Effective removal of microplastics by filamentous algae and its magnetic biochar: Performance and mechanism

Xinyang Li; Wenjia Liu; Jingshen Zhang; Zhibin Wang; Zhiwei Guo; Jafar Ali; Lei Wang; Zhisheng Yu; Xiru Zhang; Yangzhao Sun

doi:10.1016/j.chemosphere.2024.142152

Effective removal of microplastics by filamentous algae and its magnetic biochar: Performance and mechanism

Chemosphere. 2024 Apr 26:358:142152. doi: 10.1016/j.chemosphere.2024.142152. Online ahead of print.

Authors

Xinyang Li¹, Wenjia Liu², Jingshen Zhang³, Zhibin Wang⁴, Zhiwei Guo¹, Jafar Ali⁵, Lei Wang⁶, Zhisheng Yu², Xiru Zhang², Yangzhao Sun⁷

Affiliations

¹ College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China; School of Ecology and Environment, Zhengzhou University, Zhengzhou, 450001, China.
² College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
³ College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
⁴ College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: wzbin@ucas.ac.cn.
⁵ Key Lab of Groundwater Resources and Environment (Jilin University), Ministry of Education, Changchun, 130021, China.
⁶ Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
⁷ Norwegian Water Research Institute, Økernveien 94, 0579, Oslo, Norway.

PMID: 38679178
DOI: 10.1016/j.chemosphere.2024.142152

Abstract

In recent years, filamentous algae blooms and microplastics (MPs) pollution have become two major ecological and environmental problems in urban water systems. In order to solve these two problems at the same time, this study explored the loading capacity of MPs on fresh filamentous algae, and successfully synthesized magnetic filamentous algae biochar loading with Fe₃O₄ by hydrothermal method, with the purpose of removing MPs from water. The magnetic filamentous algal biochar was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and so on. Experiments on adsorption kinetics, adsorption isotherms and optimum pH were carried out to explore the adsorption mechanism of MPs on magnetic filamentous algal biochar. The adsorption kinetics and adsorption isotherm models were evaluated, and the selection criterion for the appropriate model was determined by using the residual sum of squares (RSS) and Bayesian information criterion (BIC). Microscope images revealed that fresh filamentous algae could interact with MPs in the form of entanglement, adhesion and encapsulation. The average load of MPs in filamentous algae samples was 14.1 ± 5 items/g dry weight. The theoretical maximum adsorption capacities of polystyrene MPs (PS-MPs) by raw biochar (A500) and magnetic biochar with Fe₃O₄ (M2A500) were 176.99 mg/g and 215.58 mg/g, respectively. The adsorbent materials gave better reusability because they could be reused up to five times. Overall, these findings have provided new insights into the use of filamentous algae for in situ remediation of fluvial MPs pollution, as well as feasible strategies for the recycling of algal waste.

Keywords: Adsorption; Filamentous algae; Magnetic biochar; Microplastic pollution; Urban river.