Iron-carbon Ratio Research Articles

Degradation Efficiency and Mechanism of Tetracycline in Water by Activated Persulfate Using Biochar-Loaded Nano Zero-Valent Iron.

Tetracycline (TC) contamination in water is one of the key issues in global environmental protection, and traditional water treatment methods are difficult to remove antibiotic pollutants.Therefore, efficient and environmentally friendly treatment technologies are urgently needed. In this study, activated persulfate (PS) using a biochar-loaded nano zero-valent iron (BC-nZVI) advanced oxidation system was used to investigate the degradation effect, influencing factors, and mechanism of TC. BC-nZVI was prepared using the liquid-phase reduction method, and its structure and properties were analyzed by various characterization means. The results showed that nZVI was uniformly distributed on the surface or in the pores of BC, forming a stable complex. Degradation experiments showed that the BC-nZVI/PS system could degrade TC up to 99.57% under optimal conditions. The experiments under different conditions revealed that the iron-carbon ratio, dosing amount, PS concentration, and pH value all affected the degradation efficiency. Free radical burst and electron paramagnetic resonance (EPR) experiments confirmed the dominant roles of hydroxyl and sulfate radicals in the degradation process, and LC-MS experiments revealed the multi-step reaction process of TC degradation. This study provides a scientific basis for the efficient treatment of TC pollution in water.

Effect and mechanism of iron-carbon micro-electrolysis pretreatment of organic peroxide production wastewater.

The wastewater from organic peroxide production has high chemical oxygen demand (COD) concentration and poor biodegradability, so it is necessary to find a cost-effective treatment method. The iron-carbon microelectrolysis (IC-ME) technology was used to pretreat the organic peroxide production wastewater, and the influence of reaction conditions on the removal effect of pollutants and the degradation mechanism were studied. The effects of initial pH, iron filings, iron-carbon ratio, and reaction time on the wastewater treatment were investigated by single-factor and response surface optimization experiments, and the degradation mechanism was analyzed by three-dimensional fluorescence spectroscopy, UV-Vis, and gas chromatography mass spectrometry (GC-MS). The experimental results showed that the COD removal efficiency was 35.67% and the biodegradability of wastewater was increased from 0.113 to 0.173 under the conditions of initial pH of 3.1, the dosage of iron filings of 30.5g/L, the ratio of iron-carbon of 1.01, and the reaction time of 122.8min, and the process of IC-ME for degrading COD of wastewater from the production of organic peroxide was consistent with the secondary reaction. The IC-ME process could decompose macromolecular organic compounds such as tyrosine proteins and aromatic proteins, and improve the biodegradability of wastewater. It provides a theoretical reference for the practical application of IC-ME to treat this type of wastewater.

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.

Preparation of Micro-Electrolytic Iron-Carbon Filler for Sewage by Recycling Metallurgical Dust

In this paper, a new iron-carbon micro-electrolytic filler for wastewater treatment was prepared using the blast furnace dust. The effects of preparation conditions on the performance of the filler during the wastewater treatment were investigated. The optimal preparation conditions of the filler were obtained, which provided an experimental theoretical basis for the use of metallurgical dust sludge in the preparation of micro-electrolytic fillers. From the results of treating methyl orange-simulated wastewater with fillers of different preparation conditions, it could be obtained that the improvement of the filler processing performance requires a suitable iron to carbon ratio, sintering time, and sintering temperature. The optimum preparation conditions were a 1:2 iron-carbon ratio, 30 min sintering time, and 1100 °C sintering temperature. The effect of treatment conditions on the performance of the iron-carbon micro-electrolytic filler was also investigated. The results showed that increasing the filler addition, increasing the treatment temperature, and decreasing the initial pH could effectively improve the treatment efficiency of the filler for methyl orange-simulated wastewater. More than 99% of the methyl orange could be removed in the wastewater under the conditions of 5 g of filler, 40 °C, and pH = 3.

A novel recycling way of blast furnace dust from steelworks: Electrocoagulation coupled micro-electrolysis system in indigo wastewater treatment

In this study, a novel electrocoagulation electrode, based on blast furnace dust (BFD) from steelworks waste, was prepared for indigo wastewater treatment, and the performance was compared with different ratios of Fe–C composite electrodes. The BFD electrode exhibited great electrochemical performance and removal effect. The presence of Fe–C micro-electrolysis in the electrocoagulation system of the BFD electrode was demonstrated by FT-IR, Raman, ESR, and quenching experiments. Density Functional Theory (DFT) calculations further demonstrated that the iron-carbon ratio could influence the degree of O–O breaking and enhance ·OH generation. Finally, the BFD electrode's operating parameters were perfected, and the COD removal and decolorization could reach 75.7% and 95.8% within 60 min, respectively. Fe–C composite electrodes reduce energy consumption compared with the traditional Fe/Al electrode and have a lower production cost, which provides a potential way to recycle and reuse the resources of solid waste in steelworks, the concept of “waste controlled by waste” is realized.

