Fig. 4
a The time-dependent absorption intensity of TCH by ESM and MnO2 NPs/ESM treatment. b The UV-vis absorption spectra of TCH before and after ESM or MnO2 NPs/ESM treatment. c The time-dependent UV-vis absorption spectra of TCH and (d) removal efficiency treated by MnO2 NPs/ESM. (Conditions: 20 slices of MnO2 NPs/ESM or ESM, the initial concentration of TCH was 50 mg/L, controlled pH was 3.0)