A Modified Potentiometric Method for the Estimation of Phenol in Aqueous Systems

Authors: FARHAT HUMA, MUHAMMAD JAFFAR, KHALID MASUD

Abstract: A modified potentiometric titration is proposed for the estimation of phenol in aqueous systems. The method is evolved on the basis of a critical dependence of pH on log V rather than simple V, as used in conventional potentiometric titrations. The method incorporates titrants in a concentration range several orders of magnitude greater than that of phenol in the aqueous phase. Derivative potentiometric curves so obtained provide a clear exposition of the equivalence point and the overall error is found to be between \pm 1.0 and 1.5%. The range of phenol concentration investigated was from 10^{-2} to 10^{-3} M. and that of sodium hydroxide used as the titrant from 10^{-1} to 4.0 M. The maximized titrant concentrations were found to be helpful in controlling the dilution problem during titration. The lowest detection limit achieved was 50 mg phenol/L and the method is well-suited to direct aqueous phase municipal sewage, home effluents and industrial discharges for phenol determination.

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