Adsorption of polyacrylamide onto Fuller's earth surface

The adsorption of polyacrylamide onto Fuller's earth surface has been studied at tixed pH (4.0) and ionic strength of the medium. The adsorption isotherms display semi-Langmuirian nature but the kinetic curves show that after a detinite time period the exchange phenomenon occurs between the polyacrylamide chain arriving at the interface and those already ad­ sorbed. The adsorption is appreciably affected by the pH, presence of low molecul ar weight sa lts , organic solvents, tem­ perature, molecular weight and degree of hydrolysis of the polymer. Various adsorption and kinetic parameters such as the adsorption coefficient, modified Freundlich adsorption isotherm constants, distribution coefticient, rate constants for ad­ sorption and desorption have also been evaluated. Clay-polymer interactions are involved in several technical areas such as soil stabilization, water treat­ ment, mud formulations for drilling oil wells, injec­ tion of water soluble polymers as mobility control agents for improving oil recovery etc 1.2_ The clays can be considered as the most suitable model adsorbent for any adsorption study as their hydrophillic nature, cation exchange properties and presence of organic moieties offer good opportunities to investigate vari­ ous unexplored faces of adsorption mechanisms. In the present study it is proposed to carry out a well organized investigation on adsorption of polyacryla­ mide (PAM) onto Fuller's earth surface which has been recognised as an adsorbent for selective adsorp­ tion of impurities and coloring materials from oils and fats.