Electrochemical Remediation Research Articles

Prospective study on the electrochemical remediation as an alternative to treat heavy metals in solid waste landfills

Prospective study on the electrochemical remediation as an alternative to treat heavy metals in solid waste landfills

Interface engineering of laminated redox-copolymers for electrochemical remediation of perfluoroalkyl substances

Redox polymers now show promise for selective removal of perfluoroalkyl substances from a complex aqueous matrix at high energy efficiency and no secondary pollution. However, self-agglomeration of redox polymers is a dominating barrier to constructing a low-cost, stable system in practical applications. Herein, we introduce polymer interface engineering strategy to enhance the activity of amine functionalities and nitrous oxide radicals in copolymers composed of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl and 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine. The grafted laminated redox polymer on multi-walled carbon nanotubes (termed MWCNT-g-P(TMPMA-co-TMA)) via free-radical polymerization demonstrated a 19.1–59.9 % increase in the electrosorption capacity with a maximum value (Qm) of 725.09 mg g−1 and a pseudo-first-order rate constant k1 = 1.46 min−1 and sustainable regeneration efficiency at ∼80 %. The core–shell structure of MWCNT-g-P(TMPMA-co-TMA) with a laminated redox polymer layer of ∼5 nm processed a low charge transfer resistance, which is expected to contribute to the enhanced capture performance and stability. An integrated system consisting of a MWCNT-g-P(TMPMA-co-TMA) electrode and a boron-doped diamond electrode can efficiently separate and degrade trace-concentration PFOA from industrial wastewater at high mineralization efficiency. This work provides insight into the design and optimization of redox active materials for water purification and beyond.

Polybenzimidazole Membranes for Waste Stream Remediation to High Value Products

Electrochemical remediation of industrial waste products represents an economically attractive method to continuously convert waste streams to high value products. Electrochemical remediation has been more limited for processes that are very dry, very acidic, or a combination of both, because the most widely used polymer membranes (for example, Nafion™) need external humidification to maintain conductivity. We show that para-polybenzimidazole (PBI) membranes can be used as an effective polymer membrane separator in these types of harsh environments, improving the performance of the current state-of-the-art aqueous HCl electrolyzer, enabling the first completely anhydrous gas-phase HCl electrolyzer, and pushing the electrolysis of SO2 in the Hybrid Sulfur (HyS) cycle to the point of economic viability. The discussion will also cover how PBI membrane preparation affects electrochemical performance and the development of a Computational Fluid Dynamics (CFD) model that both provides insight into the transport phenomena of the anhydrous electrolyzer and allows us to examine operating parameters that are dangerous experimentally.

Electrochemical remediation of methyl orange over reusable biochar ferrite coated photocatalytic plates

Biochar (BC) obtained from biomass pyrolysis holds immense potential for environmental remediation. The efficiency of BC can further be enhanced by incorporating metal nanoparticles (NPs) in the porous carbon matrix. In the present work nanocomposites (NCs) were prepared by the addition of ferrite nanoparticles (FNPs) into an oxidized BC matrix to create BC /Fe3O4 (BCF). This process improves BC stability, electron transfer, conductivity, and photocatalytic ability for dye degradation. Microstructure and functional group analysis of BCF was performed by SEM, XRD, and FTIR showing intercalation of FNPs with surface functionalities of oxidized BC matrix. The B-H curve of FNPs and BCF reveals super paramagnetic behavior with saturation magnetization (Ms, emu/g) of 67.36 and 20.01 respectively. BET surface area analysis shows surface area (m2/gm) 45.81 and 44.19 for oxidized BC and BCF respectively, that attributed to partial blocking of porous carbon matrix by FNPs. UV-DRS supports the semiconducting behavior of BCF with a significantly reduced band gap (eV) of 2.95 over pristine BC (4.76). BCF-coated photocatalytic plates (PCPs) were developed and utilized for the remediation of methyl orange (MeO) in water samples. Degradation of MeO was investigated over time by electrochemical methods. The square wave voltammetric method showed the limit of detection and quantification of 0.09 ppm and 0.28 ppm respectively for MeO over a glassy carbon electrode in 0.1 M acetate buffer. BCF-derived PCPs rendered ∼99 % degradation efficiency against MeO (50 mgL−1) under UV radiation over 240 min. Developed PCPs demonstrate reusability up to 5 cycles without any further purification step and offer efficient degradation of MeO making them suitable for the treatment of water polluted with dyes.

