Fe EDTA Research Articles

High–Field EPR Studies on Three Binuclear μ–Oxo–Bridged Iron(III) Complexes: Na4[Fe(edta)]2O ⋅ 3H2O, [Fe(phen)2(H2O)]2O(NO3)4 ⋅ 5H2O and [Fe(salen)]2O

AbstractA High–Field, High–Frequency Electron Paramagnetic Resonance (HFEPR) study was performed on the binuclear μ–oxo bridged complexes Na4[Fe(edta)]2O ⋅ 3H2O, [Fe(phen)2(H2O)]2O(NO3)4 ⋅ 5H2O and [Fe(salen)]2O, where edtaH4 = ethylenediaminetetraacetic acid, phen=1,10–phenanthroline and salenH2 is NN′–ethylenebis(salicylideneimine). The spin Hamiltonian parameters were determined for the thermally excited spin states with spin S=1, 2 and 3. The contributions to the zero–field splitting due to the local zero field splitting on individual iron ions and to the anisotropic metal–metal interactions were evaluated. Surprisingly large magnitudes of the anisotropic exchange interactions were found.

Deficiency of Iron in Eucalyptus Plantations of Variable Age in Punjab and its Amelioration

The experiment was conducted during March, 2018 to March, 2020 at Research Farm of Punjab Agricultural University, Ludhiana and a few villages in Ludhiana district of Punjab, India to standardize the application of iron (Fe) in eucalyptus plantations varying from one to five years of age to eradicate Fe deficiency in these plantations. The treatments (g plant-1) consisted of plants without Fe application, 100 g S+100 g FeSO4.7H2O, 200 g S+200 g FeSO4.7H2O, 300 g S+300 g FeSO4.7H2O, 50 g Fe EDTA (iron chelate), 100 g Fe EDTA, 200 g Fe EDTA, 300 g Fe EDTA and 400 g Fe EDTA. The diameter at breast height (DBH) and height of plants were measured at the time of fertilizer application and one year after application. The DBH and height one year after application improved over increase in control by 6.86 and 7.13% respectively in first year plants with 50 g plant-1, 8.58 and 10.16% respectively in second year plants and 9.41 and 10.2% respectively in third year plants with 100 g plant-1, and 10.85 and 11.21% respectively in fourth year plants and 10.27 and 11.87% respectively in fifth year plants with 200 g plant-1 Fe EDTA alongwith correction of Fe deficiency completely. Therefore, the deficiency of Fe can be corrected by application of 50 g plant-1 Fe EDTA to first year plantations, 100 g plant-1 Fe EDTA to second and third year plantations and 200 g plant-1 Fe EDTA to fourth and fifth year plantations of eucalyptus.

Asymmetric dual-chamber electrochemical reactor for reducing Fe(Ⅲ)EDTA to remove NOx by enhanced complexing absorption

The complexing absorption technology possesses broad application prospects in the efficient removal of pollutant NO from industrial flue gas. However, the absorbent Fe(Ⅱ)EDTA is readily oxidized to Fe(Ⅲ)EDTA by the inherent O2 in flue gas, which severely impairs denitrification efficiency due to the inability of Fe(Ⅲ)EDTA to absorb NO. Here, a novel asymmetric dual-chamber electrochemical reactor (ADER) was designed to efficiently reduce Fe(Ⅲ)EDTA to Fe(Ⅱ)EDTA. The key to high-efficient reduction was to improve the reaction kinetics utilizing a unique design of larger cathode–anode area ratio. Moreover, cloth served as separator simultaneously satisfied the needs of H+ transfer and diffusion limitation of Fe(Ⅱ)EDTA and Fe(Ⅲ)EDTA, thus safeguarding the reduction efficiency while avoiding membrane contamination. The reduction efficiency and current efficiency of Fe(Ⅲ)EDTA up to 78.05 and 98.19 % in ADER system, respectively, with energy consumption of 0.078 kWh/mol Fe(Ⅲ)EDTA. And the ADER systems coupled with complexing absorption exhibited excellent NO removal efficiencies exceeding 92 % even in the presence of O2. The ADER provided an efficient, convenient and low-cost strategy for the regeneration of absorbent Fe(Ⅱ)EDTA as well as NOx removal.

