CRAES, Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University uses Easysensor DGT to publish the article as below:
Highlights
•Modified zeolites that enable O2 loading and N and P adsorption was developed.
•Application of the LOZ totally reversed N and P releasing from the sediment.
•LOZ addition triggered adsorption and immobilization of internal P.
•LOZ addition enhanced adsorption and biological approach towards N removal.
•The O2 delivery generates anaerobic and aerobic environment across the sediment.
Abstract
Nutrients released from lake sediments contribute to the total nutrient load of an aquatic ecosystem. In this study, we used the oxygen-loaded lanthanum modified zeolites (LOZ) for absorbing internal phosphorus (P) and nitrogen (N) meanwhile with potential to trigger biological transformation of the nutrients. The results showed that the lanthanum modification of the zeolites manifested both the P and N adsorption in comparison to the pristine zeolites (enhanced by 129.13 % for PO43−-P and 27.53% for NH4+−N, respectively). In addition, lanthanum modified zeolites also exhibited the excellent oxygen-loading capability (0.73 mmol/g) than the pristine one. Apart from the blocking of P and N, the LOZ application over surface sediment substantially improved the benthic and aquatic DO level as the DO concentration in overlying water was 3–5 mg/L and diffused to 12 mm depth of sediment. The increased oxygen level in sediment favored the phosphate and Fe oxy(hydr)oxides combination and reduced FeS formation with subsequent decline in PO43−-P release from sediments. The improvement of water DO level also induced the microbial community shifts and promoted the abundance of nitrifiers in the surface sediment while denitrifiers in the deeper layer. Consequently, the release of total phosphorus and total nitrogen from the sediment to overlying water was reduced by 80% and 92%, respectively. Thus, the application of LOZ to sediment was beneficial to not only the anaerobic and aerobic processes that involved in nitrogen removal, but also the inactivation of phosphate. The study delivered positive outcomes regarding the control of internal nutrients release with a quick, efficient and sustainable remediation approach to rehabilitate polluted water systems.
Graphical abstract
Writers
Wei GN, Yuan RY, Muhammad Salam, et., 2022. Achieving simultaneous removal of nitrogen and phosphorus in sediment via combined adsorption and oxygen supplement, Chemical Engineering Journal, Volume 441, 136056, ISSN 1385-8947, https: //doi. org/10. 1016/j. cej. 2022. 136056.
Link
https://www.sciencedirect.com/science/article/abs/pii/S1385894722015546?via%3Dihub=