An Innovative Phenolic Resin and Its Application in Wastewater Treatment for Paracetamol Removal

Abstract

Water scarcity has been a concern worldwide, especially since the presence of micropollutants in wastewater has increased. In this scenario, adsorption and advanced oxidative processes have gained increasing attention in environmental chemistry, emerging as promising alternatives for water decontamination. Drugs are a good example of those pollutants and, among all drugs, paracetamol is a widely used one and was used in the current study. Thus, alternative precursors of phenolic compounds, as a blend of Kraft black liquor and tannin, were used for an innovative activated phenolic resin (APR) production and investigated for paracetamol removal. When the APR was used in a photocatalytic process, the paracetamol removal mechanism was predominantly by adsorption rather than by photocatalysis. The paracetamol adsorption onto APR was almost 70 % higher than in the conventional thermally treated photocatalysts, encouraging a further assessment of paracetamol adsorption onto APR. The adsorption capacity reached a maximum value for an APR weight of 0.02 g, with an adsorption capacity of 19.43 mg g-1. Moreover, the paracetamol solution pH did not show noteworthy effect on the adsorption capacity in the pH range evaluated. Chemical structure characterization pointed out a variety of functional groups on the APR surface, which are characteristic of bio-phenolic compounds structure. The drug adsorption onto APR may be explained by the adsorbent - adsorbate p-p interactions and hydrogen bonding. At the maximum adsorption capacity, the use of APR as adsorbent provided a paracetamol removal of about 45 %, which can be increased to greater than 90 % by increasing the adsorbent weight. This confirmed the resin’s potential as an adsorbent for paracetamol removal.