Permeable Reactive Barrier References Frame 3, Heijman to Ozdemir

References Heijman through Özdemir


(zero valent unless specified)






Iron, Fe-reducing microbes 10 Nitrobenzenes Column Columns to assess abiotic/biotic processes in reactive Fe & Fe-reducing bacteria. Nitrobenzene to analines. Nitroaromatic reduction by Fe(0), serving as mediators for transfer of e- from microbial oxidation of organics by Fe-reduction bacteria. Heijman, C.G., et al., ES&T, 29:775 (1995)
Fe CCl4 Batch CCl4:1.5-5.5 µM; Fe(0) powder: 1 to 10g per 265 ml distilled water in anoxic and oxic batch reactors Products: CHCl3, CH2Cl2. Anoxic Rate: 0.290 h-1, 1 g Fe(0); 1.723 h-1, 10 g Fe(0); incr. with SA (2.4 mg/g) & time. Slower oxic rates: 0.085 h-1, 1g Fe(0); DOi 7.4 mg/L. pH rapid inc. after O2 depleted. Helland, B., et al., 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:732 (1995)
Pd/C 2-chloro-2 propen-1-ol, CT, Chlorobenzene Batch 2-chloro-2-propen-1-ol, CT, Chlorobenzene, both bare and pallaized graphite electrodes in aqueous solution over 24 hours. Chlorobenzene rate limiting step in dechlorination of compounds such as PCBs. Pd reduces CT by factor of 5; more products (methane) dechlor inated. Favor acidic media at higher ionic strength, O2 does not effect. 2-chloro-2-propen-1-ol dechlorinates rapidly with Pd/C but by different mechanism. Chlorobenzene ­> benzene w/ Pd/C. Helvenston, M.C., et al., 213th National ACS Meeting, San Francisco, CA. 37:294-297 (1997)
Fe/Pyrite mixture TCE Column TCE pumped through stainless steel column w/ mixtures of granular iron & pyrite. Products not considered. Interaction of GW & geochemical environ. using MINTEQA2. Pyrite in granulated Fe mixtures provided pH control Holser, R.A., et al., 209th Nat'l ACS Meeting, Anaheim, CA, April 2-7, 35:778 (1995)
Reactive Wall Various Selection Method Method to determine cost and select site specific treatment for 122 m wide PCE plume, 24 to 37 m bgs. Permeable reactive wall chosen and emplacement method was hydrofracturing and injection of iron in two 76 mm thick walls. Hubble, D., et al., Internat'l Contain. Tech. Conf. & Exhib. St. Petersburg, FL, 872 (1997)
Mn2+, Fe2+, steel wool(Fe) Cr(VI) Batch Low hexavalent, high hexavalent soils had 105, 460 mg/kg Cr(VI); 1.8, 104 g total Cr; 8.5, 10.4 pH, respectively. Mn2+ reduced 50 to 100% Cr(VI) in both soils (no pH adjustment). Fe2+, steel wool reduced soluble & insol. Cr(VI) reduction dependent on pH, reducing agent and soil. James, B.R., J. of Environ. Quality, 23:227 (1994)
Fe TCE, PCE, TCA Column, reactor, Belfast, Ireland EnviroMetal treatability study w/ Fe filing, Belfast site water. Res. time ~ 12h to reach regulatory limits. Designed 12m tall x 1.2m dia. Fe reactor with 5 m flow path entry and exist zones to collect and disperse flow. Reactor in cut-off wall to funnel flow. t1/2 TCE ~ 1.2h. Small conc. cisDCE, Cl- inc., VC from dechlor. (Up to 700 µg/L) in treatability study. Solvents degraded rapidly. Site Installation: After 7 mo. TCE 5 µg/L but slightly higher at exit due to backflow from sampling. DCE formed but ND at 3m. VC at 4 mo 0.4 µg/L and ND 7 mo. At 6 m TCE 2µg/L and DCE is ND. Jefferis, S.A., et al., Internat'l Contain. Tech. Conf. & Exhib. St. Petersburg, FL, Feb 9-12, pp. 817-826 (1997)
Fe CCl4 Column 15-cm-dia Plexyglass pipe 90 cm long. Holes every 2.5 cm first 40 cm, rest 5 cm. Up & downgrad. sand zone w/ intermed. Fe zone to simulate permeable iron barrier. CCl4 (up to 1.6mM) fully dehalogenated by first sample port in Fe zone. CCl4 ­> CHCl3 ­> CH2Cl2. CCl4 t1/2 no > 0.25 h, 2.5 cm/h. CHCl3 t1/2 slower but increased 2-fold w/ 5-fold increase in flow velocity. Johnson, T.L. & P.G. Tratnyek. 33rd Hanford Symp. on Health & the Environ.­ In Situ Remed., pp. 931 (1994)
