INTERPOLYMER SYSTEMS OF POLY(METHACRYLIC ACID): POLY(4-VINYLPYRIDINE) FOR THE SELECTIVE SORPTION AND DESORPTION OF RHENIUM IONS

Abstract

Introduction. Rhenium is a rare transition metal used in alloys and catalysis. Industrial recovery comes mainly from sulfuric acid effluents formed during copper and molybdenum processing. Sorption is the main method, but the choice of effective sorbents remains an issue. Aims. Interpolymer systems (IPS) of poly(methacrylic acid) (PMAA) and poly(4-vinylpyridine) (P4VP) were prepared and tested. IPS samples with different PMAA:P4VP ratios were prepared and tested. Sorption capacity, desorption behavior, and structural as well as thermal characteristics were investigated. Results and Discussion. The sorption efficiency varies with polymer composition. The 2:4 PMAA:P4VP ratio gave the highest uptake. Desorption in 2% nitric acid was moderate, with a maximum of about 75.6%. FTIR spectra showed shifts in carboxyl and pyridyl bands, confirming the role of functional groups. TGA/DSC data indicated stabilization of the polymer network after rhenium binding. Conclusion. The PMAA:P4VP system at a 2:4 ratio combined high sorption, moderate desorption, and improved structural stability. This system may be applied for rhenium recovery from metallurgical wastewater.