Retention Profile and Selective Separation of Trace Concentrations of Phenols from Water onto Iron(III) Physically Loaded Polyurethane Foam Solid Sorbent: Kinetics and Thermodynamic Study

Abstract

Phenols are included in the list of potential toxins for motor neurons. Thus, fast and selective method for removal of phenols has been developed. The method was based upon the extraction of iron (III) phenolate complex anions [Fe(phenolate) 6 ] 3by tri-n-butylphosphine (TBP)-plasticized iron(III) immobilized polyurethane foam (PUF) from the test aqueous solution adjusted to pH≈1 followed by subsequent formation of ternary ion association complex of these species with the protonated urethane and/or ether linkages on the PUF solid phase extractor (SPE). The rate of removal of phenols from the aqueous solution by TBP plasticized iron (III) immobilized PUF were studied in batch conditions employing a series of kinetic models. Initially, phenols uptake onto plasticized iron (III) treated PUF was fast followed by kinetically pseudo-second order rate equation with an overall rate constant (k) of 0.014 and 0.018 g (mg min)-1 for phenol and 2-chlorophenol (2-CP), respectively. Endothermic nature of phenols sorption is governed by the positive value of ∆H where as the negative values of ∆G dictate that the uptake of the analyte onto the sorbent is spontaneous phenomena. The positive values of ΔS for both phenols may be indicative of moderate sorption step of the complex anion [Fe(C 6 H 5 O) 6 ] 3and ordering of ionic charges with a compensatory disordering of the sorbed species onto the sorbents. PUF sorbent provides efficient removal of phenols traces from various water samples.