Iron Carbon Micro Research Articles

Mechanistic insights into removal of bisphenol A from activate peroxymonosulfate by Fe-C coupled biochar with the assistance of electric-field activation

Iron-carbon micro electrolysis activated persulfate (Fe-C/PS) treatment of wastewater is characterized by high oxidation efficiency and no secondary pollution, Limitations such as short reaction lifetime and hardening of Fe-C usually make it insufficient to achieve the desired treatment effect.The research is a new type of electric field in the auxiliary, promote biochar activation peroxymonosulfate (PMS) by micro electrolysis produce active free radicals to degradation of organic pollutants in water. namely IC-BC/PMS-EC，Using biochar as electron shuttle, electric field was introduced in the process of iron-carbon microelectrolysis activation of PMS promoted the electron transfer in the solution， The results showed that the reaction system could achieve 100% removal effect in 20 min. Fe2+/Fe3+ released by Fe-C was below the ambient concentration, which constituted a stable cycle in the electrocatalytic system and efficiently activated PMS. The work found that applied electric field and Fe-C micro-electrolysis activation both improved the efficiency of persulfate advanced oxidation progress. The activated system superimposition strengthened on coupled action and enhanced the performance for the degradation of organic pollutants in water. In summary, IC-BC/PMS-EC system is an economical, efficient and promising new system in the process of activating PMS to degrade pollutants.

Preparation of blast furnace dust particle electrodes and their application in synergistic electrochemical degradation of saline polyvinyl alcohol wastewater

Polyvinyl alcohol (PVA) has been widely used as a water-soluble plastic in laundry and dish detergent pods, yet wastewater contaminated with PVA is too difficult to be treated due to its high salinity and foaming. Here, we fabricated blast furnace dust (BFD) particle electrodes, and developed a three-dimensional electrocatalytic system (3DEC) to treat saline PVA wastewater. The optimum preparation condition for BFD particle electrode was iron carbon ratio of 2:1 doping with TiO2. The optimal parameters of 3DECs for PVA wastewater degradation were thoroughly investigated, with current density of 30 mA/cm2, electrode distance of 30 mm, pH value of 7.0, and particle electrode filling rate of 50%. PVA wastewater degradation rate could reach 89.33% within 120 min. The underlying mechanism of iron-carbon micro electrolysis and electrocatalytic system was further studied. PVA wastewater was degraded by direct catalytic oxidation from electrodes. A scavenger experiment showed that free radicals consisting of •OH and HClO mainly contributed to the PVA wastewater degradation. HClO was generated by Cl− at the electrocatalysis and micro electrolysis of particles. In addition, the lifetime of the prepared BFD particle electrode was 120 h, which exhibited electrochemical stability. These findings highlight that the 3DECs coupled with BFD particle electrode is a promising electrocatalysis process for the removal of PVA wastewater.

Effective reinforcement ozone oxidation degradation of N,N-dimethylformamide with cobalt doping micro electrolysis composite

Here we report a novel cobalt doping iron carbon micro electrolysis composite Fe-Co-AC (FCA) that exhibits excellent catalytic performance for the remove of N,N-Dimethylformamide (DMF). The catalytic effects of FCA micro electrolysis (ME), only ozone oxidation (O3), and micro electrolysis synergetic ozonation (ME-O3) on the degradation of DMF were carried out. The results proved that the ME-O3 could obtain high •OH radical yield, showing eminent catalytic efficiency. This is attributed that Co doping optimizes the electron transport path in the material, improves the micro electrolysis synergetic catalytic ozonation performance. Additionally, the relative contribution of reactive oxygen species (ROS) and related reactions were qualitatively evaluated, and the reaction mechanism of ROS generation and pollutant removal was explored. According to the conversion of organic nitrogen and the detection of intermediate, the possible degradation paths of DMF were speculated. The column experiments showed that the ME-O3 process has a certain potential in practical application.

Activated persulfate by iron-carbon micro electrolysis used for refractory organics degradation in wastewater: a review.

