Multivariable optimization of activated carbon production from microwave pyrolysis of brewery wastes - Application in the removal of antibiotics from water

This study aimed at optimizing the one-step chemical activation and microwave pyrolysis of an agro-industrial waste to obtain a microporous activated carbon (AC) with superior textural and adsorptive properties by a fast, low-reagent and low-energy process. Spent brewery grains were used as precurso...

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Detalles Bibliográficos
Autores: Sousa, Érika M. L., Otero, Marta, Rocha, Luciana S, Gil Matellanes, María Victoria, Ferreira, Paula, Esteves, Valdemar I, Calisto, Vânia
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2022
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/303943
Acceso en línea:http://hdl.handle.net/10261/303943
https://api.elsevier.com/content/abstract/scopus_id/85125602495
Access Level:acceso abierto
Palabra clave:Fractional factorial design
Spent brewery grain
Waste-based adsorbents
Pharmaceuticals
Water treatment
Descripción
Sumario:This study aimed at optimizing the one-step chemical activation and microwave pyrolysis of an agro-industrial waste to obtain a microporous activated carbon (AC) with superior textural and adsorptive properties by a fast, low-reagent and low-energy process. Spent brewery grains were used as precursor, and the antibiotics sulfamethoxazole (SMX), trimethoprim (TMP) and ciprofloxacin (CIP) were considered as target adsorbates. A fractional factorial design was applied to evaluate the effect of the main factors affecting the preparation of AC (activating agent, activating agent:precursor ratio, pyrolysis temperature and residence time) on relevant responses. Under optimized conditions (K2CO3 activation, pyrolysis at 800 °C during 20 min and a K2CO3:precursor ratio of 1:2), a microporous AC with specific surface area of 1405 m2 g-1 and large adsorption of target antibiotics (82-94%) was obtained and selected for further studies. Equilibrium times up to 60 min and maximum Langmuir adsorption capacities of 859 µmol g-1 (SMX), 790 µmol g-1 (TMP) and 621 µmol g-1 (CIP) were obtained. The excellent textural and adsorptive properties of the selected material were achieved with a very fast pyrolysis and low load of activating agent, highlighting the importance of optimization studies to decrease the environmental and economic impact of waste-based AC.