Enhanced adsorptive removal of oxidation intermediate 1,4-benzoquinone using thermally treated activated carbon fibres

Abstract

As an oxidation intermediate generated in advanced oxidation processes, 1,4-benzoquinone, a toxic intermediate has drawn increasing attentions due to its high toxicity. Activated carbon fibre (ACF) was calcined and employed for the efficient removal of 1,4-benzoquinone by adsorption. Although no noticeable change was observed on the surface morphologies of the ACF after calcination at 300°C, the results showed that the adsorptive removal efficiency of the thermally treated ACF was enhanced by 25.1% compared to the raw ACF. Energy dispersive X-ray analysis indicated that the oxygen content of the thermally treated ACF increased significantly, which might contributed to its higher adsorption capacity. Langmuir isotherm and pseudo-second-order model well fitted the experimental data. Maximal adsorption capacity of 315.2 mg/g was achieved at neutral pH and 25°C. Both neutral and acidic conditions were favorable for the 1,4-benzoquinone adsorption on the calcined ACF. The ionic strength effect experiment showed that 1,4-benzoquinone formed inner-sphere surface complexes and coexisting anions had a minor influence on the adsorption. The enthalpy and entropy of adsorption were found to be −43.62 kJ mol⁻¹ and −102.51 J mol⁻¹ k⁻¹, respectively, which indicates the adsorption process, was exothermic. Easy regeneration and repeated use suggest that the thermally treated ACF could be an alternative sorbent for 1,4-benzoquinone removal.

Keywords:

• Adsorption
• Activated carbon fibre
• 1,4-benzoquinone
• Calcination

Acknowledgment

The authors thank the financial support by the North China University of Water Resources and Electric Power to Dr Fazhan Li and the support by the National Natural Science Foundation of China (Grant No. 51378205).