Sergio Ferro - Academia.edu (original) (raw)

Papers by Sergio Ferro

In the electrolysis of a soln. contg. glucose, as a model substrate in the wastewater from food i... more In the electrolysis of a soln. contg. glucose, as a model substrate in the wastewater from food industry, and a dil. NaCl, the formation of active Cl makes the glucose mineralization at the stable DSA electrode substantially insensitive to the nature of the electrode surface. The mineralization rate being the same at Ti/Pt, Ti/PbO2, TiSnO2-Pt, and Ti/IrO2 electrode. [on SciFinder (R)]

IrO2-based films are well known for their excellent electrocatalytic activity when applied as ano... more IrO2-based films are well known for their excellent electrocatalytic activity when applied as anodes in the chlor-alkali industry, wastewater treatment, organic synthetic application, as well as oxygen-evolving electrodes in the galvanic industry [1]. A so-called dimensionally stable anode (DSA) consists of an electrochemically active coating, which is generally a mixture of metal oxides, deposited on a given base metal, usually Titanium. A correlation between the electronic properties of oxides and their structure and morphology is fundamental for understanding the behavior of thin films, whose synthesis may be accomplished with different procedures. In this work, we focused on different IrO2SnO2 film compositions prepared at ambient temperature by rf-reactive magnetron sputtering. This approach allows a better control on mixture composition and a better homogeneity than the conventional sol–gel methods, typically based on the thermal decomposition, or pyrolysis, of suitable precur...

The surface of boron-doped diamond (BDD) electrode has been modified by Nafion®. The polymer film... more The surface of boron-doped diamond (BDD) electrode has been modified by Nafion®. The polymer film was applied by solvent evaporation on BDD electrode surface. Nafion®-BDD electrode is used as a sensor for the detection of dopamine (DA) in acidic and neutral media. Favourable ionic interaction between the Nafion® film and DA enhances the current response compared to that at the bare electrode. In cyclic voltammetric measurements, Nafion®-BDD electrode can successfully separate the oxidation/reduction DA peaks in both media, but an evident increase in the response was obtained in acidic media. In preliminary experiments with differential-pulse voltammetry, the sensitivity of the Nafion®-BDD electrode for DA was higher and it permits the calculation of the range detection with this technique. The modified electrode exhibits a stable and sensitive response to DA. The results are described and discussed in the light of the existing literature.

Chemosphere

Physicochemical methods such as adsorption on activated carbon, oxidation with either ozone or Fe... more Physicochemical methods such as adsorption on activated carbon, oxidation with either ozone or Fenton reagent, and chemical precipitation (coagulation), were assessed for the removal of polyethylene glycol (PEG) from wastewater. This contaminant is rarely investigated due to its low toxicity, although its presence limits the use of large water resources. The experimental tests showed that adsorption on activated carbon is well approximated by a Langmuir isotherm, and influenced by contact time, PEG molecular weight, pH, temperature, and initial PEG concentration. Ozonation allowed fragmenting the polymeric chains but was unable to remove completely the PEG, while about 85% of the total organic carbon (TOC) was removed by Fenton oxidation reaction by using a ratio between H2O2 and FeII close to 4. Coagulation did not produce results worthy of note, most likely because the uncharged PEG molecule does not interact with the iron hydroxide flocs. However, when performed after the Fenton oxidation (i.e., by simply raising the pH to values > 8), it allowed a further reduction of the residual TOC, up to 96% of the total, in the best case. Based on the resources used by each process studied and in consideration of the effectiveness of each of them, a semi-quantitative comparison on the sustainability of the different approaches is proposed.

Theoretical Foundations of Chemical Engineering

Landfill leachate is one of the problems related to waste landfills with the most important envir... more Landfill leachate is one of the problems related to waste landfills with the most important environmental impact, as the extreme variability of the substances inside the landfill gives rise to high heterogeneity of the leachate itself. In the present work, an electrochemical approach has been considered as a relatively simple and low-cost solution to the problem of ammonia removal, given the impossibility of resorting to biological treatments. An extensive experimental campaign was conducted to identify the best solution, evaluating any preventive filtration or precipitation sections, and considering the efficiency of the process in terms of energy costs. Based on the data obtained, the electrochemical approach appears feasible, and it is possible to operate either with high current densities (and higher energy costs) or with lower current densities (which, in addition to lower energy costs, allow longer service life for the electrodes), after pre-treatment of the solution by coagulation/flocculation with aluminum polychloride.

