Aluminum chloride hexahydrate (AlCl36H2O), magnesiumchloride hexahydrate (MgCl26H2O) and sodium hydroxide(NaOH) were all purchased from Sigma Aldrich (Germany). Malic acid (MA) was purchased from Merck (Germany). These chemicals and the other reagents were chemically pure grade, and all solutions were prepared to use deionized water. The purity of the substances studied provided in Table 1 as mass fraction.