Iron-carbon Micro-electrolysis Research Articles

Application research of internal electrolysis as pre-treatment for berberine wastewater biodegradation

The composition of the berberine wastewater is complicated with high concentration of chemical oxygen demand (COD). Because it is hard to be degraded by traditional biochemical treatment and causes serious environmental pollution. The applicability of internal electrolysis to improve the biodegradability of berberine wastewater to be treated biologically was investigated. The wastewater was originated from a factory producing berberine. Treatability studies were conducted under laboratory conditions in order to determine the operational conditions to enhance the biodegradation of the wastewater.The major operational conditions, such as the initial pH, the second stage pH, the volume ratio of iron-carbon microelectrolysis filler to waste water and aeration time were investigated in the paper. The result of the experiment shows that the initial pH 2.0-2.5, second stage pH 9, the best volume ratio of iron-carbon micro-electrolysis packing and wastewater is 1:1 and the the residence time control in 120 minutes are the best operating parameters on the berberine wastewater treatment.

Identification of adsorption or degradation mechanism for the removal of different ionic dyes with iron-carbon micro-electrolysis process

The Fe-C micro-electrolysis materials (Fe-C MEM) are thought to be a good candidate in dyes removal. In this work, two Fe-C MEM (M1 and M2) with different physiochemical properties were compared in the dyes removal. Three cationic dyes (Three cationic dyes (malachite green (MG), crystal violet (CV), methylene blue (MB)), as well as two anionic dyes (methyl orange (MO), sunset yellow (SY)), were chosen in the study. The results showed that the M2 exhibited a better porosity with higher ZVI content, contributing to a higher dyes removal efficiency for all five dyes. Meanwhile, the cationic dyes had a higher dyes removal efficiency than anionic dyes. When the dyes were mixed together, CV had a higher removal efficiency than MG, although MG was the highest in the single dye solution. The removal mechanism of the five dyes was different. The two cationic triphenylmethane dyes (CV and MG) could be degraded while the two anionic azo dyes (MO, SY) were not degraded but adsorbed on Fe-C MEM. MB was removed mainly based on adsorption and coagulation.

Enhanced degradation of reactive brilliant red X-3B by photocatalysis integrated with micro-electrolysis.

The microwave electrodeless lamp UV photocatalysis (MWUV) integrated with iron carbon micro-electrolysis (ME) was applied to degrade reactive brilliant red X-3B. In the present study, the removal rate of X-3B by MWUV/ME was 95%, which was significantly higher than 56% of MWUV and 62% of ME system. The experiment results demonstrated a synergistic effect in MWUV/ME system, wherein the ME system played an important role in color removal and the formation of ·OH in photocatalysis contributed most for the mineralization of X-3B and its intermediates. The removal efficiency of TOC was 32%, 7.5%, and 59.5% under MWUV, ME, and MWUV/ME processes at the end of the reaction, respectively. The Fe3+ existed in the system was an enhancer of producing ·OH via self-generation of ·OH by UV irradiation or improving the separation of electron-hole in photocatalysis by capturing the electrons. Therefore, the combined treatment of MWUV and ME system has the potential of synergistic effect compared to the separate process. Lowering the initial solution pH and increasing the iron filing dosage and dissolved oxygen were beneficial for the enhancement of degradation efficiency. The inorganic anions showed a diversity influencing the degradation of X-3B. NO3-, CO32-, and SO42- (at higher concentration) promoted the degradation reaction, while Cl- had non-significant effect.

Parameters optimization for eutrophic lake water treatment by a novel process of iron-carbon micro-electrolysis coupled with catalytic ozonation using response surface methodology

Abstract A novel process of iron-carbon micro-electrolysis (ICME) coupled with catalytic ozonation (CO) for treatment of eutrophic lake water was developed. A series of batch experiments with ICME alone and CO alone was designed to investigate the effects of process parameters, such as initial pH, dose of Fe-C, time of micro-electrolysis, ozone flux, dose of TiO2/activated carbon (TiO2/AC), and time of ozonation, on the removal rates of total nitrogen (TN), total phosphorus (TP), CODMn and Chl-a. The process parameters were optimized using response surface methodology. The results showed that initial pH, dose of Fe-C and ozone flux had significant effects on removal of TN, TP, CODMn and Chl-a. Within the range of selected operating conditions, the optimized values of initial pH, dose of Fe-C, time of micro-electrolysis, ozone flux, dose of TiO2/AC, and time of ozonation were 3.8, 13.7 g/L, 29.6 min, 3.19 L/min, 294.74 mg/L and 106.73 min, respectively. Furthermore, ICME alone had significant advantages in TP and CODMn removal and CO alone favored TN and Chl-a. Under the optimal process conditions, the final removal rates of TN, TP, CODMn, and Chl-a by the hybrid ICME-CO process reached 75.33%, 86.29%, 94.42% and 97.57%, respectively. The present research provides a new alternative technology with promise for treatment of eutrophic lake water.

