Manganese-containing mixed oxide electrodes as anode materials for degradation of model organic pollutants

Mixed oxide thin film electrodes have been prepared by thermal decomposition from alcoholic solution on Pt substrate. In particular, three different anodes have been obtained by co-deposition of Ru (Ruthenium) and Mn (Manganese) oxides, Ru, Mn and Cu (Copper) oxides and co-deposition of Ru, Mn and Co (Cobalt) oxides. The electrochemical behaviour of the prepared electrodes was evaluated by potentiodynamic polarization curves and cyclic voltammetry tests. We also tested and compared their oxidizing ability in the degradation of aqueous solutions containing methyl orange as model compound and small amount of chloride. Galvanostatic experiments were conducted in a membrane-free reactor. The treatment extent was assessed by detection of color and TOC decay. The electrogeneration of active chlorine, chlorate and perchlorate was also monitored. The preliminary results show that ternary oxides coated electrodes exhibit enhanced electrocatalytic activity without producing undesired chlorinated by-products

Shortcut Biological Nitrogen Removal (SBNR) in an MFC anode chamber under microaerobic conditions. The effect of C/N ratio and kinetic study

In this work, the feasibility of the Shortcut Biological Nitrogen Removal (SBNR) in the anodic chamber of a Microbial Fuel Cell (MFC) was investigated. Thirty day experiments were carried out using synthetic wastewaters with a Total Organic Carbon vs. nitrogen ratio (TOC/N) ranging from 0.1 to 1. Ammonium, nitrite, nitrate, pH, and TOC were daily monitored. Results showed that microaerobic conditions in the anodic chamber favored the development of nitritation reaction, due to oxygen transfer from the cathodic chamber through the membrane. Nitritation was found to depend on TOC/N ratio: at TOC/N equal to 0.1 an ammonium removal efficiency of up to 76% was observed. Once the oxygen supply to the cathodic chamber was stopped, denitritation occurred, favored by an increase of the TOC/N ratio: a nitrite removal of 80.3% was achieved at TOC/N equal to 0.75. The presence of nitrogen species strongly affected the potential of the electrochemical system: in the nitritation step, the Open Circuit Voltage (OCV) decreased from 180 mV to 21 mV with the decrease of the TOC/N ratio in the investigated range. Lower OCV values were observed in the denitritation steps since the organic carbon acted as the energy source for the conversion of nitrite to nitrogen gas. A kinetic analysis was also performed. Monod and Blackman models described the ammonium and the organic carbon removal processes well during the nitritation step, respectively, while Blackman-Blackman fitted experimental results of the denitritation step better

Shortcut biological nitrogen removal (SBNR) in microbial fuel cells (MFCs)

Microbial Fuel Cells (MFCs) represent nowadays a promising technology for the treatment of industrial wastewater. In this work the Shortcut Nitritation/Denitritation process in H-type MFC was investigated. The cell was fed by sodium acetate and fumaric acid, as organic carbon source, and ammonium sulphate, sodium nitrite and sodium nitrate as nitrogen source. Anaerobic digestion supernatant (digestate) was used as bacterial source. Batch tests were performed at a TOC/N ratio of 0.35, and Total Organic Carbon (TOC), pH and Open Circuit Voltage (OCV) were daily monitored. High organic carbon removal (up to 85%) in short time (within 6 days) were achieved. The nitritation proved to be independent of organic carbon amount and composition: an ammonium content reduction of about 45% was observed. Regarding the denitritation step, an almost quantitative removal of nitrite and nitrate was observed when fumaric acid was used as a carbon source

Photolysis of in-situ electrogenerated hydrogen peroxide for the degradation of emerging pollutants

This study investigates the degradation of paracetamol, an emerging contaminant widely used as pain and fever reliever, by means of hydrogen peroxide either alone or in combination with UV-C photolysis. In particular, we provide a comparison between the performance of both commercial and electrogenerated H2O2 whose production has been achieved by galvanostatic electrolysis in undivided reactor with a gas diffusion cathode. The performance of the treatments has been assessed in terms of both pollutant decay and mineralization. The influence of the H2O2 to paracetamol molar ratio is discussed. The results show that the electrogenerated hydrogen peroxide, when activated by UV-C irradiation, results in faster degradation and mineralization of paracetamol. However, under the conditions adopted, complete depletion of the total organic carbon (TOC) has never been attained

