Fig. 1. XRD analysis of Hangjin2^# clay and activated Hangjin2^# clay

Fig. 2. XPS spectra of Hangjin2^# clay
(a): Si(2p); (b): Al(2p); (c): O(1s); (d): Fe(2p)

Fig. 3. XPS spectra of activated Hangjin2^# clay
(a): Si(2p); (b): Al(2p); (c): O(1s); (d): Fe(2p)

Fig. 4. Py-FTIR analysis of Hangjin2^# clay and activated Hangjin2^# clay

Fig. 5. NH₃-TPD analysis of Hangjin2^# clay and activated Hangjin2^# clay

Fig. 6. Catalytic performance of Hangjin2^# clay and activated Hangjin2^# clay

Fig. 7. Heterogeneous Fenton reaction mechanism of activated Hangjin2^# clay