Combined removal and degradation approaches for the decontamination of bisphenol A in water

Bisphenol A (BPA) is an endocrine-disrupting chemical recognized by its inherent toxicity that has been found in the effluent of wastewater treatment plants. Thus, there is an urgent need for decontamination processes targeting wastewater effluent containing BPA. In this work, we combined previous experience using adsorbent materials [1] and catalytic systems [2] to tackle this challenge.

The aim of this study was to implement a combined process for BPA water removal using alginate spheres containing activated carbon (AS-AC), followed by its enzymatic degradation using Laccase as the enzymatic system. For this, AS-AC were prepared as before [1] and tested as adsorbent material for the water removal of 5 mg/L of BPA for 24 h at room temperature. Desorption assays were achieved using ethanol for 24h and followed up by enzymatic catalysis of desorbed BPA with the Laccase enzyme for 24h at room temperature. The quantification of BPA was carried out using a reverse-phase HPLC analytical system containing a C18 column.

The AS-AC were shown to be an efficient material for the removal of BPA from an aqueous solution, attaining removal rates above 90%. The desorption of BPA from the AS-AC using ethanol was achieved with a desorption rate of 60%. And, finally, total degradation of the desorbed BPA was achieved with Laccase in the presence of ethanol, which suggests the efficiency of this enzyme in transforming the pollutant.

In conclusion, it was possible to demonstrate that the sequential combination of different approaches such as adsorption, desorption, and enzymatic degradation allows for BPA elimination from water, which could be very interesting for further applications. Still, the desorption process needs to be improved to obtain better efficiencies, and other emerging pollutants should also be investigated to understand the application spectrum of this system.

[1] Marques-da-Silva et al 2022 - https://doi.org/10.3390/pr10112300

[2] Lopes et al 2022 - DOI: 10.2174/1389203723666220704090416