Conjugated organic ligand enhancing chelating iron-based deep eutectic solvents for catalytic oxidation of hydrogen sulfide

In recent years, non-aqueous iron-based ionic liquid (Fe-IL) desulfurization technology has garnered widespread attention for its avoidance of the excessive oxidation of hydrogen sulfide in aqueous systems. However, the hydrogen bond network in ionic liquids restricts molecular motion, resulting in poor reactivity of Fe-IL. In this work, the chelated Fe-ILs (BmimFeEDTA and BZKFeEDTA) were synthesized and dissolved in PEG200 to construct chelated iron-based deep eutectic solvents (Bm-Fe-DES, BZK-Fe-DES). 1,3-Dimethyl-2-imidazolidinone (DMI), as a conjugated active ligand, was introduced to enhance the catalytic oxidation of H2S by the two Fe-DESs. After five cycles, both Fe-DES/DMI systems exhibited excellent desulfurization and regeneration performance. POM and FT-IR analyses revealed that BZKFeEDTA with a long carbon chain exhibited a more ordered spatial structure, which was more conducive to the cycling of Fe(III) and Fe(II). CV, Py-IR, bond length analysis, and LUMO-HOMO energy gap indicated that DMI weakens the limitation of EDTA to Fe(III) by coordinating with Fe(III), which significantly enhances the catalytic activity of Fe-DES. UV–vis and CPA analysis demonstrated the transfer of π electrons from DMI to the EDTA ligand, facilitating the loss of electrons from [Fe(II)EDTA]2-. Therefore, the two types of chelated iron-based deep eutectic solvents prepared in this work have great application potential in the field of hydrogen sulfide catalytic oxidation.

Oxidation-complexation removal of nitric oxide by anatase titanium dioxide with exposed (0 0 1) facets ultraviolet-induced ferrous ethylenediaminetetraacetate

Ferrous ethylenediaminetetraacetate (Fe(II)EDTA) accompanied by regeneration is thought to be a very efficient method to remove nitric oxide (NO) from flue gas. However, Fe(II)EDTA regeneration requires a large amount of regenerant consumption. For this purpose, anatase titanium dioxide with exposed (001) facets by fluorination (nF-TiO2) was synthesized and combined with Fe(II)EDTA solution for NO removal with ultraviolet light (UV). The result showed that 5F-TiO2 with approximately 30 % (001) facets exposed can significantly promote NO removal of Fe(II)EDTA under UV irradiation, with an average removal efficiency of up to 94.83 % over a 60-minute period. The mechanism study indicated that the excellent removal performance of 5F-TiO2 was mainly because the moderate co-exposure of its (001) and (101) facets could greatly suppress the electron hole recombination rate, accelerate the Fe(Ⅱ)EDTA/Fe(III)EDTA cycle, and form catalytic oxidation-complexation synergism denitrification. Under this synergistic effect, NO from simulated flue gas was mainly transformed to NO3–, NO2–, NH4+, N2, and N2O. Subsequently, NO removal performance using UV/Fe(Ⅱ)EDTA/5F-TiO2 under different parameters demonstrated that appropriate oxygen concentration (3 vol%), suitable 5F-TiO2 mass (0.5 g), low temperature (30 ℃), and weak acidic environment (pH = 4) were favorable for NO removal. The kinetics demonstrated that NO removal by the UV/Fe(Ⅱ)EDTA/5F-TiO2 system was a pseudo-first-order process. Finally, UV/Fe(II)EDTA/5F-TiO2 denitrification technology shows great potential in practical applications. This work offers a new route for the greenandlow-costapplication of Fe(Ⅱ)EDTA denitrification in flue gas treatment.

