Luciana Sarabando Rocha

Luciana Sarabando Rocha
Universidade do Algarve | UALG · Departamento de Química e Farmácia

About

34
Publications
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Introduction
Skills and Expertise

Publications

Publications (34)
Article
Metal uptake from contaminated waters by living Ulva lactuca was studied during 6 days, under different relevant contamination scenarios. In mono-metallic solutions, with concentrations ranging from 10 to 100 μg L⁻¹ for Hg, 10–200 μg L⁻¹ for Cd, and 50–1000 μg L⁻¹ for Pb, macroalgae (500 mg L⁻¹, d.w.) were able to remove, in most cases 93–99% of me...
Article
Environmental contextStudying the mechanism of binding between metals and natural organic matter is fundamental to understanding the transport and availability of these contaminants in the environment. The influence of sample treatment on the purification of organic matter showed significant differences in the interaction with metals. The results w...
Article
Results of 7-days exposure to metals, using environmentally realistic conditions, evidenced the high potential of living Fucus vesiculosus to remove Pb, Hg and Cd from contaminated salt waters. For different contamination scenarios (single- and multi-contamination), ca 450 mg L(-1) (dry weight), enable to reduce the concentrations of Pb in 65%, of...
Article
Six copolymers of styrenesulfonate-styrene (SS-S) of varying molecular weights were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization and proven to give rise to micelles in aqueous solution. Three are diblock copolymers (PSS-b-PS), while the other three have a random distribution of the two monomers, probably formin...
Article
Mercury and cadmium are considered by the water framework directive priority hazardous substances. In this work, the capacity of crab carapace and clam shell wastes to remove mercury and cadmium from water was evaluated under batch conditions, for realistic contamination scenarios in monometallic and binary solutions. The results evidenced that in...
Article
This study aimed to assess and explore the bioaccumulation capabilities of three different macroalgae species, Ulva lactuca (green), Gracilaria gracilis (red) and Fucus vesiculosus (brown), very common on temperate coasts and estuaries, for the removal of mercury (Hg) from contaminated waters (with high salinity), using environmentally realistic co...
Article
The present study aims to establish unambiguously the conditions required for the validity of the average diffusion ( ) approximation in fully labile systems with significant ligand size polydispersity. The average diffusion coefficient is a key parameter in mass transfer that affects signal interpretation in dynamic electroanalytical techniques. T...
Article
Ex-situ plated Bi film electrodes (Bi-FE) have been employed, for the first time, to measure the free concentration of Pb(II) in aqueous solutions using AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) with Stripping Chronopotentiometry (SCP) quantification. The amount of deposited Pbº, below a certain threshold, follows a Nernstian...
Article
We report on an international proficiency test (PT) scheme for mercury (Hg) determination in soil, sediment, fish and human-hair samples (ILAE-Hg-02). For total-Hg determination, 74% of participants had a satisfactory performance (|z-score| ≤ 2), 8% had a questionable performance and 18% required action (|z-score| > 3). The best results were obtain...
Article
A microporous material denoted ETS-4 was used as the decontaminant agent to treat water with a low level of Hg contamination. The effectiveness of the treatment was evaluated by assessment of the efficiency of Hg removal and ecotoxicological responses. The results showed that under highly competitive conditions the removal of Hg ranged between 58 %...
Article
In the present work, the efficiency of rice husk to remove Hg(II) from river waters spiked with realistic environmental concentrations of this metal (μg L(-1) range) was evaluated. The residual levels of Hg(II) obtained after the remediation process were compared with the guideline values for effluents discharges and water for human consumption, an...
Article
In this work, the efficiency of a local and highly, available agricultural waste, the raw rice husk, was used to remove mercury (Hg) from synthetic and natural waters, spiked with concentrations that reflect the contamination problems found in the environment. Different operating conditions were tested, including initial pH, ionic strength, the pre...
Article
Environmental context Electroanalytical methods have found wide application in trace metal speciation analysis in environmental systems. The need to find functional alternatives to mercury electrodes for in situ speciation studies has encouraged the use of bismuth as a solid-state electrode substrate. We demonstrate the utility of bismuth electrode...
Article
Full-text available
The technical feasibility of using stopper-derived cork as an effective biosorbent towards bivalent mercury at environmentally relevant concentrations and conditions was evaluated in this study. Only 25 mg/L of cork powder was able to achieve 94 % of mercury removal for an initial mercury concentration of 500 μg/L. It was found that under the condi...
Article
