Testing Permeable Reactive Barrier Media for Remediation of Uranium Plumes in Groundwater

2001 ◽  
Author(s):  
Dirk Mallants ◽  
Hugo Moors ◽  
Lian Wang ◽  
Norbert Maes ◽  
Hildegarde Vandenhove ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Removal Efficiency ◽  
Dissolved Inorganic Carbon ◽  
Cost Effective ◽  
Permeable Reactive Barriers ◽  
Zero Valent Iron ◽  
Permeable Reactive Barrier ◽  
Carbonate Content ◽  
Equilibration Time ◽  
Reactive Materials

Abstract In-situ treatment of contaminated groundwater by means of permeable reactive barriers (PRBs) is becoming a cost-effective remediation technique. Various reactive materials that might be used in PRBs were tested in their ability to remove uranium from groundwater. Materials tested include ferric oxyhydroxides, coarse- and fine-grained zero-valent iron, aluminium-iron oxides, and zeolites. Batch tests were used to evaluate the removal efficiency of these materials. To analyse the effect of groundwater composition on the interaction between dissolved uranium and reactive materials, two types of groundwater were used, mainly differing in carbonate content and pH. Considering an equilibration time of 48 hours and initial uranium concentrations between 2.4 and 24 mg/1, finegrained zero-valent iron proved to be most effective with a uranium removal efficiency of more than 96% for carbon-rich groundwater and 99% for carbon-poor groundwater. Intermediate efficiency was observed for coarsegrained zero-valent iron and aluminium-iron oxides. Less than 10% of the dissolved uranium was adsorbed on the iron oxyhydroxides. Zeolites did not remove any uranium from solution. Results further indicated a positive correlation between dissolved inorganic carbon content and dissolved uranium at equilibrium. Because it can be easily obtained at a fairly low price, zero-valent iron is a promising material for use in PRBs.

scholarly journals Application of permeable reactive barriers near roads for chloride ions removal

2010 ◽  
Vol 42 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Joanna Fronczyk ◽  
Katarzyna Pawluk ◽  
Marta Michniak
Keyword(s):  
Activated Carbon ◽  
Chloride Ions ◽  
Permeable Reactive Barriers ◽  
Zero Valent Iron ◽  
Permeable Reactive Barrier ◽  
Polluted Water ◽  
Reactive Material ◽  
Reactive Materials ◽  
Run Off ◽  
Reactive Barriers

Application of permeable reactive barriers near roads for chloride ions removal One of the most critical sources of pollutants are road run-offs. Road run-off is a complex mixture of toxicants e.g. heavy metals, de-icing agents, organic compounds and water suspensions of solid substances. One of the most negative impact on the environment has sodium chloride which is used as de-icing agent. In the case of incorrect environment protection in the vicinity of roads pollutants may migrate to groundwater causing hazard to sources of potable water. One of the methods to prevent the migration of pollutants to groundwater is imposing the flow of polluted water through a reactive material filling a permeable reactive barrier (PRB). This paper examines the feasibility of selected reactive materials for the reduction chlorides concentration in road run-offs. Four different reactive materials: zero valent-iron, activated carbon, zeolite and geza rock have been chosen for studies. The tests results indicated that the most popular reactive materials used in PRB technology, activated carbon and zero-valent iron, removed exhibited the highest efficiency in chloride ions removal. Moreover, the composition of road run-off in samples collected along roads in Warsaw was determinated.

scholarly journals Remediation of 4-Nitroaniline by Plaster-Based Permeable Reactive Barriers Containing Zero Valent Iron (ZVI): Precast Plaster Retaining Wall Blocks for Environmental Applications

2021 ◽  
Author(s):  
saliha boudia ◽  
farida fernane ◽  
patrick j sharrock ◽  
marina m.l. fiallo
Keyword(s):  
Retaining Wall ◽  
Retaining Walls ◽  
Permeable Reactive Barriers ◽  
Zero Valent Iron ◽  
Permeable Reactive Barrier ◽  
Chemical Degradation ◽  
Metal Particles ◽  
Environmental Applications ◽  
Reactive Barrier ◽  
Vis Spectroscopy

