Mercury poly cations

Chitosan has been widely accepted in the purification process of water by virtue of its metal ion chelating capability and acting as a flocculating agent because of its poly-cationic character. It is also used as an adsorbent for removal of dyes from water. Pesticides and chemicals such as phenols, methyl mercury acetate, plutonium, etc., can be removed from wastewater [170]. 

A potentiometric determination of saccharin was proposed by Fatibello-Filho et al. [86]. In this method, saccharin was potentiometrically measured using a silver wire coated with a mercury film as the working electrode. With this, the main difficulty was the presence of a precipitate (mercurous saccharinate) that could adsorb on tube walls and the electrode surface. To avoid these undesirable effects, a relocatable filter unit was placed before the flow-through potentiometric cell and a surfactant was added to the carrier solution (Figure 24.12). The same investigation team reported the construction and analytical evaluation of a tubular ion-selective electrode coated with an ion pair formed between saccharinate anion and toluidine blue O cation incorporated on a poly(vinyl chloride) matrix [87]. This electrode was constructed and adapted in a FIA system. The optimum experimental conditions found were an analytical path of 120 cm, an injection sample volume of 500 pL, a pH of 2.5, a flow rate of 2.3 mL/min, and a tubular electrode length of 2.5 cm. 

Solvent extraction of Ag(I), Hg(II), Cu(II) and Cd(II) from nitrate aqueous solutions with copolymers 6 was studied. Poly(14-thiacrown-4) and poly(20-thiacrown-6) copolymers were selective for Au(I) since, as soft acids, they have a high affinity for thiacrown ethers, as soft bases. On the other hand, 2-aminomethyl-17-thiocrown-5 on a polystyrene support, was found to be selective for Hg(II) [6]. In competitive studies of metal cations, mercury(II) was... 

---