Evaluation of the SBA-15 materials ability to accumulation of 4-chlorophenol on carbon paste electrode

Abstract

The adsorption of 4-chlorophenol (4-CP) from an aqueous solution on three ordered mesoporous silica materials (commercial unmodified SBA-15-Sigma, synthesized unmodified SBA-15 and amino-functionalized SBA-15-NH2) was studied. The adsorption isotherms were analyzed using the Generalized Langmuir equation taking into account the energetic heterogeneity. The adsorption capacities of the mesoporous silicas increased in order: SBA-15 < SBA-15-Sigma < SBA-15-NH2. The materials were used for the modification of the carbon paste electrodes (CPEs) for detection of 4-CP based on differential pulse voltammetry. Different parameters that affects the DPV signal such as scan rate, accumulation time and paste composition were investigated. Compared with the bare (graphite) CPE, the SBA-15 modified electrodes greatly increased the oxidation peak current of 4-CP, showing strong signal enhancement effects. The SBA-15-NH2 modified CPE showed a larger peak current and higher sensitivity for the 4-CP in comparison with the SBA-15 and SBA-15-Sigma modified carbon paste electrodes. The results showed high usefulness of the ordered mesoporous silica materials as an electrode modifiers in the electroanalytical techniques.