Fig. 6. Solubility of ZnO NPs in different systems at different time. (a) Solubility of 15 mg L−1 ZnO NPs at 24 h; (b) solubility of 120 mg L−1 ZnO NPs at 6 h. Data are presented as the mean ± S.D. *P < 0.05 compared with the group of ZnO NPs plus CPP. **P < 0.01 compared with the group of ZnO NPs plus CPP. #p < 0.05 compared with the group of ZnO NPs plus VC. ##p < 0.01 compared with the group pf ZnO NPs plus VC.