Reutilize tire in microbial fuel cell for enhancing the nitrogen removal of the anammox process coupled with iron-carbon micro-electrolysis

Reutilize tire in microbial fuel cell for enhancing the nitrogen removal of the anammox process coupled with iron-carbon micro-electrolysis

Role of Iron-Carbon Micro-Electrolysis in Constructed Wetlands for Nitrate Removal: A Review

Nitrate (NO- 3), as one of the main causes of eutrophication in water body, has contaminated seriously groundwater and surface water due to the excessive discharge of nitrogenous wastewater from agriculture and industry. Compared to other nitrate removal techniques, constructed wetlands (CWs) are frequently used to reduce nitrate to nitrogen gas (N2). Among the numerous methods of enhancing nitrate removal performance in CWs, iron-carbon Micro-Electrolysis (Fe/C-M/E) system, provides a unique occasion of waste material (iron scrap) for handling wastewater containing nitrate. Currently, the introduction of Fe/C-M/E structure could enhance nitrate removal rates by 20 % ~ 50 % in different types of CWs. Although the application of iron as the special substrate in nitrogenous wastewater treatment is intensively investigated with a large variety of CWs, research about Fe/C-M/E impact on the removal of nitrogen in CWs so far is very limited. Particularly, the information about the comprehensive interaction of biological and electrochemical effects with several distinct factors is inadequate, making it hard to obtain essential and universal conclusions. This paper offers a summary of research regarding Fe/C-M/E system in CWs used to remove nitrogen, discussing nitrogen removal pathways and mechanism via the effect of microorganism or Fe/C system. It also mainly focuses on the influence in the converting NO- 3 to N2 process by different operation parameters such as the type of carbon, the iron-carbon doping ratio, dissolved oxygen (DO), hydraulic retention time (HRT) and pH. It is worth noting that Fe/C-M/E CWs have not only high nitrate remove rate, but also relatively very little emissions of nitrous oxide (N2O), which as one of the main potential sources of greenhouse gases. Finally, this paper proposed some suggestions on future study and application.

Enhancing nitrogen removal performance of anammox process after short-term pH and temperature shocks by coupling with iron-carbon micro-electrolysis

Abstract Nitrogen contamination is regarded as a major threat to terrestrial net productivity and environmental sustainability. Anaerobic ammonium oxidation (anammox) is a cost-effective and promising technology in wastewater treatment. In this study, the effects of pH/temperature and their short-term shocks on a hybrid system of anammox coupled with iron-carbon micro-electrolysis (IC-ME) were investigated. Results indicated that the hybrid system significantly enhanced the total nitrogen (TN) removal and expanded the stable pH operating range (TN removal efficiencies over 50%) from pH 6.5–8 to pH 5.5–8.5. Free nitrous acid (FNA) in acid environment, when its concentration was higher than 396.36 ± 5.51 μg/L, was thought to be one critical degradation inhibitor. After suffering a short-term (one day) pH shock, the hybrid system exhibited the improved performance of both stability and nitrogen removal, mainly because Fe corrosion maintained the pH value by IC-ME. More diverse nitrogen removal processes promoted by IC-ME enhanced the TN removal of hybrid after high temperature shocks. However, the susceptibility and inferior adaptability of anammox bacteria were considered to inhibit the nitrogen removal performance of the hybrid and individual anammox system. Microbial analysis identified Candidatus Kuenenia as the major anammox genus, accounting for 3.61% of the microbial community biomass, and the genus of SM1A02 might be one novel potential strain that help the anammox process.

Advanced treatment of pharmaceutical wastewater with a combined Fe-C micro-electrolysis/EGSB system assisted by microalgae

ABSTRACT An integrated process of iron/carbon micro-electrolysis (ICME)–expanded granular sludge bed (EGSB)–microalgae reactor (MR) was developed for treating pharmaceutical wastewater with initial chemical oxygen demand (COD) of 25000–28500 mg/L. The results show that, under the optimum conditions, the removal ratio of COD, total suspended solids (TSS), color, NH3-N, and total phosphorus were 99.2%, 98.4%, 97.5%, 95.3%, and 78.9%, respectively. The ICME removed a considerable proportion of TSS and color, and improved the biodegradability of the wastewater, while the EGSB played an important role in the removal of residual COD, and finally, post-polish treatment was achieved in the MR.

