Variable surface charge of humic acid-ferrihydrite composite: Influence of electrolytes on ciprofloxacin adsorption.

Cristian Urdiales, Manuel Gacitua, Loreto Villacura, Carmen Pizarro, Mauricio Escudey, Camila Canales, Mónica Antilén

Journal: Journal of hazardous materials 2020;385():121520

PMID: 31784135

Full Text on Elsevier Science View on PubMed

Abstract

Antimicrobial compounds are found in a range of environments as pollutants. Here, we evaluated the influence of two common anions, NO and PO, on ciprofloxacin adsorption on humic acid/ferrihydrite composite (HA-DIG/Fh), synthetic ferrihydrite (Fh), and humic acid (HA-DIG) under controlled pH (7.0), ionic strength (0.1 M) and temperature (25 °C). All materials were characterized by isoelectric point (IEP), while the composite and the iron oxide were characterized by Mössbauer spectroscopy. Kinetic and isotherm adsorption studies were carried out using cyclic voltammetry (in KHPO) and square wave voltammetry (in KNO). The application of kinetic models for both anions revealed Fh to fit to a pseudo second order model (R = 0.941); while HA-DIG (R = 0.950) and HA-DIG/Fh (R = 0.993) were fitted to pseudo first order models. The adsorption results showed a high dependency electrolyte, especially in Fh, where different shape curves (H-type in KNO and C-type in KHPO) and maximum experimental adsorbed amount C were observed. This finding is supported by the distinct IEP values and change in sign of surface charge between the two ions. Finally, results suggest that HA-DIG could be potentially used in environmental remediation to remove antibiotics from natural matrices, though the risk of antibiotic transportation increased with depth in the soil profile.

Address: Pontificia Universidad Católica de Chile, Facultad de Química y de Farmacia, Vicuña Mackenna 4860, Santiago, 7820436, Chile. Electronic address: [email protected].; Universidad de Santiago de Chile, Facultad de Química y Biología, USaCh, Av. L.B. O'Higgins 3363, Santiago, 7254758, Chile. Electronic address: [email protected].; Universidad de Chile, Facultad de Ciencias, Las Palmeras 3425, Santiago, 7800024, Chile. Electronic address: [email protected].; Universidad de Santiago de Chile, Facultad de Química y Biología, USaCh, Av. L.B. O'Higgins 3363, Santiago, 7254758, Chile; Centro para el Desarrollo de la Nanociencia y Nanotecnologia (CEDENNA), Av. L.B. O'Higgins 3363, Santiago, 7254758, Chile. Electronic address: [email protected].; Universidad de Santiago de Chile, Facultad de Química y Biología, USaCh, Av. L.B. O'Higgins 3363, Santiago, 7254758, Chile; Centro para el Desarrollo de la Nanociencia y Nanotecnologia (CEDENNA), Av. L.B. O'Higgins 3363, Santiago, 7254758, Chile. Electronic address: [email protected].; Pontificia Universidad Católica de Chile, Escuela de Ingeniería, Departamento de Ingeniería Hidraúlica y Ambiental, Vicuña Mackenna 4860, Santiago, 7820436, Chile. Electronic address: [email protected].; Pontificia Universidad Católica de Chile, Facultad de Química y de Farmacia, Vicuña Mackenna 4860, Santiago, 7820436, Chile; Centro para el Desarrollo de la Nanociencia y Nanotecnologia (CEDENNA), Av. L.B. O'Higgins 3363, Santiago, 7254758, Chile. Electronic address: [email protected].

DOI: 10.1016/j.jhazmat.2019.121520

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MeSH Terms: Adsorption, Anti-Bacterial Agents, Ciprofloxacin, Ferric Compounds, Humic Substances, Kinetics, Nitrates, Phosphates, Static Electricity, Surface Properties