Grantee Research Project Results
2021 Progress Report: Novel Mineral-Hydrogel Composites for Effective Nutrient Removal to Manage Harmful Algal Blooms
EPA Grant Number: R840084Title: Novel Mineral-Hydrogel Composites for Effective Nutrient Removal to Manage Harmful Algal Blooms
Investigators: Jun, Young-Shin , Tang, Yinjie
Institution: Washington University in St. Louis
EPA Project Officer: Ludwig-Monty, Sarah
Project Period: September 1, 2020 through August 31, 2023 (Extended to August 31, 2024)
Project Period Covered by this Report: September 1, 2020 through August 31,2021
Project Amount: $800,486
RFA: Approaches to Reduce Nutrient Loadings for Harmful Algal Blooms Management (2020) RFA Text | Recipients Lists
Research Category: Harmful Algal Blooms , Water
Objective:
Harmful algal blooms (HABs) not only threaten industries like fisheries and tourism, but also affect public health by producing cyanobacterial toxins. To address the growing concerns caused by HABs, we aim to develop mineral-hydrogel composites comprised of calcium alginate hydrogels seeded with calcium phosphate (CaP), calcium silicate hydrate (CSH), and wollastonite (CaSiO3) for effective phosphate(P) removal and recovery and construct predictive kinetic and equilibrium models to quantify the composite’s performance. We further demonstrate the mineral-hydrogel composites effectiveness for HAB mitigation using benchtop cyanobacteria growth experiments.
Progress Summary:
By varying the formulation used to synthesize mineral-hydrogel composites, we concluded that CaP mineral seeds synthesized using higher concentrations of calcium in the gelation bath and using more ionic P precursor perform better with regards to P removal to low P concentrations. These findings enable the newly developed composites’ application for HAB mitigation through removal of excess phosphate in surface waters, a key nutrient implicated in HAB formation.
Furthermore, we successfully integrated CSH into the CaP mineral-hydrogel composites by addition of sodium silicate to the formulation. The synergistic combination of CSH and CaP inside the mineral-hydrogel composites enables the fast removal of P and expands the aqueous conditions in which the mineral-hydrogel composite can effectively recover P. This strategy also provides a way to lower the chemical requirements for synthesis, which is important for optimizing the cost of the mineral-hydrogel composites in the future.
Synthesis of millimeter-scale heterogeneous (compartmentalized) mineral-hydrogel composites with different mineral-seeds in different compartments of the hydrogel (e.g., in the center and on the outside of a spherical particle) was accomplished using a 3D printed nozzle. Use of heterogeneous mineral-hydrogel composites allows us to tailor the mineral-hydrogel composite compositions and architectures for more effective P and nitrogen (N) removal/recovery.
Based on the synergistic combination of fast-dissolving CSH and CaP mineral seeds, we created and tested mineral-hydrogel composites that combine wollastonite and CaP. Their combination resulted in excellent heterogeneous P removal performance (from 6.2 mg-P/L to 0.1 mg-P/L in 72 hours) inside the mineral-hydrogel composites and improved their overall P-removal capacity. The demonstrated P-removal performance of the mineral-hydrogel composites will ensure effectively lower P concentrations to mitigate HABs. Meanwhile, the captured P inside the mineral-hydrogel composites can also be reused as a slow-release P source/fertilizer for supplying photo-biorefineries.
We have demonstrated the effect that the mineral-hydrogel composites have on algal growth: The mineral-hydrogel composites are chemically stable during algal growth and removed >90% P from synthetic wastewater. Moreover, the use of mineral-hydrogel composites to pretreat the synthetic wastewater reduced algal growth rate by 75% (pure cyanobacterial culture) and by 48% (natural algal community from a local lake). In addition, the composites can be placed in algal cultures as a P source without negative growth impacts (shading effect). Overall, these advancements will allow for the mineral-hydrogel composites to both act as an effective mitigation and a remediation platform to address nutrient pollution and also have a secondary usage as slow-release fertilizer to sustain P management.
Future Activities:
We will develop the mineral-hydrogel composites to be able to recovery nitrogen (N) from aqueous solutions. We will also investigate the effect of N concentrations on algal growths and microcystins production. Then, we will systematically evaluate the core-shell/heterogeneous mineral-hydrogel composite structures for nutrient removal and recovery. After optimal mineral-hydrogel composites are engineered for nutrient removal and recovery, a model will be developed to describe the nutrient removal/recovery performance in complex aqueous matrixes. Throughout this engineering and scientific process, different algal species will be cultured at the bench to large-scale to determine the effect of the mineral-hydrogel composites on algal growth under different environmental and water chemistry conditions. Then, this knowledge will be captured in algal growth models.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
| Other project views: | All 19 publications | 8 publications in selected types | All 8 journal articles |
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Jun Y, Zhu Y, Wang Y, Ghim D, Wu X, Kim D, Jung H. Classical and nonclassical nucleation and growth mechanisms for nanoparticle formation. Annual Review of Physical Chemistry 2022;73:453-477. |
R840084 (2021) R840084 (Final) |
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Xiao Z, Tan AX, Xu V, Jun YS, Tang YJ. Mineral-hydrogel composites for mitigating harmful algal bloom and supplying phosphorous for photo-biorefineries. Science of The Total Environment 2022;847:157533. |
R840084 (2021) R840084 (Final) |
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Supplemental Keywords:
Harmful Algal Blooms, Hydrogels, Calcium Phosphate, Nitrogen, Composites, Phosphate, Calcium silicate hydrate, Nitrate, CyanotoxinRelevant Websites:
Dr. Young-Shin Jun’s research group Exit
Dr. Yinjie Tang’s research group Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.