Na-montruorillonite (Na-MMT) was exchanged with three quaternary alkylphosphonium salts: decyl tributylphosphonium bromide (DTBPBr), dodecyl tributylphosphonium bromide (DDTBPBr) and hexadecyl tributylphosphonium bromide (HDTBPBr), to investigate the effects of phosphonium salts species and relative molecular mass on the characteristics, morphology, thermal stability and long-acting antibacterial property of phosphonium montmorillonites. The resulting modified montmorillonites were characterized by the FTIR, XRD, TEM, and TG/DTG techniques. And minimum inhibitory concentration (MIC) was used to investigate antibacterial activity. The results show that the phosphonium salts are intercalated into Na-MMT, and the basal spacing of P-MMTs is enlarged with the increase of phosphonium salt content or the growth of alkyl chain length. DDTBP-MMT-3 with 19.83% (mass fraction) of dodecyl tributylphosphonium salts, displays excellent thermal stability and long-acting antibacterial activity.
New layered perovskite compounds, AgxNa2-xLa2Ti3O10 (x=0.2, 0.3 and 0.5) were synthesized by an ion-exchange reaction of Na2La2Ti3O10 with AgNO3 solution and characterized by energy dispersive X-ray analysis(EDX), X-ray diffractometry(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). The ion-exchange processes were optimized, and the antibacterial activity, light permanency and water-resistance were evaluated. Surprisedly, no significant changes in crystal structure of Na2La2Ti3O10 are found by the exchange of silver ions. The Ag0.3Na1.7La2Ti3O10 particles conglomerate obviously with irregular shape and size. Ag0.3Na1.7La2Ti3O10, possessing the minimum inhibitory concentrations(MICs) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) of 180 mg/L and 240 mg/L, has high antibacterial activity, good light permanency and water-resistance. The ionic state silver in AgxNa2-xLa2Ti3O10 is the antibacterial active component.
