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2328516 
Journal Article 
Adsorption and desorption characteristics of phenoxyacetic acids and chlorophenols in volcanic soil: Single component fixed bed studies 
Susarla, S; Bhamidimarri, SMR; Bhaskar, GV 
1999 
Yes 
Environmental Technology
ISSN: 0959-3330
EISSN: 1479-487X 
SELPER LTD, PUBLICATIONS DIV 
LONDON 
20 
1 
1-9 
English 
WOS:000078814700001 
Widespread application of herbicides and pesticides in recent years resulted in environmental contamination of soils and groundwaters. In this paper, we examine the adsorption and desorption characteristics of three phenoxyacetic acids and three chlorophenols in a volcanic soil using fixed bed soil columns. A theoretical model incorporating sorption, dispersion, film transfer and surface diffusion in soils particles has been developed to predict the solute movement in fixed bed soil columns. The main feature of this model is that all the model parameters were obtained from independent experiments or from literature correlations. Experiments were carried out to examine the effect of concentration and flow rate on the breakthrough and elution of phenoxyacetic acids and chlorophenols from soil columns. The results indicated that increasing the initial concentration and flow rate resulted in a faster breakthrough and elution of solutes. The order of breakthrough and elution for phenoxyacetic acids was: 2,4-dichlorophenoxyacetic acid (2,4-D) > 2-methyl, 4-chlorophenoxyacetic acid (MCPA) > 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and while for chlorophenols the order was: 2,4-dichlorophenol (2,4-DCP) >para-chloro-ortho-phenol (PCOC) > 2,4,5-trichlorophenol (2,4,5-TCP). The results have also shown that the equilibrium sorption played a dominant role in the breakthrough and elution of these chemicals from soil columns. The results of numerical calculations using the model are compared with experimental results and in general, good agreement was obtained for all chemicals considered. 
chlorophenols; equilibrium sorption; dispersion; fixed beds; phenoxyacetic acids; surface diffusion; volcanic soil