According to Zaharaki et al. [38], all bands near 1000 cm−1 (950–1200 cm−1) were a major “fingerprint” of the inorganic matrix, defining an extent of aluminum incorporation. Consequently, the band at 1080–1040 cm−1 in the presence of DI water and 7 ppm chlorine in SPW for MT 500 SA nanoparticles, respectively (Fig. 5b), might be due to Tisingle bondOsingle bondAl asymmetric stretching vibration [39].