Performance and reaction kinetics of NO absorption by Fe(II)EDTA in a multistage zeolite absorption column-H2-MBfR system

Efficient NOX complexation absorption is a key to biological flue gas denitrification. In this study, the influencing factors, efficiency, and kinetic parameters of Fe(II)EDTA absorption of NO in a multistage zeolite absorption column were evaluated. The response surface methodology (RSM) was used to determine the ideal absorption conditions. Based on these results, a combined process of a multistage zeolite absorption column and a hydrogen-based membrane biofilm reactor (H2-MBfR) was built to verify the efficiency of denitrification. The optimal conditions for achieving maximum efficiency in the absorption of NO by Fe(II)EDTA were obtained as pH of 6.5, Fe(II)/EDTA molar ratio of 1:1.1, and temperature of 30 ℃. The kinetic parameters, including liquid phase mass transfer coefficient (KNO,L) and gas phase mass transfer coefficient (KNO,G), all increased with temperature, while the NO interfacial-area concentration (aNO) exhibited the opposite trend. The reaction for Fe(II)EDTA absorption of NO was a conjugation reaction, and its activation energy was 50.38 kJ·mol-1. More than 90 % of NO in flue gas on 14 days was removed in the combined multistage zeolite absorption column-H2-MBfR process, which provided a sustainable NO treatment solution without secondary pollutants or CO2 emissions and demonstrated its potential for NO removal in industrial applications.

Strongly reducing NaHS regenerates Fe(II)EDTA for efficient NO removal with high cycling performance under high oxygen conditions

Fe(II)EDTA can remove NO efficiently, but it has not been industrially applied. This is because the oxygen present in the flue gas will oxidize Fe(II)EDTA and Fe(II)EDTA-NO to Fe(III)EDTA and deactivate them. In order to solve this problem, this paper innovatively proposes to use NaHS to reduce Fe(III) EDTA, because NaHS has high reducing ability and low price. Therefore, a series of experimental conditions were explored in order to obtain the best reaction setup. The results indicate that increasing the concentrations of NaHS, temperature, and pH enhances the rate of NaHS reduction. The mechanism of the increase in reduction rate was studied in depth using potentiometric titration. It was found that an increase in OH- concentration will generate S8 precipitate, which is beneficial to the forward progress of the reaction and promotes the large-scale production of the active component Fe2+. Oxygen is an inevitable factor in actual flue gas, so this study innovatively proposed a kinetic model under aerobic conditions and used this model to predict the trend of Fe(III)EDTA reduction by NaHS. On this basis, NO removal experiments were conducted under high oxygen conditions. After 15 cycles, the reduction performance of NaHS was still very high, and the NO removal rate was higher than 70%. The reason for this phenomenon is that the stabilizer exists in a form that is conducive to the removal of NO by the active component Fe2+. Therefore, this study provides theoretical guidance for promoting the industrial application of Fe(II) EDTA technology for NO removal.

Foliar application of cyanobacterial formulations stimulates plant growth and fruit quality in tomato under protected cultivation

ABSTRACT Cyanobacterial biofertilizers enhance plant and soil productivity across crops, through soil-seed application at the field level; however, their use as foliar treatment is less investigated. This study evaluated the role of foliar sprays, initiated 4 weeks after transplantation of nursery-raised seedlings in beds, and effected at weekly intervals for a period of eight weeks. towards enhancing plant growth, yield and quality of tomato grown in a climate-controlled polyhouse. Sprays were composed of aqueous formulations of carrier alone, and those amended with the formulations of plant-growth-promoting cyanobacterium Anabaena laxa (A. laxa) or biofilm Anabaena torulosa -Trichoderma viride (An-Tr) or suspension of 100 µM Fe EDTA. A. laxa brought about a significant increase in nitrate reductase and glutamine synthetase activity in leaves by 13%–17%, along with 3-fold stimulation in carbonic anhydrase activity. Cyanobacterium-amended foliar agents significantly enhanced soil dehydrogenase, urease activity, along with increments in organic carbon, Fe, Zn in soil and stimulated yield, fresh weight and quality of fruits. Both cyanobacterial formulations were promising in enhancing plant growth, fruit yield and quality, however, A. laxa also significantly improved microbiological activity and nutrient enrichment in soil. Future research is focused towards optimising the dose and storage life of such foliar agents for protected horticulture.

