Application of coupled zero-valent iron/biochar system for degradation of chlorobenzene-contaminated groundwater

2016 ◽  
Vol 75 (3) ◽  
pp. 571-580 ◽  
Author(s):  
Xu Zhang ◽  
Yanqing Wu
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Ph Value ◽  
Cost Effective ◽  
Zero Valent Iron ◽  
Contaminated Groundwater ◽  
Mass Ratio ◽  
Chlorinated Organic Compounds ◽  
Initial Ph ◽  
Chlorinated Organic

A novel iron-carbon micro-electrolysis system, bamboo-derived biochar coupled with zero-valent iron (ZVI), was investigated for chlorobenzene (CB)-contaminated groundwater removal. Influences of initial pH value, mass ratio of the ZVI/Biochar, initial CB concentration and ionic strength of the ZVI/Biochar micro-electrolysis were studied. The results indicated that the increase of initial pH led to the decrease of the CB removal efficiency. While the optimum mass ratio of ZVI to biochar was 2:1, the improved initial concentration and reaction time were 33.68 mg/L and 4 h, respectively. When pH of 2, mass ratio of 2:1 and reaction time of 4 h were applied, the CB removal efficiency was 99.92%. Enhanced degradation of CB was observed with increased Cl− concentration. When the Cl− concentration of 1,000 mg/L and reaction time of 1 h were applied, the CB removal efficiency arrived at 98.2%. Additionally, considering that biochar is cost-effective and readily produced, the coupled ZVI/Biochar micro-electrolysis could represent an effective approach for the treatment of groundwater containing chlorinated organic compounds in the future.

Degradation of bromamine acid by nanoscale zero-valent iron (nZVI) supported on sepiolite

2012 ◽  
Vol 66 (12) ◽  
pp. 2539-2545 ◽  
Author(s):  
Xuening Fei ◽  
Lingyun Cao ◽  
Lifeng Zhou ◽  
Yingchun Gu ◽  
Xiaoyang Wang
Keyword(s):  
Ph Value ◽  
Energy Dispersive Spectrometer ◽  
Zero Valent Iron ◽  
Mass Ratio ◽  
Initial Concentration ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Initial Ph ◽  
Set Up

Sepiolite, a natural nano-material, was chosen as a carrier to prepare supported nanoscale zero-valent iron (nZVI). The effects of preparation conditions, including mass ratio of nZVI and activated sepiolite and preparation pH value, on properties of the supported nZVI were investigated. The results showed that the optimal mass ratio of nZVI and sepiolite was 1.12:1 and the optimal pH value was 7. The supported nZVI was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS), and furthermore an analogy model of the supported nZVI was set up. Compared with the nZVI itself, the supported nZVI was more stable in air and possessed better water dispersibility, which were beneficial for the degradation of bromamine acid aqueous solution. The degradation characteristics, such as effects of supported nZVI dosage, initial concentration and initial pH value of the solution on the decolorization efficiency were also investigated. The results showed that in an acidic environment the supported nZVI with a dosage of 2 g/L showed high activity in the degradation of bromamine acid with an initial concentration of 1,000 mg/L, and the degree of decolorization could reach up to 98%.

Treatment of Pharmaceutical Wastewater by Micro-Electrolysis and Fenton Oxidation Process

2011 ◽  
Vol 356-360 ◽  
pp. 1622-1625 ◽  
Author(s):  
Chong Hao Huang ◽  
Meng Xing Cao ◽  
Jun Hong Luo ◽  
Chao Zhang
Keyword(s):  
Reaction Time ◽  
Oxidation Process ◽  
Ph Value ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Fenton Process ◽  
Mass Ratio ◽  
Pharmaceutical Wastewater ◽  
Initial Ph ◽  
Fenton Oxidation Process

Pharmaceutical wastewater was treated by micro-electrolysis and Fenton process.The aim of this research was to optimize operating parameters in micro-electrolysis and Fenton process. Effectiveness of important process parameters such as mass ratio of iron to carbon, the initial pH, reaction time and H2O2 dosage on the performance of micro-electrolysis and Fenton process were investigated. The results show that the removal efficiency of pharmaceutical wastewater chemical oxygen demand (COD) could reach 37.3% at the optimal pH of 4 with the iron to carbon ratio of 1:1 after 80 min treatment. The operating conditions of Fenton process are 0.5% of H2O2 dosage, the pH value of 4 and the reaction time of 180 min. The pharmaceutical wastewater COD removal could reach 79.4%.

