Phosphorus sorption characteristics of a light-weight aggregate

A light-weight aggregate (LWA) made of expanded clay used as a filter media in wastewater treatment, was tested for sorption of phosphorus (P) in laboratory experiments. The objectives were to investigate the different P retention pools and how grain size, time, temperature and changed P concentration influenced the P binding mechanisms in this type of filter. Three different grain sizes (0-2 mm, 2-4 mm and 0-4 mm) were tested in a batch experiment. The isotherm for the P sorbed by the contact medium (including retention and fixation) was obtained under laboratory conditions. Fifty percent of the P sorption occurred in the first 4-8 hours. Temperature did not substantially influence P sorption for 0-2 mm grain size LWA. In the LWA suspension system, P desorption did not occur when the P content in the loading solution decreased. Fractionation analysis indicated that Ca-bound P, loosely-bound P, and Al-bound P were the predominant P retention pools. The loosely-bound P pool was determined primarily by the equilibrated P concentration in the system. Fe-bound P was negligible in the P sorption of LWA.

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

Marine and Freshwater Research ◽

10.1071/mf9921535 ◽

1992 ◽

Vol 43 (6) ◽

pp. 1535 ◽

Cited By ~ 13

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.

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Soil phosphorus sorption properties in different fertilization systems

Plant Soil and Environment ◽

10.17221/696/2018-pse ◽

2019 ◽

Vol 65 (No. 2) ◽

pp. 78-82 ◽

Cited By ~ 1

Author(s):

Ewa Szara ◽

Tomasz Sosulski ◽

Magdalena Szymańska

Keyword(s):

Binding Energy ◽

Soil Phosphorus ◽

Sorption Properties ◽

Phosphorus Sorption ◽

Sorption Coefficient ◽

P Sorption ◽

P Content ◽

Sorption Parameters ◽

Total P

The study aimed at the evaluation of the accumulation and vertical distribution of different forms of phosphorus (P) in reference to phosphorus sorption properties subject to mineral (NPK), mineral-organic (NPK + M), and organic (M) fertilisation. It was carried out in a long-term experimental field in Skierniewice (Central Poland) conducted since 1923 under rye monoculture. Total P content in the M and NPK soil profile was similar and lower than in the NPK + M soil. The content of organic P in Ap and Eet horizons of both manured soils was similar and higher than in the NPK soil. The Langmuir P sorption maximum (Smax) in the studied soils ranged from 39.7 to 90 mg P/kg, while the Freundlich P sorption coefficient aF ranged from 6.9 to 41.9 mg P/kg. Higher variability of parameters related to the binding energy from the Lanqmuir (k) and Freundlich (aF) equations was determined between soil horizons than between the fertilisation systems. Nonetheless, in M and NPK + M soils, sorption parameters aF and Smax and binding energy (k, bF) were considerably lower than in the NPK soil. The content of water extracted P in manured soils was higher than in the NPK soil.

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Kinetics of phosphorus sorption in soils in the state of Paraíba¹

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832011000400024 ◽

2011 ◽

Vol 35 (4) ◽

pp. 1301-1310 ◽

Cited By ~ 6

Author(s):

Hemmannuella Costa Santos ◽

Fábio Henrique Tavares de Oliveira ◽

Ignácio Hernan Salcedo ◽

Adailson Pereira de Souza ◽

Valério Damásio da Mota Silva

Keyword(s):

Soil Properties ◽

Clay Content ◽

The State ◽

Phosphorus Sorption ◽

P Adsorption ◽

Soil P ◽

P Sorption ◽

P Concentration ◽

Elovich Equation ◽

Kinetics Of

The soil P sorption capacity has been studied for many years, but little attention has been paid to the rate of this process, which is relevant in the planning of phosphate fertilization. The purpose of this experiment was to assess kinetics of P sorption in 12 representative soil profiles of the State of Paraíba (Brazil), select the best data fitting among four equations and relate these coefficients to the soil properties. Samples of 12 soils with wide diversity of physical, chemical and mineralogical properties were agitated in a horizontal shaker, with 10 mmo L-1 CaCl2 solution containing 6 and 60 mg L-1 P, for periods of 5, 15, 30, 45, 60, 90, 120, 420, 720, 1,020, and 1,440 min. After each shaking period, the P concentration in the equilibrium solution was measured and three equations were fitted based on the Freundlich equation and one based on the Elovich equation, to determine which soil had the highest sorption rate (kinetics) and which soil properties correlated to this rate. The kinetics of P sorption in soils with high maximum P adsorption capacity (MPAC) was fast for 30 min at the lower initial P concentration (6 mg L-1). No difference was observed between soils at the higher initial P concentration (60 mg L-1). The P adsorption kinetics were positively correlated with clay content, MPAC and the amount of Al extracted with dithionite-citrate-bicarbonate. The data fitted well to Freundlich-based equations equation, whose coefficients can be used to predict P adsorption rates in soils.