Use of nano zero-valent iron to reduce inorganic species electrogenerated during anodic oxidation on boron doped diamond anodes

In this paper, the solution coming from an anodic oxidation on boron doped diamond of chloride-containing solution is treated with addition of nano zero-valent iron (nZVI) to reduce the amount of chlorinated byproducts into chloride ions. The electrolyzed solutions have been obtained under galvanostatic conditions in an undivided reactor. The evolution and depletion of all the chlorinated species have been monitored by spectrophotometry and ion chromatography. The nanoscale iron particles have been synthesized in our laboratory by a fast and facile method through reaction of FeSO4 and NaBH4 solutions without addition of dispersants. The effect on the conversion yield of several operative parameters has been investigated and discussed. The preliminary results indicate that a nZVI postreatment can be considered a viable technology for the treatment of solutions containing active chlorine and chlorate. However, the reduction of perchlorate, either in mixed solutions or alone, requires too drastic conditions to be completed

Chest pain caused by multiple exostoses of the ribs: A case report and a review of literature

Abstract The aim of this paper is to report an exceptional case of multiple internal exostoses of the ribs in a young patient affected by multiple hereditary exostoses (MHE) coming to our observation for chest pain as the only symptom of an intra-thoracic localization. A 16 years old patient with familiar history of MHE came to our observation complaining a left-sided chest pain. This pain had increased in the last months with no correlation to a traumatic event. The computed tomography (CT) scan revealed the presence of three exostoses located on the left third, fourth and sixth ribs, all protruding into the thoracic cavity, directly in contact with visceral pleura. Moreover, the apex of the one located on the sixth rib revealed to be only 12 mm away from pericardium. Patient underwent video-assisted thoracoscopy with an additional 4-cm mini toracotomy approach. At the last 1-year followup, patient was very satisfied and no signs of recurrence or major complication had occured. In conclusion, chest pain could be the only symptom of an intra-thoracic exostoses localization, possibly leading to serious complications. Thoracic localization in MHE must be suspected when patients complain chest pain. A chest CT scan is indicated to confirm exostoses and to clarify relationship with surrounding structures. Video-assisted thoracoscopic surgery can be considered a valuable option for exostoses removal, alone or in addiction to a mini-thoracotomy approach, in order to reduce thoracotomy morbidity

Design of a dedicated circular coil for Magnetic Resonance Spectroscopy studies in small phantoms and animal acquisition with a 3 Tesla Magnetic Resonance clinical scanner

Abstract Introduction: Magnetic Resonance Spectroscopy (MRS) is a very powerful tool to explore the tissue components, by allowing a selective identification of molecules and molecular distribution mapping. Due to intrinsic Signal-to-Noise Ratio limitations (SNR), MRS in small phantoms and animals with a clinical scanner requires the design and development of dedicated radiofrequency (RF) coils, a task of fundamental importance. In this article, the authors describe the simulation, design, and application of a 1H transmit/receive circular coil suitable for MRS studies in small phantoms and small animal models with a clinical 3T scanner. In particular, the circular coil could be an improvement in animal experiments for tumor studies in which the lesions are localized in specific areas. Material and methods: The magnetic field pattern was calculated using the Biot–Savart law and the inductance was evaluated with analytical calculations. Finally, the coil sensitivity was measured with the perturbing sphere method. Successively, a prototype of the coil was built and tested on the workbench and by the acquisition of MRS data. Results: In this work, we demonstrate the design trade-offs for successfully developing a dedicated coil for MRS experiments in small phantoms and animals with a clinical scanner. The coil designed in the study offers the potential for obtaining MRS data with a high SNR and good spectral resolution. Conclusions: The paper provides details of the design, modelling, and construction of a dedicated circular coil, which represents a low cost and easy to build answer for MRS experiments in small samples with a clinical scanner

Manipulation of Charge Delocalization in a Bulk Heterojunction Material Using a Mid-Infrared Push Pulse