Ligands regulate the application of Fe(Ⅲ)-ligands on Se(Ⅳ) bioreduction: Electron transfer, metabolism activity and EPS secretion

Ligands influence the performance of Fe(Ⅲ) on pollutant biotreatment by affecting the properties of Fe(Ⅲ), but few studies focused on the effect and mechanism for Fe(Ⅲ)-ligands on Se(Ⅳ) bioreduction. Results showed that 5 mM Fe(Ⅲ)-ligands (ethylenediaminetetraacetic acid ferric sodium salt (Fe(Ⅲ)EDTA) and ferric citrate (Fe(Ⅲ)Cit)) could accelerate 4–5 times of Se(Ⅳ) bioreduction rate by accelerating electron transfer rate, improving metabolism activity and enhancing extracellular polymeric substances (EPS) secretion, while the performance of Fe(Ⅲ)Cit and Fe(Ⅲ)EDTA to accelerate Se(Ⅳ) bioreduction was influenced by ligands. Cyclic voltammetry (CV) results showed that the specific capacitance in BK + Fe(Ⅲ)EDTA was 64.43% higher than BK + Fe(Ⅲ)Cit. But, the adenosine triphosphate (ATP) in BK + Fe(Ⅲ)Cit was 67.29 ％ higher than BK + Fe(Ⅲ)EDTA. Meanwhile, electron transport system activity (ETSA), reduced coenzyme Ⅰ (NADH) and cytochrome c contents in BK + Fe(Ⅲ)Cit were also higher than those in BK + Fe(Ⅲ)EDTA. EPS analysis showed that Fe(Ⅲ)EDTA led to decreased aromatic protein content in EPS, while Fe(Ⅲ)Cit could enhance aromatic protein content in EPS. This study provided a new insight and valuable mechanism for Fe(Ⅲ)-ligands to regulate Se(Ⅳ) bioreduction.

Performance, kinetics and mechanism of Fe(II)EDTA regeneration with surface-fluorinated anatase TiO2 with exposed (001) facets

Fe(II)EDTA regeneration mainly referring to Fe(III)EDTA and Fe(Ⅱ)EDTA-NO reduction has a very remarkable significance for NO removal using Fe(II)EDTA solution. Here, surface-fluorinated anatase TiO2 nanosheets with exposed (001) facets (F-TiO2) was prepared and firstly served for Fe(II)EDTA regeneration with ultraviolet light. The performance and kinetics of Fe(II)EDTA regeneration had been investigated under different F-TiO2 dose, varied pH, and diverse temperatures, in which Fe(III)EDTA and Fe(II)EDTA-NO reduction rate raised and then decreased under pH increasing or F-TiO2 dose rise. High temperature was conducive to Fe(II)EDTA regeneration. Fe(III)EDTA and Fe(II)EDTA-NO reduction presented first order reaction. Moreover, the F-TiO2 still maintained an excellent reduction efficiency after three recycle. Mechanism study showed that excellent Fe(II)EDTA regeneration ability could be partly explained by the high separation efficiency of photogenerated electrons and holes of F-TiO2. The bonded NO was converted into NH4+, N2, and N2O. Finally, compared with other Fe(II)EDTA regeneration systems, photocatalytic regeneration is a more suitable alternative in Fe(II)EDTA complexation denitrification technology.

