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19 results on '"Martí, Vicenç"'

4. Improvement in Arsenic Adsorption and Calcite Dissolution Kinetics through Size Reduction of a Ferric Hydroxide-Calcite Adsorbent.

Author

Fernandez-Rojo, Lidia, Martí, Vicenç, Jubany, Irene, Bahí, Neus, Janer, Marcel, Martínez-Lladó, Xavier, and Rovira, Miquel

Subjects
ARSENIC removal (Water purification), CALCITE, ARSENIC, ADSORPTION kinetics, ADSORPTION (Chemistry), ADSORPTION isotherms
Abstract

The employment of granular ferric iron-(oxy)hydroxides, a well-known economic and effective method, lowers arsenic concentrations in different water types. However, for direct application in polluted groundwaters, there is a need to develop new injectable adsorbents for aquifers that could also neutralize acidic media. In this context, a granular ferric hydroxide-calcite (GFH-C) adsorbent was size-reduced to 0.4–50 µm by sonication with the aim of improving (i) the adsorption of As(III) and As(V) at different pHs and (ii) the pH control through the dissolution of calcite. Batch experiments were conducted to determine As(III) and As(V) adsorption isotherms and kinetics, as well as calcite dissolution kinetics, using GFH-C of two sizes (granular and sonicated). Results showed that the arsenic binding capacity of sonicated adsorbents did not improve significantly. On the contrary, the As(III) and As(V) adsorption kinetics improved with the sonication, as in the case of calcite dissolution kinetics. The dissolution of calcite from the adsorbent made the water pH increase to around 9.2–9.4. The sonicated adsorbent offers an advantage in depolluting As-containing groundwater due to its smaller size, which is linked with faster arsenic adsorption and effective acidic water neutralization. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Reclamation of urban pollution impacted groundwater by advanced treatment processes: Effect of prechlorination on the removal of metals, ammonium and NOM at pilot scale

Author

Abenza, Misael, Rodríguez, Julio, Fernández de Labastida, Marc, de Pablo, Joan, Cortina, José Luis, Martí, Vicenç, Vázquez-Suñé, Enric, Gibert, Oriol, Abenza, Misael, Rodríguez, Julio, Fernández de Labastida, Marc, de Pablo, Joan, Cortina, José Luis, Martí, Vicenç, Vázquez-Suñé, Enric, and Gibert, Oriol

Abstract

The need for new water resources in water scarcity regions has driven the exploration of water reclamation through a variety of treatment technologies. The present study aims at reclaiming impacted urban groundwater through two different treatment routes: one based on adsorption and ion-exchange processes on consecutive pyrolusite, granular activated carbon, zeolite and Fe(oxy)hydroxide filters (route L1) and a second one relying on sorption (on pyrolusite) and RO-membrane filtration (route L2). Both routes were operated without and with prechlorination to ascertain whether NaClO, beyond inactivating undesired pathogens, affected the removal of target parameters (Mn, As, NH4+, DOC) and the formation of trihalomethanes (THMs). Results showed that route L1 was successful at removing Mn, As, pathogens and THMs at levels below those stipulated by the legislation on reuse and drinking water. Only NH4+ failed to decrease below its threshold limits for drinking water, but only in the absence of prechlorination. However, concentration of Cl− and Na+ increased during treatment due to the chemicals used, compromising reuse of the produced water in specific industrial sectors requiring low contents of these ions. Route L2 showed a consistent high removal of all targeted parameters (also NH4+) without and with prechlorination conditions, producing a finished water with high potential for reuse and production of drinking water. DOC and its fluorescent fulvic and humic-like fractions were moderately removed by route L1 but highly removed by route L2. The outperformance of route L2 in terms of produced water quality must be balanced by the associated treatment cost, as it was 8–10 % higher for route L2 than for route L1. This made evident that a trade-off between quality and cost must be faced. This study demonstrates that reclamation of urban groundwater through the proposed treatment routes has a huge potential for reuse for a wide diversity of final purposes (urban, agricultura

Published
2023

12. Direct As(V) Determination Using Screen-Printed Electrodes Modified with Silver Nanoparticles

Author

Torres-Rivero, Karina, Pérez-Ràfols, Clara, Bastos-Arrieta, Julio, Florido, Antonio, Martí, Vicenç, and Serrano, Núria