Role of porous polymer carriers and iron-carbon bioreactor combined micro-electrolysis and biological denitrification in efficient removal of nitrate from wastewater under low carbon to nitrogen ratio

In the current research, a novel bioreactor composed of porous polymer carriers and iron-carbon (PPC@FeC) was established through bacterial immobilized technology. The influence of key factors was studied on the nitrate removal performance of the PPC@FeC bioreactor. The experimental results showed that the highest removal rate of nitrate (7.33 mg L−1 h−1) can be obtained with short hydraulic retention times (HRT = 2.0 h) and low carbon-to-nitrogen ratio (C/N = 2.0). The results of high-throughput sequencing revealed that Zoogloea sp. L2 was the dominant strain in bioreactor responsible for nitrate removal. Moreover, the SEM and XRD analyses elucidated that Fe2O3 was the final product produced by the interaction of FeC and strain L2. These findings showed that the PPC@FeC bioreactor successfully combined micro-electrolysis and biological denitrification, which exhibited great potential in removing nitrate effectively from wastewater under low C/N ratio and short HRT conditions.

Removal mechanism of persistent organic pollutants by Fe-C micro-electrolysis

ABSTRACT The degradation of persistent organic pollutants (POPs) in the simulated wastewaters was investigated by Fe-C micro-electrolysis system. With phenanthrene (PHE) and 2,4-dichlorophenol (2,4-DCP) as target pollutants, different iron-carbon (Fe-C) micro-electrolysis systems have been established. The effects of initial pH, Fe/C mass ratio, and intake air flow on the degradation and mineralization of PHE and 2,4-DCP were studied. At the initial pH of 5.0, Fe/C of 1.5:1, and an aeration flow rate of 1.5 L/min, after 120 min of reaction, the removal efficiency of FHE and COD was 94.3% and 73%, respectively. Under the conditions of initial pH is 3.0, Fe/C is 1:2, aeration flow rate of 1.5 L/min, and reaction time of 90 min, the best removal efficiency of 2,4-DCP can be obtained in the Fe-C micro-electrolysis system as 97% and COD removal efficiency can reach 76%. The results of kinetic studies show that the Fe-C micro-electrolysis process of PHE and 2,4-DCP follows pseudo-first-order kinetics. Commercial activated carbon (AC) was used for comparison under the same condition. The results indicated that the removal rate of organic pollutants and chemical oxygen demand (COD) of Fe-C micro-electrolysis were superior to that of AC. Analyze the structure of iron after reaction by SEM and XRD. The degradation pathway and mechanism for PHE and 2,4-DCP were proposed based on LC-MS analyses of treated wastewater.

Micro-electrolysis biological fluidized bed process for coking wastewater treatment

In this study, the internal circulation iron–carbon micro-electrolysis (ICE) method was combined with activated sludge (AS) to form micro-electrolysis biological fluidized bed (MBFB) process for the treatment of coking wastewater with a low carbon-to-nitrogen (C/N) ratio. The MBFB process has chemical oxygen demand and total nitrogen removal rates of 92 and 95 %, respectively, which is much higher than those of the ICE process and single AS process. The results of three-dimensional fluorescence spectra showed that the MBFB process can not only remove protein-like substances, but can also degrade fulvic acid-like and humic acid-like substances. Fe2+/Fe3+ and active hydrogen atoms promoted the electron transfer inside and outside the microbial cells, thereby enhancing the metabolism of the microorganisms (such as Acidovorax), which is beneficial to the degradation of organics and nutriments. Therefore, the MBFB process has synergistic degradation properties and is promising for treating industrial wastewaters with low C/N ratios.

