The catalytic oxidation of malachite green by the microwave-Fenton processes

2010 ◽  
Vol 62 (6) ◽  
pp. 1304-1311 ◽  
Author(s):  
Huaili Zheng ◽  
Huiqin Zhang ◽  
Xiaonan Sun ◽  
Peng Zhang ◽  
Tiroyaone Tshukudu ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Malachite Green ◽  
Removal Rate ◽  
Operating Conditions ◽  
Dominant Factor ◽  
Optimum Operating ◽  
Fenton Process ◽  
Confirmatory Tests ◽  
Initial Ph ◽  
Cod Removal Rate

Catalytic oxidation of malachite green using the microwave-Fenton process was investigated. 0% of malachite green de-colorization using the microwave process and 23.5% of malachite green de-colorization using the Fenton process were observed within 5 minutes. In contrast 95.4% of malachite green de-colorization using the microwave-Fenton was observed in 5 minutes. During the microwave-Fenton process, the optimum operating conditions for malachite green de-colorization were found to be 3.40 of initial pH, 0.08 mmol/L of Fe2 +  concentration and 12.5 mmol/L of H2O2 concentration. Confirmatory tests were carried out under the optimum conditions and the COD removal rate of 82.0% and the de-colorization rate of 99.0% were observed in 5 minutes. The apparent kinetics equation of −dC/dt = 0.0337 [malachite green]0.9860[Fe2 + ]0.8234[H2O2]0.1663 for malachite green de-colorization was calculated, which implied that malachite green was the dominant factor in determining the removal efficiency of malachite green based on microwave-Fenton process.

scholarly journals Catalytic Ozonation for Effective Degradation of Coal Chemical Biochemical Tail Water by Mn/Ce@RM Catalyst

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 206
Author(s):  
Yicheng Wang ◽  
Yingkun Wang ◽  
Xi Lu ◽  
Wenquan Sun ◽  
Yanhua Xu ◽  
...  
Keyword(s):  
Reaction Time ◽  
Removal Rate ◽  
Catalytic Ozonation ◽  
Operating Conditions ◽  
Cod Removal ◽  
X Ray ◽  
Initial Ph ◽  
Catalyst Dosage ◽  
Cod Removal Rate ◽  
Tail Water

An Mn/Ce@red mud (RM) catalyst was prepared from RM via a doping–calcination method. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used to characterize the surface morphology, crystal morphology, and elemental composition of the Mn/Ce@RM catalyst, respectively. In addition, preparation and catalytic ozonation conditions were optimized, and the mechanism of catalytic ozonation was discussed. Lastly, a fuzzy analytic hierarchy process (FAHP) was adopted to evaluate the degradation of coal chemical biochemical tail water. The best preparation conditions for the Mn/Ce@RM catalyst were found to be as follows: (1) active component loading of 3%, (2) Mn/Ce doping ratio of 2:1, (3) calcination temperature of 550 °C, (4) calcination time of 240 min, and (5) fly ash floating bead doping of 10%. The chemical oxygen demand (COD) removal rate was 76.58% under this preparation condition. The characterization results suggested that the pore structure of the optimized Mn/Ce@RM catalyst was significantly improved. Mn and Ce were successfully loaded on the catalyst in the form of MnO2 and CeO2. The best operating conditions in the study were as follows: (1) reaction time of 80 min, (2) initial pH of 9, (3) ozone dosage of 2.0 g/h, (4) catalyst dosage of 62.5 g/L, and (5) COD removal rate of 84.96%. Mechanism analysis results showed that hydroxyl radicals (•OH) played a leading role in degrading organics in the biochemical tail water, and adsorption of RM and direct oxidation of ozone played a secondary role. FAHP was established on the basis of environmental impact, economic benefit, and energy consumption. Comprehensive evaluation by FAHP demonstrated that D3 (with an ozone dosage of 2.0 g/H, a catalyst dosage of 62.5 g/L, initial pH of 9, reaction time of 80 min, and a COD removal rate of 84.96%) was the best operating condition.

scholarly journals Ti/RuO2-IrO2-SnO2 Anode for Electrochemical Degradation of Pollutants in Pharmaceutical Wastewater: Optimization and Degradation Performances

2020 ◽  
Vol 13 (1) ◽  
pp. 126
Author(s):  
Guozhen Zhang ◽  
Xingxing Huang ◽  
Jinye Ma ◽  
Fuping Wu ◽  
Tianhong Zhou
Keyword(s):  
Removal Rate ◽  
Inorganic Compounds ◽  
Oxide Coating ◽  
X Ray Diffraction ◽  
Pharmaceutical Wastewater ◽  
High Concentration ◽  
Dimensionally Stable Anodes ◽  
X Ray ◽  
Initial Ph ◽  
Cod Removal Rate