Journal of Cleaner Production

Abstract Chromium shavings are toxic waste produced by the tanning industry and include both liqu... more Abstract Chromium shavings are toxic waste produced by the tanning industry and include both liquid and solid materials contaminated with chromium(III). Their treatment by pyro-gasification in a plasma torch allows to convert them into an inert solid residue; unfortunately, the high temperatures involved in the process (∼1500 °C) induce the volatilization of some metals, the subsequent condensation of which leads to the formation of hazardous powders that require appropriate management. The aim of this work is to study the most convenient approach to deal with these powders, generated as a by-product when chromium-containing tannery waste is treated with plasma pyrolysis, and recover the heavy metals they contain. Initially, the best conditions were identified to extract those components (Pb, Zn and Cd) that can be leached from the powder, testing solutions of HCl and H2SO4 at various concentrations; subsequently, their recovery was studied considering different treatment strategies. Fractional precipitation by neutralization with 1M NaOH has proven effective for the selective recovery of Pb and Zn, followed by adsorption on chitosan for the extraction of Cd. Finally, an integrated process is proposed, which includes the two separation approaches mentioned above and allows a complete recovery of Cd and Pb, in addition to 96.3% of the initial content of Zn.

Renewable and Sustainable Energy Reviews

Abstract The possible optimization of metal recovery from Printed Circuit Boards (PCBs) and Centr... more Abstract The possible optimization of metal recovery from Printed Circuit Boards (PCBs) and Central Processing Units (CPUs) has been investigated. Usual practice is to recover primarily the metals with the highest market price. In contrast, the present work shows how strategic considerations of the value share (%) of metals content and data regarding the environmental impact of their recovery can instruct about the best strategies to adopt, pointing at the metals to be recovered as a priority depending on the case. An accurate PCBs’ characterization carried out through microwave digestion with a mixture of HNO3, HF and HCl, is a first essential step of the procedure. Then, metals are recovered through chemical leaching with different chemical substances, exploiting both chemical and physical steps. A proposal is presented to improve the environmental and economic sustainability of the treatment of PCBs, which provides for the initial recovery of Cu, Pb and Sn from the whole boards, through leaching with 6M HNO3, followed by the recovery of gold and other precious metals from the board components once removed and appropriately crushed. Although unusual, the recovery procedure can be adapted accordingly, allowing greater profits, easier management and higher metals recovery rates.

Journal of Environmental Management

Due to limited economic resources, which impede access to specific advanced technologies, many de... more Due to limited economic resources, which impede access to specific advanced technologies, many developing countries are still facing the challenge of reducing human exposure to heavy metals, which is primarily associated with the consumption of water contaminated through the discharge of poorly treated wastewater. In wastewater treatment technology, adsorption is sometime preferred to other approaches because of its high efficiency, easy handling, availability of different substrates and cost effectiveness. Moreover, increasing emphasis has recently been given to the use of low-cost adsorbents (generally solid wastes) for the treatment of polluted water, with a resulting double benefit for the environment. In this paper, the use of red mud and pyrolusite has been investigated for the removal of As and Mn from drinking water. Adsorption equilibrium data have been examined through the application of constant temperature models (isotherms), while batch and dynamic tests have been used to clarify the effects of pH, initial metal ion concentration and temperature on the adsorption performance, aiming at identifying the best conditions for the treatment. The combined use of the two adsorbents allows exploiting their properties synergistically, maximizing efficacy and sustainability without affecting process design and costs. In particular, 'clean' water (i.e. water with heavy metals contents below law limits) has been obtained even after the passage of a volume of solution higher than 40 bed volumes, and considering initial unrealistically high concentrations for the metals.

