Immobilized Thiosalicylic Ligand System Potentials for the Detoxification of Some Heavy Metals from Tannery Wastewater

摘要

Polysiloxanes are characterized by silicon and oxygen backbone and are hydrophobic in nature with low moisture uptake widely used for medical applications. Polysiloxane immobilized thiosalicylic acid ligand system has been prepared through sol-gel method, gelation was observed after 40 minutes. The immobilized ligand was characterized using FTIR, the spectrum showed characteristic absorption bands (cm~(-1)) at: 3377 (OH), 2981 (C-H stretch); 2631 (SH); 1587 to 1684 (C=C, C=O); 1032 to 1144 (Si - O) respectively. SEM analysis showed irregular particle sizes of the polysiloxane matrices while EDX elemental composition gave (wt %): 3-CPPS; Si (50.45), O (25.02) and Cl (24.57). F - 3CPPS showed, O (58.68), Si (41.32); thiosalicylic (7.14 of S). The extraction of metal ions (Cr~(3+), Fe~(3+), Pb~(2+), Cu~(2+) and Zn~(2+)) were studied using Microwave Plasma Atomic Emission Spectrophotometer (Agilent MPAES-4200) at pH 6.0. Thermodynamic range with respect to Cr~(3+), Fe~(3+), Pb~(2+), Cu~(2+) and Zn~(2+) yielded negative values forΔG~(o): Cu~(2+)-(11.483 to 14.842) to Zn~(2+) -(14.368 to 14.842)KJmol~(-1); positive values for ΔH~(o): Fe~(3+) (0.000) to Pb~(2+) (105.130)KJmol~(-1) and ΔS~(o): Zn~(2+) (47.421) to Pb~(2+) (389.328)Jmol~(1)K~(1) respectively, indicating spontaneous, endothermic reactions and high degree of disorderliness with respect to metal ion binding capacity to the ligand system.