Electrochemical oxidation technology is an effective technique to treat high-concentration wastewater, which can directly oxidize refractory pollutants into simple inorganic compounds such as H2O and CO2. In this work, two-dimensionally stable anodes, Ti/RuO2-IrO2-SnO2, have been developed in order to degrade organic pollutants from pharmaceutical wastewater. Characterization by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) showed that the oxide coating was successfully fabricated on the Ti plate surface. Electrocatalytic oxidation conditions of high concentration pharmaceutical wastewater was discussed and optimized, and the best results showed that the COD removal rate was 95.92% with the energy consumption was 58.09 kW·h/kgCOD under the electrode distance of 3 cm, current density of 8 mA/cm2, initial pH of 2, and air flow of 18 L/min.

The treatment of zinc-cyanide electroplating rinse water using an electrocoagulation process

2013 ◽  
Vol 68 (10) ◽  
pp. 2220-2227 ◽  
Author(s):  
Elif Senturk
Keyword(s):  
Electrode Material ◽  
Operating Time ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Operating Parameters ◽  
Initial Ph ◽  
Electrocoagulation Process ◽  
Removal Efficiencies ◽  
Rinse Water ◽  
Electrode Connection

This paper investigates the treatment of zinc-cyanide electroplating rinse water using an electrocoagulation process (ECP). The effects of operating parameters such as electrode material, current density (2.5–40 A/m2), operating time (0–60 min), initial pH (5–12) and electrode connection mode (monopolar parallel (MP-P), monopolar series and bipolar series) on the ECP were evaluated to find the optimum operating conditions. At 20 A/m2, 60 min, the highest removal efficiencies were obtained with 85 and 99% for Fe and 64 and 33% for Al electrodes, for cyanide and zinc, respectively. The optimum operating conditions were found to be 30 A/m2 and 40 min, for the Fe electrode at the original pH (9.5) of the rinse water. Considering efficiency and economy, the MP-P connection mode was determined as the optimum connection mode.

Synergetic Degradation of Zidovudine Wastewater by Ultrasonic and Iron-Carbon Micro-Electrolysis

2011 ◽  
Vol 347-353 ◽  
pp. 1949-1952 ◽  
Author(s):  
Liang Li ◽  
Bing Zhe Xu ◽  
Chang Yu Lin ◽  
Xiao Min Hu
Keyword(s):  
Reaction Time ◽  
Degradation Rate ◽  
Removal Rate ◽  
Cod Removal ◽  
Mass Ratio ◽  
Initial Ph ◽  
Cod Removal Rate

Zidovudine wastewater is difficult to biodegradation due to high COD and toxicity. The synergetic treatment of Zidovudine wastewater by Ultrasonic and iron-carbon micro-electrolysis technology was studied. The influence of initial pH, reaction time, mass ratio of iron and carbon and mass ratio of iron and water on degradation rate of COD was researched. The result showed that the COD removal rate was only about 54.3% and the degradation speed is very slow when iron-carbon micro-electrolysis treated Zidovudine wastewater　separately. However, when ultrasonic synergy micro-electrolysis to treat Zidovudine wastewater, the COD removal rate could was up to 85% and the reaction time was also decreased. Moreover, the BOD5 / COD rose from 0.15 to 0.35, which meant the wastewater became easily biodegradable.

The pretreatment of acrylonitrile and styrene with the ozonation process

1997 ◽  
Vol 36 (2-3) ◽  
pp. 263-270 ◽  
Author(s):  
Cheng-Nan Chang ◽  
Jih-Gaw Lin ◽  
Allen C. Chao ◽  
Bo-Chuan Cho ◽  
Ruey-Fang Yu
Keyword(s):  
Organic Nitrogen ◽  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Acrylonitrile Butadiene Styrene ◽  
Ozone Treatment ◽  
Oxidation Reduction ◽  
Initial Ph ◽  
Cod Removal Rate ◽  
Ozonation Process