Fe CCl4 Column, Batch 100-mesh untreated Fisher Fe powder (SA 0.057)<325 mesh in N2 purged unbuffered water and 20­32 mesh Fluka Fe turnings SA 0.019 m2 g-1 in carbonate buffer. Mixed in dark, 36 rpm, 23±1°C. Table of new and previous experimental conditions provided. New/previous kosb from batch and column varied widely. Normalization to Fe surface conc. yields specific rate constant kSA (vary by only 1 order of mag.). Dechlorination more rapid in saturated carbon centers and high degrees of halogenation favor rapid reduction. Representative kSA values provided for solvents. Johnson, T.L., et al., ES&T, 30:2634 (1996)
Fe Colloids Chemical Barrier Batch, Column Hanford Site: Column/batch studies looking at injection of micrometer-sized Fe(0) colloids into subsurface to form chemical barrier. Surfactants in low ionic strength solutions increased length of time dense colloids (7.8 g cm-3) remained in suspension by 250%. Removal efficiency of sand column partially controlled by injection rate. Kaplan, D., et al., In Situ Remed., Battelle Press, pp. 821 (1994)
Fe(0) Colloids Chemical Barrier Column PVC column study evaluating Fe(0) colloid injection rate and conc. on colloid retention by a sand bed. CaCl2 tracer studies to compare transport rates of colloids. Colloids controlled by rate & influent conc. As colloids accumulate, efficiency decreased due to gravitational settling. Colloids were evenly distributed & high flow required to mobilize. Kaplan, D., et al., J. of Environ. Qual., 25(5):1086 (1996)
Mineral oxides in presence of Fe2+ 10 monosub- stituted Nitrobenzenes Batch Suspensions of magnetite, geothite, lepiodocrocite, aluminum oxide, amorphous silica, titanium dioxide in presence and absence of Fe2+ addition. Fast nitroaromatic reduction in all Fe hydroxides at 0.5 pH. Mineral oxides (no Fe2+) show slow reduction, but increased w/ Fe (hydr)oxide coatings. Rates pH-dependent, decreasing with increasing compound to solids concentration ratio. Klausen, J., et al., 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:716 (1995)
Palladized iron Chlorinated contaminants Batch Bimetallic process evaluated as a means of increasing rates of reaction. TCE dehalogenation increased 2-X using Pd/Fe instead of Fe and extends process to less reactive dichloromethane. Korte, N., et al., 209th Nat'l ACS Meeting, Anaheim, CA, April 2-7, 35:752 (1995)
Pyrite CCl4 Batch 1 µM CCl4 reacted with 1.2-1.4 m2/L pretreated pyrite at pH 6.5, 25°C except experiments conducted with sulfide at pH 7.75; aerobic & anaerobic. Pyrite 75-300 µm. >90% CCl4 transform in 12-36 d (all conditions). Aerobic >70% CCl4 ­> CO2. Anaerobic 50% CCl4 ­> CHCl3. FeOOH coat on pyrite (aerobic). Pyrite depleted of ferrous Fe in all reactions. Kriegman-King, M.R. & M. Reinhard, ES&T, 28:692 (1994)
Sulfide, Biotite, Vermiculite CCl4 Batch Biotite, vermiculite, muscovite wet-ground to 200-50 mesh (73-300 µm). Ampules w/ 13.5 mL buffer, spiked with solution saturated with CCl4 and flame sealed. ~ 80-85% CCl4 ­> CO2 via intermediate CS2. Chloroform 5-15%, 5% unidentified nonvolatile and CO. At 25° 1mM HS t1/2 2600, 160, 50 d for homogeneous, vermiculite, biotite system, respectively. Kriegman-King, M.R. & M. Reinhard, ES&T, 26:2198 (1992)
