Simultaneous removal of Microcystis aeruginosa and phosphorus by lanthanum-engineered metal-azolate frameworks: performance and mechanisms

Breaking the vicious cycle of “phosphorus (P) enrichment– Microcystis blooms–endogenous P release” at the source is a pivotal strategy for addressing cyanobacterial bloom contamination. Herein, lanthanum (La) engineered metal-azolate framework (LaMs) were developed, structurally characterized, and applied for the simultaneous removal of Microcystis aeruginosa ( M. aeruginosa ) and P. The inhibition rate of M. aeruginosa treated with only 10 mg L −1 LaMs quickly reached 77% after 72 h, while the P removal rate attained 89%. Meanwhile, LaMs exhibited strong pH adaptability and anti-ion interference ability. The mechanism of dual functionality was attributed to their capacity to expeditiously destroy the photosystem of M. aeruginosa , thereby inducing excessive oxidative stress response. Furthermore, the positive charges on its surface and La 3+ achieved multi-layer chemical adsorption of P. Impressively, the LaMs treatment of simulated P-rich Microcystis blooms was highly effective. After 120 h of treatment, M. aeruginosa turned yellow and died, and the P content decreased from 1 mg L −1 to approximately 0.1 mg L −1 . This study provided a eutrophication-control agent, laying the foundation for the comprehensive management of eutrophication and cyanobacterial blooms.