Removal of phenol by acid-washed zero-valent aluminium in the presence of H2O2

• Acid washing can enhance the reactivity of ZVAl in the removal of phenol.
• Phenol was efficiently removed by AW-ZVAl in the presence of H2O2.
• The removal mechanism of phenol in AW-ZVAl/Air/H+ system was discussed.
• The factors affecting the phenol removal were studied.
• It provides a new method for the removal of organic pollutants from wastewater.

Currently, organic pollution is becoming increasingly severe with continued industrialization. In this study, the characterization of acid-washed zero-valent aluminium (AW-ZVAl) and the mechanism of using AW-ZVAl/Air/H+ system in the presence of H2O2 to remove phenol were investigated. The influencing factors including acid washing time, AW-ZVAl concentration, pH, H2O2 concentration, air or N2 conditions, and humic acid (HA) on phenol removal were studied. AW-ZVAl exhibited a greater capacity to remove phenol than that of ZVAl. In the presence of 4.0 mM H2O2, the phenol concentration decreased from initial 20.0 mg/L to 0.3 mg/L by 6.0 g/L AW-ZVAl in 3 h at initial pH 2.7. The addition of H2O2 into AW-ZVAl/Air/H+ system facilitated the reaction due to the enhancement of hydroxyl radicals generation, while the addition of HA inhibited the reaction due to the competitive reaction of HA and phenol with hydroxyl radicals. The reusing of AW-ZVAl showed that the AW-ZVAl was consistently effective in 5 cycles. The removal mechanism of phenol in the AW-ZVAl/Air/H+ and AW-ZVAl/N2/H+ were discussed. This study demonstrates that AW-ZVAl has a great potential to be applied in treating wastewater containing organic pollutants.

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