 and 0.38, respectively). When only topsoils were considered, AlOM and FeOX became more important than clay content in influencing P sorption (b′ = 0.47, 0.47, and 0.33, respectively). Native P, estimated by oxalate and anion-resin extractions, was associated with the hydrous iron oxides only, although soil pH also affected the resin-extractable P fraction. Key words: P retention, solubility, Luvisols, solodic soils

scholarly journals The Fate of Glyphosate in Soil and Water: A Review

2021 ◽  
Vol 7 (SpecialIssue) ◽  
pp. 389-399
Author(s):  
Suwardji Suwardji ◽  
‪I Made Sudantha
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Phosphate Adsorption ◽  
Suspended Material ◽  
Soil Sediment ◽  
Soils And Sediments ◽  
Soil Evidence ◽  
Soil Constituents ◽  
Soil And Water

The fate of glyphosate in soil and water is dependent on the properties of glyphosate and its envoronement. Behaviour of glyphosate in soil, sediment and water is strongly influenced the way by which it can be adsorbed by soils, sediments, and suspended material in water. The role of soil organic matter, clay mineral, and amorphous minerals on the adsorption of glyphosate depends primarily on the nature and properties of the soil itself and the properties of glyphosate. Environmental factors have some influence on sorption and degradation of glyphosate. Glyphosate is rapidly inactivated in soil, is in part due to adsorption. Some soil properties have been identified strongly influence adsorption of glyphosate, such as clay minerals, composition of cations in exchangeable site of clay and organic matter, unoccupied phosphate adsorption site, degree of humification, and soil pH. Adsorption limits the availability of glyposate for microbial degradation. The sorbed glyphosate is not directly available to microorganisms in soil. Evidence also suggests that not only a strongly sorbed compound such as paraquat but also weakly sorbed compounds such as flumetsulam and picloram can persist for long periods when they are sorbed by soil constituents. This suggests that the interaction between sorption and biodegradation should be considered in predicting the fate of pesticides in soils and sediments.

Phosphorus sorption-desorption by some sediments of the Johnstone Rivers catchment, northern Queensland

1992 ◽  
Vol 43 (6) ◽  
pp. 1535 ◽  
Author(s):  
C Pailles ◽  
PW Moody
Keyword(s):  
Equilibrium Solution ◽  
Buffer Capacity ◽  
Sea Water ◽  
Phosphorus Sorption ◽  
Constant Amount ◽  
Inorganic P ◽  
P Sorption ◽  
P Concentration ◽  
Extractable P ◽  
Water Columns

Phosphorus (P) sorption-desorption characteristics were determined for 11 sediments from the Johnstone Rivers catchment, northern Queensland. Sediments were selected to cover a range in values of Bray extractable P from 0.1 to 10.4 mg P kg-1. P sorption curves were determined by using 0.01 M NaCl to simulate fluvial water conditions and, on a restricted number of sediments, 0.5 M NaCl to simulate sea water. The amounts of P released in 10 successive extractions for 30 min with 0.01 M CaCl2 were determined for each sediment. The amounts of P desorbed either declined to nondetectable levels or declined to a constant amount. These desorption curves were used to delineate 'rapidly desorbable' P from 'slowly desorbable' P. Bray extractable P and adsorption characteristics (equilibrium solution P concentration and P buffer capacity) were poorly correlated with 'rapidly desorbable' P. Most sediments in the suite would act as P sinks in both fluvial and marine environments because their equilibrium P concentrations are lower than the dissolved inorganic P concentrations of their respective water columns. For those sediments acting as potential sources (5 from 11 in 0.01 M NaC1, 2 from 6 in 0.5 M NaCl), amounts of P that could potentially be desorbed into the fluvial water column ranged from 0.1 to 3.9 mg P kg-1 sediment.

Effects of decalcification on the phosphate sorption characteristics of eight calcareous soils

Soil Research ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 919 ◽  
Author(s):  
ICR Holford ◽  
M Chater ◽  
GEG Mattingly
Keyword(s):  
Calcareous Soils ◽  
Sorption Isotherms ◽  
Phosphate Sorption ◽  
Surface Equation ◽  
P Sorption ◽  
Surface Areas ◽  
Freundlich Equation ◽  
Sorption Parameters ◽  
Parameter Values ◽  
Sorption Characteristics

Phosphate sorption isotherms and parameter values were determined on eight calcareous soils which were carefully decalcified using a procedure which minimized changes in cation saturation. Calcite content of the original soils varied from 0.8 to 24 2% and calcite surface areas from 4 . 0 to 8.5 m2 g-1. Sorption parameters were derived from the Langmuir 'two-surface' equation. Decalcification increased phosphate sorption at low residual P concentrations (<0.8 mg L-1) but decreased it at higher concentrations. The higher P sorption was associated with an increase in affinity because the calculated sorption capacities of high-affinity surfaces were not increased. These sorption capacities were well correlated with iron oxide contents of the soils, so the increase in phosphate affinity of these surfaces was consistent with the decrease in pH (0.5 to 1.5 units) of the decalcified soils. The lower P sorption at higher concentrations was associated with a substantial decrease in sorption capacity of the postulated low-affinity surfaces. These latter decreases were quantitatively correlated with the calcite surface areas of the original soils. These and other changes in phosphate sorption characteristics support the utility of the Langmuir 'two-surface' equation in providing information, compatible with what would be expected from more complex mechanistic models, and which exceeds what one would expect from other simpler models such as the Freundlich equation. They also support an hypothesis that an important component of low-affinity surfaces of these calcareous soils is calcite on which organic anions are co-adsorbed.