Non-sealed water hastens the efficiency of microbial electrochemical remediation system

Soil petroleum hydrocarbon contamination has become a global problem and microbial remediation is a friendly technology. The scarcity of electron acceptors and the low activity of functional microbes are limiting factors which are overcome by the soil microbial electrochemical system (MES). Using the petroleum hydrocarbon polluted soils as substrates, soil MESs were constructed with four different water-sealed levels to optimize the system configuration. After 65 days of operation, the accumulated charge of the group with the lowest water level (MES0) was 1282 C, while that of the highest water level group (MES5) was only 151 C. Compared with the original soil (OS), the hydrocarbon removal near the anode and cathode in MES0 were 28%–30%, which were 4%–11% higher than those in MES5. Additionally, the co-occurrence networks analysis revealed dominance in positive than negative links among bacterial, fungal, and archaeal communities in MES0 compared to MES5 and OS. In MES0 bacteria were more densely populated and connected into more closely related groups with higher interactions than those in MES5 as well as in OS. Contrary to bacteria, MES5 favored the growth and connections of fungal and archaeal communities compared to those in MES0. The above changes were ascribed to the dissolved oxygen, redox potential, and reduction of resistance, which shifted the electron acceptors hence contributing to the process of electrons and substrates transfer in soil, suggesting that bacteria synergistically cooperated with fungi, and archaea in the removal mechanisms of hydrocarbons in the MES. Our findings revealed the optimization of low water seal on the MES performance by providing a detailed overview of the synergistic behavioral characteristics of bacterial, fungal, and archaeal in soil MESs.

Trap-n-zap: Electrocatalytic degradation of perfluorooctanoic acid (PFOA) with UiO-66 modified boron nitride electrodes at environmentally relevant concentrations

Poly- and per-fluoroalkyl substances (PFAS) are synthetic chemicals of increasing global concern due to their toxicity and environmental persistence. Hexagonal boron nitride (h-BN) is an electrochemically active semiconductor that generates a hydrophobic electron-hole with a high affinity for the fluorinated tail of perfluorooctanoic acid (PFOA), which enhances surface interactions in aqueous solutions. We demonstrate that h-BN electrocatalytically oxidizes PFOA to shorter chains. The degradation is enhanced by modifying the h-BN surface with an adsorbent, UiO-66 (UiO-66@BN), that facilitates proximal adsorption to catalytic sites (trap-and-zap). At the environmentally relevant concentration of 100 µg/L, electrochemical trap-and-zap removes 99.5% of PFOA with 70% defluorination in 3 h at a pH 4.5. Computational results show that PFOA requires an overpotential of 1.87 V vs. SCE, which is close to the experimental overpotential. The electrical energy per order (EE/O) of UiO-66@BN is 6.1 kWh/m3, indicating that it is a competitive material for PFOA electrochemical remediation.