Food Control

Abstract By definition, foodborne outbreaks are illnesses affecting two or more people, correlate... more Abstract By definition, foodborne outbreaks are illnesses affecting two or more people, correlated in terms of space and time, as a result of the ingestion of etiologic agents present in a common food. Ready-to-eat food products are normally subjected to treatments of sanitisation during processing that aims to miminise the microbial load. However, microorganisms have developed mechanisms to withstand adverse environmental conditions and fight for survival, including the ability to reduce their exposure to external attack through reversible modification of the morphology and physiology of their cell. This results in a significant change of their viability, which becomes undetectable through conventional culture techniques. Subsequent ‘resuscitation’ of these organisms in favourable food environment can represent a serious public health risk. This review aims to examine the existing experimental evidence on the role of different sanitising approaches in inducing ‘viable but nonculturable’ state in microorganism and discuss possible approaches to reduce its occurrence.

Applied Sciences, Apr 24, 2020

Scientific Reports

There is increasing demand for safe and effective sanitizers for irrigation water disinfection to... more There is increasing demand for safe and effective sanitizers for irrigation water disinfection to prevent transmission of foodborne pathogens to fresh produce. Here we compared the efficacy of pH-neutral electrolyzed oxidizing water (EOW), sodium hypochlorite (NaClO) and chlorine dioxide (ClO2) against single and mixed populations of E. coli, Listeria and Salmonella under a range of pH and organic matter content. EOW treatment of the mixed bacterial suspension resulted in a dose-dependent (<1 mg/L free chlorine), rapid (<2 min) and effective (4–6 Log10) reduction of the microbial load in water devoid of organic matter under the range of pH conditions tested (pH, 6.0, 7.0, 8.4 and 9.2). The efficacy of EOW containing 5 mg/L free chlorine was unaffected by increasing organic matter, and compared favourably with equivalent concentrations of NaClO and ClO2. EOW at 20 mg/L free chlorine was more effective than NaClO and ClO2 in reducing bacterial populations in the presence of high...

Chemical Engineering Journal, 2017

The ElectroKinetic Remediation Technology (EKRT), when applied to an earthy matrix, is generally ... more The ElectroKinetic Remediation Technology (EKRT), when applied to an earthy matrix, is generally targeted to the extraction of one or more pollutants, often inorganic and typically belonging to the category of heavy metals. The technique exploits the effects caused by the application of an electric field for allowing the mobilization of the targeted pollutants, whose displacement is often facilitated by the use of suitable chemicals, which act as complexing agents. The EKRT represents a very promising approach, as it is able to produce results comparable to those of other on/off-site interventions, though with appreciably higher levels of acceptability. Moreover, in spite of expectations (which are substantially based on the high use of energy and consumables), we showed that, once properly configured, the EKRT may represent an excellent choice even when judged based on the environmental sustainability. With the present study, we aim at discussing further the plant configuration, with a special focus on the water management. In fact, as anticipated in our previous communications, the modifications that we implemented in our EKRT approach allow presenting it as an electrochemically-assisted soil flushing. Several are the elements of innovation introduced, which proved to increase the effectiveness of the remediation, but at the price of a potentially very high water (and energy) consumption. It is therefore important to have an advanced water management system, preferably coupled with a reliable wastewater recovery system in order to avoid the waste of water resources, and consequently keep down costs as well as the ecological footprint related with the implementation of this technology, thus maximizing its benefits.

Journal of hazardous materials, Jan 10, 2016

A hybrid approach for the remediation of recalcitrant dye wastewater is proposed. The chlorine-me... more A hybrid approach for the remediation of recalcitrant dye wastewater is proposed. The chlorine-mediated electrochemical oxidation of real textile effluents and synthetic samples (using Ti/IrO2-RuO2-TiO2 anodes), lead to discoloration by 92% and 89%, respectively, in 100min, without significant mineralization. The remediation was obtained through biodegradation, after removing the residual bio-toxic active chlorine species via sunlight exposition. Results show that the electrochemical discoloration enhances the effluent biodegradability with about 90% COD removal employing acclimatized naphthalene-degrading bacterial consortia, within 144h. Based on results obtained through FT-IR and GC-MS, it is likely that azo group stripping and oxidative cleavage of dyes occur due to the nucleophilic attack of active chlorine species during electro-oxidation. This leads to generation of aromatic intermediates which are further desulfonated, deaminated or oxidized only at their functional groups. ...