Fig. 1

FTIR spectrum of PLP before (B) and after (A) fluoride adsorption. [In “A”—a = 3442 cm⁻¹, b = 2936 cm⁻¹, c = 2876 cm⁻¹, d = 2122.13 cm⁻¹, e = 1739 cm⁻¹, f = 1662.23 cm⁻¹, g = 1439 cm⁻¹, h = 1297 cm⁻¹, i = 1192 cm⁻¹, j = 1039.4 cm⁻¹, k = 684.6 cm⁻¹. In “B”—a = 3431.7 cm⁻¹, b = 2899.4 cm⁻¹, c = 2854.26 cm⁻¹, d = 2111.8 cm⁻¹, e = 1744.7 cm⁻¹, f = 1639.5 cm⁻¹, g = 1437.1 cm⁻¹, h = 1249 cm⁻¹, i = 1167.2 cm⁻¹, j = 1027 cm⁻¹, k = 672.3 cm⁻¹]