Treatment of Sodium Formate Wastewater by Fenton Oxidation Process

2012 ◽  
Vol 573-574 ◽  
pp. 627-630
Author(s):  
Zhi Gang Chen ◽  
Rui Xue Zhang ◽  
Bo Zhang ◽  
An Ping Wei
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Oxidation Process ◽  
Ph Value ◽  
Sodium Formate ◽  
Cod Removal ◽  
Fenton Oxidation ◽  
Fenton Process ◽  
Initial Ph ◽  
Fenton Oxidation Process

In this study, in order to reduce the sodium formate concentration thereby reducing toxicity, the treatment of this wastewater by Fenton process was investigated. The effects of initial PH value, reaction time, concentration of FeSO4• 7H2O, and H2O2 dosage on the removal efficiency of COD were studied respectively. The experiment results show that when using Fenton oxidization pretreatment process, with pH 2.0, FeSO4•7H2O concentration 4000mg/L, H2O2(30 % ) portion 4ml/L, and reaction time 20min, COD removal efficiency was more than 50%, oxidization efficiency was good.

scholarly journals Efficient Sequestration of Hexavalent Chromium by Graphene-Based Nanoscale Zero-Valent Iron Composite Coupled with Ultrasonic Pretreatment

2021 ◽  
Vol 18 (11) ◽  
pp. 5921
Author(s):  
Haiyan Song ◽  
Wei Liu ◽  
Fansheng Meng ◽  
Qi Yang ◽  
Niandong Guo
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Inhibitory Effect ◽  
Ultrasonic Cavitation ◽  
Zero Valent Iron ◽  
Ultrasonic Pretreatment ◽  
Nanoscale Zero Valent Iron ◽  
Passivation Layers ◽  
Initial Ph ◽  
Two Phases

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI (nZVI/rGO) composites coupled with ultrasonic (US) pretreatment were studied to solve the above problems and conduct the experiments of Cr(VI) removal from an aqueous solution. SEM-EDS, BET, XRD, and XPS were performed to analyze the morphology and structures of the composites. The findings showed that the removal efficiency of Cr(VI) in 30 min was increased from 45.84% on nZVI to 78.01% on nZVI/rGO and the removal process performed coupled with ultrasonic pretreatment could greatly shorten the reaction time to 15 min. Influencing factors such as the initial pH, temperature, initial Cr(VI) concentration, and co-existing anions were studied. The results showed that the initial pH was a principal factor. The presence of HPO42−, NO3−, and Cl− had a strong inhibitory effect on this process, while the presence of SO42− promoted the reactivity of nZVI/rGO. Combined with the above results, the process of Cr(VI) removal in US-nZVI/rGO system consisted of two phases: (1) The initial stage is dominated by solution reaction. Cr(VI) was reduced in the solution by Fe2+ caused by ultrasonic cavitation. (2) In the following processes, adsorption, reduction, and coprecipitation coexisted. The addition of rGO enhanced electron transportability weakened the influence of passivation layers and improved the dispersion of nZVI particles. Ultrasonic cavitation caused pores and corrosion at the passivation layers and fresh Fe0 core was exposed, which improved the reactivity of the composites.

Effects of operational parameters on defluoridation efficiency using electrocoagulation process

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
M. Behbahani ◽  
M.R. Alavi Moghaddam ◽  
M. Arami
Keyword(s):  
Reaction Time ◽  
Anode Material ◽  
Removal Efficiency ◽  
Fluoride Concentration ◽  
Fluoride Removal ◽  
Operational Parameters ◽  
Applied Current ◽  
Initial Ph ◽  
Electrocoagulation Process ◽  
Electrode Connection

The aim of this study is to examine the effect of operational parameters on fluoride removal using electrocoagulation method. For this purpose, various operational parameters including initial pH, initial fluoride concentration, applied current, reaction time, electrode connection mode, anode material, electrolyte salt, electrolyte concentration, number of electrodes and interelectrode distance were investigated. The highest defluoridation efficiency achieved at initial pH 6. In the case of initial fluoride concentration, maximum removal efficiency (98.5%) obtained at concentration of 25mg/l. The increase of applied current and reaction time improved defluoridation efficiency up to 99%. The difference of fluoride removal efficiencies between monopolar and bipolar series and monopolar parallel were significant, especially at reaction time of 5 min. When aluminum used as anode material, higher removal efficiency (98.5%) achieved compared to that of iron anode (67.7%). The best electrolyte salt was NaCl with the maximum defluoridation efficiency of 98.5% compared to KNO3 and Na2SO4. The increase of NaCl had no effect on defluoridation efficiency. Number of electrodes had little effect on the amounts of Al3+ ions released in the solution and as a result defluoridation efficiency. Almost the same fluoride removal efficiency obtained for different interelectrode distances.

scholarly journals Comparison of sorption efficiency of natural and MnO2 coated zeolite for copper removal from model solutions

2021 ◽  
Vol 900 (1) ◽  
pp. 012003
Author(s):  
M Balintova ◽  
Z Kovacova ◽  
S Demcak ◽  
Y Chernysh ◽  
N Junakova
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Ph Value ◽  
Batch Experiments ◽  
Modified Zeolite ◽  
Optimum Ph ◽  
Removal Of Heavy Metals ◽  
Initial Ph ◽  
Correlation Factors ◽  
Maximum Removal

Abstract Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0.

