چكيده فارسي :
LaMO3 (M = Mn, Fe, Co) nanoperovskites were prepared via citrate method [1]. The synthesized materials were characterized by X-ray diffraction (XRD), FT-IR and UV-Vis spectroscopy. The degradation of anthraquinones dyes [alizarin (A) and alizarin red s (AS)] were investigated in acidic solution in the presence of nanocatalysts under dark and visible-light irradiation. The progress of the reaction was monitored by UV–Vis spectroscopy absorption. The percentage of dye degradation was calculated by the following equation:
D%=((C_0-C))/C_0 ×100
Where C0 and C are the dye concentration at the initial and after intervals of time, respectively [2]. The controlled experiments revealed that the degradation of A and As were unaltered under dark and visible-light irradiation in the absent of nanocatalyst. Thus, the catalyst was required for an effective degradation of A and AS. Fig. 1 shows the degradation of an aqueous solution of A and AS at pH 2.5 under dark and visible light irradiation. Results show that the A and AS are degraded over LaMnO3 catalyst to ~80% after 180 min under both conditions. Generally, among the three types of nanocatalysts, LaMnO3 is the sample which shows the highest activity and LaFeO3 shows the lowest activity for degradation of A and AS under dark and photo conditions [3]. The greatest activity of the lanthanum manganite is probably due to its high surface area, and also because of its defect structure, which is favorable for development of active sites. Finally, the nanocatalysts reported in this work were effective in anthraquinones dyes degradation when compared to other similar existing catalysts.