With the rapid economic development, the discharge of industrial wastewater and municipal wastewater containing many refractory organic pollutants is increasing, so there is an urgent need for processes that can treat refractory organics in wastewater. Iron-carbon micro electrolysis and advanced oxidation based on persulfate radicals (SO4-·) have received much attention in the field of organic wastewater treatment. Iron-carbon micro electrolysis activated persulfate (Fe-C/PS) treatment of wastewater is characterized by high oxidation efficiency and no secondary pollution. This paper reviews the mechanism and process of Fe-C/PS, degradation of organics in different wastewater, and the influencing factors. In addition, the degradation efficiency and optimal reaction conditions (oxidant concentration, catalyst concentration, iron-carbon material, and pH) of Fe-C/PS in the treatment of refractory organics in wastewater are summarized. Moreover, the important factors affecting the degradation of organics by Fe-C/PS are presented. Finally, we analyzed the challenges and the prospects for the future of Fe-C/PS in application, and concluded that the main future directions are to improve the degradation efficiency and cost by synthesizing stable and efficient catalysts, optimizing process parameters, and expanding the application scope.

Effect of iron nitrate modification on elimination of organic matter from landfill leachate by sludge-based activated carbon.

Sludge-based activated carbons (SACs) prepared from sewage sludge and corn straw, were modified by ferric nitrate, and the unmodified SAC and modified SAC were used as the adsorbing agent to treat the landfill leachate, the elimination capacity for chemical oxygen demand (COD) and organic matter in leachate were studied. Based on this, the physicochemical properties of SACs and the components changes in leachate were analyzed and characterized by X-ray photoelectron spectroscopy and three-dimensional fluorescence spectroscopy. The results showed that under optimal experimental conditions, the elimination capacities of SAC372 for COD, biological oxygen demand over 5 days, and NH4+-N in the leachate were 81.58%, 54.73%, and 69.08%, respectively; while the adsorption capacities of modified SAC for these three substances were 86.25%, 63.51%, and 79.15%, respectively. The ferric nitrate modification improved the ability of SAC to eliminate COD and organic matter from leachate slightly, and made the adsorption occurred easily. The adsorption process of unmodified SAC was dominated by multi-layer adsorption, while the adsorption process of modified SAC was dominated by monolayer adsorption. The mass fraction of Fe (2p) in modified SAC remarkably increased, from 0.70% to 26.01%, organic functional groups certain phase of Fe oxides with different valence states were generated in SAC, which provided a substrate for iron-carbon micro electrolysis. After adsorbed by unmodified SAC and modified SAC adsorption, the total fluorescence intensity of in the leachate increased by 17.01% and 116.84%, respectively. Both two SACs could decompose the humic acid-like substances into aromatic protein organic compounds, and modified SAC could further decompose the soluble microbial byproduct-like substances.

Experiment on pretreatment of waste water from bamboo heat treatment by combination of iron-carbon micro-electrolysis and Fenton method

Abstract The chemical oxygen demand (COD) of waste water from bamboo heat treatment is mainly organic macromolecule compound which degraded from hemicellulos, lignin and extractives. COD is toxic to aquatic organism and human body and very difficult to degrade. The paper studied the possibility of pre-treating the bamboo heat treated waste water (BHTWW) by combination of iron-carbon micro electrolysis and Fenton method. Orthogonal experiment was designed with 3 factors: the initial pH value, retention time and H2O2 dosage, and carried out with a dynamic sampling device with 2:1 iron carbon ratio. Results showed that the iron-carbon micro electrolysis and Fenton were proved to be a potential method in pre-treating BHTWW, and the optimum parameter should be pH 3.0, 40 min residence time and 0.5 % H2O2. After pre-treating, the removal rate of COD was 60.29 %, and B/C (biochemical oxygen demand after 5 days (BOD5)/COD increased from 0.037 to 0.32, the biodegradability was significantly improved. During the pretreatment, the nutrients in BHTWW had been oxidized, the double bound, conjugated double bond in guaiac lignin were opened or broken and degraded into more small molecular, nutrients such as TOC (total organic carbon) content, total nitrogen and total sugar content all decreased which all contributed for the increase of B/C. The microstructure of activated carbon appeared broken and collapses after pretreatment which indicated that they were eroded or involved during the micro electrolysis reaction.