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.

Effect of Environment Factors on Phosphorus Removal Efficiency of Phosphate Reduction System

2011 ◽  
Vol 255-260 ◽  
pp. 2797-2801
Author(s):  
Chen Yao ◽  
Chun Juan Gan ◽  
Jian Zhou
Keyword(s):  
Removal Efficiency ◽  
Phosphorus Removal ◽  
Ph Value ◽  
Removal Rate ◽  
Mass Rearing ◽  
Phosphate Removal ◽  
Environment Factors ◽  
Reduction System ◽  
Initial Ph ◽  
The Impact

Effect of environment factors such as initial pH value, dissolved oxygen (DO) and temperature on phosphorus removal efficiency of phosphate reduction system was discussed in treating pickled mustard tube wastewater. Results indicate that environment factors have significant influence on dephosphorization efficiency. And, the impact of DO on phosphate reduction is mainly by affecting the distribution of micro-environment inner biofilm, manifest as phosphate removal rate decreased with a fall in DO concentration, while overhigh DO can lead to detachment of biofilm, thus causing the increase of effluent COD concentration, and so DO need to be controlled in the range of 6 mg/L. Moreover, a higher temperature is more beneficial to phosphorus removal by PRB. Unfortunately, exorbitant temperature can result in mass rearing of Leuconostoc characterized with poor flocculability in reactor, and that cause turbidity in effluent appeared as a rise in COD of effluent. Hence, the optimal temperature is found to be about 30°C.

Isolation and Degradation Characterization of Trichloroethylene-Degrading Bacteria

2012 ◽  
Vol 610-613 ◽  
pp. 3136-3139
Author(s):  
Hui Xing Liang
Keyword(s):  
Fermentation Medium ◽  
Chlorinated Organic Compounds ◽  
Degradation Temperature ◽  
Degrading Bacteria ◽  
Initial Ph ◽  
Chlorinated Organic ◽  
Bacterium Strain ◽  
Rotary Speed ◽  
Degradation Time

Trichloroethylene is one of chlorinated organic compounds widely used as a solvent and degreasing agent in industry. Because of uninformed disposal in the past, trichloroethylene has become one of major contaminant in environment, and this situation has brought about a serious public concern for its toxicity. A promising approach to solving this problem is bioremediation using degrading-bacteria. A bacterium(strain TC-1) was isolated from environment, which could degrade trichloroethylene. It was preliminary identified as the genus of Sporosarcina sp.. The results showed that the optimal degradation temperature, degradation time, rotary speed and the initial pH of fermentation medium were 25°C, 60 h, 180 rpm and 7.5 respectively, the ratio of degradation reached 95.56% under this conditions.

Fe0/Zn0 PRB Technology for the Remediation of PCBs Contaminated Groundwater

2013 ◽  
Vol 295-298 ◽  
pp. 1364-1367 ◽  
Author(s):  
Jun Du ◽  
Yuan Yuan Liu ◽  
Xue Qing Zhang ◽  
Ming Ying Qiu ◽  
Lan Ying Zhang ◽  
...  
Keyword(s):  
Ph Value ◽  
Iron Concentration ◽  
Effective Porosity ◽  
Zero Valent Iron ◽  
Contaminated Groundwater ◽  
Reactive Medium ◽  
Set Up

The vast majority of PRB currently in use utilize zero valent iron (ZVI) as the reactive medium. In this paper, three laboratory columns were set up and operated under conditions simulating those anticipated in the groundwater to investigate the feasibility and efficiency of the enhanced Fe0 PRB for the remediation of the PCBs contaminated groundwater. Operating under 10°C and an effective porosity of 61% to 67% and infiltration velocity of groundwater of 0.7 to 0.8m•d-1, the average iron concentration of effluent was 0.241mg•L-1, 0.129mg•L-1 and 0.201mg•L-1, respectively, and the average dechlorination efficiency reached 49.6%, 72.6% and 58.6%, respectively, the Fe0/Zn0 based columns can accomplish 94% of PCBs removal and pH value raised from 6.87 to 10.2. Comprehensive consideration suggested that Fe0/Zn0 based PRB technology is feasible for the remediation of PCBs contaminated groundwater.

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