<p>Electrochemical oxidation processes are promising solutions
for wastewater treatment due to their high efficiency, easy control and
versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to
their low cost and specific catalytic properties. Here, we propose an
innovative thermal decomposition methodology using <a>polyvinyl
alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub>
anodes. Comparative anodes were prepared by conventional method employing a
polymeric precursor solvent (Pechini method). The calcination temperatures
studied were 300, 400 and 500 °C. The physical characterisation of all
materials was performed by X-ray diffraction and scanning electron microscopy
coupled with energy dispersive spectroscopy, while electrochemical characterisation
was done by cyclic voltammetry, accelerated service lifetime and
electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub>
have rutile-type structures for all anodes. Rougher and more compact surfaces are
formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using
PVA as solvent is the most suitable one to produce anodes with expressive
increase in voltammetric charge (250%) and accelerated service lifetime (4.3
times longer) besides reducing charge-transfer resistance (8 times lower). Moreover,
the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive
Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than
that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point
out improved mineralisation potential of PVA anodes. Finally, this study
reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub>
anodes with improved properties that can be further extended to synthesise
other MMO compositions.</p>
Effect of Polyvinyl Alcohol on the Rheological Properties of Cement Mortar
