Browsing by Author "Escudey, Mauricio"

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    Advancements in the Synthesis of Building Block Materials: Experimental Evidence and Modeled Interpretations of the Effect of Na and K on Imogolite Synthesis
    (2017) Arancibia Miranda, Nicolás; Escudey, Mauricio; Ramírez Leiva, Ricardo; González, Rafel I.; Van Duin, Adri C. T.; Kiwi Tichauer, Miguel Germán
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    Application of Polypyrrole/Humic Acid Composite Electrode for Copper Ion Extraction from Drinking Water
    (2012) Antilén Lizana, Mónica; Guzmán de la Cerda, Diego José Edgardo; Valle de la Cortina, María Angélica del; Río Quero, Rodrigo del; Letelier Solar, María Victoria; Lagos, Gustavo; Escudey, Mauricio; Pizarro, Carmen
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    Sorption and Selectivity Sequences of Cd, Cu, Ni, Pb, and Zn in Single- and Multi-Component Systems in a Cultivated Chilean Mollisol
    (TAYLOR & FRANCIS INC, 2010) Molina, Mauricio; Manquian Cerda, Karen; Escudey, Mauricio
    The heavy-metal sorption ability of soils is one of the most important factors that determine the fate of these contaminants in this medium of the biosphere. When heavy-metal containing soil amendments are land applied, a multi-component soil-solution equilibrium may occur in which various metals compete simultaneously for the sorption sites on the soil particles. In order to determine the effect of competition among Cd, Cu, Ni, Pb, and Zn on sorption characteristics and the selectivity sequence of those heavy metals in a cultivated Mollisol of central Chile, batch sorption experiments were carried out in single- and multi-component systems. Heavy metal sorption isotherms in both types of system were well described by the Langmuir's equation. For all the metals evaluated, competition among them (multi-component system) decreased both the maximum sorption capacity, obtained from the Langmuir's isotherm, and the partition coefficient (Kd) compared to the single-component system. In addition, the simultaneous presence of the five metals promoted the sorption of Cd, and to a lesser extent of Ni, on more specific sorption sites of soil particles. Either in single- or multi-component system, Pb and Cu showed a higher selectivity and retention compared to Cd, Ni and Zn, which indicates that the later heavy metals would present a higher mobility in the soil-plant-water system. Since Langmuir's parameters and Kd were highly affected by competition for all heavy metals evaluated, the use of single-component parameters in modeling assessment might lead to an incorrect description of the transport and fate of these contaminants in receiving Mollisols.
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    Trace Element Composition of Selected Fertilizers Used in Chile: Phosphorus Fertilizers as a Source of Long-Term Soil Contamination
    (TAYLOR & FRANCIS INC, 2009) Molina, Mauricio; Aburto, Fabian; Calderon, Raul; Cazanga, Marcia; Escudey, Mauricio
    Anthropogenic activities like agriculture have resulted in increased concentrations of some trace elements of toxicological and environmental concern in soils. Application of fertilizers has been one of the major inputs of these contaminants to agricultural soils in developing countries. Twenty-two fertilizers, including straight nitrogen (N), phosphorus (P), potassium (K), and NK fertilizers and micronutrient sources, were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES)for arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn). As expected, the trace element content of fertilizers was highly variable and related to the origin of the material. Phosphorus fertilizers, especially triple superphosphate, presented the highest As, Cd, Cu, Cr Ni, V and Zn concentrations. In some of these fertilizers, the Cr V and Zn contents reached values greater than 3475 mg kg(-1) of P, and the Cd content (up to 288 mg kg(-1) of P) was several times higher than the regulatory limits of different countries. Some micronutrient sources presented the highest concentrations of Mn and Pb. In the cases of N, K, and NK fertilizers, the trace element concentration was very low, sometimes below the detection limits. In some agricultural systems the input of trace elements such as As and Cd to the soil through P fertilizers application may be higher than the outputs through plant uptake and leaching; therefore the long-term use of these fertilizers may cause the trace element concentration to increase in the plow layer of agricultural soils.