The present work explores the sorption capacity of an inexpensive and highly available agricultural waste, rice husk, to remove mercury using realistic concentrations of this metal. The efficiency of the process was evaluated for two initial Hg(II) concentrations, one representing the maximum value for Hg discharges from industrial sectors (0.05 mg...
Article
Full-text available
In the present work the removal of mercury from aqueous solutions media and for realistic concentrations of this metal was evaluated, by using an inexpensive and highly available agricultural waste, rice husk. An economical method was developed based on the use of the natural/unmodified form of rice husk and on the amount of material required, whic...
Article
The potentiality of the ex situ deposited bismuth film electrode, allied to the rotation of a glassy carbon disk electrode (BiFE-RDE), was exploited in trace metal analyses of lead(II) and cadmium(II) by stripping chronopotentiometry (SCP). A single BiFE (6.2 nm film thickness) can be used for a 1-day term with no significant variation in the analy...
Article
To better understand the impacts posed by soil contamination to aquatic ecosystems it is crucial to characterise the links between ecotoxicity, chemical availability and geochemical reactivity of potentially toxic elements (PTE's) in soils. We evaluated the adverse effects of water extracts obtained from soils contaminated by chemical industry and...
Article
In the present work, the applicability of thin mercury film on a rotating disk electrode (TMF-RDE), to assess the free metal ion concentration by the absence of gradients and Nernstian equilibrium stripping (AGNES), is evaluated. The thickness of the mercury film and several AGNES parameters has been optimized. A nominal 16 nm film is chosen due to...
Article
In this work, polyelectrolyte coatings assembled on glassy carbon/thin mercury film electrodes, as an adsorbed layer of poly(sodium 4-styrenesulfonate) (PSS), were studied. The goal was to search for the best conditions for the production of stable PSS-coated electrodes that could present high negative charge densities within the thin polymeric fil...
Article
In this work, the performance and applicability of the thin mercury film electrode (TMFE) in the heavy metal speciation, by stripping chronopotentiometry (SCP), were exploited. The TMFE thickness was optimized and a 7.6nm mercury film was selected. This TMFE was mechanically stable and able to perform 60 SCP consecutive measurements, with no signif...
Poster
Jornadas de Electroquímica e Inovação 2006 – Forum on Electrochemistry and Innovation 2006 – Porto, Portugal
Article
This work aimed to produce improved polymer coatings for the modification of thin mercury film electrodes (TMFEs). The goal is to obtain sensitive, reproducible, mechanically stable and antifouling devices suitable for the determination of trace metal cations in complex media. Therefore, novel mixed coatings of two sulfonated cation-exchange polyme...
Article
The incorporation/exclusion features of dopamine (DA), ascorbic acid (AA) and uric acid (UA) are evaluated for Nafion (NA)-coated glassy carbon electrodes (GCE) of different thicknesses. The ion-exchange partition of DA(+) between the NA film and the sodium phosphate electrolyte is evaluated by determining the partition coefficient (k(D)) and the a...
Article
A simple, rapid procedure for the determination of organic mercury in sediments, plants and fish tissues has been developed and validated. Extraction and separation of organic mercury compounds from the sample matrix was achieved by an established procedure based on an acid leaching of the sample (H2SO4/KBr/CuSO4), followed by extraction of the org...
Presentation
Full-text available
11th International Conference on Electroanalysis – ESEAC 2006
Article
The adsorptive stripping voltammetric behaviour of trimethoprim (TMP) was studied at pH 3.8 and 7.0 by linear-sweep (LS) and cyclic voltammetry at the hanging mercury drop electrode. The charges and surface concentrations of the protonated TMP species were determined at both pH values. Taking advantage of the adsorption features of TMP fast voltamm...
Article
In the present work the anodic stripping voltammetric (ASV) methodology using a thin mercury film electrode in situ plated in thiocyanate media was re-assessed in order to allow the simultaneous determination of copper and lead in seawater. Under previously suggested conditions [6], i.e. using a concentration of thiocyanate of 5mM, the ASV peaks of...

Projects

Project (1)
Project
The overarching goal of this project is to decipher how physico‐chemical processes, promoted by NP and colloidal organic matter modifies the speciation and fate of trace elements in aquatic systems. The specific objectives of the present proposal are to: • Build and develop an in-situ measurement probe based in SSCP/AGNES/DMT, • Perform laboratory studies in complex mixtures of polymers, nanoparticles and naturally occurring particles in order to understand the response of our techniques. • Perform laboratory studies in complex mixtures of polymer coated nanoparticles and natural colloids in order to understand the role of NP as new vector of trace elements, • Apply our in-situ probe to a pilot-scale study of a controlled microcosm and study the probe response as we add our successively more complex model systems, • Validate the method of the in-situ probe in field samples taken in different seasons.