skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Transition metal-doped MgO nanoparticles for nutrient recycling: an alternate Mg source for struvite synthesis from wastewater
Title: Transition metal-doped MgO nanoparticles for nutrient recycling: an alternate Mg source for struvite synthesis from wastewater
Nutrient nitrogen (N) and phosphorus (P) recovery from wastewater is an important challenge for enhanced environmental sustainability. Herein we report the synthesis and properties of mesoporous MgO nanoparticles doped with copper (Cu), iron (Fe), and zinc (Zn) as an alternative low-solubility high-abundance magnesium (Mg) source for crystalline struvite precipitation from nutrient-laden wastewater. Undoped MgO was shown to have the fastest phosphate (PO 4 3− ) adsorption kinetics with a k 2 value of 0.9 g g −1 min −1 at room temperature. The corresponding rate constant decreased for Cu–MgO (0.175 g g −1 min −1 ), Zn–MgO (0.145 g g −1 min −1 ), and Fe–MgO (0.02 g g −1 min −1 ). Undoped MgO resulted in the highest PO 4 3− removal at 94%, while Cu–MgO, Fe–MgO, and Zn–MgO resulted in 90%, 66% and 66%, respectively, under equivalent reaction conditions. All dopants resulted in the production of struvite as the main product with the incorporation of the transition metals into the struvite crystal lattice. X-ray absorption spectroscopy (XAS) showed that the majority of the Cu, Fe, and Zn were primarily in the +2, +3, and +2 oxidation states, respectively. XAS also showed that the Cu atoms exist in elongated octahedral coordination, while Fe was shown to be in octahedral coordination. Zn was shown to be in a complex disordered environment with octahedral sites coexisting with the majority of the tetrahedral sites. Finally, X-ray photoelectron spectroscopy data suggest a two-fold struvite surface enrichment with dopant metals, with Cu exhibiting an interesting new local binding structure. The dopant concentrations utilized were consistent with those found in natural Mg minerals, suggesting that (a) utilizing natural mineral periclase as the Mg source for struvite production can result in struvite formation, albeit at the expense of the reaction kinetics and overall yields, while also (b) supplying essential micronutrients, such as Zn and Cu, necessary for balanced nutrient uptake.  more » « less
Award ID(s):
1710120
PAR ID:
10292516
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Environmental Science: Nano
Volume:
7
Issue:
11
ISSN:
2051-8153
Page Range / eLocation ID:
3482 to 3496
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; (, Environmental Science: Water Research & Technology)
    null (Ed.)
    Simultaneous major nutrient nitrogen (N) and phosphorus (P) recovery from wastewater is key to achieving food–energy–water sustainable development. In this work, we elucidate the reaction kinetics, crystalline structure and chemical composition of the resulting solid precipitate obtained from simulated N and P containing wastewater solution using widely abundant low solubility magnesite (MgCO 3 ) particles in the presence of common transition metal ions, such as zinc (Zn 2+ ) or copper (Cu 2+ ). We show that up to 100 ppm Zn 2+ from the simulated wastewater can be incorporated into the struvite lattice as isolated distorted Zn 2+ while even at very low concentrations of ∼5 ppm Cu 2+ ions almost completely inhibit struvite crystal formation. The resulting solid precipitate distinctly affects soil microbial biomass carbon and soil dehydrogenase enzyme activity. These results show a cautionary case where abundant natural mineral MgCO 3 exhibits very different chemistry in Cu 2+ containing simulated wastewater and does not readily adsorb or retain NH 4 + and PO 4 3− ions, unlike less sustainable but more water-soluble magnesium sources, such as MgCl 2 , at the equivalent [Mg 2+ ] : [NH 4 + ] : [PO 4 3− ] molar ratio of 1.4 : 1 : 1. 
    more » « less
  2. ; ; ; ; ; ; (, Water Research)
    In this study, a suite of natural wastewater sources is tested to understand the effects of wastewater composition and source on electrochemically driven nitrogen and phosphorus nutrient removal. Kinetics, electrode behavior, and removal efficiency were evaluated during electrochemical precipitation, whereby a sacrificial magnesium (Mg) anode was used to drive precipitation of ammonium and phosphate. The electrochemical reactor demonstrated fast kinetics in the natural wastewater matrices, removing up to 54% of the phosphate present in natural wastewater within 1 min, with an energy input of only 0.04 kWh.m−3. After 1 min, phosphate removal followed a zero-order rate law in the 1 min - 30 min range. The zero-order rate constant (k) appears to depend upon differences in wastewater composition, where a faster rate constant is associated with higher Cl− and NH4+ concentrations, lower Ca2+ concentrations, and higher organic carbon content. The sacrificial Mg anode showed the lowest corrosion resistance in the natural industrial wastewater source, with an increased corrosion rate (vcorr) of 15.8 mm.y−1 compared to 1.9–3.5 mm.y−1 in municipal wastewater sources, while the Tafel slopes (β) showed a direct correlation with the natural wastewater composition and origin. An overall improvement of water quality was observed where important water quality parameters such as total organic carbon (TOC), total suspended solids (TSS), and turbidity showed a significant decrease. An economic analysis revealed costs based upon experimental Mg consumption are estimated to range from 0.19 $.m−3 to 0.30 $.m−3, but costs based upon theoretical Mg consumption range from 0.09 $.m−3 to 0.18 $.m−3. Overall, this study highlights that water chemistry parameters control nutrient recovery, while electrochemical treatment does not directly produce potable water, and that economic analysis should be based upon experimentally-determined Mg consumption data. 
