ABSTRACT
Polyhydroxy polyurethane sorbent was modified by the addition of halogen atoms to its matrix to produce a new sorbent distinguished by high surface polarity, enhanced capacity, and improved stability in both acidic and alkaline media. Halo polyhydroxy polyurethane foam (X-PPF) was characterized by NMR, FTIR, UV–Vis, Raman spectroscopy, pHZCP values, and scanning electron microscopy images. Experimental studies have proven that X-PPFs have a great potential for the extraction and recovery of cobalt ions and this was attributed to the presence of halogen, phenolic, and urethane groups. The pHZCP value of X-PPFs was determined to be 0.91 and the maximum metal recovery was achieved at a pH range of 6–7. The kinetics of the process was best described by pseudo-second-order model (R2 = 1). ΔH, ΔS, and ΔG values were calculated to be −57.2 kJ mol−1, −172.6 J K−1 mol−1, and −5.8 kJ mol−1, respectively. A perfect isotherm curve with zero intercept (0.002), good correlation (R2 = 0.999), and capacity of 246.8 mg g−1 was obtained.
GRAPHICAL ABSTRACT
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