The adsorption of poly(vinylpyrrolidone) (PVP) onto Fuller's earth surface was studied at fixed pH (4.2) and room temperature (27 +/- 0.2 degreesC). The kinetics of the adsorption process was monitored and various adsorption and kinetic parameters such as the adsorption coefficient, the rate constants for adsorption and desorption, the diffusion constant, and the penetration constant were evaluated. The effects of various experimental factors such as the pH and the presence of inorganic and organic anions or aliphatic alcohols were also studied on the adsorbed amounts of PVP. The role of temperature was also investigated and various thermodynamic parameters such as the standard Gibb's free energy, enthalpy, and entropy were also evaluated.