Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Biofortification of kale microgreens with selenate-selenium using two delivery methods: Selenium-rich soilless medium and foliar application(Elsevier BV, 2024-01-01) Tavan M; Wee B; Fuentes S; Pang A; Brodie G; Viejo CG; Gupta DSelenium (Se) is essential for human health as it is involved in various fundamental biological functions. This study aimed to assess the effects of Se enrichment in kale microgreens through biofortification in a soilless cultivation system. Two Se (as sodium selenate) application methods were assessed, including supplementation into the nutrient solution or as a foliar spray at four concentrations: 0, 10, 20 and 40 µM Se in a completely randomized design considering triplicates. For this purpose, minerals, nitrate and ammonium content, as well as fresh yield and dry matter of kale microgreens, were recorded after a 14-day growing period in an environmentally controlled vertical farm. Results showed that kale microgreens successfully accumulated up to 893.3 and 24 µg Se/ kg dry matter under the nutrient solution and foliar treatments, respectively, while yield remained unaffected. Selenium (Se) enrichment of the nutrient solution at 20 µM Se concentration resulted in the optimum treatment for fresh consumption purposes and supplying this element in human diets in the future, providing adequate dietary Se in less than five grams of the fresh kale microgreens.Item Analysis of current equine feeding practices in the Netherlands and identification of potential nutrient leaching and environmental contamination factors.(Elsevier B.V., 2024-06-01) Karasu GK; Rogers CWThe aim of this study was to estimate the potential for nutrient leaching based on current feeding practices of horses in the Netherlands. An online survey of horse owners collected data on the demographics of the horses (n = 274) and feeding practices. The median age was 8 years, the majority being warmblood and geldings with a mean bodyweight of 542.4 ± 101.9 kg. Most horses (85 %) had access to a limited area of pasture (<200m2 per horse), with a median grazing time of 10 hours. Grass hay was the predominant conserved forage offered (77 %) within diets. Concentrate feeds were provided to most horses (93.8 %) as well as the dietary supplements (80 %). The majority of the horses were offered high levels of metabolizable energy (ME) (90 %), starch (mean 2.4 ± 0.8 g/kg bw) and sugar intake (mean 1.4 ± 1.2 g/kg bw) compared to NRC recommendations. The estimated potential nitrogen excretion per horse per day was 228 ± 134 g, or 8.47 kg of nitrogen per ton of manure. Consequently, the estimated daily fecal excretion rates of microminerals for each horse were as follows: Copper (Cu) at 141.0 ± 151.3 mg, Zinc (Zn) at 593.1 ± 504.4 mg, Manganese (Mn) at 957 ± 541.2 mg, and Cobalt (Co) at 2.3 ± 3.5 mg. The analysis indicated that many equine diets in the Netherlands offered excess ME, CP and the minerals Cu, Zn, Mn and Co. To mitigate these concerns, it is crucial to promote sustainable feeding practices and better educate horse owners.Item Origin and Fate of Vanadium in the Hazeltine Creek Catchment following the 2014 Mount Polley Mine Tailings Spill in British Columbia, Canada(American Chemical Society, Washington, 2019-04-16) Hudson-Edwards KA; Byrne P; Bird G; Brewer PA; Burke IT; Jamieson HE; Macklin MG; Williams RDResults from the analysis of aqueous and solid-phase V speciation within samples collected from the Hazeltine Creek catchment affected by the August 2014 Mount Polley mine tailings dam failure in British Columbia, Canada, are presented. Electron microprobe and X-ray absorption near-edge structure (XANES) analysis found that V is present as V3+ substituted into magnetite and V3+ and V4+ substituted into titanite, both of which occur in the spilled Mount Polley tailings. Secondary Fe oxyhydroxides forming in inflow waters and on creek beds have V K-edge XANES spectra exhibiting E1/2 positions and pre-edge features consistent with the presence of V5+ species, suggesting sorption of this species on these secondary phases. PHREEQC modeling suggests that the stream waters mostly contain V5+ and the inflow and pore waters contain a mixture of V3+ and V5+. These data, and stream, inflow, and pore water chemical data, suggest that dissolution of V(III)-bearing magnetite, V(III)- and V(IV)-bearing titanite, V(V)-bearing Fe(-Al-Si-Mn) oxhydroxides, and V-bearing Al(OH)3 and/or clay minerals may have occurred. In the circumneutral pH environment of Hazeltine Creek, elevated V concentrations are likely naturally attenuated by formation of V(V)-bearing secondary Fe oxyhydroxide, Al(OH)3, or clay mineral colloids, suggesting that the V is not bioavailable. A conceptual model describing the origin and fate of V in Hazeltine Creek that is applicable to other river systems is presented.Item Niobium K-Edge X-ray Absorption Spectroscopy of Doped TiO2 Produced from Ilmenite Digested in Hydrochloric Acid(American Chemical Society, 2022-08-16) Haverkamp RG; Kappen P; Sizeland KH; Wallwork KSNiobium doping of TiO2 creates a conductive material with many new energy applications. When TiO2 is precipitated from HCl solutions containing minor Nb, the Nb in solution is quantitatively deposited with the TiO2. Here, we investigate the structure of Nb doped in anatase and rutile produced from ilmenite digested in hydrochloric acid. Nb K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) are used to characterize the environment of 0.08 atom % Nb doped in TiO2. XANES shows clear structural differences between Nb-doped anatase and rutile. EXAFS for Nb demonstrates that Nb occupies a Ti site in TiO2 with no near neighbors of Nb. Hydrolysis of Ti and Nb from acid solution, followed by calcination, leads to a well dispersed doped material, with no segregation of Nb. Production of Nb-doped TiO2 by this method may be able to supply future demand for large quantities of the material and in energy applications where a low cost of production, from readily available natural resources, would be highly desirable.Item Controlled Hydrolysis of TiO2 from HCl Digestion Liquors of Ilmenite(American Chemical Society, 2022-05-18) Haverkamp RG; Wallwork KS; Waterland MR; Gu Q; Kimpton JATraditionally, industrial scale production of the TiO2 pigment is achieved by hydrolysis from H2SO4 solution or by hydrolysis of TiCl4. However, the H2SO4 route produces FeSO4 waste, which is problematic, and the TiCl4 route requires a high grade rutile feedstock or chemically upgraded ilmenite (FeTiO3). Here, we investigate a direct route from ilmenite to TiO2 using aqueous HCl. New Zealand ilmenite digested in 35 wt % HCl to achieve a solution containing typically 1.18 mol kg-1 Fe(aq)2+ and 1.14 mol kg-1 Ti(aq)4+ was hydrolyzed under reflux, after seed preparation in water, or with phosphoric or citric acid. The structure of the seed was determined by Raman spectroscopy and X-ray powder diffraction using pair distribution function analysis, the latter enabling the identification of short-range order in poorly crystalline materials. TiO2 hydrate was precipitated from HCl in either the anatase or the rutile structure. Unlike from H2SO4, the natural structure formed without the use of structure determining agents is rutile. However, seed preparation using 0.4 mol H3PO4 per mole of Ti (resulting in 0.35 wt% H3PO4 in the hydrate) results in anatase hydrate formation. Sodium citrate or citric acid addition also seed anatase hydrate. The mechanism for polymorph control may be kinetic rather than a structural template or surface adsorption. This process has the potential to be used for the commercial scale production of the TiO2 pigment. Anatase hydrate has the advantage that traces of iron may be more readily removed by washing than from rutile precipitate, making the HCl process from ilmenite feasible for pigment grade material.