PENTACHLOROPHENOL INTERACTIONS WITH SOIL

Pentachlorophenol (PCP) adsorption and desorption equilibrium was stud ied with two Menfro silt loam soils - upper horizon and lower horizon. For the adsorption studies the variables were: temperature (10 and 30 -degrees-C) and the amount of organic matter. The variables for the de sorption studies were: temperature (10 and 30-degrees-C), pH and the p resence of an anionic and a cationic surfactant. The results from thes e studies confirmed the importance of soil organic matter for adsorpti on of PCP on the soils. The adsorption data at different temperatures indicated the physical nature of the adsorption process. The desorptio n data produced non-singularity and some PCP was irreversibly adsorbed onto the soil despite repeated washings. Increased pH increased the d esorption of PCP from the soil. The anionic surfactant, sodium dodecyl benzene sulfonate (SDS) was able to desorb significant amounts of PCP from the soil at doses equal to critical micelle concentration (CMC). But, the nonionic surfactant, surfactant, Triton X-405 required a much higher dose (twice the CMC) to cause a significant desorption of PCP from the soil.