Electrochemical Treatment for Real Hospital Wastewater and its Future Prospect

<p>Purpose: This study investigates the efficacy of electrochemical remediation techniques in treating hospital wastewater, focusing on parameters including turbidity, color, BOD, COD, DO, coliform, and E. coli. Design/Methodology/Approach: The study conducts a comprehensive analysis of various pollutant parameters, evaluating the impact of contact time on pollutant reduction. Electrochemical methods are explored for their potential in mitigating these parameters. Conclusions: The findings demonstrate the effectiveness of electrochemical techniques in reducing a range of pollutant parameters, with significant reductions observed in turbidity (up to 99%), color (51%), BOD (99%), COD (60%), and microbial contaminants such as E. coli and coliform (up to 48%). Notably, the study reveals that higher voltage doesn't consistently result in superior performance. Limitations/Consequences of Research: While the study showcases promising results, certain limitations and challenges are acknowledged, including the need for further research to address these constraints and optimize electrochemical remediation processes. Practical Value: The study highlights the practical potential of electrochemical techniques as an effective means of wastewater treatment in hospital settings, offering insights into their application and benefits for environmental sustainability. Originality and Significance of Results: This research contributes novel insights into the application of electrochemical methods for hospital wastewater treatment, emphasizing their efficacy in reducing various pollutant parameters and providing a foundation for future research directions in this field.</p>

Sustainable Electrochemical Activation of Self-Generated Persulfate for the Degradation of Endocrine Disruptors: Kinetics, Performances, and Mechanisms.

This study presents an electrolysis system utilizing a novel self-circulation process of sulfate (SO42-) and persulfate (S2O82-) ions based on a boron-doped diamond (BDD) anode and an activated carbon fiber (ACF) cathode, which is designed to enable electrochemical remediation of environmental contaminants with reduced use of chemical reagents and minimized residues. The production of S2O82- and hydrogen peroxide (H2O2) on the BDD anode and ACF cathode, respectively, is identified as the source of active radicals for the contaminant degradation. The initiator, sulfate, is identified by comparing the degradation efficiency in NaSO4 and NaNO3 electrolytes. Quenching experiments and electron paramagnetic resonance (EPR) spectroscopy confirmed that the SO4-· and ·OH generated on the ACF cathode are the main reactive radicals. A comparison of the degradation efficiency and the generated S2O82-/H2O2 of the divided/undivided electrolysis system is used to demonstrate the superiority of the synergistic effect between the BDD anode and ACF cathode. This work provides evidence of the effectiveness of the philosophy of "catalysis in lieu of supplementary chemical agents" and sheds light on the mechanism of the generation and transmission of reactive species in the BDD and ACF electrolysis system, thereby offering new perspectives for the design and optimization of electrolysis systems.

Current perspectives, challenges, and future directions in the electrochemical detection of microplastics.

Microplastics (5 μm) are a developing threat that contaminate every environmental compartment. The detection of these contaminants is undoubtedly an important topic of study because of their high potential to cause harm to ecosystems. For many years, scientists have been assiduously striving to surmount the obstacle of detection restrictions and minimize the likelihood of receiving results that are either false positives or false negatives. This study covers the current state of electrochemical sensing technology as well as its application as a low-cost analytical platform for the detection and characterization of novel contaminants. Examples of detection mechanisms, electrode modification procedures, device configuration, and performance are given to show how successful these approaches are for monitoring microplastics in the environment. Additionally included are the recent developments in nanoimpact techniques. Compared to electrochemical methods for microplastic remediation, the use of electrochemical sensors for microplastic detection has received very little attention. With an overview of microplastic electrochemical sensors, this review emphasizes the promise of existing electrochemical remediation platforms toward sensor design and development. In order to enhance the monitoring of these substances, a critical assessment of the requirements for future research, challenges associated with detection, and opportunities is provided. In addition to-or instead of-the now-in-use laboratory-based analytical equipment, these technologies can be utilized to support extensive research and manage issues pertaining to microplastics in the environment and other matrices.