Subjects
screen-printed electrodes, silver nanoparticles, Microscòpia, Microscopy, water analysis, Carbon electrodes, Elèctrodes de carboni, arsenic determination, Article, anodic stripping voltammetry
Abstract

Carbon-nanofiber-based screen-printed electrodes modified with silver nanoparticles (Ag-NP-SPCNFEs) were tested in a pioneering manner for the direct determination of As(V) at low μg L-1 levels by means of differential pulse anodic stripping voltammetry. Screen-printed electrodes were modified with two different types of Ag-NPs, nanoseeds (NS), and nanoprisms (NPr) and characterized both microscopically and electrochemically. Furthermore, after optimizing the direct voltammetric determination of As(V), the analytical performance of considered sensors was compared for the direct determination of As(V). These results suggest that Ag-NS offer a better analytical response compared to Ag-NPr, with a detection and quantification limit of 0.6 and 1.9 µg L-1, respectively. The proposed methodology was validated using a spiked tap water sample with a very high reproducibility and good agreement with inductively coupled plasma - mass spectrometry (ICP-MS) measurements.

Published
2020

18. Effect of different seasonal conditions on the potential of wetland soils for groundwater denitrification

Author

Ribas, David, Calderer, Montse, Martí, Vicenç, and Rovira, Miquel

Abstract

AbstractWetlands, as active riparian areas in denitrification processes, are largely dependent on the environment. The main objective of this paper is to evaluate changes in the denitrification potential of wetland soils at laboratory scale promoted by climatic and seasonal influences. Several batch denitrification tests were performed with fresh wetland soil (peat) from Brynemade (Denmark) under: three different temperatures (20, 10, and 5°C), drought period, and freeze-thaw event. Results show that nitrate was eliminated in all the experiments in percentages over 90%. However, not all the nitrate removed was reduced to nitrogen gas via the denitrification process; dissimilatory nitrate reduction to ammonium (DNRA) was also present. In fact, the percentage of total nitrogen eliminated at the end of the tests was: 79.7% at 20°C, 84.1% at 10°C, 82.9% at 5°C, 41.0% in the dried soil, and 57.0% in the frozen soil. Thus, it can be concluded that the drying and freezing of the soil favor the DNRA process. Furthermore, in these conditions, nitrite increased sharply and was also accumulated possibly, as a DNRA or denitrification intermediate. Nitrate removal was fitted to a zero-order model, and an increase of the denitrification rates with the temperature was observed (3.8 mg  L−1 d−1at 20°C, 3.0 mg  L−1 d−1at 10°C, and 2.9 mg  L−1 d−1at 5°C). These overall rates were modeled as a function of temperature by the Arrhenius equation and activation energy of 12.88 kJ mol−1was determined. The fact that the activation energy is low in this work (unstirred batches) compared to previous publications (stirred batches) could be the result of a strong restriction on the nitrate mass transfer in the soil vs. reaction kinetics, which masks kinetic regulating factors of the denitrification rate. Thus, the variation of the denitrification rate with temperature is possibly the result of a combination of changes in mass transfer (diffusive transport) and kinetic constant variation, successfully modeled by the Arrhenius equation.

Published
2015
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19. Direct As(V) Determination Using Screen-Printed Electrodes Modified with Silver Manoparticles.

Author

Torres-Rivero K, Pérez-Ràfols C, Bastos-Arrieta J, Florido A, Martí V, and Serrano N

Abstract

Carbon-nanofiber-based screen-printed electrodes modified with silver nanoparticles (Ag-NP-SPCNFEs) were tested in a pioneering manner for the direct determination of As(V) at low μg L -1 levels by means of differential pulse anodic stripping voltammetry. Screen-printed electrodes were modified with two different types of Ag-NPs, nanoseeds (NS), and nanoprisms (NPr) and characterized both microscopically and electrochemically. Furthermore, after optimizing the direct voltammetric determination of As(V), the analytical performance of considered sensors was compared for the direct determination of As(V). These results suggest that Ag-NS offer a better analytical response compared to Ag-NPr, with a detection and quantification limit of 0.6 and 1.9 µg L -1 , respectively. The proposed methodology was validated using a spiked tap water sample with a very high reproducibility and good agreement with inductively coupled plasma - mass spectrometry (ICP-MS) measurements.

Published
2020
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