Effects of solution pH and UV irradiation on the streaming potential of the titanium dioxide membranes

Synthesis, characterization and photocatalytic activity of neodymium, nitrogen and neodymium–nitrogen doped TiO2

“…The effect is explained by the fact that the model pollutant exists in the solution in cationic form, so its sorption on the catalyst will be enhanced by the negatively charged surface. The pH value for z-potential of Degussa P25 is 6.8 [75] and for La 2 Ti 2 O 7 is 7.2 [74]. If we suppose that the potentials of the slightly Nd-doped TiO 2 and Nd 2 Ti 2 O 7 will be of the same order, then at pH = 7 the repulsion between the TiO 2 -Nd and the dye ion will be decreased, the sorption will increase moderately (as is proven from the experimental data) and the photocatalysis will be enhanced but no significant change will occur in the Nd 2 Ti 2 O 7 -containing slurry.…”

Influence of salts on the rejection of polyethyleneglycol by an NF organic membrane: Pore swelling and salting-out effects

“…Streaming potential measurements can be performed in two different ways: by flow through the membrane pores [41][42][43][44][45][46] or by flow along the top surface of the membrane (TSP) [26,27,44,[46][47][48][49]. The first method has the advantage of experimental simplicity but interpretation of experimental data is quite cumbersome when measurements are carried out with NF membranes because of the non-negligible contribution of their support layer to the overall signal [50][51][52], and non-linearities induced by concentration gradients arising through pores of the active layer [52][53][54][55][56].…”

Photoelectrocatalytic decomposition of dye in aqueous solution using Nafion as an electrolyte

“…Dyestuff MB had an acid dissociation constant (pK a ) below 0 [23] so it would be positively charged in aqueous solution at all the times. The zero point of charge of TiO 2 suspension and membrane were measured to be 6.8 and 6.5, respectively [24]. The TiO 2 surface was positively charged and would repel with positively charged MB molecules as long as pH was lower than 6.5.…”

“…The removal efficiency obtained from the experiment conducted with electrolyte concentration of 0.10 M was higher than that obtained from the experiment conducted without supporting electrolyte addition. The reason may be that the chloride ions would capture the photogenerated holes [24]. However, the rates of degradation and the amount degraded increased as the concentrations of NaCl increased from 0.01 to 0.10 M. This may be attributed to higher reduction in ohmic resistance in aqueous MB solution.…”