Treatment of landfill leachate RO concentration by Iron–carbon micro–electrolysis (ICME) coupled with H2O2 with emphasis on convex optimization method

ABSTRACTA combined technology between Iron-carbon micro-electrolysis (ICME) and H2O2 using scrap iron and granular active carbon was extensively investigated and optimized (three main independent parameters chosen) for chemical oxygen demand (COD) removal of landfill leachate reverse osmosis (RO) concentration by batch experiments. A regression quadratic equation was developed to model the outcome using central composite design (CCD) coupled with response surface methodology. A global optimization method–the convex optimization was applied to determine the optimal parameters. Under optimal parameters determined as C/Fe (Surface area) of 717143.8, H2O2 concentration of 1687.6 mg/L and pH of 3.8, the corresponding COD removal efficiency was up to 86.9%. Consequently, the COD in the effluent was less than 300 mg/L. The treated water can meet the level B standards of Wastewater Quality Standards for Discharge to Municipal Sewers (CJ 343—2010).

Enhanced removal of organic matter and typical disinfection byproduct precursors in combined iron–carbon micro electrolysis-UBAF process for drinking water pre-treatment

The organic matter and two types of disinfection byproduct (DBP) precursors in micro-polluted source water were removed using an iron–carbon micro-electrolysis (ICME) combined with up-flow biological aerated filter (UBAF) process. Two pilot-scale experiments (ICME-UBAF and UBAF alone) were used to investigate the effect of the ICME system on the removal of organic matter and DBP precursors. The results showed that ICME pretreatment removed 15.6% of dissolved organic matter (DOM) and significantly improved the removal rate in the subsequent UBAF process. The ICME system removed 31% of trichloromethane (TCM) precursors and 20% of dichloroacetonitrile (DCAN) precursors. The results of measurements of the molecular weight distribution and hydrophilic fractions of DOM and DBP precursors showed that ICME pretreatment played a key role in breaking large-molecular-weight organic matter into low-molecular-weight components, and the hydrophobic fraction into hydrophilic compounds, which was favorable for subsequent biodegradation by UBAF. Three-dimensional fluorescence spectroscopy (3D-EEM) further indicated that the ICME system improved the removal of TCM and DCAN precursors. The biomass analysis indicated the presence of a larger and more diverse microbial community in the ICME-UBAF system than for the UBAF alone. The high-throughput sequencing results revealed that domination of the genera Sphingomonas, Brevundimonas and Sphingorhabdus contributed to the better removal of organic matter and two types of DBP precursors. Also, Nitrosomonas and Pseudomonas were beneficial for ammonia removal.

The coupling use of advanced oxidation processes and sequencing batch reactor to reduce nitrification inhibition of industry wastewater: Characterization and optimization

The excess emission of ammonia nitrogen is a common issue encountered by many industry wastewater treatment plants, due to the elevated concentrations and toxicities of compounds released from a large number of industries which might inhibit the growth of nitrifying bacteria. In this work, we are aiming at addressing the above issue raised by an industry wastewater treatment plant and elucidating the nitrification inhibitory mechanisms. A straight-forward and reliable method i.e., respirometry, was developed for the characterisation of nitrification inhibition. The pretreatment methods of Fenton and ozone oxidations and iron carbon micro electrolysis have been attempted to reduce the nitrification inhibition and the former two turned out to be effective. The nitrification inhibition rate (NIR) of the wastewater after Fenton oxidation was reduced from 87% to 13.6% with the optimized condition (pH = 3.0, H2O2 dosage of 14.7 mM, Fe2+ dosage of 4.90 mM, and reaction time of 20 min). The optimal parameters for ozonation were: pH = ∼8.2 (original pH of wastewater), reaction time of 25 min (equivalent to an ozone dosage of 381 mg/L), under which the NIR was declined to 12.7%. The nitrification inhibition might be attributed to the presence of compounds with hydrophobic properties, high molecular weight, and aromatic and unsaturated structures in industry wastewater. The coupling use of Fenton-SBR and ozone-SBR achieved NH3-N removal efficiency of 98% and 93%, respectively. The effluent NH3-N finally met with the Integrated Wastewater Discharge Standard (DB31/199-2009).

