Development of Quantitative Structure–Activity Relationships for Nanoparticle Titanium Dioxide Aggregation in the Presence of Organic Contaminants

摘要

This study investigated the influence of organic wastewater contaminants (OWCs) on the aggregation of nanoparticle titanium dioxide (n-TiO2) because aggregation experiments are important to obtain fundamental information about the potential fate of n-TiO2 in environmental systems. Aggregation experiments showed that surface modification of n-TiO2 such as different aggregation behaviors and changes of zeta potentials was clearly influenced by the adsorption of OWCs based on t-test results. Largest diameter changes of n-TiO2 were observed by chlorothalonil (359nm) at 0h and alachlor (436nm) at 12h, while smallest diameter changes of n-TiO2 were observed by cyanazine (84nm) at 0h and butylate (53nm) at 12h. The most significant zeta potential changes of n-TiO2 were observed by pendimethalin and butylate with -15.2mV at 0h and with -16.7mV and -17.1mV at 12h, respectively. These results may demonstrate insights into the microscopic and/or molecular interaction between n-TiO2 and OWCs that result in surface modification of n-TiO2. Thus, we developed quantitative structure-activity relationships (QSARs) between n-TiO2 aggregation rate kinetics and representative seven descriptors of OWCs including pK(a), Solubility (C-w), log K-ow, molecular weight, polar surface area (P.S.A.), molar volume, and # of H Bond Donor (# of H.B.D.). The developed QSARs showed that experimental n-TiO2 aggregation rate kinetics were strongly related to seven descriptors of all OWCs except for butylate. Particularly, some polarity descriptors such as C-w, log K-ow, P.S.A., and # of H.B.D. seem to have influences on the developed QSARs. Therefore, our developed QSARs for n-TiO2 aggregation rate kinetics according to seven descriptors of OWCs provide solid information to the general nanoparticle (NP) researches and significant insights about the effects of emerging OWCs on microscopic and/or molecular interaction with NPs, which would demonstrate the roles of physicochemical descriptors of OWCs on n-TiO2 aggregation.