0000000000005620
AUTHOR
Pengfei Ma
Electrochemical Treatment of Synthetic Wastewaters Contaminated by Organic Pollutants at Ti 4 O 7 Anode. Study of the Role of Operative Parameters by Experimental Results and Theoretical Modelling
In the last years, an increasing attention has been devoted to the utilization of anodic oxidation (AO) technologies for the treatment of wastewater polluted by recalcitrant organics. Recently, Ti4O7 was proposed as a promising anode for AO for the treatment of various organics. Here the potential utilization of commercial Ti4O7 anodes has been evaluated considering the electrochemical treatment of synthetic wastewater contaminated by three very different organic molecules (namely, oxalic acid, phenol and Acid Orange 7), all characterized by a very high resistance to AO. The performances of Ti4O7 were compared with that of two largely investigated anodes: Boron-doped diamond (BDD), which is…
Electrochemical treatment of real wastewater with low conductivity
In the last years, many efforts have been devoted to the development of electrochemical processes for the effective treatment of wastewater contaminated by organic pollutants resistant to conventional biological processes and/or toxic for microorganisms [1–5]. It was shown that some electrochemical approaches, including the direct anodic oxidation at suitable anodes such as boron-doped diamond (BDD) and/or electro-Fenton (EF) at suitable operating conditions and cells [1–6] could allow treating effectively a very large number of organic pollutants. However, most of the investigations were performed using synthetic wastewater. Hence, it is now mandatory to study the problems connected to the…
Electrochemical Treatment of Wastewater by ElectroFenton, Photo-ElectroFenton, Pressurized- ElectroFenton and Pressurized Photo ElectroFenton: A First Comparison of these Innovative Routes
In the last few years increasing attention has been devoted to the utilization of electroFenton (EF) and EF based technologies for the treatment of wastewater polluted by recalcitrant organics. It has been shown that the performances of EF can be strongly improved using ultraviolet (UV) irradiation, e.g., by the photo-electroFenton (PEF) method, or pressurized air or oxygen, e.g., by the pressurized-electroFenton (PrEF) one. Although several studies were carried out on the degradation of many organic pollutants using EF, PEF or PrEF, a systematic comparison between PEF and PrEF was never reported as well as the possibility to couple the irradiation with pressurized air. In this study the pe…
Removal of Phenol from Water in the Presence of NaCl in Undivided Cells Equipped with Carbon Felt or Ni Cathodes: Effect of Air Pressure
Recently, the electrochemical treatment of wastewater polluted by recalcitrant organics and containing chlorides was shown to be significantly improved adopting proper operative conditions such as suitable anodes and cathodes and low current density. In particular, the use of suitable cathodes such as carbon felt or silver could increase the removal of TOC and reduce the formation of chlorinated by-products. In this study, attention was focused on the utilization of carbon felt cathodes with the main aim to evaluate the effect of air pressure on the process using phenol as model organic pollutant. It was shown that, in the presence of carbon felt cathode, the use of pressurized air allows b…
Assisted reverse electrodialysis for CO2 electrochemical conversion and treatment of wastewater: A new approach towards more eco-friendly processes using salinity gradients
Abstract In this paper, the utilization of assisted reverse electrodialysis (A-RED), recently used for pre-desalination, is proposed as a general method to reduce the energy requirements of electrolysis processes and evaluated for two model processes: (i) the cathodic conversion of carbon dioxide to formic acid; (ii) the anodic treatment of water contaminated by organics. In A-RED, two solutions with different salt content and an external potential difference, applied in the direction of the natural salinity gradient, are both used to drive redox processes. It was shown, for the first time, that the cathodic conversion of CO2 to formic acid can be performed by both reverse electrodialysis (…
Specific separation and recovery of phosphate anions by a novel NiFe-LDH/rGO hybrid film based on electroactivity-variable valence