Effective nitric oxide removal from flue gas using UV/H2O2 solution catalyzed by Fe3O4@FeEDTA

AbstractBACKGROUNDHow to control NOx emission in flue gas economically and efficiently is the focus in the field of energy and environment in the world. In this work, Fe3O4‐magnetic microspheres were employed as the matrix with loading FeEDTA (where EDTA is ethylenediaminetetraacetic acid) to prepare magnetic denitrification absorbent Fe3O4@FeEDTA. The performance of nitric oxide (NO) removal using Fe3O4@FeEDTA dispersed in H2O2 solution with ultraviolet (UV) was first investigated.RESULTSThe results showed that Fe3O4@FeEDTA could be used as a good catalytic oxidation denitrification agent. Increasing H2O2 concentration and O2 concentration could promote NO absorption. NO removal efficiency increased as pH value increased from 1.5 to 3.0, then decreased when pH continued to increase. The elevated temperature was conducive to NO removal. CO2 hardly affected the removal of NO, while SO2 with high concentration was not conducive to NO absorption. In addition, the NO removal mechanism was preliminarily analyzed with X‐ray photoelectron spectrometry, electron spin resonance and ion chromatography. The mechanism study indicated that NO removal by Fe3O4@FeEDTA/H2O2 was a catalysis–complexation–oxidation–absorption process, in which •OH was determined to be the main oxidizing species, and NO captured by Fe(II)EDTA was mainly oxidized by •OH to NO3−.CONCLUSIONThe catalytic activity of Fe3O4@FeEDTA could maintain stability during the repeat experiment, realizing the recycling and reuse of Fe3O4@FeEDTA. The UV‐Fe3O4@FeEDTA‐activated H2O2 advanced oxidation technology is suitable for wet denitrification. © 2023 Society of Chemical Industry (SCI).

Simultaneous Reduction of NO/SO2 Gas Using Fe(II)EDTA Solution at Low Temperature Conditions and Analysis of Solution Regeneration Characteristics by Zn

Simultaneous Reduction of NO/SO2 Gas Using Fe(II)EDTA Solution at Low Temperature Conditions and Analysis of Solution Regeneration Characteristics by Zn

Experimental and kinetics study of NO absorption in mixed solutions of Fe(II)EDTA and (NH4)2SO3

Experimental and kinetics study of NO absorption in mixed solutions of Fe(II)EDTA and (NH4)2SO3

NaHS regenerated Fe(II) EDTA denitrification mechanism and kinetics investigation

Fe(II) EDTA regeneration is a hot research topic in wet denitrification. In this study, NaHS was used to regenerate Fe(II)EDTA. The effects of Fe(II)EDTA-NO concentration, temperature and pH on the reduction of NaHS were investigated separately. On this basis, the reduction reaction mechanism and kinetics are clarified. A comparison was made with other reductants in terms of reduction efficiency and cost. The experimental results show that the reduction of Fe(II)EDTA-NO by NaHS is a first-order reaction for Fe(II)EDTA-NO. The NaHS reduction rate increases with increasing temperature. The destination of N in the reduction reaction is N2 and the destination of S is mainly S monomer. In addition, the activation energy (Ea) for the reduction of Fe(II)EDTA-NO by NaHS was 34.328 kJmol-1, the enthalpy of activation (ΔH#) was31.7879 kJmol-1, and the entropy of activation (ΔS#) was −160.3614 Jk-1mol-1. In addition, NaHS can simultaneously reduce Fe(II)EDTA-NO and Fe(III)EDTA, and Fe(II)EDTA-NO will reduce the efficiency of NaHS reduction of Fe(III)EDTA. These data can further promote the industrial denitrification of Fe(II)EDTA.

