Adsorption and thermal degradation of Atenolol using carbon materials: Towards an advanced and sustainable drinking water treatment

With the aim to present an alternative material that can be used in adsorption/degradation processes to remove pharmaceutical pollutants present in water, a biocarbon was designed from Melia Azedarach stones. Material has a high surface area (1230 m2 g-1) with mainly oxygenated groups; these properties give it exceptional characteristics for removing Atenolol. To show the versatility of the material, the adsorption of Atenolol in different water matrices was tested: Ultrapure water (0 mg L-1 CaCO3), solution model (200 mg L-1 CaCO3), and tap water from Lisbon city (80 mg L-1 CaCO3). The pseudo-second-order model can well describe the adsorption kinetics; kinetic constants obtained were: 75.70, 46.18, and 42.58 g mmol h-1, respectively. The adsorption isotherms are correctly described by the Langmuir model, obtaining maximum adsorption capacities of 1.83, 2.00, and 1.81 mmol g-1, respectively. Physisorption phenomena carry out the adsorption mechanism (E < 1 kJ mol-1) between the atenolol molecule, positively charged, and the material's surface, negatively charged, forming a monolayer onto the material's surface. Once the material was saturated, its regeneration was studied by employing thermal treatment at 450 degrees C. Results show a decrease in the surface area after treatment, resulting in a loss of adsorption capacity (30 %). This procedure makes it possible to achieve repeat cycles of adsorptiondegradation until the adsorbent is completely exhausted. The results obtained show this new material as a promising adsorbent for wastewater treatment contaminated with pharmaceutical pollutants since it has higher adsorption capacities than those reported in the literature in different water matrices.

Automated summary

A biocarbon material was designed from Melia Azedarach stones to remove pharmaceutical pollutants present in water through adsorption/degradation processes. The material showed high surface area and mainly oxygenated groups, making it effective in removing Atenolol. The material proved to be versatile and capable of adsorbing Atenolol in different water matrices, with a pseudo-second-order adsorption kinetics and Langmuir adsorption isotherms.