Acrylonitrile and styrene are used as the raw materials for manufacturing acrylic fiber, thus they are often found as pollutants in the petrochemical wastewater. This study utilizes ozone to decompose the organic nitrogen contained in acrylonitrile and styrene, and the oxidation process was monitored using on-line measurements of oxidation-reduction potential (ORP) and pH. The efficiency of organic nitrogen decomposition was also estimated based on the COD, organic nitrogen, TOC, ammonia-N, nitrite, and nitrate measurements. Both the initial pH and alkalinity are observed to affect the degradation rate of organic nitrogen. The acrylonitrile sample with the lowest initial pH value (i.e., 4.0) has a shorter t1/2 of 18.9 min and that for samples of the highest initial pH (i.e., 11) was 34 min. The alkalinity of one acrylonitrile sample was boosted by adding 500 mg/l CaCO3, to simulate the field ABS (Acrylonitrile-Butadiene-Styrene) wastewater effluent. It was observed that within a short ozone contact time, the acrylonitrile sample spiked with 500 mg/l CaCO3 had the highest COD decomposition rate of 0.411 min−1, or 1.3 times more than that for samples without addition of CaCO3. Results of the ozonation process can be fitted with a modified Nernst equation for the various pH conditions. Additionally, the ozone treated synthetic ABS sample shows a faster COD removal rate in the subsequent biological process than those samples without ozone treatment.

Research on Low Concentration Municipal Wastewater Removal Rate with Chemical-Biological Flocculation and Suspended Medium Process

2012 ◽  
Vol 599 ◽  
pp. 387-390
Author(s):  
Xing Yu Bian ◽  
Xing Sheng Kang ◽  
Yi Li ◽  
Yu Lin Sun ◽  
Min Kong ◽  
...  
Keyword(s):  
Municipal Wastewater ◽  
Removal Rate ◽  
Pilot Scale ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Optimal Operating ◽  
Operational Parameter ◽  
Low Concentration ◽  
Scale Test

In this paper, chemical and biological flocculation and suspended medium process was applied to treat low concentration municipal wastewater in a pilot scale test in order to find the optimum operational parameter. The results showed that: system on pollutant removal mainly on chemical and biological flocculation reaction pool, Under the optimal operating condition, CODCr, TP and SS removal efficiencies reached 75.5％, 76％and 90.5％ respectively, and the CODCr, TP, SS concentrations of effluent meet the National Wastewater Integrated Discharge Standard. The optimum operating conditions according to the local actual situation, running for more than half a year, for the optimization of control parameters for the contrast obtained.

Removal of Organic Pollutants from Reverse Osmosis Concentrate by Electro-Fenton Process

2014 ◽  
Vol 955-959 ◽  
pp. 2294-2299 ◽  
Author(s):  
Hui Ling Du ◽  
Bao Yuan Pan ◽  
Jing Li
Keyword(s):  
Organic Pollutants ◽  
Pulse Generator ◽  
Treatment Time ◽  
Removal Rate ◽  
High Voltage Pulse ◽  
Aeration Rate ◽  
Cod Removal ◽  
Fenton Process ◽  
Voltage Pulse Generator ◽  
Cod Removal Rate

The RO concentrate containing non-degradation organic pollutants was treated by electro-Fenton process. The high voltage pulse generator was used as discharge power. The effects of pulsed electric field parameters, aeration rate and pH on COD removal rate was investigated. The results indicate that the COD removal rate is up to 80.71% when pulsed voltage, pulsed frequency, treatment time, aeration rate and pH are 30000 V, 5 Hz, 240 s, 1.0 m3/h and 10, respectively.

scholarly journals Electrocoagulation for ammonium removal in Nam Son landfill leachate

2017 ◽  
Vol 33 (2) ◽  
Author(s):  
Thanh Son Le ◽  
Khải Cao Lê ◽  
Hà Thị Nguyễn ◽  
Linh Tuấn Đoàn ◽  
Anh Thị Đoàn
Keyword(s):  
Landfill Leachate ◽  
Operating Time ◽  
Operating Conditions ◽  
Current Intensity ◽  
Optimum Operating ◽  
Applied Current ◽  
Ammonium Removal ◽  
Treatment Performance ◽  
Iron Electrodes ◽  
Initial Ph

In this paper, an electrocoagulation reactor was set up to investigate the ammonium removal in Nam Son landfill leachate. The research focused on studying several factors that affect to the ammonium removal namely current intensity, operating time, initial pH and electrode materials. Mono-polar electrocoagulation reactor was conducted in a batch system with iron electrodes and 1.8 L leachate. The research indicated that current intensity and operating time are directly proportional with NH4+ treatment performance. When applied current increased from 1 to 4A, the NH4+ removal percentage went up from 14.03 to 24.99% after a 1 hour treatment. The effect of initial pH in range of 5 to 10 has showed that the best NH4+ treatment efficiency in neutral and mild alkaline conditions. It is noticeable that iron electrodes had higher NH4+ removal than aluminum one during nearly the first 40 min, however this trend has been reversed later with the advantage belonging to aluminum anode. The optimum operating conditions found are aluminum electrodes, applied current of 3A, electrolysis time of 60 min, raw pH of 8, resulting in NH4+ treatment performance of approximately 24%. As a result, the electrocoagulation method is not really effective in NH4+ removal and might be applied as a pre-treatment.