Membrane-less Paired Electrolysis for Cooperative Conversion of Complex NO in a Complexing Absorption System

The complexing absorption method serves as an important wet process for potential application in NO removal of industrial exhaust gas. However, gradual saturation of the absorbent severely limits its continuous operation and denitration efficiency. Herein, a membrane-less paired electrolysis (MLPE) process was first introduced for cooperative conversion of complex NO, thereby regenerating the absorbent. Fe(II)EDTA(NO) was converted on the anode and cathode directly and indirectly; namely, complex NO was not only oxidized to NO3–, but also reduced to NH4+, N2, and N2O. Furthermore, NO3– and NH4+ acted as the potentially valuable products for further reclamation and utilization. Compared with membrane anodic electrolysis (MAE) and membrane cathodic electrolysis (MCE) systems, the MLPE system achieved the lowest energy consumption and highest conversion efficiency of Fe(II)EDTA(NO). Finally, the influences of key process parameters on the complex NO electro-conversion were investigated. The MLPE process provided an efficient and convenient strategy for electro-conversion of complex NO together with absorbent regeneration and NO resource utilization.

Complexing agents-free bioelectrochemical trickling systems for highly-efficient mesothermal NO removal: The role of extracellular polymer substances

The biological treatments are promising for nitric oxide (NO) reduction, however, the biotechnology has long suffered from high demands of NO-complexing agents (i.e., Fe(II)EDTA), leading to extra operation costs. In this study, novel complexing agents-free bioelectrochemical systems have been developed for direct NO reduction. The electricity-driven bioelectrochemical trickling system (ED-BTS, a denitrifying biocathode driven by the external electricity and an acetate-consuming bioanode) achieved approximately 68% NO removal without any NO-complexing agents, superior to the bioanode-driven BTS and open-circuit BTS. The extracellular polymeric substances from the biofilms of ED-BTS contained more polysaccharides, humic substrates, and hydrophobic tryptophan that were beneficial for NO reduction. Additionally, the external electricity altered the microbial community toward more denitrifying bacteria and a higher abundance of NO reduction genes (nosZ and cnorB). This study provides a comprehensive understanding of microbial behaviors on the adsorption and reduction of NO and proposes a promising strategy for mesothermal NO biotreatment.

The origin of highly efficient and selective activated carbon supported bimetallic Fe@Cu composite for Fe(II)EDTA-NO reduction in Fe(II)EDTA complexation denitrification process

Fe(II)EDTA complexing absorption is a promising technology for nitric oxide removal; however, inefficient and slow Fe(II)EDTA regeneration from Fe(II)EDTA-NO reduction and undesirable NH4+ as the major N-containing product are still challenges that should be resolved. This study investigated the performance, kinetics, and product selectivity of Fe(II)EDTA-NO reduction by activated carbon supported bimetallic Fe@Cu composite (AC-Fe@Cu) and unraveled the origin of highly efficient and selective AC-Fe@Cu for Fe(II)EDTA-NO reduction. The reduction efficiency reaches 95.34 % in 30 min, accompanied by 86.78 % N2 selectivity, outperforming most of the reduction systems reported previously. AC-Fe@Cu is resilient at wide pH (3–8), temperature (20–50 °C), and O2 concentration ranges (0–10 %) and maintains high efficiency (76.23 %) after three successive cycles (3 h). Simultaneous reduction of Fe(III)EDTA and Fe(II)EDTA-NO indicates that Fe(II)EDTA-NO reduction is the rate-determining step in the Fe(II)EDTA regeneration process. The bimetal configuration and atomic ratio mediate the reduction efficiency, rate, and N2 selectivity. Unique AC@Fe@Cu structure and optimal atomic ratio of Fe to Cu (1:1) increase the dispersity and provide space proximity and abundant interfaces, which create numerous iron–carbon and iron–copper galvanic cells and promote two-way electron transmission. Fast electron transfer and nascent hydrogen formation contribute to efficient, rapid, and selective Fe(II)EDTA-NO reduction. The maximization of the roles of Cu as stabilizer and active sites for selective N2 formation also contributes. This study sheds light on reduction system design for Fe(II)EDTA regeneration.