Corrin, reductant CCl4 Batch CCl4 in vials w/ corrin (B12, cobinamide dicyanide, or aquocobalamin), reductant (Ti(III), dithiothrietiol, or S2 /cystenine), pH 8.2. Products in headspace and mixture determined by GC/MS, HPLC, NMR or TLC. Proposed pathway: trichlromethyl radical forms adduct with reductant. In S2-/cysteine produces CS2 or thiazolidines by way of thiophosgene. --Or-- radical further reduced to from CHCl3 and CH2Cl2 or CO and formate by dichlorocarbene intermediation. Lewis, T.A., et al., ES&T, 30:292 (1996)
Pd/Zn TCE Batch TCE dechlorination by Zn0 in aqueous solutions at room temperature. Bimetallics Ag, Ni, Pd to enhance Zn. Dechlorination few h to several d. Best rates w/ cryo-Zn (ultrafine Zn) & Pd. Ethylene, ethane, monochlorinated hydrocarbons products. Li, W. & K.J. Klabunde, HSRC/WERC Joint Conf. on Environ., 5/20 Paper 35 (1997)
Fe TCE Batch ZHEs w/ 3 Fe filings (Fisher, Columbus Chemical, MBS). TCE 0.5 to 20 ppm. Fisher Fe pretreated with HCl Rates varied by factor of 2 for 3 Fe's. TCE sorbed then reduced by MBS. Fisher Fe 7 to 5 h. TCE/Fe ratios changed rate as well. Liang, L., et al., 209th Nat'l ACS Meeting, Anaheim, CA, April 2-7, 35:728 (1995)
Fe, Pd/Fe TCE Batch 25g of 40-mesh Fe filings added to ZHEs, containing 125 mL solution (nominally 2 mg/L of TCE) at 30 rpm. Pd/Fe prepared according to Muftikian et al. (1995). 5 ppm TCE produced ~ 140 ppb of VC (persists up to 73d). Remaining 10 ppb VC order mag. < Fe(0). TCE reduction w/ Pd/Fe (0.05% Pd) > order mag. faster than Fe(0). With a 5:1 solution-to solid ratio TCE t1/2 Fe(0) =7.41 h; Pd/Fe = 0.59 h. Liang, L., et al., GWMR Winter, 122 (1997)
Fe and sulfur CCl4 Batch Sodium sulfate, sodium sulfide, ferrous sulfide, pyrite, organic acid, electrolytic zero valent iron powder, Fe(0) degradation of CCl4 under aerobic conditions. Products: chloroform, potential for carbon disulphide (toxic). Sulphur significantly increased rates under aerobic conditions. Pyrite can regenerate ferrous ions, produce sulfate & pH control. Lipczynska-Kochany, E., et al, Chemosphere, 29(7):1477 (1994)
Fe Precipitation Batch Tracers, aqueous inorganic profiles, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and wavelength dispersive spectroscopy (WDS) to determine precipitates and porosity loss in Fe systems. Precipitation change color from black to gray. Loss of alkalinity and calcium, no signif. magnesium loss. Most loss (5-15%) early and levels off. SEM shows crystals form on the surface of Fe. Tracers indicate fairly uniform loss of porosity throughout. MacKenzie, P.D., et al., Emerg. Technol. in Haz.Waste Manag. VII, Sept. 17-20, Atlanta, GA, pp. 59-62 (1995)
Fe TCE, DCE Column 148 lbs VWR coarse Fe filings in columns. Initially used buffered DI water (40 mg/L CaCO3). pH 7-8.5. Later used gw, 400 mg/L CaCO3 and pH 7-8. Flow velocities much higher than typical to accelerate effects of aging. TCE t1/2 36 min at 40, 20, 12 ml./min. trans-DCE t1/2 `~ 100 min., 1,1-DCE t1/2 200 min, although 1st order fit not as good as for TCE. cis-DCE was particularly poor. Siderite formed at the top of column 1, throughout column 2 and at the bottom of column 3. Mackenzie, P.D., et al., 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:796 (1995)
Fe Precipitation Batch Tracers, aqueous inorganic profiles, scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and wavelength dispersive spectroscopy (WDS) to determine precipitates and porosity loss in Fe systems. GW forms precipitates (Fe(OH)2, FeCO3, CaCO3) on Fe surfaces, which may affect reactivity. However, this effect, to date, small. Also, H2 produced from anaerobic corrosion of Fe a factor controlling the measured porosity losses in iron systems. Mackenzie, P.D., et al., National ACS Meeting, 37:154-157 (1997)