APPLICATION OF THE ELECTROCHEMICAL TREATMENT METHOD FOR THE REMEDIATION OF PETROLEUM HYDROCARBONS FROM CONTAMINATED SOILS

Contaminated soils with toxic and persistent pollutants pose significant potential hazards to the environment and human health. The problem of polluted soils and choosing the most appropriate remediation strategy is a current concern throughout the world. As a result of the industrial activities related to the energy sector (mainly from the extractive industry), the contaminants of interest at the national and international level in terms of the remediation of contaminated sites are petroleum hydrocarbons. In this context, the main aim of the present research was to evaluate the degree of remediation of these contaminants during the application of the electrochemical remediation method. The soil contaminated with crude oil, subject to remediation, is from Teleorman county, Siliștea commune, an area where oil and natural gas extraction wells are located. Following the application of the electrochemical process, a decrease in the TPH concentration level was observed from an initial concentration of 5000 mg/kg s.u. to 2228 mg/kg s.u., thus obtaining a 55% remediation percentage, after a period of 14 days. Consequently, it can be appreciated that the electrochemical process applied in order to remediate a soil contaminated with petroleum products is advantageous in terms of the short duration of time, but the method also presents some disadvantages such as energy consumption and implicitly significant related costs.

Study of electrochemical remediation of clay spiked with C12-C18 alkanes

To date, the management of polluted soils and sediments is challenging because they can be characterized by heterogeneous conditions, miscellaneous contaminants (organic and inorganic ones), fine grains and low-hydraulic permeability. In these cases, the current treatment methods are poorly effective. ElectroChemical Remediation Technologies (ECRTs) are considered some of the main appealing strategies for the remediation of such complex sites. The ECRTs are based on the application of a relatively low cell potential value, between two or more electrodes, inducing an electric field (E) through the polluted media, which prompts the remediation of the contaminated site. This work was focused on the study of the electrochemical remediation of kaolin artificially spiked with a miscellaneous of five alkanes (C12H26, C13H28, C14H30, C16H34, C18H38), namely C12-C18. Kaolin was selected as a model reproducible, low-buffering, and low-permeability clay and the mixture C12-C18 as a hazardous model of petrol hydrocarbon compounds. The effect of several operative conditions, including the E intensity, type of technology, presence of supporting electrolyte, was investigated. It was found that adopted low E values can simultaneously mobilize and degrade in situ the C12-C18 mixture and that the shorten the chain compound, the easier the remediation efficiency, R. It was shown that the usage of E of approximately 0.50 V cm−1 allows to reach a total C12-C18 removal (R(C12-C18)) of ∼70% after 96 h. Finally, it was demonstrated that the usage of sodium chloride improves the performances of the process: R(C12-C18) increased from 61 to 83% when NaCl was added.

Electrochemical remediation of synthetic and real marine sediments contaminated by PAHs, Hg and As under low electric field values

To date, remediation, protection, and restoration of contaminated sites is a global concern. The current technologies to restore sediments characterized by heterogeneous characteristics, several pollutants, fine grains, and low hydraulic permeability are poorly effective; hence their remediation is still challenging. A promising approach for the sediment's remediation could be the electrochemical route since it is a not-expensive, effective and noninvasive in situ technology. Electrochemical remediation (ER) is commonly studied under relatively high electric fields (E ≥ 1 V cm−1) and using costly processing fluids in a three compartments cell aiming to desorb and transport the contaminants into the processing fluids (secondary dangerous effluent). In this work, contaminated marine sediments were electrochemically treated focusing on the insertion of electrodes directly in the sediments and adopting, for the first time for real sediments, low E values (≤ 0.25 V cm−1) for 4-days period. It was observed that PAHs can be simultaneously transported and degraded in situ preventing the production of a secondary dangerous effluent and reducing the energy consumption. Firstly, clay marine sediments dragged from Capo Granitola Coast (Trapani, Italy) spiked with five PAHs congeners (5PAHs), Hg and As were used as a simplified model matrix and treated to simulate a real case study. A total PAHs removal efficiency of 57% was reached after 96 h of treatment under 0.05 V cm−1. Then, real polluted marine sediments from Augusta Bay (Syracuse) and Bagnoli-Coroglio Bay (Naples) in the southern Italy were treated as real contaminated sediments to be restored, to validate the proposed approach for real cases. A quite good removal efficiency of PAHs was reached after 96 h of electrochemical treatment coupled with a low energetic consumption due to the rather E values adopted. In addition, it was observed that this approach, under the adopted conditions, is unsuitable for the remediation of Hg and As.