Abstract Permeable reactive barrier (PRB) containing zero valent iron (ZVI), plaster and additives to make a porous composite structure was tested to remove an organic nitro compound as model pollutant. An aqueous solution of 4-nitroaniline (PNA) was passed through a porous plaster composite column and chemical degradation quantified by UV-Vis spectroscopy. PNA was reduced to p-phenylenediamine and the rate of the reduction was strongly related to ZVI amount, pollutant volume, and the contact rate with metal particles. The parameters could be controlled by reactor design and operation. The columns were made to test the materials for making precast plaster blocks containing ZVI. The results showed that such porous plaster blocks could be efficient as retaining walls for environmental applications.

scholarly journals Assessment of optimum width and longevity of a permeable reactive barrier installed in an acid sulfate soil terrain

2015 ◽  
Vol 52 (7) ◽  
pp. 999-1004 ◽  
Author(s):  
Udeshini Pathirage ◽  
Buddhima Indraratna
Keyword(s):  
Groundwater Flow ◽  
Residence Time ◽  
Cost Effective ◽  
Permeable Reactive Barriers ◽  
Permeable Reactive Barrier ◽  
Reactive Material ◽  
Reactive Barrier ◽  
Acidic Groundwater ◽  
Different Types ◽  
Optimum Width

Removal of contaminants from groundwater using permeable reactive barriers (PRBs) is a cost-effective and popular engineering solution used throughout the world. Dissolved pollutants in groundwater are removed through geochemical processes that make PRBs effective for different types of contaminants. In achieving this, it is vital to determine the optimum width of the PRB to allow adequate residence time within the barrier and to establish its longevity. For this purpose, both field monitoring and geochemical modelling were conducted for a trial PRB located in the Shoalhaven Floodplain, south of Wollongong in Australia. In this study, the optimum PRB width is evaluated numerically, based on the neutralization effectiveness, i.e., when acidic groundwater travels through the alkaline PRB. A model developed previously has been extended considering the residence time, reaction kinetics, mineral precipitation–induced reduction in porosity and hydraulic conductivity, influent concentrations of the contaminants, and groundwater flow velocity. Longevity of the PRB is determined with respect to groundwater flow rates and amount of reactive material consumed.

scholarly journals Remediation of Multiply Contaminated Ground via Permeable Reactive Barrier and Electrokinetic Using Recyclable Food Scrap Ash (FSA)

2020 ◽  
Vol 10 (4) ◽  
pp. 1194
Author(s):  
Dongchan Kim ◽  
Junggeun Han
Keyword(s):  
Heavy Metal ◽  
Acetic Acid ◽  
Removal Efficiency ◽  
Organic Contaminants ◽  
Contaminated Soils ◽  
Permeable Reactive Barriers ◽  
Permeable Reactive Barrier ◽  
Contaminant Removal ◽  
Copper Adsorption ◽  
Reactive Barrier

A study of the application of electrokinetic (EK) remediation and Permeable Reactive Barriers (PRB) using recyclable Foods Scrap Ash (FSA) in multiple contaminated soils was carried out. An FSA was chosen as a PRB fill material due to its highly efficient capacity for contaminant removal. Acetic acid and Brij30 were used as enhancers on copper and phenanthrene, respectively, to improve EK remediation performance in removing the heavy metal and organic contaminants. Copper adsorption in PRB was so substantial that the confirmed removal efficiency was 83.86–90.17% and the remaining amount was 105–212 mg. While a high removal efficiency of acetic acid was observed on copper in multiple contamination soils; the removal of phenanthrene was hardly detected and the recovery rate of the contaminant was low during pretreatment. Therefore; an additional study of pretreatment on the phenanthrene-contaminated kaolinite needs to be performed.

scholarly journals Color removal efficiency of rice husk biochar modified with magnetized iron oxides and nano zero valent iron for decolorization of dyeing wastewater

2020 ◽  
Vol 3 (2) ◽  
pp. 105-114
Author(s):  
Bao-Son Trinh ◽  
Pham Thi Kieu Chinh ◽  
Ha Đoan Tram
Keyword(s):  
Iron Oxides ◽  
Removal Efficiency ◽  
Rice Husk ◽  
Reactive Dyes ◽  
Zero Valent Iron ◽  
Color Removal ◽  
Dyeing Wastewater ◽  
Nano Zero Valent Iron ◽  
Initial Color ◽  
Rice Husk Biochar

