Browsing by Author "Ginocchio, R."

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    Efficacy of fresh and air-dried biosolids as amendments for remediation of acidic and metal-polluted soils: A short-term laboratory assay
    (2013) Ginocchio, R.; Carcamo, V.; Bustamante, E.; Trangolao, E.; de la Fuente, L. M.; Neaman, A.
    Biosolids have been used as amendments on mine degraded soils for in situ immobilization of metals, neutralization, and improvement of nutritional, microbiological, and physical characteristics to reestablish a self-sustaining plant community. Fresh and air-dried biosolids have been used but dried ones are preferred as they are cheaper to transport, contain less pathogens and are much easier to handle. The same efficacy has been assumed for both biosolids. The study evaluated the effects of fresh and air-dried biosolids on physical, chemical and microbiological characteristics of an acidic and metal/As-rich soil of the Puchuncav valley, central Chile, and on plant yield under laboratory conditions. Two doses of each biosolids were used (50 and 100 ton ha(-1), dry weight). Fresh and air-dried biosolids similarly increased organic matter, total nitrogen (N) and available N and phosphorous contents of study soil. However, air-dried biosolids exhibited lower field capacity and higher wilting point, salinity, higher levels of dissolved organic carbon, concentrations of total dissolved copper and zinc, and lower activity of free Cu2+ ions in pore water. Basal respiration was significantly increased by incorporation of biosolids into soils, irrespective of being fresh or air-dried ones. In terms of aerial plant productivity, fresh biosolids and low doses of air-dried biosolids significantly increased this characteristic. However, high doses of air-dried biosolids limited aerial biomass and root cover, probably due to soil salinity and water stress. Therefore, fresh biosolids are suggested for remediation of this mine degraded soils.
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    Rising Copper Exposure Effects on Nutrient Uptake in Two Species with Distinct Copper Tolerance
    (2021) Selles, I.; Neaman, A.; Krutyakov, Yu. A.; Ginocchio, R.
    Excessive copper concentrations affect nutrient uptake in sensible species. However, the effects of copper on nutrient uptake in tolerant species have not been studied equally well. Thus, the main objective of this study was to determine the effect of rising Cu exposure on nutrient uptake rates and root/shoot nutrient contents in two species with distinct copper tolerance: Acacia caven (Mol.) Mol. and Helianthus annuus L. To this end, a hydroponic experiment was conducted. Copper treatments were applied at concentrations of 0, 2.0, 3.9, 7.9, and 15.7 mu M. Relative root elongation was chosen as the endpoint for Cu toxicity assessment. The results of our study demonstrate that A. caven and H. annuus differ greatly in their tolerance to Cu. Copper concentration in the solution associated with the calculated EC25 was found to be six times higher in A. caven (15 mu M) than in H. annuus (2.3 mu M). When effective concentrations were instead based on the measured root Cu concentrations, the difference observed was ten times greater (1044 and 98 mg/kg for A. caven and H. annuus, respectively). Both species showed equal Cu uptake kinetics, with root absorbing power (alpha) of 7.5 +/- 0.7 x 10(-6) and 7.8 +/- 0.5 x 10(-6) cm s(-1) for A. caven and H. annuus, respectively. Rising Cu concentrations in the exposure solution progressively diminished the influx of Ca into the roots of H. annuus, whereas no significant effect was noted for A. caven.
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    Role of biosolids on hydrophobic properties of sulfide ores
    (2011) Reyes-Bozo, L.; Herrera-Urbina, R.; Escudey, M.; Godoy-Faundez, A.; Saez-Navarrete, C.; Herrera, M.; Ginocchio, R.
    The effect of biosolids on hydrophobic properties of sulfides ores was studied. The principal components of biosolids are humic substances, mainly humic acid, and phosphorus compounds. The feasibility of using biosolids as collector for copper sulfide ores (CSO) was performed through zetapotential measurements, FT-IR analysis and film flotation tests. Addition of different dosages of biosolids, a commercial humic acid (CHA), and an industrial collector makes the zeta potential of a copper sulfide ore more electronegative in the entire pH range studied. FT-IR spectra show that CHA can interact with mineral surfaces through outer-sphere linkages. CHA can adsorb physically on chalcopyrite and pyrite through hydrogen bonds or Van der Waals forces. Orthophosphate, however, adsorbs chemically on the surfaces of these mineralogical species through inner-sphere linkages. Therefore, biosolids that contains both humic acid and phosphorus compounds can interact with CSO surfaces through a complex mechanism involving both inner and outer-sphere linkages. Further, film flotation tests - in accordance with zeta potential results - show that biosolids adsorb on the surface of the sulfide ores investigated, changing their hydrophobicity. Biosolids show greater affinity for pyrite while commercial humic acid show similar behavior to industrial collectors. Therefore, both biosolids and humic acids can change the hydrophobic properties of sulfide ores and can be used as collectors in froth flotation processes. Further research will be needed in order to scale-up laboratory results to industrial mineral operations. (C) 2011 Elsevier B.V. All rights reserved.