Micro-electrolysis Method Research Articles

Internal Micro-electrolysis Using Fe/C Material for Pre-Treatment of Concentrated Coking Wastewater

Abstract Untreated coking effluent presents a great challenge for sustainable development of the steel industry and environment preservation. In this study, an internal micro-electrolysis method using Fe/C materials was employed for pretreatment of real coking wastewater with high mass concentration. The Fe/C materials were prepared by Fe powder and graphite powder; and the characteristics of surface morphology, structure, composition of the synthesized materials were examined by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS). The effects of factors namely dosage of Fe/C material, treatment time, initial pH and temperature were investigated via chemical oxygen demand (COD) and phenol removal efficiencies. Optimal treatment efficiency was attained at pH of 4, Fe/C dosage of 40 g/L, treatment time of 360 minutes and temperature of 25°C. After the internal electrolysis process, the values of COD, BOD5, and phenol of the wastewater were 6500, 4850 and 0.1 mg/L, respectively.

Research on dynamics and mechanism of treatment on phenol simulated wastewater by the ultrasound cooperated electro-assisted micro-electrolysis.

In the research, the ultrasound was introduced to the electric-assisted micro-electrolysis system to improve the treatment efficiency of phenol simulated wastewater. The results showed that the phenol removal efficiency was significantly enhanced by the electric-assisted micro-electrolysis method in the presence of ultrasound, which could reach 88.61% under the initial value of pH 4, an iron dosage of 50g/L, a mass ratio of iron/carbon of 1:1, and the initial phenol concentration of 100mg/L. The degradation kinetics of phenol was in accordance with a second-order kinetic model. The synergistic effect of the ultrasonic and electric-assisted micro-electrolysis method was obvious with a synergistic factor at 98.02%. The degradation mechanism of phenol was that the treatment could effectively destroy the benzene ring structure of phenol in the liquid phase with ring-opening reaction and small molecules substances generated. PRACTITIONER POINTS: The article was the pretreatment of coking wastewater. First, the synergistic effects between ultrasound and electrochemical method through the removal ratio of phenol were found. Second, it was showed that the initial pH and applied intensity of voltage had the effects on removal ratio of phenol by the UEME method. Third, the synergy factor (Syn ) between ultrasonic and electrochemical method was 98.02%. Finally, the mechanism of the UEME degradation of phenol was researched. The technology could effectively improve the biodegradability of coking wastewater and provide conditions for subsequent biochemical treatment. So, we thought this article was suitable for the journal.

Iron-carbon could enhance nitrogen removal in Sesuvium portulacastrum constructed wetlands for treating mariculture effluents

This study investigated an Iron–carbon (Fe-C) micro-electrolysis method to enhance nitrogen removal of Sesuvium portulacastrum constructed wetlands (CWs) when treating mariculture effluents. The main objective was to investigate the effects of Fe-C on nitrogen purification performance and microbial characteristics of Sesuvium portulacastrum CWs. Results showed that the presence of Fe-C and Sesuvium portulacastrum could improve nitrogen removal efficiency by 20–30% and 15–30%, respectively. CWs with 33% v/v Fe-C addition performed well on nitrogen removal: TAN, 41.49 ± 13.64%; NO2–-N, 13.32%; NO3–-N, 60.02 ± 6.17%; TIN, 63.40 ± 12.11%. Microbial analysis revealed that Fe-C altered the microbial communities, and improved the abundance of denitrification related genera. Based on microbial enzyme activities and genes abundance, the anammox and denitrification processes were promoted by Fe-C in CWs. These findings indicate that Sesuvium portulacastrum CWs with 33% v/v Fe-C represents an effective nitrogen removal for mariculture wastewater with insufficient carbon source.

Factors influencing hydroquinone degradation in aqueous solution using a modified microelectrolysis method.

The discharge of hydroquinone (HQ), an important chemical raw material, to natural waters poses different ecological threats to aquatic organisms. In this study, we investigated the removal performance of traditional and modified microelectrolysis methods in aqueous solutions. The traditional microelectrolysis packing was modified by adding manganese (Mn), zinc (Zn), and copper (Cu) powder as additives. The factors affecting the removal performance of HQ, such as catalytic metal type, mass fraction of additive, reaction time, and initial pH, were examined. The results showed that the Mn modified packing exhibited the best performance compared to Zn and Cu powder. The removal rate of HQ using Mn modified packing can reach 94% after 4 h. In addition, 9% of Mn packing has a higher removal rate than other mass fractions. The acidic solution pH shows a more favorable degradation than a neutral and alkaline solution. The intermediates of HQ degradation by modified microelectrolysis were identified and then the pathway of HQ degradation was proposed. Our result indicates that Mn as catalytic metal holds promising potential to enhance HQ removal in water using the microelectrolysis method.

