Effective adsorption of bisphenol A from aqueous solution over a novel mesoporous carbonized material based on spent bleaching earth

In this study, the novel mesoporous carbonized material (HSBE/C) was prepared from clay/carbon composite (SBE/C) treated with hydrofluoric acid (HF) for the first time, and was employed to efficiently adsorb bisphenol A (BPA) in water. Specifically, SBE/C was derived from the pyrolysis of spent bleaching earth (SBE), an industrial waste. HF removed SiO2 from SBE/C and increased the specific surface area of HSBE/C (from 100.21 to 183.56 m(2)/g), greatly providing more adsorption sites for enhanced BPA adsorption capacity. The Langmuir monolayer maximum adsorption capacity of HSBE/C (103.32 mg/g) was much higher than the commercial activated carbon (AC) (42.53 mg/g). The adsorption process by HSBE/C followed well with the Freundlich isotherm model and the pseudo-second-order kinetic model and also was endothermic (Delta H-0 > 0) and spontaneous (Delta G(0) < 0). Based on the systematic characterization and factor experiment (temperature, dosage, initial pH, co-existing ions), BPA adsorption mechanism by HSBE/C likely included the hydrogen bonding, electrostatic interaction, and hydrophobic interaction. Moreover, there was no secondary pollution during the total adsorption process. Extraordinary, HSBE/C manifested stability by NaOH desorption regeneration. This study provides a new sight for application of waste-based materials as the promising adsorbents in the treatment of endocrine disruptors.

Automated summary

In this study, a novel mesoporous carbonized material (HSBE/C) was prepared from clay/carbon composite (SBE/C) treated with hydrofluoric acid (HF) for the efficient adsorption of bisphenol A (BPA) in water. The enhanced adsorption capacity of HSBE/C was achieved by increasing the specific surface area, and the adsorption mechanism likely involved hydrogen bonding, electrostatic interaction, and hydrophobic interaction, with stability and no secondary pollution observed during the process.