Simultaneous removal of tetracycline hydrochloride and As(III) using poorly-crystalline manganese dioxide

• Tetracycline hydrochloride and As(III) were simultaneously oxidized by δ-MnO2.
• Removal efficiency of TC and As(III) positively increased with initial δ-MnO2 dosage.
• Competition between TC and As(III) for adsorption–oxidation sites occurs on δ-MnO2 surface.

Simultaneous removal of antibiotic tetracycline hydrochloride (TC) and As(III) by poorly-crystalline Mn dioxide was investigated. TC and As(III) can be effectively oxidized and removed by MnO2. High concentrations of TC and As(III) competed with each other for oxidation or adsorption sites on MnO2 and thus affected their removal efficiency. The intermediates and products of TC after reaction with poorly-crystalline manganese dioxide were identified by LC–ESI–MS (liquid chromatography–electrospray ionization–mass spectrometry), and the decomposition pathways of TC by MnO2 were proposed. This study is helpful for understanding the importance of environmental Mn dioxides in the decontamination of combined pollution by organic pollutants and metal(loid)s.