Research on Micro-Electrolysis Method to Treat the Copper-Containing Electroplating Wastewater

Iron-carbon micro-electrolysis was applied in the treatment of the electroplating wastewater containing copper, and the parameters that affected the efficiencies of the wastewater treatment had been discussed, The results indicated that the optimal experimental conditions were initial pH 4, stirring speed 100r/min, total mass of iron and carbon 4g/0.1L, iron carbon mass ratio of 1, reaction time was 40min. The removal rate of the Cu2+was 99% or more, the effluent can meet emissions standards

Research on Micro-Electrolysis Method to Treat the Chrome-Containing Steel Wastewater

Iron-carbon micro-electrolysis was applied in the treatment of the steel wastewater containing chromium,The effects of initial pH, stirring speed, Fe /C (quality), reaction time were investigated by single factor experiments. According to the results of the static experiments, the dynamic test is carried out in a fixed bed reactor composed of iron and carbon,the experimental results show that when the flow rate of less than 40ml/min, the system can be continuously stable operation 6h.

Research on Cavitation and Impinging Stream Microelectrolysis Reactor for Treating Organic Wastewater

Starting with the research of the mechanism of treating organic wastewater, this paper found out various factors affecting electrode reaction, generation of hydroxyl free radical and flocculation reaction and the conditions promoting reinforcement of reaction, then associating with the advantage features of cavitation and impinging stream technology for degrading wastewater, it developed the "cavitation and impinging stream microelectrolysis technology", designed a novel structure of cavitation and impinging stream microelectrolysis reactor. In the technique of treating high concentration organic wastewater using microelectrolysis method, the problems of passivation and hardening can be solved by using this reactor with the features of high efficiency, environmental protection, safety, and good economics etc.

Research on the treatment of phosphoric wastewater by ultrasound-assisted microelectrolysis method

In this research work, ultrasound was introduced to the microelectrolysis (ME) method to improve the treatment efficiency for phosphoric wastewater. The effects of treatment time, Fe/C ratio (v/v) and iron filings dosage on the efficiency of phosphorus removal from wastewater with different initial pH values were investigated. The results showed that the phosphorus removal efficiency by the ME method was significantly enhanced in the presence of ultrasound. The maximum removal rate of phosphorus (RRP) for the wastewater with an initial pH value of 4.0 was 92.4% after 60 min of treatment when the Fe/C and Fe/H2O volume ratio were 2/1 and 1/10, respectively. The reaction kinetics analysis indicated that the phosphorus degradation processes for the ultrasonic and ME methods as well as the ultrasonically assisted ME method (UME) were in accordance with the pseudo-first-order kinetic model. The synergetic effect of the combined ultrasound and ME method for phosphorus removal was also studied by reaction kinetics analysis.

Treatment of naphthalene derivatives with iron-carbon micro-electrolysis

The degradation of five naphthalene derivatives in the simulated wastewater was investigated using the iron-carbon micro-electrolysis method. The optimal initial pH of solution and adsorption of iron-carbon and removal efficiency of the total organic carbon(TOC) were investigated. The results show that the removal efficiency of the naphthalene derivatives can reach 48.9%–92.6% and the removal efficiency of TOC is 42.8%–78.0% for the simulated wastewater with 200 mg/L naphthalene derivatives at optimal pH of 2.0–2.5 after 120 min treatment. The degradation of five naphthalene derivatives with the micro-electrolysis shows the apparent first-order kinetics and the order of removal efficiency of the naphthalene derivatives is sodium 2-naphthalenesulfonate, 2-naphthol, 2, 7-dihydroxynaphthalene, 1-naphthamine, 1-naphthol-8-sulfonic acid in turn. It is illustrated that the substituents of the naphthalene ring can affect the removal efficiency of naphthalene due to their electron-withdrawing or electron-donating ability.