abstract
Water contamination with antibiotics is a serious environmental threat. Ciprofloxacin (CIP) is one of the most frequently detected antibiotics in water. Herein, silica-based magnetic nanosorbents prepared using three seaweed polysaccharides, alginic acid, kappa- and lambda-carrageenan, were developed and evaluated in the uptake of ciprofloxacin. The sorbents were firstly characterized in detail to assess their morphology and composition. A systematic investigation was conducted to study the adsorption performance towards CIP, by varying the initial pH, contact time and initial CIP concentration. The maximum adsorption capacity was 464, 423 and 1350 mg/g for particles prepared from alginic acid, kappa- and lambda-carrageenan respectively. These high values indicate that these materials are among the most effective sorbents reported so far for the removal of CIP from water. The kinetic data were consistent with the pseudo-second-order model. The CIP adsorption on lambda-carrageenan particles followed a cooperative process with sigmoidal isotherm that was described by the Dubinin-Radushkevich model. The high charge density of lambda-carrageenan and the propensity of CIP molecules to self-aggregate may explain the cooperative nature of CIP adsorption. The sorbents were easily regenerated in mild conditions and could be reused in CIP removal up to 4 times without a significant loss of adsorptive properties. (C) 2019 Elsevier B.V. All rights reserved.
keywords
WASTE-WATER; AQUEOUS-SOLUTION; ADSORPTION BEHAVIOR; ACTIVATED CARBON; MESOPOROUS CARBON; OXIDE COMPOSITE; HUMIC-ACID; SORPTION; GRAPHENE; NANOPARTICLES
subject category
Biochemistry & Molecular Biology; Chemistry; Polymer Science
authors
Soares, SF; Rocha, MJ; Ferro, M; Amorim, CO; Amaral, JS; Trindade, T; Daniel-da-Silva, AL
our authors
Ana Luísa Daniel da Silva
Principal Researcher
Carlos Amorim
Assistant Researcher
João Cunha de Sequeira Amaral
Assistant Researcher
Sofia Soares
Junior Researcher
Tito Trindade
Full professorGroups
G1 - Porous Materials and Nanosystems
G2 - Photonic, Electronic and Magnetic Materials
G6 - Virtual Materials and Artificial Intelligence
Projects
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2019)
Projeto de Investigação Exploratória: João Amaral (IF/01089/2015)
acknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES (Fundacao para a Ciencia e Tecnologia/Ministerio da Ciencia, Tecnologia e Ensino Superior). The authors thank the RNME (National Electronic Microscopy Network) for microscopy facilities. S.F. Soares thanks the Fundacao para a Ciencia e Tecnologia (FCT) for the Ph.D. grant SFRH/BD/121366/2016. J.S.A. acknowledges FCT IF/01089/2015 grant. A. L. D.-d.-S. acknowledges FCT for the research contract under the Program 'Investigador FCT' 2014.