Ferric Oxyhydroxide Se Batch, Site Samples Three sediment samples from Kesterson, Merced County, CA with elevated levels of Se subjected to in situ Fe(II) amendment. Both Se(IV) & Se(VI) occluded within FeOOH produced during Fe(II) ox. & hydrolysis. Fe(II) salt amendment potenital in situ remediation for trace Se. Manning, B.A. & R.G. Burau, ES&T. 29(10):2639 (1995)
Fe U Column Rocky Flats seep w/ Cl- organics, metals, radionuclides. Seep water in glass columns w/ steel wool (Fe(0)) at 5(1st d); 10(2nd d); 30 ml/min (next 4 d). Rates increased for effects on U removal. DO 5 to 6 mg/L, pH 8, 13 to 21°C. Fast removal of U by Fe(0). Chloro-organics determine residence time in design. Studies also test various media on removal of plutonium and americium at site and excess Fe from barrier effluent. EnviroMetal Tech. Inc. to determine res. time for barrier design. Marozas, D.C., et al., Internat'l Contain. Tech. Conf. & Exhib. St. Petersburg, FL, Feb 9-12, pp. 1029-1035 (1997)
Fe TCE, CCl4 Batch Evaluated core samples from actual field sites. Microbiology and geochemistry characterized. Granular Fe dechlorinated CCl4 & chloroform. Direct electrolytic process with metal surface may occur in combination with reactions involving hydrogen, ferrous iron, sulfur and microbes. Matheson, L.J. & P.G. Tratnyek. 1993. 205th ACS Meeting, 33:3
Fe TCE Batch Fe(0) participate by direct reduction, ferrous iron, and hydrogen produced during corrosion. Surface reaction is predominant granular Fe. Investigating possible microbial activity that might affect dechlorination. Matheson, L.J. & P.G Tratnyek, ES&T 28:2045-2053 (1994)
Fe CCl4, cis- trans 1,2-dichloro- ethylene Batch Temperature, steric, pH dependance of degradation and reactions of pollutants in response to untreated iron powder (finer than 100 mesh), under aerobic conditions. Electronic (orbital) & conformational preference. Nature of reductant appeared to determine the stereo chemical course of redox reaction More investigation needed. Milburn, R., et al., 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:822 (1995)
Chemical Barriers Mo, U Column 10 cm dia acrylic pipe w/ ~1,250 ml sand mixed with test material. U and Mo measured. Used hydrated lime. Chemical barriers low cost alternative. Evaluate site to determine type of chemical barrier (e.g. sorption or precipitation). Morrison, S.J. & R.R. Spangler, Env. Progr., 12(3):175 (1993)
Amorphous ferric oxyhyfroxide Mo, U Batch Lab experiments to evaluate material for use in chemical barrier under a repository containing uranium mill tailings. No additive extracts both U & Mo over pH range. Hydrated lime lowered U in pore fluid. Soluble ferrous materials extract Mo. Morrison, S.J. & R.R. Spangler, ES&T, 26(10):1922 (1992)
Palladized iron (Pd/Fe) TCE, DCE, cis & trans-1,2-di chloroethy1ene, PCE Batch Sealed 12 ml glass vial. Pd/Fe [3.6g-10µm (Aldrich), or 3.6 Fe fillings (Baker & Adamson), or 10g- 40 mesh Fe (Fisher)] with 10 ml of chorinated comp. (20 ppm in H2O), shaken. Sampled with a syringe for GC analysis. Dechlor. 1,1,2-TCE, 1,1-DCE, cis & trans-1,2-DCE & PCE at 20 ppm to ethane in few min. No intermed. products detected at > 1 ppm. Chloromethanes, CCl4, CHCl3, CH2Cl2 also dechlorinated to methane. CCl4 in a few minutes, CHCl3 in < 1 h, CH2Cl2 in 4-5 h. Muftikian, R., et al., Water Research, 29:2434-2439 (1995)
Palladized iron (Pd/Fe) TCE Batch 1x1-cm pure Fe foil, 0.254 mm thick welded to stainless steel stub. Sketched w/ 8 keV argon ions. Potassium hexachloropalladate added and allowed to react. Pd(lV) to Pd(II), protons on hydroxylated Fe oxide form Pd(II) O-Fe bonds, collapsing to Pd/Fe. TCE forms hydroxylated Fe oxide film that deactivates Pd/Fe. Dilute acid removes film. Muftikian, R., et al., ES&T, 30:3593-3596 (1996)
