Introducing La(OH)3 nanoparticles into attapulgite for the control of sediments internal phosphorus release: Effectiveness, mechanisms, and microbial community response

Abstract

In-situ passivation of engineering materials is an economical and effective method to control internal phosphorus load in aquatic systems. However, few studies have simulated aerobic and anaerobic environments to compare the engineering materials control sediment phosphorus release performance with or without sediment re-suspension. In this study, we prepared and optimized lanthanum modified thermally attapulgite (LMTA) for sediment phosphorus immobilization with a maximum adsorption capacity of 97.99 mg/g. An 88-day sediment core cultivation experiment revealed that LMTA reduced the concentration of soluble reactive phosphate (SRP) and total phosphorus (TP) by 89.3% and 79.4% in absence of re-suspension, and by 89.8% and 78.3% with re-suspension, respectively. LMTA also transformed sediment Mobile-P into HCl-P and Res-P, which are inert phosphorus forms. Moreover, high-throughput sequencing showed that Nitrospirae abundance was significantly increased with LMTA, which could promote the water nitrogen cycle. The results confirmed that LMTA effectively controls internal phosphorus release, even under sediment re-suspension conditions.