Перспективи впровадження практичного заняття «Визначення зон забруднення ґрунтів тпв та розрахунок енерговитрат їхнього очищення» з дисципліни Безпека життєдіяльності

In this paper, a method of engineering calculations is proposed, which is necessary for the implementation of the practical lesson “Definition of soil contamination zones of municipal solid waste and calculation of energy costs of their cleaning” from the normative discipline of life safety in order to promote the deepening of knowledge on the protection of the lithosphere, as a component of the natural environment, of future specialists.
 The purpose of the article is the development of the engineering calculation methodology necessary for the implementation of the practical exercise “Definition of zones of soil contamination by municipal solid waste and calculation of energy costs of their cleaning” from the discipline of life safety to promote the deepening of knowledge on the protection of the lithosphere of future specialists.
 The proposed method of engineering calculations includes the calculation of: the size of the zones of soil contamination by pollutants (heavy metals, benzapyrene, petroleum products) around municipal solid waste landfills, the specific energy consumption of landfill soil cleaning by electrochemical remediation from heavy metal contamination, the energy consumption of soil cleaning of municipal solid waste disposal landfills of municipal solid waste both by individual heavy metals and general. The specific energy costs of cleaning the soil of municipal solid waste landfills by the method of electrochemical remediation from pollution were determined depending on the required level of heavy metal concentrations. The energy costs of cleaning the soil of municipal solid waste landfills by the electrochemical remediation method of pollution were determined taking into account the size of the pollution zones and the size of the municipal solid waste landfill. Based on the comparison and comparison of the experimental data obtained as a result of the research, it was established that the success rate of the students of both experimental groups according to the stobal scale was significantly higher than the success rate of the students of the control groups, which means the introduction of the proposed practical lesson from the regulatory discipline “Life Safety” into the educational process is promising. The construction of methods of engineering calculations for the protection of the atmosphere and hydrosphere require further research.

Intuitionistic fuzzy-based entropy weight method-TOPSIS for multi-attribute group decision-making in drilling fluid waste treatment technology selection.

Drilling fluid waste is produced by oil and gas industry operations and can potentially cause serious environmental pollution and energy consumption if not properly treated. Currently, there are several treatment methods available for drilling fluid waste such as bioremediation, thermal treatment, solidification/stabilization treatment, electrochemical remediation, physiochemical treatment, and supercritical fluid treatment. However, selecting an adequate method to treat drilling fluid waste is a critical consideration. The objective of this work is to analyze the problem of drilling fluid waste pollution and treatment methods, establish a drilling fluid waste treatment decision index system that takes into account various factors, and apply the intuitionistic fuzzy-based entropy weight method (EWM)-technique for order of preference by similarity to ideal solution (TOPSIS) method to make a multi-attribute group decision on drilling fluid waste treatment methods. The method is then applied to the WBQ004-1-H1 drilling project as an example for comprehensive analysis. The final decision results show that A3 (0.566) > A1 (0.537) > A6 (0.526) > A5 (0.485) > A4 (0.478) > A2 (0.447), so the solidification/stabilization treatment is the most suitable method for this project, providing new insights into selecting drilling fluid waste treatment methods in actual projects.