Phosphate sorption capacity of European volcanic soils

2010 ◽  
Vol 59 (1) ◽  
pp. 77-84
Author(s):  
Gy. Füleky
Keyword(s):  
Sorption Capacity ◽  
Soil Property ◽  
High Ratio ◽  
Surface Reactivity ◽  
Soil Horizon ◽  
Phosphate Adsorption ◽  
Volcanic Soils ◽  
Phosphate Binding ◽  
Phosphate Sorption ◽  
Sorption Ability

The aim of the presented study was to prepare the phosphate sorption isotherms of 20 European volcanic soil profiles and some other Hungarian and German volcanic soils (n = 114) used in the experiment and to establish the soil characteristics determining the phosphate sorption capacity of these soils. The Langmuir isotherm well describes the phosphate sorption of European volcanic soils at bright concentration interval 0–600 mg·dm -3 P. The calculated phosphate adsorption maximum (P max ) is an excellent soil property for characterizing the surface activity of soils developed on volcanic parent material. The calculated phosphate sorption maxima of soils included in the experiment ranged from 0 to 10.000 mg P·kg -1 . Some of the volcanic soils sorbed a high ratio of the added phosphate at low concentrations, while others sorbed somewhat less. The difference in the phosphate binding affinity of soils caused the differences in the shape of the Langmuir adsorption isotherms. P retention % is a WRB diagnostic requirement of andic soil horizon. It was supposed that the phosphate sorption maximum (P max ) gives a better characterization of the surface reactivity of volcanic soils. As it was predicted, oxalate soluble Al is the most important soil property, which dominantly (in 73%) explained the phosphate sorption ability of European volcanic soils.

Effects of Phosphate on Pit Stabilization and Propagation in Copper in Synthetic Potable Waters

CORROSION ◽  
10.5006/0883 ◽  
2013 ◽  
Vol 69 (7) ◽  
pp. 703-718 ◽  
Author(s):  
Hung M. Ha ◽  
John R. Scully
Keyword(s):  
Pitting Corrosion ◽  
Phosphate Concentration ◽  
Bulk Solution ◽  
Pitting Potential ◽  
Inhibition Effect ◽  
Drinking Waters ◽  
Pit Depth ◽  
Deep Pits ◽  
High Phosphate

Addition of less than 0.32 mM phosphate (10 mg/L as P) to synthetic potable waters delayed pit stabilization in copper by raising the pitting potential. Phosphate additions to synthetic drinking waters also repassivated propagating artificial copper pits but only at high phosphate concentrations such as 1.6 mM or 3.2 mM (50 mg/L or 100 mg/L as P). The inhibition efficacy of phosphate was a function of both phosphate concentration and preexisting artificial pit depth. Pit growth was easier to suppress when artificial pits were shallow (e.g., ~20 μm) compared to deep pits (e.g., ~250 μm). The inhibition effect of phosphate on copper pitting corrosion was reversible. Upon removal of phosphate from the bulk solution, pits grew at increasing rates. Two inhibition mechanisms capable of explaining the effect of phosphate on copper pitting are discussed.

scholarly journals Phosphate sorption indices as affected by the calcareousness of soils

2019 ◽  
Vol 28 (1) ◽  
pp. 93-110
Author(s):  
Tasmeena Sultana Yousuf ◽  
Mohammad Enayet Hossain ◽  
Mohammad Zafar Afsar ◽  
Khan Towhid Osman
Keyword(s):  
Soil Solution ◽  
Calcareous Soils ◽  
Threshold Value ◽  
Phosphate Sorption ◽  
Soil P ◽  
Freundlich Isotherms ◽  
Centrifuge Tube ◽  
Phosphorus Buffering Capacity ◽  
Langmuir And Freundlich Equations ◽  
High Phosphate

An experiment was carried out to study the effects of calcareousness on phosphate sorption indices of soils using three representative calcareous soils, namely Sara (Aquic Eutrochrept), Gopalpur (Aquic Eutrochrept), and Ishurdi (Aeric Haplaquept) series of Bangladesh. Three non-calcareous soils, namely Belabo (Typic dystrudepts), Sonatala (Aeric Endoaquepts) and Ghatail (Aeric Haplaquept) series were also selected for comparison purposes. Phosphate sorption indices of soils were calculated using Langmuir and Freundlich isotherms. Isotherms were constructed taking one gram of air-dried sieved (< 2 mm) soil into a 50 ml centrifuge tube, and subsequently adding seven initial P concentrations, namely 0, 1, 10, 25, 50, 100 and 150 μg/ml to each centrifuge tube employing a soil/solution ratio of 1 : 20 (w/v). According to the Langmuir equation, the amount of phosphate sorbed followed the order: Sonatala > Ghatail > Sara = Gopalpur > Ishurdi > Belabo. The abundance of amorphous iron rather than the calcareousness was putatively responsible for the high phosphate sorption capacity of soils. Maximum phosphorus buffering capacity (MPBC) of the calcareous soils ranged from 33.4 - 62.8 l/kg. Langmuir and Freundlich equations produced different values for soil P requirements (SPR) at 0.2 and 1.0 mg P/l. Calcareous soils would require 27 - 44 mg P/kg soil to attain 0.2 mg P/l soil solution, which is deemed sufficient for crop growth. The soils would require 32 - 58 mg P/kg soil to reach 1.0 mg P/l soil solution, which is regarded to be safe for soils in terms of susceptibility to P losses. The calculated Langmuir constant b values were higher than the threshold value of 0.07 l/mg for two of the calcareous soils. Therefore, even though the non-calcareous soils sorbed more phosphate, higher bonding energy of P sorption for calcareous soils makes them less vulnerable to loss via surface runoff. Dhaka Univ. J. Biol. Sci. 28(1): 93-110, 2019 (January)

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