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Runu Chakraborty ¹, Siddhartha Datta ², S. K. Sanyal ²

Affiliations
1 Department of Food Technology and Biochemical Engineering, Jadavpur University, Calcutta 700032, IN
2 Department of Chemical Engineering, Judavpur University, Calcutta 700032, IN

Abstract

Hydrodynamic characteristics of a liquid membrane permeation system for separation of toluene from a mixture of heptane and toluene were studied. The mass transfer coefficient was well correlated in terms of three dimensionless numbers: Sherwood, Schmidt and Reynolds. By using the correlation equation, a correction factor with respect to intrinsic permeation rate was evaluated from the experimental data under various non-ideal flow conditions.

Keywords

Liquid Surfactant Membrane, Hydrocarbon, Mass Transfer Coefficient, Intrinsic Permeation Rate.

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A. Datta ¹, S. Saha ¹, S. K. Sanyal ¹

Affiliations
1 Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Kalyani 741235, West Bengal, IN

Abstract

The kinetics of phosphate sorption/desorption in eight acidic soils were studied. The data were fitted to a modified Freundlich-type of kinetic equation and the modified Elovich equation to yield several kinetic parameters. The kinetic experiments were conducted at 35 ± 1°C and for some soil, also at 45 ± 1°C. The phosphate sorption rate coefficients and the Elovich kinetic parameters were in agreement with the trend of phosphate sorption equilibrium behaviour of the present soils. The phosphate sorption kinetic parameters showed significant correlations with soil organic matter and oxalate-extractable aluminium and iron of the soils. The possibility that an association of organic matter in acidic soils with the hydrous sesquioxides of iron and aluminium leads to the formation of chelate complexes having large active surface area for phosphate sorption has been considered for the present soils. The sorption rate coefficients increased with temperature, in agreement with the simple Arrhenius behaviour. The activation energies for phosphate sorption suggested the chemical nature of the given sorption process.

During desorption, the sorption rate parameter was lower than that during the corresponding sorption run, indicating the possibility that the sorted phosphate might have undergone transformations that render it less susceptible to release.

Keywords

Phosphate Sorption/Desorption Kinetics, Modified Freundlich-Type of Kinetic Equation, Elovich Equation, Soil Organic Matter and Hydrous Sesquioxides.

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P. K. Mani ¹, S. K. Sanyal ¹

Affiliations
1 Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Kalyani 741 235, West Bengal, IN

Abstract

Three surface soil samples (0-1.15 m) were collected from different locations of West Bengal, India, namely, Jhargram (Alfisol), Bolpur (Alfisol), and Mohitnagar (Inceptisol) having contrasting physicochemical properties. The charge characteristics of the clay fraction of these soils were probed in terms of the zero-point of charge (ZPC) of the soils. The high values of ZPC noted for the Jhargram and the Bolpur soils may be due to the presence of a large amount of free (variable-charge) sesquioxides in these soils; lower ZPC values were noted in the Mohitnagar soil. Furthermore, the negative magnitudes of ΔpH [pH (KCl) - pH (H₂0)] values, noted for the present soils, suggested that the Mohitnagar soil had less developed characteristics, whereas the Jhargram and the Bolpur soils were in more advanced stages of pedogenic development. The soil samples studied for ZPC were also treated with aqueous KH₂PO₄ solution, and the ZPC values of these phosphate-treated soil samples registered shifts to lower pH values. This may have arisen from an increase in negative charge on soil colloids, following ligand exchange with the added phosphate. The surface potential and the surface charge density of each soil were found to increase in negative magnitude on phosphate application, possibly due to concomitant increases of the negative charges of the clay fraction of the given soils on phosphate fixation through ligand exchange mechanism. The implication of the above parameters, especially their changes on phosphate treatment of the soils, have been related to the tendency of the given soils to immobilize the added phosphate.

Keywords

Zero-Point of Charge (ZPC), Surface Potential, Variable Charge Density, Permanent Charge Density.

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S. K. Sanyal ¹, B. S. Dwivedi ², V. K. Singh ³, K. Majumdar ⁴, S. C. Datta ², S. K. Pattanayak ⁵, K. Annapurna ²

Affiliations
1 Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia 741 252, IN
2 Indian Agricultural Research Institute, New Delhi 110 012, IN
3 Farming Systems Research, Modipuram, Meerut 250 110, IN
4 International Plant Nutrition Institute, South Asia Programme, Gurgaon 122 016, IN
5 Orissa University of Agriculture and Technology, Bhubaneswar 751 003, IN

Abstract

Soils vary widely in their capacities to supply phosphorus (P) to crops because only a small fraction of the total P in soil is available to crops. Thus, the crop growth and yield are likely to suffer adversely unless soil is endowed with adequate native supply of plantavailable P, or else the soil receives readily available (inorganic) P fertilizers. In order to rationalize fertilizer P application to support sustained high productivity on one hand and address the environmental and economic concerns on the other, an in-depth understanding of native P supplies and P dynamics in soil is inevitable. In this context, the present article takes stock of the available information on the occurrence of P in soils, chemistry of P in soil, P quantity, intensity, and buffer capacity attributes of different soils vis-àvis the P uptake modelling, P dynamics in soil, P management in important cropping systems for enhancing its use efficiency, soil testing for plant-available P to prescribe fertilizer P application and losses of P through erosion and runoff to the water bodies leading to eutrophication.

Keywords

Cropping Sequences, Phosphorus Dynamics, Phosphorus in Soils.

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G. C. Banik ¹, S. K. Sanyal ²

Affiliations
1 Department of Soil Science and Agricultural Chemistry, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar 736 165, IN
2 Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia 741 252, IN

Abstract

Inorganic soil arsenic (As) in three soils was fractionated adopting phosphorus fractionation schemes. Among these fractions, iron-bound arsenic (Fe-As) was found highest, followed by aluminium-bound arsenic (Al-As). The freely exchangeable arsenic was relatively small compared to the arsenic held by internal surfaces of soil aggregates. The arsenic fractions exhibited positive correlation with phosphorus content presumably due to the fact that high P in soil releases more arsenic from soil adsorption sites owing to the competition for the same adsorption sites. Predominantly, negative correlation of arsenic with organic carbon confirms the fact of lowering of arsenic mobility in presence of organics in soil.

Keywords

Arsenic Fractions, Arsenic Extractants, Soil Properties, Resin Extractable Arsenic.

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S. K. Sanyal ¹

Affiliations
1 Chemical Engg. Department, Jadavpur University, Calcutta-700032, IN

Abstract

After having enjoyed a preeminent position on All India level in industrial development, the growth rate of industries particularly chemical industries came down sharply in the Eastern Region viz-a-viz West Bengal during the last two decades and the centre of activities shifted to the Western Coast.

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