Electrochemical abatement of aquatic metoprolol by porous foam-titanium based metal oxide anodic membranes

Electrochemical membrane filtration (EMF) is a promising advanced oxidation technology for eliminating aquatic refractory pharmaceuticals. In this work, three porous foam-titanium based metal oxide (MOx) anodic membranes were prepared for comparison of their effectiveness against the model pharmaceutical pollutant metoprolol. The electrooxidation efficiencies of metoprolol by all flow-by operated anodic membranes were found to be elevated with increasing charging voltage and decreasing electrolyte solution pH, in which the PbO2 membrane exhibited more efficient metoprolol degradation efficiency over SnO2 and RuO2 membranes. At the chosen charging voltage of 2 V and electrolyte solution pH 7, compared to the flow-by mode, the higher total organic carbon (TOC) removal and less electrical energy consumption was achieved by the flow-through operated PbO2 membrane, ascribed to the enhanced mass-transfer of metoprolol and its intermediate by-products toward the anode surface. The physisorbed and free HO• produced by PbO2 membrane were found to be the key oxidants accounting for metoprolol degradation, which induced the transformation of metoprolol by attacking its benzene ring and side chains. Apart from the capacity for detoxifying metoprolol-containing influent, PbO2 membrane also exhibited favorable stability in flow-through mode. The study provides an effective strategy for the electrochemical remediation of pharmaceutical-polluted water and wastewater.

Electrochemical remediation of phenol contaminated kaolin under low-strength electric fields

Soil degradation is a global concern. Electrochemical remediation (ER) technology is considered an appealing strategy for soil remediation because it is a low-cost, adaptable, and effective noninvasive in situ technology. Currently, the remediation of soil characterized by fine grains, low-hydraulic permeability, heterogeneous conditions, and mixtures of contaminants is still challenging since other conventional technologies are poorly effective. ER of soil is based on the application of low potentials between a couple of electrodes which induces an electric field (E) in the contaminated field. In this work, very low values of electric field (E≤ 0.25 V cm−1) were used for the ER of contaminated kaolin. Phenol was selected as model hazardous organic compound and kaolin as model, reproducible and low buffering and low permeability clay. The effect of several factors, including the nature of the electrodes, treatment time, kind of current, the strength of the E and the nature of supporting electrolyte, on the performance of the process was investigated in detail and discussed in terms of the normalized phenol concentration and its total removal from the kaolin. Overall, the main finding is that the use of very low value of E (0.15 V cm−1) can allow to simultaneously desorb, mobilize and also in-situ degrade phenol. The highest removals of phenol up to approximately 80% and 90% from the kaolin under both direct and sinusoidal E, respectively, were reached using compact graphite as electrodes in presence of Na2SO4 into the kaolin.

The urbanization impacts on potentially toxic metals: the distribution, sources and contamination risks in river situated in typical megacity, China

The excessive presence of potentially toxic metals (PTMs) in urban river ecosystem deteriorates water quality and presents high potential health issues on both aquatic and urban residents’ life. River water was thus collected around Beijing and Tianjin megalopolis to evaluate urban water pollution. Inverse distance weighted (IDW) method was adopted to reveal PTMs distributions, principle component analysis (PCA) was applied to identify metal origins, and metal pollution indices were applied to evaluate potential contamination threat. PTMs contents displayed in the sequence of Zn > Ni > V > As > Cu > Sb > Fe > Mn > Cr > Co, and Mn concentrations of the most downstream site (321.12 μg/L) far exceeded standard limitation, indicating intense input of urban pollutants near estuary. The distribution of Ni, Co, Cr, V and Sb exhibited a similar variation trend which decreased in middle reach of the Yongding River. As for the Chaobai River, all PTMs concentration in mainstream generally displayed an emerging trend from upper to lower reach without a specific variation pattern. PCA results indicated that Cr, Ni, V, Sb, Co and As mainly originated from mixing sources directly impacted by industrial (thermal) pollution and natural reactions, whereas sources from cultivation (agriculture) and weathering process were associated with Fe and Zn presence. Mn and Cu were mainly responsible for urban activities. The water quality level of the Yongding-Chaobai River varied between “good” and “undrinkable”, and water quality near the river estuary was much lower than other area. Heavy metal pollution index calculation revealed low risks of metal contamination in river water. The electrochemical remediation is more appropriate for PTMs pollution control in megacity river. These findings support the development of effective assessments and monitoring strategies to control urban river pollution and maintain sustainable environment.