Fe(0)-Pd(0) chlorophenols (CPs) Batch Batch Fe(0)-Pd(0) in unbuffered, DI water, room temp, dark, usually with [Fe(0)-Pd(0)]= 69.4 g/L and initial aqueous chlorophenols [CP] ~ 0.08 mM, 40 rpm. Initial rapid loss CP (t1/2 < 0.2 h) due to sorption to Fe(0)-Pd(0) surface. Rate constant, kobs, proportional increase with Pd(0) used and SA of Fe(0)-Pd(0). Higher cosolvent corresp. decrease in kobs. Neurath, S. K., et al., 213th ASC National Meeting, San Francisco, CA, 37:159-161 (1997)
Fe CCl4, TCM, TCE, PCE Batch Fe catalyst and aquifer material collected from Canadian Forces Base, Borden, Ontario. Initial conc. of CCl4-4050, TCM-4650, TCE-4080, & PCE-3970 µg/L at 12 ° C. t1/2 2.2, 850, 1520 and 4000 minutes for CCl4, TCM, TCE, and PCE, repectively. No Eh change in controls, reactive vials showed highly reducing cond, but no significant pH change. O'Hannesin, S.F. & R.W. Gillham, 45th Canadian Geotechnical Soc. Conf., Oct 25-28 (1992)
Fe Halo-organic compounds Wall, Bordon Reactive wall 22% Fe, 78% concrete sand; 5.5 m downgradient. Cell driven 9.7 m to bottom silty clay lens. TCE reduced 95%, PCE 91%. No TCM downstream of wall. Cl- inc. consistent with quantity degraded. Traces DCE; no VC. O'Hannesin, S.F. & R.W. Gillham, 45th Canadian Geotechnical Soc. Conf., Oct 25-28 (1992)
Fe TCE, PCE Reactive Wall, Bordon Field demonstration in 1991 at Borden, Ontario. TCE 270 and PCE 43 mg/L. Wall 1.5m wide of 22% granular Fe and 78% sand placed in path of plume moving 19 cm/d. 90% TCE and 88% PCE removed from solution and Cl- indicated dechlorination. Major product was cDCE with peak of 2200 µg/L followed by tDCE and 1,1-DCE, VC below detection. O'Hannesin, S.F., et al., Emerg. Technol. in Haz. Waste Mangmt VII, ACS, Sep 17-20, Atlanta, GA, pp. 55-58 (1995)
Fe TCE Column Plexyglass columns packed with mixture 15% electrolytic iron and 85% silica sand. TCE pumped at 0.1 ml/min. Initial TCE conc. of 1.3, 4.7, 10.2, 61 mg/l. TCE Co = 4.7 mg/L. Products: ethene 40%, ethane 18%, C1 to C4 10%. 3-DCE isomers & VC. c1,2-DCE primary product of degradation, though sum of all chorinated's was only 3 to 3.5%. Orth, W.S. & R.W. Gillham, 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:815 (1995)
Fe TCE Column Columns used simulated groundwater containing 1.3 to 61 mg/L TCE. Column packed with 15% iron powder mixed with sieved 35-mesh silica sand. SA of iron 0.287m2/g, iron SA to solution volume ratio 0.21m2/mL. Pseudo-1st-order rates. Products :ethene > ethane >>> other C1­C4 hydrocarbons. 3.0-3.5% TCE appeared as chlorinated products. Most TCE probably sorbs to iron surface until complete dechlorination achieved. Orth, W.S. & R.W. Gillham, ES&T, 30:66-71 (1996)
Fe Chorine removal Batch

Chlorine solutions stirred in 250 ml reactor at 20°C. Granular Fe 0.2~.5 dia. added. 10 ml taken at 5, 10, 15, 20, 25 min and analysed for chlorine & chloride contends. Experiments also carried out at pH 4, 5, 6, 7, 8, and 9.

Granular metallic iron used to reduce the chlorine species into chloride in chlorine solutions. Optimum conditions investigated for pH, particle size, and contact period. Species of OCl- and HOCl removed by 100% between pH 4 and 7 within 25 min. Özdemir, M. & M. Tüfekci, Water Research, 31:343-345 (1997)

Abbreviations: PV = Pore Volume; US = Ultrasound; SA = Surface Area; GW = Groundwater; ZHE = Zero Head-Space Extractors;

MBS = Master Builders Supply; ND = Nondetectable; RT = Residence Time.