Sorption and determination of Hg(II) on clay modified carbon paste electrodes

Sorption of mercury(II) both in cationic and in anionic form was studied by means of carbon paste electrodes modified with typical clay minerals (mont morillonites) and with mica (biotite). Significant anionic exchange of mont morillonites was found in complexing media such as solutions containing ace tates and chlorides. Anionic sorption of [HgCl4](2-) can be used for the de termination of Hg(II) in media with high content of chlorides. Linear calib ration dependences were found in the concentration range 1.24 x 10(-7)-9.86 x 10(-7) mol/l (10 min accumulation at -1.2 V) and in the range 4.9 x 10(- 8)-1.74 x 10(-7) mol/l (15 min accumulation). Model samples of table water and saline water were analysed. (C) 1999 Elsevier Science B.V. All rights r eserved.