Fate and removal of aromatic organic matter upon a combined leachate treatment process

Mature leachates contain extremely recalcitrant aromatic organic matter, and require appropriate treatment before discharge. The combined process for treating mature landfill leachate is a common and proper due to its inexpensiveness and high performance. Identification of refractory components and insights into the physicochemical properties transformations of the organics are essential for the development of efficient treatment process. Optical, three-dimensional chromatography and electrochemical techniques were applied to characterize aromatic organic matter in leachate from a pilot landfill leachate treatment plant. Results showed that the combination of biological contact oxidation, iron-carbon micro-electrolysis, Fenton, coagulation and integrated activated sludge system could efficiently remove 95.5% COD and 88.3% DOC in leachate organic matter, together with a simultaneous reduction in its molecular weight (MW), aromaticity, polarity, and humification degree. The low MW proteinaceous, carboxylic acid and amine-containing fractions were preferentially removed in biological contact oxidation process, whereas the hydrophilic humic substances with the MW > 4.0 kDa were the main species against biological treatment. Conversely, the advanced oxidation processes (AOPs) could efficiently destroy high MW, aromatic rings and conjugated moieties fractions, resulting in an increase in the leachate biodegradability. The oxygen-containing moieties generated in the AOPs were bridged by the flocculants to promote precipitate during the coagulation process, and the polymerized metastable organic fractions formed during the process were partly biodegraded in the integrated activated sludge system. This study highlights the potential of combined optical-electrochemical measurements to monitor the intrinsic reactivity of aromatic organic matter and guide the practical leachate treatment.

Treatment of water hyacinth anaerobic fermentation wastewater by combining Fe-C micro-electrolysis with Fenton reaction

Abstract The anaerobic fermentation of water hyacinth is an effective way to turn waste-water hyacinth (a noxious plant of malignant growth) into treasure (methane). However, the technology also brings much water hyacinth anaerobic fermentation wastewater with high COD value, high ammonia nitrogen value and deep color, and thus specific treatment of wastewater is required before its drainage. In this study, iron-carbon micro-electrolysis combined with Fenton reaction was used to treat the water hyacinth anaerobic fermentation wastewater. Removal rate of COD after iron-carbon treatment and Fenton reaction were around 85 % and 80 %, and removal rate of ammonia nitrogen and color were 95 % and nearly 100 % after adjusting pH to alkaline following Fenton reaction in the optimal processing conditions: pH before micro-electrolysis and before Fenton reaction was adjusted to 2.0 and 3.0, 0.15 % (v/v) hydrogen peroxide was the most economical and efficient concentration for Fenton reaction. After iron-carbon micro-electrolysis and Fenton reaction, COD, ammonia nitrogen and absorbance of wastewater were reduced to less than 50 mg/L, 25 mg/L, and almost 0 from the initial value 720 mg/L, 275 mg/L and 0.155, respectively, and all of these satisfy the national emission standards. In the scale up and continuous treatment, good results were also obtained under the optimal conditions. Overall, iron-carbon micro-electrolysis combined with Fenton reaction can effectively treat water hyacinth fermentation wastewater and this technology will make the utilization of water hyacinth resources to be much more environmentally friendly.

Influence characteristics and mechanism of organic carbon on denitrification, N2O emission and NO2− accumulation in the iron [Fe(0)]-oxidizing supported autotrophic denitrification process

Abstract Iron [Fe(0)]-oxidizing supported autotrophic denitrification [Fe(0)-AD] is a promising process for low-carbon water treatment. Organic-carbon (OC) has been a common pollutant associated with nitrogen pollution. However, its interaction with Fe(0)-AD remains unclear. In this study, influence characteristics and mechanism of OC on Fe(0)-AD were investigated. Fe(0)-AD was established based on iron-scraps (ISs) and iron-carbon micro-electrolysis (ME) (ME-ISs-AD). The results showed that the OC-free ME-ISs-AD obtained denitrification load of 0.191 ± 0.028 kgN/(m3·d), which shifted to 0.445 ± 0.011 kgN/(m3·d) at OC-dosage of 1.0 mgCOD/mgTN. N2O (1.52 ± 0.16 mgN/L) and NO2− (6.86 ± 1.11 mgN/L) accumulated markedly in Fe(0)-AD and were reduced to 0.03 ± 0.01 mgN/L and 0.31 ± 0.20 mgN/L at OC-dosage of 1.0 mgCOD/mgTN, respectively. XRD analysis demonstrated that OC could reduce the Fe(0)-passivation, accelerating biological transformation and storage of iron-compounds, enhancing H2 (from 0.06 ± 0.01 to 0.22 ± 0.04 mg/L) and Fe2+ (from 7.4 ± 1.0 to 13.9 ± 1.5 mg/L) production. High-throughput sequencing revealed the enrichment of iron-oxidizing bacteria (e.g. Sphaerotilus and Ferriphaselus) and autotrophic denitrifiers (e.g. Hydrogenophaga and Hyphomicrobium). Real-time qPCR and enzyme activity analysis indicated that the nosZ-encoded NosZ and nirK-encoded NIR controlled N2O and NO2− accumulation in OC-dosed Fe(0)-AD, respectively. Overdose of OC (≥1.5 mgCOD/mgTN) accelerated the bio-organics-Fe complexes (BioFe) production and blocked the H2/Fe2+ transfer. NaAC was more efficient and cost-effective than Glucose and EtOH for Fe(0)-AD enhancement. The utilization of ISs under the enhancement of ME reduced the cost of Fe(0)-AD by 3.87-times comparing to the in-situ ZVI-AD process, and the dose of OC further improved the denitrification load by 1.33-times. This study provided an in-depth understanding of the influence of OC on Fe(0)-AD and could contribute to the application, optimization and secondary pollutants control of Fe(0)-AD process in low-carbon water treatment.

