Final Report: Novel Lignin-Based Magnetite Nanocomposites for Removal of Phosphate from Contaminated WatersEPA Contract Number: EPD12027
Title: Novel Lignin-Based Magnetite Nanocomposites for Removal of Phosphate from Contaminated Waters
Investigators: Bourdo, Shawn , Toland, Alan
Small Business: Synanomet LLC
EPA Contact: Manager, SBIR Program
Project Period: March 1, 2012 through August 31, 2012
Project Amount: $79,368
RFA: Small Business Innovation Research (SBIR) - Phase I (2012) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water and Wastewater
Phosphorus (P) remediation is a difficult and costly environmental problem predicted to cost as much as $44.5B using conventional wastewater treatment plants to meet EPA requirements. Phosphorus runoffs can lead to “dead zones” due to eutrophication and hypoxia, leading to death of aquatic life that thrive in an oxygen-rich environment. There are no commercial products in the market for P reduction and removal from large water sources to meet recent, stringent EPA requirements in an economical manner. The upper limit for P in stream discharge is typically 1 mg/L and further lowering to < 0.1 mg/L is required to meet or exceed current EPA standards.
Synanomet, LLC has an exclusive license for the manufacture and use of patented and patent pending technologies for water purification from the University of Arkansas. The technology utilizes magnetic nanocomposites made from renewable resources and is an environmentally safe, fast and economical process.
In Phase I, we demonstrated that high surface area magnetite particles embedded in wood as well as carbon are highly efficient in reducing P to ultra-low levels (as low as 0.01 mg/L). The adsorbed P can be recovered from the media and potentially recycled as fertilizers in the form of solids, calcium phosphate and struvite (MgNH4PO4) or as liquid fertilizer solutions of potassium or ammonium phosphate. We also showed that the media can be regenerated at least 10 times for successive P removal. These wood-based nanocomposites can also be completely carbonized to yield carbon-magnetite nanocomposites with P removal capability and additional multifunctional applications, such as visible-light photodegradation of organics and odor suppression.
We discovered that using tannin-containing wood was more effective than powdered lignin in producing magnetic composites with the desired properties. We also discovered that a desirable quaternization of wood using Quat 188 (a material that imparts positive charge to wood) prior to impregnation of magnetic particles gave a high performing nanocomposite.
In all, four different types of nanocomposites were prepared during Phase I.
They are as follows:
- Magnetic particles impregnated in pine wood.
- Highly dispersed magnetic particles impregnated in pine wood prepared by incorporation of salt during the synthesis procedure.
- Magnetic particles impregnated in quaternized pine wood.
- Completely carbonized wood-based composites obtained by pyrolysis of magnetite embedded wood.
- The synthetic procedure for wood-based magnetite composites in this project is environmentally safe, fast, easy and cost-effective. All wash solutions used in the process can be reused and will not be a source of pollution.
- The four (4) different composites prepared show very good to excellent performance in the removal of Phosphorous, and showed the ability to reduce Phosphorous levels to ultralow (< 0.01mg /L) levels.
- All samples characterized are ferromagnetic with magnetite particles exhibiting high surface area in the nano dimension and are dispersed in and on the wood (or the carbon matrix in case of completely carbonized material).
- Following Phosphorous adsorption the media can be recovered using a dilute NH4OH wash and the P can be precipitated from the wash and be potentially used as a fertilizer. The regenerated media can be reused several times for further P removal from contaminated water.
- The Phosphorous removal capacity and regeneration data shows that overall the Quat-modified wood-magnetite composite performed the best, followed by wood-magnetite with spacer. The wood-magnetite (without spacer) ranks third in terms of overall efficacy.
- Completely carbonized C-magnetite composite has a lower P removal capacity in terms of P removed per gram of iron in the composite. However the product has value because of odor-removing function as well as a host of other multi-functional application. This includes its use in removal of sulfur-containing compounds in biogas, removal of toxic organic compounds from contaminated water and the removal of oil following an oil spill.
- The composites prepared may potentially be used for the removal of Arsenic, Chromium and other heavy metals. It may also be used for the removal of Selenium and Fluoride.
Commercialization potential of our nanocomposites – proven feasible in the Phase I effort – will be realized once successful field pilot scale demonstrations have occurred and we complete microcolumn studies that finalize the production scale-up process for the nanocomposites. Agreements are in place with Energy & Environmental Research Center (EERC) affiliated with the University of North Dakota for scale-up work in kilogram quantities using a fluidized bed continuous reactor and a hot bed rotary kiln. The nanocomposite materials will be evaluated by Parkson Corporation and AbTech Industries for P removal and media regeneration. Norit Americas, Inc. will evaluate the materials for odor suppression.
Commercial applications of the composites include not only P removal but also the potential for removal of heavy metals such as Chromium, Arsenic and Selenium. Removal of odor from biogas and visible-light photodegradation of toxic organic compounds in contaminated waters is envisioned in plans with the above listed commercial partners. Parkson, AbTech and Norit Americas are commercial channels as well as R&D providers for our scale up efforts. Parkson will evaluate Synanomet materials in combination with Dynansand™ (Parkson’s material for P removal) while Norit Americas will conduct work for the removal of hydrogen sulfide using Synanomet’s carbon-magnetite composite. Discussions are currently ongoing with AbTech for their specific involvement with the project.