Coagulants from chestnut shell tannins- Synthesis, characterization and performance on water treatment

• Type: Article in International Scientific Journal
• Date: 2025

Authors

Isabella T. Tomasi (Author) FEUP; Sílvia C.R. Santos (Author) FEUP; Andreia Ribeiro (Author) FEUP; Vera Homem (Author) FEUP; Rui Boaventura (Author) FEUP; Cidália Botelho (Author) FEUP

Journal

Title: Journal of Water Process Engineering

Vol. 69 No. 106818

ISSN: 2214-7144

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 0 Citations

ISI Web of Science

Scopus - 0 Citations

ScienceDirect (Elsevier)

Scientific classification

CORDIS: Technological sciences > Engineering

Associated Projects

LA LSRE-LCM - Financiamento Plurianual 2020-2023 para a Unidade LA LSRE-LCM Laboratório de Processos de Separação e Reacção - Laboratório de Catálise e Materiais

LEPABE - Financiamento Plurianual 2020-2023 da Unidade de I&D LEPABE - Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia

ALiCE - ALiCE - Laboratório Associado em Engenharia Química

Other information

Authenticus ID: P-017-QRB

DOI: 10.1016/j.jwpe.2024.106818

Abstract (EN): Ensuring access to safe drinking water is essential for public health. Coagulation/flocculation processes are critical for removing suspended particles, organic matter, and other impurities in water treatment. Tannins have been identified as promising coagulant precursors; however, a chemical modification is required to enhance their effectiveness. In this study, chestnut shell (CS) tannins underwent aminomethylation to increase their cationic properties. The success of this modification was confirmed through zeta potential measurements and chemical analysis. The performance of the lab-synthesized natural coagulants was then evaluated against Tanfloc SG, demonstrating comparable efficacy in turbidity and pollutant removal. Four distinct coagulants (C1-C4) were produced by varying the tannin:NH4Cl:formaldehyde ratios. Among these, the coagulants produced with 1:2.5:7.5 and 1:2.5:10 (T:NH4Cl:FA, molar ratios), corresponding to the highest formaldehyde amount, achieved over 95 % turbidity reduction, as well as effective removal of color (about 85 %), organic matter (29 %), phosphorus (34.6 and 49.3 %, respectively), and nitrogen (53.9 and 55.4 %, respectively). The presence of formaldehyde in treated water and sludge was also examined, revealing that coagulants produced with lower formaldehyde levels resulted in higher formaldehyde concentrations in the treated water due to the need for increased coagulant usage. CS tannins demonstrate significant potential as eco-friendly coagulants for water treatment applications.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10