An integrated O/A two-stage packed-bed reactor (INT-PBR) for total nitrogen removal from low organic carbon wastewater

Total nitrogen (TN) removal from low organic carbon wastewater is challenging. Traditional heterotrophic denitrification requires additional organics as electron donors, potentially increasing the operational challenges and costs of wastewater treatment. Especially for decentralized domestic sewage in rural areas, it is essential to develop an economical and efficient integrated reactor to satisfy high TN removal demand. This study presents an integrated O/A two-stage packed-bed reactor (INT-PBR) composed of two concentric zones, with total effective volume of 30.6L. Influent is pumped into the inner oxic (O) zone for nitrification, then flows through the outer anoxic (A) zone for denitrification. Iron–carbon micro–electrolysis carriers (IC-MECs), which provide H2/[H] and Fe2+ as inorganic electron donors for autotrophic denitrifiers, and luffa cylindrical sponge (LCS), which provides slow–release organic carbon for heterotrophic denitrifiers, were placed into the A zone to achieve combined heterotrophic and autotrophic denitrification (HAD) without requiring organic carbon in influent. Thus, the INT-PBR involves no return sludge and internal recycle. Using organic-free synthetic wastewater with 39.36±0.74mg/L NH4+-N, approximately 98% of ammonia in influent was transferred to nitrate in the O zone, and approximately 93% of TN was removed by HAD process at 30±2°C in the A zone. Microbial community analysis showed that autotrophic denitrifiers (e.g., Thiobacillus) and heterotrophic/mixotrophic denitrifiers (e.g., Hydrogenophaga) were combined in the reactor, consistent with the performance findings. The results suggest a promising technology for total nitrogen removal from wastewater with low organic carbon.

Applicability of anthracite filtration‒micro electrolysis‒sand filtration for the treatment of surface waters containing high turbidity

The effect of combined filtration efficiency on the performance of anthracite filtration‒micro electrolysis‒sand filtration (AMS) was investigated. Impact of different operating parameters, such as iron‒carbon ratio of micro electrolytic units, filtration velocity of AMS, were studied. It was found that when iron‒carbon ratio was 6: 4, the AMS’s average turbidity removal rate was 96.75% at the filtration velocity of 3 m h‒1. The results showed that when the filtration rate was 3‒9 m h‒1 and iron‒carbon ratio was 6: 4, the turbidity removal efficiency was over 94%, and the turbidity of the effluent was less than 1 NTU in effective filtration cycle. The effective filtration cycle can last for more than 5 h or longer. Meanwhile, the removal rate of UV254 was above 33%, and the concentration of iron ions in the effluent is less than 0.15 mg L‒1. Turbidity and iron indicators have reached the national drinking water standards. It was also found the mechanism of iron‒carbon micro electrolytic enhanced filtration by infrared spectroscopy and scanning electron microscopy. And It was also speculated the reasons for the reaction passivation.

Iron [Fe(0)]-rich substrate based on iron–carbon micro–electrolysis for phosphorus adsorption in aqueous solutions

The phosphorus (P) adsorption properties of an iron [Fe(0)]-rich substrate (IRS) composed of iron scraps and activated carbon were investigated based on iron–carbon micro-electrolysis (IC–ME) and compared to the substrates commonly used in constructed wetlands (CWs) to provide an initial characterization of the [Fe(0)]-rich substrate. The results showed that P was precipitated by Fe(III) dissolved from the galvanic cell reactions in the IRS and the reaction was suppressed by the pH and stopped when the pH exceeded 8.90 ± 0.09. The adsorption capacity of the IRS decreased by only 4.6% in the second round of adsorption due to Fe(0) consumption in the first round. Substrates with high Ca– and Mg–oxide contents and high Fe– and Al–oxide contents had higher P adsorption capacities at high and low pH values, respectively. Substrates containing high Fe and Al concentrations and low Ca concentrations were more resistant to decreases in the P adsorption capacity resulting from organic matter (OM) accumulation. The IRS with an iron scrap to activated carbon volume ratio of 3:2 resulted in the highest P adsorption capacity (9.34 ± 0.14 g P kg−1), with minimal pH change and strong adaptability to OM accumulation. The Fe(0)–rich substrate has the considerable potential for being used as a CW substrate.