scholarly journals Kinetic Modelling and Determination of Octyl Phenol Ethoxylate (OPE) and Bisphenol A (BPA) (used as plastic additives) Inhibition Constants for Nitrogen Conversion

2021 ◽  
Keyword(s):  
Kinetic Model ◽  
Bisphenol A ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Kinetic Modelling ◽  
Ammonium Nitrogen ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Octyl Phenol ◽  
Inhibition Constants

<p>Conversion of ammonia to nitrate is sensitive to a number of inhibitors. There is limited information on the nitrification inhibition coefficient and kinetic model in the current literature. Octyl Phenol Ethoxylate (OPE) and Bisphenol A (BPA) inhibition constants were found in nitrogen removal using an activated sludge system. Firstly, OPE and BPA free wastewater was used to determine the optimum operating conditions. The effect of OPE and BPA concentration on system performance was investigated. The ammonium removal rate was less affected by lower OPE and BPA concentrations. When the BPA and OPE concentrations were increased from 0 mg/L to 30 mg/L, the outlet ammonium nitrogen concentrations were increased respectively from 2.8 mg/L to 49.8 mg/L and from 2.6 mg/L to 20.40 mg/L. Due to the inhibition created by these compounds on Nitrobacter, nitrite nitrogen increased in the medium. As the OPE and BPA concentrations increased, the conversion rate of the ammonium nitrogen into nitrate decreased. Based on the experimental results, a kinetic model was developed, and the OPE and BPA inhibition constants (KOPE and KBPA) were found to be 40.7 mg/L and 11.76 mg/L, respectively. In nitrogen removal, BPA created a higher inhibition effect in comparison to OPE.</p>

scholarly journals Treatment of industrial electroplating wastewater for metals removal via electrocoagulation continous flow reactors

2022 ◽  
Author(s):  
Hussein I. Abdel-Shafy ◽  
Rehan M. M. Morsy ◽  
Mahmoud A. I. Hewehy ◽  
Taha M. A. Razek ◽  
Maamoun M. A. Hamid
Keyword(s):  
Stainless Steel ◽  
Ferric Chloride ◽  
Contact Time ◽  
Removal Rate ◽  
Operating Conditions ◽  
Synthetic Wastewater ◽  
Optimum Operating ◽  
Chemical Coagulation ◽  
Electroplating Wastewater ◽  
Metals Removal

Abstract A real industrial electroplating rinsing wastewater was collected and subjected the physical and chemical examination. The study showed that it can be categorized as high strength wastewater, at pH- 2, COD 1430 mg/l, and high level of metals above permissible limits namely: 150, 30, 25, and 2.9 for Ni, Cu, Zn, and Fe mg/l respectively. Therefore, metals must be adequately removed before discharging to avoid any hazardous impact on the environment. Similar synthetic wastewater was prepared to study effect of chemical coagulation for the precipitation of metals. The optimum removal rate was achieved by using a combination of lime and ferric chloride at 100 and 30 mg/l respectively. The chemically treated electroplating wastewater was subjected to an electrocoagulation study. A comparison between iron and stainless-steel electrodes for the removal of metals was investigated. Furthermore, the effect of different electric voltage, and the contact time on metals removal efficiency were also examined. It was found that the optimum removal capacity was achieved when stainless steel electrode was employed in the presence of ferric chloride as coagulant, at 10 volts, 30 min. contact time, and pH 9 for synthetic solution. In a batch treatment system, the real industrial wastewater was treated at the predetermined optimum operating conditions; the removal of metals was 92.1%, 87.8% and 82.9% for Ni. Zn, and Cu respectively. By employing a continuous flow reactor for the treatment of the same real wastewater and under the same operating conditions; metals removal rate increased to 98.9%, 97.4% and 96.6% for Ni. Zn, and Cu respectively. The level of metals in the final treated wastewater copes with Egyptian Environmental Regulation. The overall results confirmed that the electro-coagulation (EC) technology offers an effective alternative process in combination with the conventional chemical coagulation process for reaching high removal performance of toxic metals from the electroplating wastewater. The advantage of EC technique is achieving high treatment efficiency instead of expensive chemical reagents, high construction cost and/or other conventional processes. In addition, the final treated water can be reused for rinsing process in electroplating industry and/or discharging without any environmental hazard effect. It is also recommended to employ solar energy instead of electricity to reduce cost of operation.

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