Also, a subsequent structural analysis (Fig. 4b) showed peaks at the binding energies of 74.3 eV for MT 500 SA nanoparticles in the presence and absence of SPW and 73.5 eV for SSL in SPW, attributing to Al(OH)3 (i.e. Al in the oxidation state of 3+) [27] and [29]. Important to note is that a slight increase in the Al 2p binding energy may indicate that alumina is strongly interacting with the TiO2 surface. Surface atom% composition shown in Table SI 1 shows an increase in Al/Ti (%) content in SSL from an initial 26.3 to 53.5% proving that chemical re-distribution of the Al(OH)3 layer took place in the presence of 7 ppm chlorine in SPW. When MT 500SA nanoparticles were subjected to the same treatment, Al/Ti (%) ratio also increased from 41% to 43%, indicating that our hypothesis was correct and SPW ingredients indeed contributed to the redistribution of a coating on the nanomaterial surface. Interestingly, when nanoparticles were subjected to SO42−, Ca2+ and CaSO4·2H2O, Al/Ti (%) ratio was nearly the same, i.e. 40%, 39.5% and 39.4%, respectively signifying the effect of chlorine onto the coating integrity.