Sulfate removal mechanism by internal circulation iron-carbon micro-electrolysis

• Internal circulation iron-carbon micro-electrolysis was used to remove sulfate. • We investigated the effects of different conditions on the sulfate removal rate. • The maximum sulfate removal efficiency was 76.6% under specific conditions. • The sulfate removal mechanism was investigated using four different techniques. Internal circulation iron-carbon micro-electrolysis (ICE) was used to treat sulfate in wastewater. The influences of the reaction time, aeration rate, pH, iron-carbon ratio, and the initial sulfate concentration on sulfate removal by ICE were investigated. The maximum sulfate removal efficiency was 76.6% under the following conditions: reaction time = 120 min, aeration rate = 0.5 m 3 /h, pH = 2, iron-carbon ratio = 1:1, and initial sulfate concentration = 500 mg/L. Scanning electron microscopy, energy-dispersive spectrometry, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy analyses were performed to study the sulfate removal mechanism. The results showed that sulfate was mainly removed by two mechanisms: 1) sulfate may initially be reduced to SO 3 2- , and then to S 2- , which combines with H + and Fe 2+ to form H 2 S and FeS, which can be removed; 2) sulfate can be removed by flocculation and precipitation of Fe(OH) 2 and Fe(OH) 3 . Therefore, the ICE process can be used as an effective method to remove sulfate from wastewater.

The effect of iron-carbon ratio and on carbon nanotube synthesis using camphor and ferrocene as carbon sources in the gauze reactor

Maximizing the quantity and quality of the product is the main goal of optimizing the material manufacturing process. The use of ferrocene as a carbon source and a catalyst in carbon nanotube (CNT) synthesis results in a significant amount of impurities. The addition of camphor as an additional carbon source is a way to overcome the high Fe/C ratio in ferrocene. This study aims to add camphor carbon sources to ferrocene to obtain an optimal Fe/C ratio to reduce the product's impurities. The application of a more reliable surface response method has not been well explored in studies of optimization of CNT synthesis. In this study, the response surface method (RSM) helps exploration in the parametric study of CNT synthesis. Ferrocene (Fe(C5H5)2) has an iron-carbon (Fe/C) ratio of 46.5%. The method used is Floating Catalyst Chemical Vapor Deposition (FCCVD), using a gauze-type 316 stainless steel substrate. Variations in the ratio of Fe/C in CNT synthesis were 0%, 6.8%, and 46.5% to obtain CNT results with the best quality and quantity. The Fe/C ratio of 6.8% has the best quality and highest quantity. The results of SEM, EDS, and TEM characterization showed that CNT at the variation of the Fe/C ratio of 6.8% had a CNT outside diameter of 20–40 nm, and the percentage of carbon mass was 86.64%. The yield at this ratio is 1.608 gs from 4 gs of precursor (40.2%). The RSM analysis with the optimum conditions for CNT yield were 49 min reaction time and 16% Fe/C ratio.

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.

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.

Research on Treatment Organic Waste Liquid of High Concentration Acid by Cavitation Impinging - Micro Electrolytic Method

The high concentration and high acid organic waste liquid is treated by using the self-developed drum type cavitation impinging stream—micro electrolysis reactor. Under optimal conditions, namely iron-carbon ratio of 1: 1, each reaction time 3h, standing reflux for 2 times, first filler dosage 200g, successive half, controlling the pH value of less than 3. Waste liquid COD removal rate can reach 93.5%, and the biodegradability of the effluent B/C is more than or equal to 0.4. By comparing the treatment effect of cavitation impinging assisted and simple micro electrolysis, it is founded that COD removal rate is high by using cavitation impinging assisted micro electrolysis method the processing time is short, the water is good biodegradability lower production cost, convenient control and operation, with a higher value.

Research on Waste Materials with Decentralized White Spirit Wastewater Pretreatment by Fe-C Micro-Electrolysis

This research adopts the important iron electrolysis, removal of the wastewater of high COD, SS, phosphorus pretreatment experiment. Discusses the different iron dosing quantity, iron carbon ratio, and pH value, reaction time on the COD and turbidity, the influence of the phosphorus removal effect. Studies show that iron important electrochemical test in brewery wastewater treatment static optimal processing conditions for: water pH value is 4, 5% dosage of iron filings, 60 min temperature response, COD removal rate was 52.31%. When the iron carbon ratio of 2:1, removing effect is good, can reach 54.53%.

Experimental Study on High Salt Acid Pretreatment of Refinery Wastewater

We pretreat the high salt level, high CODcr and strong acid refinery wastewater and analyse the influence of the iron-carbon ratio and the pH to ferric-carbon micro-electrolysis. Thereby we confirmed the reaction time and mixture component. Furthemore, we discussed the influence of supersaturated sodium on ferric-carbon micro-electrolysis. The results show that ferric-carbon micro-electrolysis can take full advantage of high salt, strongly acidic water quality characteristics of refinery wastewater to confirm that the removal rate of CODcr can reach to 49%, at the conditions of the iron-carbon ratio of 1:1, micro-electrolysis time is 45 minutes and the pH rise to 8 by lime milk. In addition, the decoloring effect is remarkable.