Tertiary treatment of pulp and paper mill wastewater by iron–carbon micro-electrolysis coupled with H2O2

Tertiary treatment of pulp and paper mill wastewater by iron–carbon micro-electrolysis coupled with H2O2

铁碳微电解技术在水处理中的应用

铁碳微电解技术在水处理中的应用

铁碳微电解对餐具清洗废水处理的初步研究

铁碳微电解对餐具清洗废水处理的初步研究

Investigating the influence of iron–carbon microelectrolysis on the performance and microbial community of constructed wetlands

AbstractIron–carbon microelectrolysis (Fe–C ‐ME) has been used extensively for the treatment of domestic sewage. In this study, CWs incorporated with Fe–C ‐ME were established, and the performance and microbial community structure of CWs were investigated. The results indicated that CWs incorporated with Fe–C‐ME had better performance for treating domestic sewage. The NO3‐–N, TN and TP removal efficiencies of CWs incorporated with Fe–C‐ME were 82.3, 80.3 and 98.2%, respectively, which were 7.8, 4.7 and 25.2% higher than those of the CWs without Fe–C‐ME. High‐throughput sequencing analysis demonstrated that Fe–C‐ME changed the microbial community structure. For example, some dominant groups at the class level, such as Betaproteobacteria (15.2%), Gammaproteobacteria (10.6%) and Deltaproteobacteria(10.0%), were promoted by Fe–C‐ME. The results demonstrated that the relative abundance of bacteria involved in nitrification, denitrification, polyphosphate accumulation or COD reduction at the genus level thrived because of the presence of Fe–C‐ME, which can improve the performance of CWs.

Promoting the nitrogen removal of anammox process by Fe-C micro-electrolysis

In this study, a process that combines iron-carbon micro-electrolysis (IC-ME) with the anammox process was successfully established for promoting nitrogen removal, especially the removal of nitrate by-product. Compared with the conventional anammox process, the average total nitrogen removal efficiency of the combined system increased from 64.6% to 90.2% and 83.8% when the system was effectively operated for 4 days (Phase 2) and 13 days (Phase 3), respectively. In this combined system, IC-ME played a dual role: 1) converting the nitrate to ammonia as the nitrogen substrate for further degradation, and 2) producing Fe2+, Fe3+ and H2 for the nitrogen removal processes of NH4+ oxidation with Fe3+ reduction (Feammox), nitrate-dependent Fe2+ oxidation (NDFO), and denitrification, in addition to the anammox process. Microbial analysis using 16S rRNA high-throughput sequencing revealed Candidatus Kuenenia and Candidatus Brocadia as the major anammox genera, accounting for 1.01% and 0.15%, respectively.

Synergetic effects of iron-carbon micro-electrolysis integrating with other technologies

The combination of iron-carbon micro-electrolysis (ICME) technology and other technologies is an important development direction for the treatment of refractory wastewater, which could overcome the disadvantages of each technology and combine the advantages of each technology. The synergetic effects of ICME combined with Fenton process not only save the cost of adding reagents, but also significantly improve the efficiency of the combination treatment. The advantage from the combination of ICME with ozone is due to plenty of hydroxyl radicals coming from ozone decomposition, which enhances the complex contaminants removal. The synergetic effects of ICME integrated with biological process include mainly two respects. One is that the galvanic cells produced around the ICME could readily convert complex organic compounds to biodegradable substrates, which is conducive to the degradation of pollutants by microbes. Another one is that the iron ions released from ICME possess great capability to promote the performance of the microbes to treat wastewater, for instance, mineral nutrients for microbes, electron transfer mediator, and vital components of enzymes. Accordingly, the integration of ICME with other technologies has great application prospect for refractory wastewater.