In organic bulk heterojunction materials, charge delocalization has been proposed to play a vital role in the generation of free carriers by reducing the Coulomb attraction via an interfacial charge transfer exciton (CTX). Pump-push-probe (PPP) experiments produced evidence that the excess energy given by a push pulse enhances delocalization, thereby increasing photocurrent. However, previous studies have employed near-IR push pulses in the range 0.4-0.6 eV which is larger than the binding energy of a typical CTX. This raises the doubt that the push pulse may directly promote dissociation without involving delocalized states. Here, we perform PPP experiments with mid-IR push pulses at energies that are well below the binding energy of a CTX state (0.12-0.25 eV). We identify three types of CTX: delocalized, localized, and trapped. The excitation resides over multiple polymer chains in delocalized CTXs, while is restricted to a single chain (albeit maintaining a degree of intrachain delocalization) in localized CTXs. Trapped CTXs are instead completely localized. The pump pulse generates a hot delocalized CTX, which relaxes to a localized CTX, and eventually to trapped states. We find that photo-exciting localized CTXs with push pulses resonant to the mid-IR charge transfer absorption can promote delocalization and contribute to the formation of long-lived charge separated states. On the other hand, we found that trapped CTX are non-responsive to the push pulses. We hypothesize that delocalized states identified in prior studies are only accessible in systems where there is significant interchain electronic coupling or regioregularity that supports either interchain or intrachain polaron delocalization. This emphasizes the importance of engineering the micromorphology and energetics of the donor-acceptor interface to exploit a full potential of a material for photovoltaic applications

Indocyanine green (ICG) fluorescent cholangiography during laparoscopic cholecystectomy using RUBINA™ technology: preliminary experience in two pediatric surgery centers

Background Recently, we reported the feasibility of indocyanine green (ICG) near-infrared fluorescence (NIRF) imaging to identify extrahepatic biliary anatomy during laparoscopic cholecystectomy (LC) in pediatric patients. This paper aimed to describe the use of a new technology, RUBINA (TM), to perform intra-operative ICG fluorescent cholangiography (FC) in pediatric LC. Methods During the last year, ICG-FC was performed during LC using the new technology RUBINA (TM) in two pediatric surgery units. The ICG dosage was 0.35 mg/Kg and the median timing of administration was 15.6 h prior to surgery. Patient baseline, intra-operative details, rate of biliary anatomy identification, utilization ease, and surgical outcomes were assessed. Results Thirteen patients (11 girls), with median age at surgery of 12.9 years, underwent LC using the new RUBINA (TM) technology. Six patients (46.1%) had associated comorbidities and five (38.5%) were practicing drug therapy. Pre-operative workup included ultrasound (n = 13) and cholangio-MRI (n = 5), excluding biliary and/or vascular anatomical anomalies. One patient needed conversion to open surgery and was excluded from the study. The median operative time was 96.9 min (range 55-180). Technical failure of intra-operative ICG-NIRF visualization occurred in 2/12 patients (16.7%). In the other cases, ICG-NIRF allowed to identify biliary/vascular anatomic anomalies in 4/12 (33.3%), including Moynihan's hump of the right hepatic artery (n = 1), supravescicular bile duct (n = 1), and short cystic duct (n = 2). No allergic or adverse reactions to ICG, post-operative complications, or reoperations were reported. Conclusion Our preliminary experience suggested that the new RUBINA (TM) technology was very effective to perform ICG-FC during LC in pediatric patients. The advantages of this technology include the possibility to overlay the ICG-NIRF data onto the standard white light image and provide surgeons a constant fluorescence imaging of the target anatomy to assess position of critical biliary structures or presence of anatomical anomalies and safely perform the operation

Simulation, design, and test of an elliptical surface coil for magnetic resonance imaging and spectroscopy

AbstractThe simplest design of surface coils for magnetic resonance imaging (MRI) applications is circular and square loops, both producing a magnetic field perpendicular to the coil plane in the central region‐of‐interest (ROI), with an amplitude that decreases along the coil axis. However, a surface coil constituted by a loop with different geometry could be necessary when particular field‐of‐views (FOVs) are desired, especially for performing imaging in an elongated region. This can be achieved by using an elliptical loop, which can guarantee a wide longitudinal FOV and a good penetration in deep sample regions. This work proposes the application of a method for elliptical coil Signal‐to‐Noise Ratio (SNR) estimation previously developed for circular and square loop design, in which coil inductance and resistance are analytically calculated and the magnetic field pattern is estimated using the magnetostatic approach, while the sample‐induced resistance is calculated with the vector potential calculation method. In the second part of the paper, we propose the simulation and the design of a transmit/receive elliptical coil for MRI in mice with a 3T clinical scanner. We also evaluated the coil performance in a preliminary magnetic resonance spectroscopy (MRS) study in phantom