Rice husk biochar, a rich-carbon material, can be modified with other reactive elements to improve its original properties for organic-contaminant removal efficiency. In this study, rice husk was heated to 600 oC without air in a closed-furnace for producing the rice husk biochar (BC600). BC600 was then magnetized for making an intermediate magnetized rice husk biochar (BC600-mag). Finally, nano zero valent iron (nZVI) was synthesized on BC600-mag for producing magnetized biochar impregnated nZVI (BC600-mag-nZVI). Batch experiments were conducted to investigate color removal efficiency of BC600-mag-nZVI for the reactive dyes yellow (RY145), red (RR195) and blue (RB19) from dyeing solutions with the initial color concentrations of approximately 400 Pt-Co. Results showed that, for RY145 and RR195, the optimum color removal efficiency (ɳopt) achieved the values of 95 and 93% at doses of 0.50 and 1.50 kg BC600-mag-nZVI/m3 dyeing solution, according to the treated color decreased to 21 and 30 Pt-Co, respectively, which are lower than the allowable discharged standard of column A (≤ 50 Pt-Co) of QCVN 40:2011/BTNMT, while for RB19, the ɳopt achieved the values of 63 % at dose of 8.00 kg BC600-mag-nZVI/m3 dyeing solution, according to the treated color decreased to 147 Pt-Co which is lower than the allowable discharged standard of column B (≤ 150 Pt-Co) of QCVN 40:2011/BTNMT. In addition, with increasing dose of the modified biochars, the color removal efficiency increased accordingly, achieving almost 100% for RY145 and RR195 and over 70% for RB19. It is concluded that the magnetic-nZVI rice husk biochars effectively removed the reactive dyes. In the other hand, the impregnation of nZVI particles on the biochar backbone spatially separates the particles, prevents their aggregation and therefore enhances their reactivity This study therefore proposes a new application of rice husk biochar modified with magnetized iron oxides and zero valent iron decolorization of dyeing wastewater.

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.

Uncertainty in air stripping tower design: implications of the air-to-water ratio

2001 ◽  
Vol 1 (4) ◽  
pp. 177-184
Author(s):  
B.I. Dvorak ◽  
J.W. Schauble
Keyword(s):  
Mass Transfer ◽  
Removal Efficiency ◽  
Cost Effective ◽  
Air Stripping ◽  
Henry's Constant ◽  
True Value ◽  
Risk Of Failure ◽  
Process Failure ◽  
Removal Efficiencies ◽  
Water Ratio

Environmental engineers are frequently faced with uncertainty in making design decisions because the true value of many process parameters is unknown. In this study, the design of countercurrent air stripping towers was modeled using fuzzy numbers, taking into account uncertainties in mass transfer and Henry's constant. It was found that, in addition to cost, the risk of failure is an important design consideration for stripping tower design. A significant over-design is both cost-effective and results in less risk of design failure. The air-to-water ratio that yielded the least risk of failure switched from low to high as the removal efficiency of the tower increased. An important result is that at lower removal efficiencies, tower design and operation is most sensitive to uncertainties in mass transfer and at higher removal efficiencies, tower design and operation is most sensitive to uncertainties in Henry's constant . The implication is that low air-to-water ratios are best when the regulatory target removal efficiency is low and/or when the uncertainty in the value of the contaminant's Henry's constant is larger than the uncertainty in the mass transfer coefficient value. Otherwise a high air-to-water ratio results in the least risk of process failure.

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.

scholarly journals Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1417
Author(s):  
Min Zhuang ◽  
Wen Shi ◽  
Hui Wang ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Surface Passivation ◽  
Bimetallic Nanoparticles ◽  
Zero Valent Iron ◽  
Molar Ratio ◽  
Particle Sizes ◽  
Iron Corrosion ◽  
Graphitized Carbon ◽  
Nanoscale Zero Valent Iron ◽  
Iron Nickel

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

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