Effect of Rare Earths on Iron-Carbon Micro Electrolysis in Dyeing Wastewater Treatment

In the paper we first discussed the principle of wastewater treatment by iron-carbon micro electrolysis. And the experimental methods were stated clear soon afterwards. Then we designed the micro electrolysis orthogonal experiments. Discussion of influences of related factors on waste water treatment followed. The main factors are cerium ion additive quantity, ratio of La3+/Ce4+ and pH in wastewater. The experimental results show that 1) The sequence of factors influence on wastewater micro-electrolysis treatment is Ce4+ > pH > La3+ > iron/carbon ratio; 2) The lanthanum and cerium ions have a synergistic effect in the wastewater treatment, and cerium ion plays a main role; 3) When pH is 6, COD removal rate arrives at maximum 89%, however when the pH is in the case of too high or too low, the effect of sewage treatment is not good.

Effect of Adding Rare Earths into Iron-Carbon Micro Electrolysis Process on Degradation of Dyeing Wastewater

Nowadays the traditional dyeing wastewater treatments based on flocculation-biochemical technology become more difficult than before. The study in this paper aim was it to probe how adding rare earths (REs) into iron-carbon micro-electrolysis process to advance dyeing wastewater degradation. Firstly, the principle was discussed. Then the experimental methods were stated and it followed by exploring effect of iron powder size on the dye decolorization rate. Next were design of the micro electrolysis orthogonal experiments and discussion of influences of related factors on waste water treatment. The experimental results show that besides common iron powder particle size and the processing time, the factors that have great influence on dyeing wastewater treatment are Ce4+, pH, La3+ and iron/carbon ratio. The sequence of factors influence on wastewater micro-electrolysis treatment is Ce4+ > pH > La3+ > iron/carbon ratio. When pH is 6, COD removal rate arrives at maximum 89%, however when the pH is in the case of too high or too low, the effect of sewage degradation is not good.

Effects of Transition Metals and Rare Earths on Iron-Carbon Micro Electrolysis Degrading Dyeing Effluent

The principle and methodology of effluent treatment by iron-carbon micro electrolysis were introduced in the paper. Then design of the orthogonal experiments for dyeing effluent treatment was formulated. Discussion of influences of related factors on effluent treatment followed. Results were got after the detailed analysis. Therefore, we deduced the mechanism that the cations of Transition Metal (TM) and rare earth (RE) assist of zero-valent irons catalyzing degradation of dyeing effluent. The mechanism is formed based on the following explanation. Cations of manganese and cobalt easily penetrate Fe0lattices, while Ce4+cations do it difficultly because of their larger radius. Thus Ce4+is weaker than both of Mn2+and Co2+for helping zero-valent irons to improve their activity. Furthermore, because the valence electron structure of Mn2+is more stable than that of Co2+, Mn2+is better for assisting zero-valent iron catalysis of degradation of dyeing effluent than Co2+. Therefore, ranking of influence for zero-valent iron catalysis activity from greatest to smallest is Mn2+, Co2+and Ce4+.

Research Progress of Acid Mine Drainage Treatment Technology in China

Acid mine drainages treatment technology is a hot issue in the mining industry. It summarizes the causes, the reaction mechanism and impact on the environment of acid mine drainage, and introduces the monitoring indicators of acid mine drainage. Further it focuses on the acid mine drainages terminal treatment technologies that including neutralization, sulfide precipitation, microbiological method, constructed wetlands, membrane method and the iron-carbon micro electrolysis, with the analysis of its theories, advantages, disadvantages and practical application. Meanwhile it introduces the major source control technologies, and further proposes the development tendency that is from terminal treatment technology to the combination of source control and terminal treatment technology. And its a focus and hotspot in the research of the acid mine drainage in China's future.

Study on Treatment of Polytetrahydrofuran Wastewater by Iron-Carbon Micro Electrolysis

The wastewater produced from the polytetrahydrofuran (PolyTHF) was treated with iron-carbon micro electrolysis process. This paper had studied the COD removal efficiency influences of primary PH value, reaction time, the quality ratio of the iron-carbon, the quality and volume ratio of Fe-wastewater. The results show that when pH value is 3, the quality ratio of the iron-carbon is 11 and the quality and volume ratio of Fe and wastewater is 17 with contact time of 90 min, the wastewater COD removal rate can reach as high as 95.0%.