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In this study, a potentiometric sensor composed of palm shell activated carbon modified with trioctylmethylammonium thiosalicylate (TOMATS) was used for the potentiometric determination of mercury ions in water samples. The proposed potentiometric sensor has good operating characteristics towards Hg (II), including a relatively high selectivity; a Nernstian response to Hg (II) ions in a concentration range of 1.0 × 10−9 to 1.0 × 10−2 M, with a detection limit of 1 × 10−10 M and a slope of 44.08 ± 1.0 mV/decade; and a fast response time (∼5 s). No significant changes in electrode potential were observed when the pH was varied over the range of 3–9. Additionally, the proposed electrode was characterized by good selectivity towards Hg (II) and no significant interferences from other cationic or anionic species.

In this study, palm shell activated carbon modified with task-specific ionic liquid was used as a novel electrode component for the potentiometric determination of cadmium ions in water samples. The proposed potentiometric sensor has good operating characteristics, including relatively high selectivity towards the Cd (II) ion, a Nernstian response to Cd (II) ions in a working concentration range of 1.0 9 10 -9 -1.0 9 10 -2 M, with a reasonable detection limit of 1 9 10 -10 M and a slope of 30.90 ± 1.0 mV/decade. No significant changes in electrode potential were observed when the pH was varied over the range of 4-9. A direct technique based on the use of ion-selective electrode potentiometry has been developed in our laboratory for the study of reaction kinetics and kinetic methods of analysis by continuous monitoring of the rate of production or consumption of an ion. The apparent adsorption rate constant was estimated assuming pseudo-second-order kinetics. Additionally, the proposed electrode has been successfully used for the determination of the cadmium content in real samples without a significant interaction from other cationic or anionic species.

A new modified palm shell activated carbon paste electrode based on 1, 4,7,10,8,4,7,10,13-Pentaoxatridecylene)-diquinoline (Kryptofix ® 5) and plasticizing agent was prepared and studied as Hg 2+ selective electrode. The best performance was observed with the electrode composition having the ionophore-palm shell activated carbon-plasticizer composition 10%:50%:40% with Nernstian response over the concentration range of 1.0 × 10 −8 -1.0 × 10 −2 M with a slope of 42 ± 1.5 mV per decade of concentration. The detection limit as determined from the calibration plot is 1.0 × 10 -7 M. The proposed electrode shows good selectivity for Hg(II) with interfering ions. The response time of the electrode is fast (≤10 s), and can be used in the pH range of 3 -11. The electrode was used to determine mercury in drinking water.

Abstract:In this study, the combination of activated carbon with task specific ionic liquids has resulted in a unique new generation paste in which the traditional components have been replaced with alternate materials. In this study, palm shell activated carbon modified with trioctylmethylammonium salicylate was used as a novel electrode component for the potentiometric determination of cadmium ions in water samples. The proposed potentiometric sensor has good operating characteristics when used to determine Cd(II), including a relatively high selectivity; a Nernstian response in a working concentration range of 1.0×10 -9 to 1.0×10 -2 M, with a detection limit of 1×10 -10 M and a slope of 30.90 ± 1.0 mV/decade; and a fast response time (~ 10 s). The proposed sensor can also be used for at least two months without considerable changes in its response characteristics. No significant changes in the electrode potential were observed when the pH was varied over the range of 4-9. Additionally, the proposed electrodes have been successfully used for the determination of the cadmium contents of real samples without a significant interaction from other cationic or anionic species.