Preparation of zirconium–manganese oxide/polyacrylonitrile (Zr–Mn oxide/PAN) composite spheres and the investigation of Sr(II) sorption by experimental design

Removal of strontium(II) and cobalt(II) from acidic solution by manganese antimonate

“…A hydrous MnO 2 -TiO 2 solid solution with an amorphous structure, has a much greater affinity to Sr 2+ at pH=7 than the single oxides [9]. A hydrous MnO 2 -ZrO 2 composite could efficiently uptake Sr 2+ ions from aqueous solutions at lower pH values (pH = 4) [16,18,19]. Based on these former successful trials, it seems that the adsorption properties of MnO 2 can be improved by doping with acid-resistant oxides.…”

“…The positive values of ∆Hº indicated that the adsorption process was endothermic. ∆Sº values were found to be positive due to the increased mobility of Sr (or Co) ions and the surrounding water molecules caused by the dehydration of the Sr 2+ (or Co 2+ ) ions [19,44,50]. …”

“…Thermodynamic parameters including the Gibbs free energy change (∆Gº), enthalpy change (∆Hº) and entropy change (∆Sº) are calculated according to the following equations [19,32,49]:…”

Experimental statistic design applied for obtaining Zn:xCe by microwave-assisted hydrothermal method with photocatalytic property

“…The ZnO doped with Ce shifts the absorption edge to the visible range and reduces the range of the band gap. Therefore, that is the largest electron easily moving from the valence band to the conduction band [8,22,23,27,28]. Figure 4 shows the predicted values versus observed values using the model equation obtained from the data of the response surface of UV-Vis spectroscopy with effect of efficiency of degradation.…”

“…(0.087 nm) being larger than that of Zn 2+ (0.074 nm), causing the expansion of the network [13,22,23].…”