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Increasing P Retention in the Peat Column Amended with Mineral Soil and Some Rock Phosphates

Jurnal Ilmu Tanah dan Lingkungan ◽

10.29244/jitl.6.1.22-30 ◽

2004 ◽

Vol 6 (1) ◽

pp. 22-30 ◽

Cited By ~ 1

Author(s):

W Hartatik ◽

K Idris ◽

S Sabiham ◽

S Djuniwati ◽

J Sri Adiningsih

Keyword(s):

Rock Phosphate ◽

Soil Column ◽

Mineral Soil ◽

Bottom Layer ◽

Rock Phosphates ◽

Complete Control ◽

P Sorption ◽

P Accumulation ◽

P Content ◽

P Retention

Peat soils have a very low capacity in retaining P. Mineral soils rich in Fe could be used as ameliorant in increasingthis capacity.The aim of this experiment was to study the use of three rock phosphates and SP-36 on peat amended withmineral soil in increasing P retention. The experiment was conducted in the laboratory of the Centre for Soil and Agroclimate Research and Development, Bogor. P treatments consist of four P fertilizer sources including Morocco rock phosphate,Christmas rock phosphate, Ciamis rock phosphate, and SP-36, and three P level (50, 100 and 200% of P sorption) plus partial and complete control in 2 replications. The experiment conducted in soil column made from PVC pipe 4 inch in diameter. Column was filled with 1 250 g peat cily weight (10.5' C), 250 g of which was amended with mineral soil and each of three rock phosphates or SP-36, and put on as the upper part of the column and incubated for 4 weeks. Leaching was conducted everyday, with 50 cc distilled water for 12 days. Filtrate was collected in 500 cc Erlenmeyer glass, and soluble P was analyzed. After this step peat in the colu~nnw as divided into seven depth that were 0-5, 5-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm, then P-Bray I was analyzed. The results showed that the applicatiorz of Morocco and Ciamis rock phosphates on peat amended with mineral soil after leaching, resulted in accumulation of P on the upper layers, suggesting that P retention on peat was increased such that P loss could be reduced. Ratio of P content in the soil column at 0-30 cm and 30-60 cm depth for Morocco rock phosphate on the dosages of 50, 100 and 200% of P sorption were 1.54; 1.90; and 2.79, respectively, and that for Ciamis rock phosphate were 1.64; 1.76 and 4.1 I, respectively. The application of Christmas rock phosphate resulted in P accumulation at 30-40 cm depth. Ratio of P content in soil column treated with Christmas rock phosphate at 0-30 cm and 30-60 cm depth on dosages of 50, 100 and 200 % of P sorption were 1..05; 1.11 and 1.38, respectively, suggesting that P was leached to bottom layer. It seems that high Fe in Christmas rock phosphate did not contribute to an increase of P retention. Although the application of SP-36 resulted in P accumulation at the upper layers, P leaching was higher.

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Soil phosphorus buffering measures should not be adjusted for current phosphorus fertility

Soil Research ◽

10.1071/sr06126 ◽

2008 ◽

Vol 46 (8) ◽

pp. 676 ◽

Cited By ~ 25

Author(s):

L. L. Burkitt ◽

P. W. G. Sale ◽

C. J. P. Gourley

Keyword(s):

Agricultural Soils ◽

Soil Phosphorus ◽

Single Point ◽

Sorption Isotherms ◽

Phosphorus Sorption ◽

Soil P ◽

P Sorption ◽

P Concentration ◽

Extractable P ◽

Fertiliser Application

Soil phosphorus (P) sorption is an important and relatively stable soil property which dictates the equilibrium between sorbed and solution P. Soil P sorption measures are commonly adjusted for the effect of current P fertility on the amount of P a soil sorbs. In the case of highly fertilised agricultural soils, however, this adjustment is likely to be inappropriate as it may mask changes in a soil’s capacity to sorb P, which could affect future P fertiliser applications. A study was undertaken to compare adjusted or unadjusted methods of measuring P sorption using 9 pasture soils sampled from southern Victoria which had previously received P fertiliser and lime. The P sorption assessment methods included: P sorption isotherms, P-buffering capacity (PBC) measures (slope between equilibrium P concentration of 0.25 and 0.35 mg P/L), and single-point P-buffering indices (PBI), with methods either adjusted or unadjusted for current P fertility. A single application of 280 kg P/ha, 6 months before sampling, resulted in a general negative displacement of unadjusted P sorption isotherm curves, indicating reduced P sorption on 8 of the 9 soils. Adding the Colwell extractable P concentration to the amount of P sorbed before calculating the slope (PBC+ColP), tended to negate this fertiliser effect and, in 2 of the 9 soils, resulted in a significant increase in PBC+ColP values. Increasing rates of P fertiliser application (up to 280 kg P/ha) resulted in a consistent trend to decreasing PBI values (unadjusted for Colwell P), which was significant at 4 of the 9 sites after 6 months. However, only minimal changes in PBI values were determined when PBI was adjusted for current P fertility (PBI+ColP). Phosphorus sorption properties appeared reasonably stable over time, although 2 soils, both Ferrosols, indicated significant linear increases in PBI values when these sites remained unfertilised for 30 months. Lime significantly increased both PBI and PBI+ColP values at all sites 6 months after application, but the effect generally diminished after 30 months, suggesting PBI measurements should not be taken immediately after liming. These results demonstrate that unadjusted measures of P sorption are more likely to accurately reflect changes in soil P sorption capacity following P fertiliser applications and suggest that the unadjusted PBI be used in commercial soil testing rather that the currently adjusted PBI+ColP.