Asymmetric Alternative Current Electrochemical Method Coupled with Amidoxime-Functionalized Carbon Felt Electrode for Fast and Efficient Removal of Hexavalent Chromium from Wastewater

A large amount of Cr (VI)-polluted wastewater produced in electroplating, dyeing and tanning industries seriously threatens water ecological security and human health. Due to the lack of high-performance electrodes and the coulomb repulsion between hexavalent chromium anion and cathode, the traditional DC-mediated electrochemical remediation technology possesses low Cr (VI) removal efficiency. Herein, by modifying commercial carbon felt (O-CF) with amidoxime groups, amidoxime-functionalized carbon felt electrodes (Ami-CF) with high adsorption affinity for Cr (VI) were prepared. Based on Ami-CF, an electrochemical flow-through system powered by asymmetric AC was constructed. The mechanism and influencing factors of efficient removal of Cr (VI) contaminated wastewater by an asymmetric AC electrochemical method coupling Ami-CF were studied. Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) characterization results showed that Ami-CF was successfully and uniformly loaded with amidoxime functional groups, and the adsorption capacity of Cr (VI) was more than 100 times higher than that of O-CF. In particular, the Coulomb repulsion effect and the side reaction of electrolytic water splitting were inhibited by the high-frequency anode and cathode switching (asymmetric AC), the mass transfer rate of Cr (VI) from electrode solution was increased, the reduction efficiency of Cr (VI) to Cr (III) was significantly promoted and a highly efficient removal of Cr (VI) was achieved. Under optimal operating conditions (positive bias 1 V, negative bias 2.5 V, duty ratio 20%, frequency 400 Hz, solution pH = 2), the asymmetric AC electrochemistry based on Ami-CF can achieve fast (30 s) and efficient removal (>99.11%) for 0.5-100 mg·L-1 Cr (VI) with a high flux of 300 L h-1 m-2. At the same time, the durability test verified the sustainability of the AC electrochemical method. For Cr (VI)-polluted wastewater with an initial concentration of 50 mg·L-1, the effluent concentration could still reach drinking water grade (<0.05 mg·L-1) after 10 cycling experiments. This study provides an innovative approach for the rapid, green and efficient removal of Cr (VI) containing wastewater at low and medium concentrations.

Electrochemical degradation of contrast media

This work provides a critical review about the most recent works in electrochemical remediation of wastewater containing contrast media, very concerning pollutants resistant to conventional treatments in wastewater treatment plants. The focus is on iodinated contrast media and gadolinium-based contrast agents (GBCAs). After a short introduction in which non-electrochemical methods are presented, electro-oxidative and electro-reductive methods are discussed in the former case. A short section is also dedicated to methods based on a combination of the two. In the case of GBCAs, a brief presentation of non-electrochemical techniques is also reported, followed by some electrochemical treatments for Gd 3+ . Considering the lack of literature on the use of electrochemical methods for the removal of this type of magnetic resonance imaging contrast agents, the potential of electrochemistry for the degradation in this field is then explored. • Contrast media in water can be successfully removed using various electrochemical oxidation, even in complex matrices. • Electrochemical reduction can help in removing iodine atoms from Iodinated contrast media, making them more biodegradable. • The combination of electrochemical oxidation and reduction showed a good mineralisation of the compounds.

Basic Study on Electrochemical Remediation of Heavy Metal Contaminated Water and Soil

Heavy metal pollution of soil is one of the major environmental problems at this stage, and soil pollution itself has the characteristics of accumulation and irreversibility, which is difficult to completely recover from the root. Therefore, the research work on soil remediation technology and practice has become the main work content. The research progress in recent years includes physical remediation, chemical remediation, bioremediation, agricultural remediation and other models. It is also imperative to study its technical characteristics and application scope.