Adsorption adaptive response exposed to algal organic matter: correlation to the characteristics of granular activated carbon.

Abstract

The release of algal organic matter (AOM) during seasonal algal blooms increases the complexity and heterogeneity of natural organic matter (NOM) in water sources, altering its hydrophilic-hydrophobic balance and posing significant challenges to conventional water treatment processes. This study aims to verify whether the (Granular activated carbon) GAC selected for the adsorption of NOM in sand filtration effluent can adapt to water quality fluctuations caused by AOM release, and identify the criteria influencing GAC adsorption performance. Results indicated that external surface area, mesopore volume, pore size and surface functional groups were key indicators of GAC adsorption performance. AOM exposure increased the soluble microbial byproducts (SMP) and humic acid components in sand filter effluent, and induced the presence of high molecular weight biopolymers. The removal characteristics of sand filtration effluent spiked with AOM indicated that GAC preferentially adsorbed unsaturated bonds and aromatic compounds, as well as organic acids like fulvic and humic acids. Its adsorption primarily involved physical and chemical processes such as pore filling, hydrophobic interactions, and reactions between chemical functional groups. AOM exposure led to an increase in hydrophilic macromolecules such as polysaccharides and proteins, causing competitive adsorption and pore blockage. This study provided a theoretical basis for the efficient and rapid selection of GAC during outbreaks of AOM pollution.