Enhanced coagulation of Microcystis aeruginosa using titanium xerogel coagulant

Shulian Wang; Yanqun Li; Lu Cai; Xian Yang; Kewu Pi; Zhu Li

doi:10.1016/j.chemosphere.2024.144017

Enhanced coagulation of Microcystis aeruginosa using titanium xerogel coagulant

Chemosphere. 2024 Dec 26:144017. doi: 10.1016/j.chemosphere.2024.144017. Online ahead of print.

Authors

Shulian Wang¹, Yanqun Li², Lu Cai³, Xian Yang⁴, Kewu Pi⁵, Zhu Li⁶

Affiliations

¹ Key Laboratory of Health Intelligent Perception and Ecological Restoration of River and Lake, Ministry of Education, Hubei University of Technology, Wuhan 430068, China. Electronic address: [email protected].
² Key Laboratory of Health Intelligent Perception and Ecological Restoration of River and Lake, Ministry of Education, Hubei University of Technology, Wuhan 430068, China. Electronic address: [email protected].
³ Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem, Institute of Hydroecology, Ministry of Water Resources and Chinese Academy of Sciences, Wuhan 430079, China. Electronic address: [email protected].
⁴ Key Laboratory of Health Intelligent Perception and Ecological Restoration of River and Lake, Ministry of Education, Hubei University of Technology, Wuhan 430068, China. Electronic address: [email protected].
⁵ Key Laboratory of Health Intelligent Perception and Ecological Restoration of River and Lake, Ministry of Education, Hubei University of Technology, Wuhan 430068, China. Electronic address: [email protected].
⁶ Key Laboratory of Health Intelligent Perception and Ecological Restoration of River and Lake, Ministry of Education, Hubei University of Technology, Wuhan 430068, China; Innovation Demonstration Base of Ecological Environment Geotechnical and Ecological Restoration of Rivers and Lakes, School of Civil and Environmental Engineering, Hubei University of Technology, Wuhan 430068, China. Electronic address: [email protected].

PMID: 39732406
DOI: 10.1016/j.chemosphere.2024.144017

Abstract

Cyanobacterial blooms are prevalent globally and present a significant threat to water security. Titanium salt coagulants have garnered considerable attention due to their superior coagulation properties and the absence of metal residue risks. This paper explored the influencing factors in the coagulation process of titanium xerogel coagulant (TXC), the alterations in cell activity during floc storage, and the release of cyanobacterial organic matters, thereby determining the application scope of TXC for cyanobacterial water treatment. The findings indicated that at a TXC dosage of 8 mg Ti/L, the removal rate of Microcystis aeruginosa (M. aeruginosa) exceeded 86% across a pH range of 5-9. The coagulation performance with anions HCO₃^-, CO₃^2- and H₂PO₄^-/HPO₄^2- was unsatisfactory at concentrations of 10, 20, and 50 mg/L, with corresponding chlorophyll a (Chl-a) levels of 168, 129, and 196 μg/L, respectively. While the presence of Cl^-, NO₃^-, SO₄^2-, K⁺, NH₄⁺, Ca²⁺ and Mg²⁺ had little influence on the removal efficiency. At sodium alginate (SA) concentration of 6 mg/L, the Chl-a content was 116 μg/L, with humic acid (HA) not affecting M. aeruginosa removal but hindering turbidity reduction, leaving a residual turbidity of 11 NTU. Following TXC treatment, a floc storage study with cyanobacteria-laden surface water showed a decrease in microcystins (MCs) content. The low residual titanium concentration post-TXC coagulation (<0.06 mg/L) and MCs reduction contributed to reduced effluent toxicity, indicating TXC's versatile applicability for treating cyanobacterial-contaminated waters.

Keywords: Coagulation; M. aeruginosa; Microcystin; Titanium xerogel coagulant.