Sorption of three divalent toxic metal ions, viz. copper, lead, and zinc, onto a low-cost aluminosilicate mineral, pyrophyllite, was studied in a single component system at four different temperatures. Four isotherms-Freundlich, Langmuir, Redlich-Peterson, and Temkin-were examined in order to test their suitability for the given sets of experimental data. A comparison of the linear least-squares method and a trial-and-error nonlinear method of the four isotherms was done. The Langmuir isotherm had four different linear forms, and all of them were individually Studied and compared with the others. The parameters of all the four forms of the Langmuir isotherm obtained by the linear method were different. Langmuir-I is the most popular form of the Langmuir isotherm having the highest coefficient of determination values (0.996886) compared with other linear forms of the Langmuir isotherm. The Redlich-Peterson isotherm produced a higher coefficient of determination values (0.999234) in comparison to all the isotherms studied.