Biopolymer recovery from waste activated sludge toward self-healing mortar crack

Cong Zhang; P Hu; Qing Liu; Zeyu Lu; Benyi Cao; Yuxin Tang; Tianwei Hao

doi:10.1016/j.scitotenv.2022.160107

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Biopolymer recovery from waste activated sludge toward self-healing mortar crack

Journal article

Peer reviewed

Biopolymer recovery from waste activated sludge toward self-healing mortar crack

Cong Zhang, P Hu, Qing Liu, Zeyu Lu, Benyi Cao, Yuxin Tang and Tianwei Hao

The Science of the total environment, Vol.858(Pt 3), 160107

01/02/2023

DOI: https://doi.org/10.1016/j.scitotenv.2022.160107

PMID: 36370773

Abstract

Biopolymers - chemistry

Polysaccharides - chemistry

Sewage

Activated sludge (AS) offers great potential for resource recovery considering its high organic and nutrient content. However, low recovery efficiency and high costs are directing the focus toward the high-valuable resource recovery. This study extracted 71.5 ± 5.9 mg/g VSS of alginate-like exopolysaccharides from AS (ALE/AS) and applied it to mortar as a novel biopolymer agent for crack self-healing. With a mortar crack of 120 μm, addition of 0.5 wt% ALE/AS yielded a high crack closure ratio of 86.5 % within 28 days. In comparison to commercial healing agents, marginal flexural strength reduction with ALE/AS addition (17.9 % vs 30.2-50.5 %) was demonstrated. The abundance of COO group in GG blocks of ALE/AS resulted in a higher cross-link capacity with Ca , while the reduction of hydrophilic residues (e.g., COO and OH) after complexation engendered a lower swelling capacity, which facilitated self-healing and flexural strength maintenance. Molecular dynamics (MD) revealed that lower Ca diffusivity, arising from the stronger electrostatic interactions between the COO groups and Ca , resulted in a high Ca concentration around the cracks, leading to CaCO deposition and healed cracks. The outcomes of this study provided light on ALE-based mortar crack healing and presented a possibility for multi-level AS resource recovery.

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Title: Biopolymer recovery from waste activated sludge toward self-healing mortar crack
Creators: Cong Zhang - Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau
P Hu - Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau
Qing Liu - Institute of Applied Physics and Materials Engineering, University of Macau, Macau
Zeyu Lu - School of Materials Science and Engineering, Southeast University, Nanjing 211189, China
Benyi Cao
Yuxin Tang - Institute of Molecule Catalysis and In-Situ/Operando Studies College of Chemistry Fuzhou University, Fuzhou 350116, China
Tianwei Hao - Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau. Electronic address: twhao@um.edu.mo
Publication Details: The Science of the total environment, Vol.858(Pt 3), 160107
Publisher: Elsevier
Date published: 01/02/2023
Date accepted: 06/11/2022
Grant note: This research was supported by the Science and Technology Development Fund, Macau SAR (grant no. 0020/2021/ITP), Research Committee of University of Macau (grant nos. MYRG2020-00148-FST and MYRG2019-00045-FST).
Identifiers: 99724165402346
Academic Unit: School of Sustainability, Civil and Environmental Engineering
Language: English
Resource Type: Journal article
SDG (Scopus 2023): SDG 6

Biopolymer recovery from waste activated sludge toward self-healing mortar crack

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