Apple tree branches derived activated carbons for the removal of β-blocker atenolol

This work approaches the preparation of KOH and K2CO3 activated carbons from apple tree small branches char with activation yields around 40%, and apparent surface areas up to 2472 m(2) g(-1). The treatment duration had a marked impact on the micropore structure, causing the widening of the narrow micropores to supermicropores. The adsorption characteristics of lab-made carbons for atenolol removal from aqueous phase was assessed by kinetic and equilibrium experiments. Monolayer adsorption capacities between 346 and 556 mg g(-1) were achieved. The commercial atenolol, consisting in a racemic mixture, gave rise to a two-step thermal decomposition process. Thermogravimetric analysis of the exhausted samples revealed that the predominant atenolol specie adsorbed is conditioned by the carbons' surface chemistry: neutral/acidic lab-made carbons generally favoured the decomposition of the more stable specie; basic commercial samples retained predominantly the less stable one.