Features of the transformation of HgII by heterogeneous photocatalysis over TiO2

Enhanced photocatalytic reduction of Hg(II) in aqueous medium by 2-aminothiazole-modified TiO2 particles

“…With HgCl 2 salts there is a high stabilization of positively charged Hg(II) and Hg(I) ions at high pH values due some hydrolytic effects, such as the formation of the complex Hg(OH)Cl. 4 Thus, since the surface of the photocatalyst appears in negative form, there is greater electrostatic interaction between the species and the catalyst, causing an increase in the adsorption process.…”

“…3 The major source of mercury pollution in aquatic environments is industrial and consists of products such as chloralkali, paint, catalysts used in the metallurgical, pharmaceutical, chemical and petrochemical industries, in electronics, cosmetics, thermometers, gauges, and batteries, as well as agricultural products such as pesticides, fungicides, herbicides, insecticides and bactericides. 4 Various physical and chemical methods have been used in the removal of mercury from water and wastewater streams. However, these processes are inefficient, generating secondary wastes in the form of by-products that must often be disposed of as hazardous.…”

“…With HgCl 2 salts there is a high stabilization of positively charged Hg(II) and Hg(I) ions at high pH values due some hydrolytic effects, such as the formation of the complex Hg(OH)Cl. 4 Thus, since the surface of the photocatalyst appears in negative form, there is greater electrostatic interaction between the species and the catalyst, causing an increase in the adsorption process.The percentage of mercury sorbed onto the photocatalysts determined after the photocatalytic experiments (Table 1) presents very small values, indicating that the reduction process removed practically the whole mercury sorbed onto the photocatalysts. …”

“…In acid and neutral pH, XRD revealed the presence of a mixture of Hg and calomel, the former in smaller amounts, while a mixture of Hg and HgO was detected in alkaline media. 4,[24][25][26] …”

Mercury removal from aqueous solutions of HgCl2 by heterogeneous photocatalysis with TiO2

“…The photocatalytic reduction of Hg(II) in aqueous solution has been previously reported [18][19][20][21][22][23], although the number of studies on this subject is relatively scarce. As an example, Serpone et al [18] investigated the removal of mercury(II) chloride and methylmercury(II) chloride from aqueous media in air-equilibrated suspensions of TiO 2 (2 g L −1 ) irradiated by AM1 simulated Sunlight.…”