Bentonitic clay as adsorbent for the decolourisation of dyehouse effluents

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Sílvia C. R. Santos (Author) FEUP; Álvaro F. M. Oliveira (Author) Other; Rui A. R. Boaventura (Author) FEUP

Journal

Title: Journal of Cleaner Production

Vol. 126

Pages: 667-676

ISSN: 0959-6526

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 0 Citations

ISI Web of Science

Scopus - 4 Citations

Associated Projects

LSRE-LCM - Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais

Other information

Authenticus ID: P-00K-HRM

DOI: 10.1016/j.jclepro.2016.03.092

Abstract (EN): Textile dyehouses generate high volumes of coloured wastewaters, which require convenient treatment in order to avoid water bodies' contamination, adverse effects to aquatic life and risks to human health. The complete decolourisation of such contaminated waters in a cost-effective manner is still a challenge nowadays. This work focuses on the use of a clayey material as a low-cost adsorbent for a basic textile dye (Red 46), commonly used in acrylic fibres dyeing. The bentonitic clay (49% of montmorillonite) presents a considerable (50 cmol(c)/kg) cationic exchange capacity and a porosity of 10%. Dye adsorption kinetics was successfully described by a pseudo-second order model, resulting an average kinetic constant of 0.23 g(dye) g(clay)(-1) min(-1). Adsorption equilibrium Was reached in 12-24 h and data were successfully fitted to Freundlich and Langmuir equations. The maximum adsorption capacity predicted by the Langmuir model depends on the pH, varying between 217 mg/g at pH 8 and 584 mg/g at pH 9 (25 degrees C). Increasing the temperature from 25 to 35 degrees C also led to an increase in adsorbed amounts. In addition to the excellent adsorption performance, the clay showed a great affinity to the dye, indicating high propensity to complete decoulorization of textile dyeing wastewaters. The results obtained in the present work show that a natural, readily-available and cheap material i.e. a bentonitic clay can be used as an effective and environmentally-friendly adsorbent for basic dyes.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10