2 2 6 6 tetramethylpiperidine temp

The natural dolomite sample used in this work was obtained from Jinyuan Co., Ltd (Zhengzhou, China). Methylene blue (MB), diphenhydramine hydrochloride (DP), and tetracycline hydrochloride (TC) with purity >98% were purchased from Sinopharm Chemical Reagent Co., Ltd (Beijing, China). Chemical reagents including acetonitrile, acetic acid, methanol, and triethylamine were high-performance liquid chromatography (HPLC) grade, and purchased from J&K Chemical Co., Ltd (Beijing, China). The spin-trapping reagents 2,2,6,6-tetramethylpiperidine (TEMP) and 5,5-dimethyl-1-pyrroline N-oxide (DMPO) used for electron paramagnetic resonance (EPR) experiments were supplied by Tokyo Chemical Industry Co., Ltd (Tokyo, Japan). Milli-Q water (18 MΩ cm⁻¹) was used to prepare all solutions.

Melamine 99% was purchased from Alfa Aesar, UK. Potassium persulfate (99%) was obtained from SD fine chemicals, India. AAP (98%), tert-Butanol (99%), and 1,4-Benzoquinone (98%) were purchased from Loba Chemie Pvt. Ltd, India. Ethylenediamine tetraacetic acid disodium hydrate (99%) was purchased from Himedia, India. Sodium azide 99% was obtained from s d fine chemicals. Buffer solutions (pH 4.00, 7.00, and 10.01) were procured from Thermo Fischer Scientific, India. Methanol, Acetonitrile and Formic acid, were of HPLC grade and purchased from FINAR chemicals, India. Sodium sulfate (99.5%) is used as an electrolyte for photocurrent measurement and was bought from Qualigens, India. Dimethyl-1-pyrroline-N-oxide (DMPO) and 2,2,6,6-tetramethylpiperidine (TEMP) were purchased from Tokyo Chemical Industry Co., Ltd. (TCI), India. All the solutions were prepared using RO water (conductivity 4.0–5.4 μS/cm).