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1049 Quality Control of Pumping Concrete Containing Artificial Light-Weight Aggregate (Materials and Execution)

Transactions of the Architectural Institute of Japan Summaries of Technical Papers ◽

10.3130/aijsaxxe.42.0_49 ◽

1967 ◽

Vol 42 (0) ◽

pp. 49

Author(s):

Masahiro Yokoyama

Keyword(s):

Quality Control ◽

Artificial Light ◽

Light Weight ◽

Light Weight Aggregate

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Biochar Chemistry in a Weathered Tropical Soil: Kinetics of Phosphorus Sorption

Agriculture ◽

10.3390/agriculture11040295 ◽

2021 ◽

Vol 11 (4) ◽

pp. 295

Author(s):

Marina Moura Morales ◽

Nicholas Brian Comerford ◽

Maurel Behling ◽

Daniel Carneiro de Abreu ◽

Iraê Amaral Guerrini

Keyword(s):

Mineral Soil ◽

Soil Surface ◽

Kinetic Studies ◽

Inorganic Phosphorus ◽

Initial Reaction ◽

Phosphorus Sorption ◽

P Sorption ◽

Published Research ◽

Kinetics Of

The phosphorus (P) chemistry of biochar (BC)-amended soils is poorly understood. This statement is based on the lack of published research attempting a comprehensive characterization of biochar’s influence on P sorption. Therefore, this study addressed the kinetic limitations of these processes. This was accomplished using a fast pyrolysis biochar made from a mix of waste materials applied to a highly weathered Latossolo Vermelho distrofico (Oxisol) from São Paulo, Brazil. Standard method (batch method) was used. The sorption kinetic studies indicated that P sorption in both cases, soil (S) and soil-biochar (SBC), had a relatively fast initial reaction between 0 to 5 min. This may have happened because adding biochar to the soil decreased P sorption capacity compared to the mineral soil alone. Presumably, this is a result of: (i) Inorganic phosphorus desorbed from biochar was resorbed onto the mineral soil; (ii) charcoal particles physically covered P sorption locations on soil; or (iii) the pH increased when BC was added SBC and the soil surface became more negatively charged, thus increasing anion repulsion and decreasing P sorption.

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Reinforcing Mechanisms of Coir Fibers in Light-Weight Aggregate Concrete

Materials ◽

10.3390/ma14030699 ◽

2021 ◽

Vol 14 (3) ◽

pp. 699

Author(s):

Xiaoxiao Zhang ◽

Leo Pel ◽

Florent Gauvin ◽

David Smeulders

Keyword(s):

Cement Hydration ◽

Natural Fibers ◽

Autogenous Shrinkage ◽

Drying Shrinkage ◽

Hydration Reaction ◽

Light Weight ◽

Limited Information ◽

Aggregate Concrete ◽

Coir Fibers ◽

Light Weight Aggregate

Due to the requirement for developing more sustainable constructions, natural fibers from agricultural wastes, such as coir fibers, have been increasingly used as an alternative in concrete composites. However, the influence of coir fibers on the hydration and shrinkage of cement-based materials is not clear. In addition, limited information about the reinforcing mechanisms of coir fibers in concrete can be found. The goal of this research is to investigate the effects of coir fibers on the hydration reaction, microstructure, shrinkages, and mechanical properties of cement-based light-weight aggregate concrete (LWAC). Treatments on coir fibers, namely Ca(OH)2 and nano-silica impregnation, are applied to further improve LWAC. Results show that leachates from fibers acting as a delayed accelerator promote cement hydration, and entrained water by fibers facilitates cement hydration during the whole process. The drying shrinkage of LWAC is increased by adding fibers, while the autogenous shrinkage decreases. The strength and toughness of LWAC are enhanced with fibers. Finally, three reinforcement mechanisms of coir fibers in cement composites are discussed.

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