Phosphorus is a non-renewable resource. Supplies are limited and much phosphorus is currently wasted during the production and utilization process, causing concerns about future supplies and widespread environmental problems. To solve these problems, a new type of NiFe-LDH/rGO electrically switched ion-selective (ESIX) film is designed, based on the dominant mechanism of inner-sphere complexation. An ESIX process allows the NiFe-LDH/rGO hybrid film to achieve a controllably selective uptake and release of the phosphate anions. This route involves tuning potential steps to regulate the redox states of the composite film and the variable metal (e.g., Ni, Fe (II)/(III)) in coordination centers…
Reduction of oxygen to H2O2 at carbon felt cathode in undivided cells. Effect of the ratio between the anode and the cathode surfaces and of other operative parameters
Abstract In the last years, the electrochemical conversion of oxygen to hydrogen peroxide at carbon felt has been largely studied in order to define a new route for the production of H2O2 and to optimize the electro-Fenton process, which is based on the cathodic generation of H2O2. In particular, many studies regarding electro-Fenton process were carried out in undivided cells in order to avoid the costs of the separator and to reduce the cell potentials. Hence, in order to optimize the cathodic conversion of oxygen to H2O2 in undivided cells, the effect of many parameters linked to the anodic process were here evaluated. In particular, it was demonstrated that the performances of the proce…
Development of a process for the treatment of synthetic wastewater without energy inputs using the salinity gradient of wastewaters and a reverse electrodialysis stack.
Abstract Electrochemical processes are considered very effective methods for the treatment of wastewater contaminated by organics resistant to conventional biological processes and various inorganic pollutants. Large sites that treat wastewaters usually deal with a large number of waters often characterized by different salinity contents, that could be potentially used to provide the energy necessary for the electrochemical remediation. Hence, in this work a reverse electrodialysis (RED) process for the treatment of synthetic wastewaters contaminated by organics, without energy inputs, using the salinity gradient of different wastewaters, was studied, for the first time. It was found that t…
A scalable three-dimensional porous λ-MnO2/rGO/Ca-alginate composite electroactive film with potential-responsive ion-pumping effect for selective recovery of lithium ions
Abstract A scalable three-dimensional (3D) porous composite electroactive film consisting of λ-MnO2, reduced graphene oxide (rGO) and calcium alginate (Ca-alg) was successfully fabricated and employed for the selective extraction of Li+ ions with low concentration via an electrochemically switched ion exchange (ESIX) technology. The Li+ ion adsorption capacity of the obtained λ-MnO2/rGO/Ca-alg composite electroactive film reached as high as 32.7 mg g−1 and more than 90% of its equilibrium adsorption capacity was achieved in 1 h. The λ-MnO2/rGO/Ca-alg composite electroactive film displayed evident selectivity towards Li+ ions. The separation factors for Li+/Na+ and Li+/Mg2+ reached 1040.57 a…
Electrochemical treatment of real wastewater. Part 1: Effluents with low conductivity
Abstract The treatment of a real wastewater characterized by low conductivity was performed by anodic oxidation at boron doped diamond (BDD) in both conventional and microfluidic cells. The electrolyses carried out in conventional cells without supporting electrolyte were characterized by very high TOC removals but excessively high energetic consumptions and operating costs. The addition of sodium sulphate, as supporting electrolyte, allowed to strongly reduce the cell potentials and consequently the energetic consumptions and the operating costs. However, under various operating conditions, the addition of Na2SO4 caused a lower removal of the TOC. The best results in terms of both TOC remo…
Electrochemically triggered iodide-vacancy BiOI film for selective extraction of iodide ion from aqueous solutions
Abstract The effective extraction and regeneration of radioactive iodide remains an urgent concern for safe nuclear energy utilization. Herein, we developed a novel electrochemically triggered iodide-vacancy BiOI film, which exhibited excellent I− ion extraction capacity of 328.3 mg·g−1. Especially, due to the ion vacancy trap effect, the film showed high selectivity towards I− ions in the existence of a large number of competitive anions. Additionally, the electrochemically switched ion extraction (ESIE) process with this iodide-vacancy BiOI film possessed fast extraction kinetics and high stability. More importantly, the trapped I− ions were easily desorbed from the film without the secon…