Influence of mechanochemical and microwave modification on ion-exchange properties of tin dioxide with respect to uranyl ions

Abstract

Wet gel and dried xerogel of precipitated tin oxy-hydroxide were subjected to mechanochemical and microwave treatments (MChT and MWT, respectively). The prepared samples were studied using DTA-TG, XRD, FTIR, nitrogen adsorption-desorption. MChT and MWT cause improvement of crystal structure, removal of structural OH-groups and increase mesopores diameter as well as form the meso-macroporous structure. As a result, drastic increase of uranyl-ions sorption for all modified samples is observed. Sorption centers can be divided into three groups: selective cation-exchange, non-selective cationexchange and anion-exchange. Keywords SnO 2 • Mechanochemical and microwave treatments • Ion-exchange properties * Barbara Charmas

Mechanochemical and microwave treatment of precipitated zirconium dioxide and study of its physical–chemical, thermal and photocatalytic properties

“…4b) increase. It should be noted that similar results were earlier obtained for silica, tin dioxide and zirconium phosphate after their MChT [19][20][21]. It is well known that the specific surface area and pore volume depend on the globules size and their packing density in the skeleton of globular porous solids [29].…”

“…This was exemplarily confirmed using oxides and phosphates [19][20][21][22]. Moreover, the efficiency of MWT and MChT application for regulation of physical-chemical properties of other semiconductor oxides was demonstrated in the studies [20,[23][24][25][26]. The analysis of the literature data shows that oxides with different characteristics and improved photocatalytic and adsorption properties can be obtained by varying the treatment conditions.…”

“…Additional possibilities for adjusting the parameters of the porous structure are provided by modification in the wet gel stage before drying [11,18]. This was exemplarily confirmed using oxides and phosphates [19][20][21][22]. Moreover, the efficiency of MWT and MChT application for regulation of physical-chemical properties of other semiconductor oxides was demonstrated in the studies [20,[23][24][25][26].…”

“…The nitrogen isotherms of adsorption-desorption were obtained using an automatic gas adsorption analyzer ASAP 2405 N (Micromeritics Instrument Corp., USA) after outgassing of the samples at 150 °C for 2 h. The specific surface area S BET , mesopores volume (V me ) and micropores volume (V mi ) were calculated from these isotherms using the BET, BJH and t-plot methods, respectively [20]. The sorption pore volume V s was determined at a relative pressure p/p 0 close to 1.…”

Structure and Photocatalytic Properties of SnO2 Doped with Titanium

“…Initial precipitated sample has composition closed to oxy-hydroxide SnO(OH) 2 that is confirmed by DTA-TG data [12,15]. According to the results of XRD analysis, it has a low crystalline structure, but the doped and calcined samples have a more perfect crystal structure.…”