Preparation and characterization of high performance hydrochar for efficient adsorption of drugs mixture

A high-performance hydrochar was prepared for the first time from a relatively abundant solid biomass waste, loquat cores, by hydrothermal treatment. The ecofriendly modifying agent, citric acid (C6H8O7), was used and compared with well know acids such as H3PO4 and HCl. In order to evaluate the effectiveness of the hydrothermal treatment assisted, adsorption tests in batch mode were carried out on three drugs: diclofenac, antipyrine and prednisolone. The results revealed that the treatment with citric acid (3 M) was significantly better than the other two agents studied. Indeed, the removal efficiency of these molecules on the prepared hydrochar, noted HC-Cit 3M, is 95.88% diclofenac, 76.21% antipyrine and 80.29% prednisolone. The characterization of the loquat cores powder in its natural state (LC) and the HC-Cit 3 M demonstrates that the hydrothermal treatment with acid significantly improves the structural and morphological properties of the adsorbent. The Brunauer-Emmett-Teller (BET) surface increased from 0.0048 (LC) to 19.2261 m(2) g(-1) (HC-Cit 3 M) and the Scanning Electron Microscope (SEM) analysis showed that the structure of HC-Cit 3 M is porous and irrigated, unlike that of LC. Furthermore, the Fourier Transform Infrared (FTIR) analysis showed that oxygenated active sites were formed on the surface of the HC-Cit 3 M. The kinetic study and the isotherms reveal that the adsorption process is favourable and follows pseudo-second order kinetics. Finally, it was studied the effective regeneration of HC-Cit 3 M by the Fenton process in presence of ultrasounds. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

The study demonstrated that hydrochar prepared with citric acid (3 M) showed significantly improved adsorption efficiency for drugs, as well as enhanced structural and morphological properties of the adsorbent.