Melt processing of polypropylene-grafted-maleic anhydride/Chitosan polymer blend functionalized with montmorillonite for the removal of lead ions from aqueous solutions.

ABSTRACT

Heavy metals such as lead ions Pb (II) are a primary concern in the aquatic environment. These is because Pb (II) is poisonous at a threshold limit above 0.01 mg/L, when consumed over a long period of time. Pb (II) poisoning is very harmful to various organs viz. heart, intestine and kidneys. Besides, it affects bones, tissues, nervous and reproductive systems. Hence, it is important to remove Pb (II) from aquatic environment. Polypropylene (PP) and polypropylene grafted-maleic-anhydride (PP-g-MA) based nanocomposites reinforced with Chitosan (CS) and modified montmorillonite clay nanofiller (CL120DT) were successfully fabricated using twin screw melt extrusion for adsorption of Pb (II). The resulting nanocomposites were characterized by XRD to analyze the dispersion properties of the material, TEM and SEM for surface morphology, FTIR analysis for the functional groups and TGA for thermal stability. Pure PP showed two sharp peaks, but there was decreased in the intensity upon adding of CS and CL120DT. Among series of nanocomposites 2.0 phr and 4.0 phr loaded samples shows better storage module than that of pure PP. The uptake of Pb (II) from lead nitrate aqueous solution by PP + PP-g-MA/CL120DT-CS 2.0 phr nanocomposites followed the Langmuir isotherm model, with a remediation of 90.9% at pH 8 and was verified by pseudo-second order kinetic model. These results indicate that PP + PP-g-MA//CL120DT-CS 2.0 phr nanocomposites performed as a superabsorbent for the Pb (II) ion removal from aqueous solution.