Fe(III)EDTA and Fe(II)EDTA-NO reduction by supported (nano)ZVI in Fe(II)EDTA complexation denitrification technology: Performance, kinetics, and pathway

Fe(II)EDTA shows superior ability in complexing absorption denitrification; however, the resulting Fe(II)EDTA-NO and its easy oxidation to Fe(III)EDTA decimate its role. Rapid Fe(II)EDTA regeneration from Fe(II)EDTA-NO and Fe(III)EDTA reduction is important for effective and successive nitrogen oxide removal, and harmless N2 is desirable as the major N-containing product. This study investigated the performance, kinetics, and pathway of Fe(III)EDTA and Fe(II)EDETA-NO reduction by four supported (nano)ZVI ((nanoscale) zero-valent iron)) and NO removal coupled with Fe(II)EDTA regeneration. Support-mediated the physicochemical and structural properties of loaded (nano)ZVI, Fe(III)EDTA and Fe(II)EDTA-NO adsorption, and reduction pathways are closely related to the efficiency, rate, and product selectivity. Activated carbon-supported nano-ZVI (AC-nZVI) is important for Fe(III)EDTA and Fe(II)EDTA-NO reduction with high efficiencies of 89.8 % and 88.2 % within 5 min and 30 min, respectively, and high N2 selectivity (52.98 %), outperforming most of the reduction systems reported previously. The pathway alternation induced by the catalysis of activated carbon and micro-electrolysis of iron–carbon is the origin of highly efficient and selective AC-nZVI for Fe(III)EDTA and Fe(II)EDTA-NO reduction. Resilient over a wide O2 content (0–10 %), pH (3–8), and temperature range (20–50 °C) and efficient for NO removal with large capacity coupled with Fe(II)EDTA regeneration, AC-nZVI would be applicable in industrial Fe(II)EDTA regeneration in Fe(II)EDTA complexation denitrification technology. This study proposes an alternative for Fe(II)EDTA regeneration and provides insights into the mediation of the performance, kinetics, and pathway for guiding reduction system design.

Engineering multiscale polypyrrole/carbon nanotubes interface to boost electron utilization in a bioelectrochemical system coupled with chemical absorption for NO removal.

The chemical absorption-bioelectrochemical reduction (CABER) integrated system provides an alternative of good potential for NO removal. The efficient utilization of cathode electrons directly determines the system performance and operating cost. Herein, we synthesize a polypyrrole/carbon nanotubes (PPy/CNTs) composite to engineer a micro-and nanoscale interface with low resistance and high biocompatibility between the cathode and biofilms in the CABER system. The resulting PPy/CNTs biocathodes exhibit 36.4% increase in biomass density, 40.7%-302.6% increase in Faraday efficiency along Fe(III)EDTA reduction, and 204% increase in Fe(II)EDTA-NO reduction rate. The enrichment of functional microorganisms is validated to be a key strengthening factor, as the proportion of which increased from 57.9% to 84.6%. Moreover, for efficient electron transfer and utilization, a low-resistance electron transfer route, "electrode substrate → PPy (→ CNTs) → microbial cells → Fe(III)EDTA or Fe(II)EDTA-NO", is realized in the multiscale conductive networks constructed of PPy/CNTs composite and microbial nanowires.

Study on NO Removal Characteristics of the Fe(II)EDTA and Fe(II)PBTCA Composite System.

Fe2+ complexation wet denitrification technology has become a research hotspot. It is very important to achieve efficient regeneration of the absorbent and increase NO absorption in the Fe2+ complexation system. They are the key to the industrial application of the Fe2+ complexation absorption process. In this paper, 2-phosphonate-butane-1,2,4-tricarboxylic acid and ethylenediamine tetraacetic acid were used as ligands to prepare a composite system for the first time. The characteristics of NO removal were investigated under different temperatures, pHs, Fe2+ concentrations, O2 contents, NO concentrations, CO2 contents, and SO2 concentrations. Compared with the single ligand, the results show that the denitrification performance of the solution with a complex ligand is significantly improved. In this system, pH 9, 40 °C temperature, and 20 mmol/L Fe2+ concentration are the economic ideal conditions for NO removal. The system can realize simultaneous removal of NO and SO2, but SO2 in flue gas has a dual effect on the NO removal reaction.