Figure 2. Linearized Langmuir isotherm for copper sorption by U. reticulata (M = 2 g/L). Initial solution pH: (◊), pH 3.0; (□), pH 3.5; (Δ), pH 4.0; (×), pH 4.5; (*), pH 5; (○), pH 5.5; (+), pH 6.0.