    more » « less
  3. ; ; ; ; ; ; (, Crop Science)
    Abstract Struvite (MgNH4PO4·6H2O) has been precipitated from liquid waste streams to recover valuable nutrients, such as phosphorus (P) and nitrogen (N), that can be used as an alternative fertilizer‐P source. Because prior research has focused on greenhouse studies, it is necessary to expand struvite evaluations to the field‐scale to include row‐crop responses. The objective of this field study was to evaluate the effects of two struvite materials (electrochemically precipitated struvite, ECST; and chemically precipitated struvite, CPST) relative to other common fertilizer‐P sources (diammonium phosphate, DAP; triple superphosphate, TSP; rock phosphate, RP; and monoammonium phosphate, MAP) on soybean [Glycine max(L.) Merr.] response and economics in two consecutive growing seasons in a P‐deficient, silt‐loam soil (Aquic Fraglossudalfs) in eastern Arkansas. Averaged across years, soybean aboveground tissue P uptake was largest (P < .05) from ECST (28.4 kg ha−1), which was similar to CPST (26.7 kg ha−1) and TSP (25.9 kg ha−1) and was smallest from RP (21.4 kg ha−1). In 2019, seed yield was largest (P < .05) from ECST (4.1 Mg ha−1), which was similar to DAP, CPST, RP, TSP, and MAP, and was smallest from the unamended control (3.6 Mg ha−1). In 2020, seed yield was numerically greatest from CPST (2.8 Mg ha−1) and was numerically smallest from ECST (2.2 Mg ha−1). Results showed that wastewater‐recovered struvite materials have the potential to be a viable, alternative fertilizer‐P source for soybean production in a P‐deficient, silt‐loam soil, but further work is needed to confirm struvite's cost effectiveness. 
    more » « less
  4. ; (, JBIC Journal of Biological Inorganic Chemistry)
    null (Ed.)
    Abstract Labile low-molecular-mass (LMM) transition metal complexes play essential roles in metal ion trafficking, regulation, and signalling in biological systems, yet their chemical identities remain largely unknown due to their rapid ligand-exchange rates and weak M–L bonds. Here, an Escherichia coli cytosol isolation procedure was developed that was devoid of detergents, strongly coordinating buffers, and EDTA. The interaction of the metal ions from these complexes with a SEC column was minimized by pre-loading the column with 67 ZnSO 4 and then monitoring 66 Zn and other metals by inductively coupled plasma mass spectrometry (ICP-MS) when investigating cytosolic ultrafiltration flow-through-solutions (FTSs). Endogenous cytosolic salts suppressed ESI-MS signals, making the detection of metal complexes difficult. FTSs contained ca. 80 µM Fe, 15 µM Ni, 13 µM Zn, 10 µM Cu, and 1.4 µM Mn (after correcting for dilution during cytosol isolation). FTSs exhibited 2–5 Fe, at least 2 Ni, 2–5 Zn, 2–4 Cu, and at least 2 Mn species with apparent masses between 300 and 5000 Da. Fe(ATP), Fe(GSH), and Zn(GSH) standards were passed through the column to assess their presence in FTS. Major LMM sulfur- and phosphorus-containing species were identified. These included reduced and oxidized glutathione, methionine, cysteine, orthophosphate, and common mono- and di-nucleotides such as ATP, ADP, AMP, and NADH. FTSs from cells grown in media supplemented with one of these metal salts exhibited increased peak intensity for the supplemented metal indicating that the size of the labile metal pools in E. coli is sensitive to the concentration of nutrient metals. 
    more » « less
  5. ; ; ; ; ; ; ; ; ; ; et al (, Journal of Physics: Condensed Matter)
    Abstract Evidence of chirality was observed at the Fe metal center in Fe(III) spin crossover coordination salts [Fe(qsal)2][Ni(dmit)2] and [Fe(qsal)2](TCNQ)2from x-ray absorption (XAS) spectroscopy at the Fe 2p3/2core threshold. Based on the circularly polarized XAS data, the x-ray natural circular dichroism for [Fe(qsal)2][Ni(dmit)2] and [Fe(qsal)2](TCNQ)2is far stronger than seen for [Fe(qsal)2]Cl suggesting this natural circular dichroism signature is a ligand effect rather than a result of just a loss of octahedral symmetry on the Fe core. The larger the chiral effects in the Fe 2p core to bound XAS, the greater the perturbation of the Fe 2p3/2to 2p1/2spin–orbit splitting seen in the XAS spectra. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email