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Jaya , P. C. Srivastava , A. K. Agnihotri , D. Ghosh

Abstract

Using batch technique, the effect of some factors like adsorbate concentration, equilibrium pH, temperature and ionic strength on adsorption-desorption of fulvic acid on goethite (α-FeOOH) was studied. The adsorption isotherms were predominantly of S-type and confirmed to Freundlich equation. The calculated value of adsorption capacity (log K) decreased while slope factor (l/n) increased with the increase in equilibrium pH from 5.0 to 6.0. An increase in temperature from 5° to 20°C increased the adsorption of fulvic acid by many folds but further increase in temperature from 20° to 30°C either decreased the adsorption or did not affect it. An increase in ionic strength decreased the adsorption of fulvic acid. In the case of all factors, the desorption of adsorbed fulvic acid has an inverse relationship with the adsorbed amount. Infra-red spectral evidence indicated that COO and phenolic (OH) moieties of fulvic acid interact with goethite.

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Nimisha Singh ¹, Anjana Srivastava ², P. C. Srivastava ³, Nivedita Srivastava ¹

Affiliations
1 Department of Applied Chemistry, M.J.P. Rohilkhand University, Bareilly (U.P.), IN
2 Department of Chemistry, College of Basic Science and Humanities, G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand), IN
3 Department of Social Science, College of Basic Science and Humanities, G.B. Pant University of Agriculture and Technology, Pantnagar, Udhamsingh Nagar (Uttarakhand), IN

Abstract

The efficacy of four microbial cultures strains i.e. P (Fluorescent pseudomonas sp.), S8 (Sphingomonas sp.), Cf (Gordonia sp.), S9P (Consortia of Bacillus and Pseudomonas sp.) was evaluated in dissipation of chlorpyriphos (O,O-diethyl-O-3,5,6-trichloro-2-pyridinyl phosphorothioate), an organophosphate insecticide in mollisols under laboratory conditions. The data obtained in dissipation of chlorpyriphos treated with four cultures in (0-15cm) depth soil was evaluated after eight consecutive samplings (0, 1, 3, 5, 7, 10, 15 and 30 days). The results indicate that the degradation of chlorpyriphos was at slower rate during the first 5 days but thereafter became faster from 7 to 30 days. Dissipation studies could be better accounted by biphasic pattern involving an initial slower and a later faster phase. The kinetics of dissipation of chlorpyriphos from soil was accounted by first order kinetics. As per the data obtained indicates that S9P consortia have shortest half life of 5.37 d with chlorpyriphos in intial phase while P, S8, Cf and control showed half life of 6.53, 9, 8.45 and 9.62 d. While in later phase culture P and S8 showed more effectiveness followed by S9P and Cf in comparison to control in dissipation of chlorpyriphos. Thus S9P consortia was found to be most potent in degradating chlorpyriphos in comparison with rest of cultures.

Keywords

Microbial Culture, Chlorpyriphos, Mollisols, Organophosphate Insecticide.

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