Permeable Reactive Barrier References Frame 2, Cheng to Hassan

References Cheng through Hassan


(zero valent unless specified)






Pd/C 4-chlorophenol Batch Palladized graphite and carbon cloth electrode in 3-neck round-bottom flask (50 mL). Cu wire threaded through 5 mm glass tubing. Central portal used for pH & cathode potential. Anodic compartment vented for O2 escape. Rapid dechlor. of 4-chlorophenol on palladized carbon cloth or palladized graphite electrodes. Hypothesize H gas interlaced in Pd lattice powerful reducing agent dechlorinating compounds. adsorbed on palladized electrode surfaces. Cheng, I.F., et al., ES&T, 31:1074-1078 (1997)
Fe Nitrate Batch 4g untreated 325 mesh iron to 50 ml of 12.5 mM nitrate buffered at pH 5.0. No O2 excluded. Vigorously stirred. Nitrate < 0.2 mM in 74 min. Ammonia 103%. Pseudo-1st order rate constant 0.0530/min. Buffer is key in nitrate reduction. Cheng, I.F., et al., 213th ACS, San Fran., CA, 37:165 (1997)
Fe PCBs (Aroclor 1221, 1254) Batch Iron powder (0.5g), 1.5 µmol PCBs in 10 ml flame-sealed glass ampule. PCBs undergo dechlor. & other reactions at > 300°C in presence of Fe powder. Virtually complete loss of chlorinated congeners. Chuang, F.-W. & R.A. Larson, ES&T, 29:2460 (1995)
Fe DCE, TCE PCE Batch Solutions incubated with lab grade iron under static conditions. Concentrations monitored as a function of time. Ox. reactions of Fe increased pH. Halocarbon convert slower at high pH. Pyrite with Fe to counterbalance pH increases. High grade pyrite more reactive. Surface area (SA) important consideration. Cipollone, M.G., et al., 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:812 (1995)
Fe TCE Column Long-term (~30 d, >300 PV) & fast velocities (5-30 cm/h) w/ 4-600 ml Fe mix columns. Rates varied by medium, SA, mixture, time. Influent 50 µM TCE at 3.15 mL/min. Fe oxidation increased pH, pyrite decreases pH. Locate pyrite at head because precip. slower at lower pH w/ wider dispersion of precip. zone throughout column and lessens plugging at head of column. Cipollone, M.G., et al., 213th ACS Nat'l Meeting, San Fran., CA, 37:151-152 (1997)
Fe(II) TcO4- Batch Fe(II) [slight acid to base] in 500-cm3 bottle w/ hydro phobic inner surface, amb. temp., anaerobic. 0.1 FeCl2 (pH 4 ) added, sampled by syringe through septum. 3 e- reduc. slow if at all. Fe(II) [sorbed to wall or precip. as Fe(OH)2(s) or FeCO3(s)] reduced TcO4-. Rates prop. to sorbed or precip. Fe(II). Discuss redox/paths TcO4- to TcO2:nH2O. Cui, D. & T.E. Eriksen, ES&T, 30:2263-2269 (1996)
Fe Background hydrocarbon formation Batch 15.0-mL sealed vials 5.00 g Fe with low CO2 water, anaerobic, 8 rpm in dark at 20 °C. . pH increased 5 - 7 when Fe added. 13C-labeled CO2 to determine if CO2 being reduced by iron to form the hydrocarbons. Non-Cl-hydrocarbons form during ethene reduction and without ethene. Mechanisms, analogous to Fischer-Tropsch synthsis of hydrocarbons, proposed for hydrocarbon production from carbide carbon. May contribute to hydrocarbons in ethene reduction. Deng, B. A.T. Stone, ES&T, 30:463-472 (1996)
Fe VC Batch 40 mesh HCl pretreated Fisher Fe filings, SA 1.18 m2/g (0.2 to 10 g) using 15 ml borosilicate in ZHE filled by VC solution, anaerobic, 8 rpm, 20°C . Also at 4, 20, 32, 45°C. 5.0g Fe/15.0ml: VC ­> ethylene (Partial absorb. to Fe). Rates inc. as Fe & temp. inc. Activ. E 40 KJ/mole indicate surface rxn. Fe2+, H2 also produced, but, Fe2+ not directly involved in reduction Deng, B., et al., 213th National ACS Meeting, San Francisco, CA. 37:81-83 (1997)
Fe U Pilot barrier at UMTRA, CO Pilot barrier using Fe to remove U from tailings effluent. at UMTRA site scheduled 5/96 to 1999. Fe foam SA 0.1 & 5 m2/g; Fe(0) SA 5.6E-3 m2/g. During 3 years U, Se, Mo, other elements monitored as well as costs and benefits. Field results coincide with exp. In Fe foam batch U removed to <DL in 10h. Metallic hydraulic conductivity maintained. Initially, conductivity 6.4 x 10^-3 cm/s; Fe foam was 0.53 cm/s. Capacity maintained after > 700 PV oxygenated water. Dwyer, B.P. & D.C. Marozas, Internat'l Contain. Tech. Conf. & Exhib. St. Petersburg, FL, Feb 9-12, pp. 844-850 (1997)
Fe Tracers, D2O Column Glass column with wet Ottawa sand or VWR coarse iron filings. 2.65g/cm3 for sand and 6.5-7.6 g/cm3 for iron. 2 tracers (D2O, KBF4) for Fe column. D2O more conservative and KBF4 easier on-line detection. Both inert with respect to Fe. Eykholt, G., et al., 209th Nat'l ACS Meeting, Anaheim, CA, April 2-7, 35:818 (1995)
Fe Alachlor, Metolachlor Batch Kinetics 100 mL ZHEs, ~ 40g course Fe filings (40 mesh, SA 13.5 m2/g), 10 mg/L or 100 mg/L alachlor and/or metalochlor, room temp, 3 rpm. Sampled over even intervals for 5 d. Rapid dechlor. by Fe(0) shown by Cl- and GC/MS analyses. Apparent 1st-order kinetics, but indication of rate limited and instant sorption. 2-site batch kinetic model derived and fitted to results. Eykholt, G.R. & D.T. Davenport, 213th Nat'l ACS Meeting, San Francisco, CA, 37:79-81 (1997)
Fe CCl4 Elemental Fe cathode Experimental reactors using a two-part glass vessel with a Nafion-117 proton permeable membrane. Precipitation of CCl4 ­> chloroform in hrs at 0.0005 to 0.005 / min. Suggest H2 serves as intermediate for CCl4 hydrogenolysis. Festa, K.D., et al., 209th Nat'l ACS Meeting, Anaheim, CA, April 2-7, 35:711-715 (1995)
Fe 1,2,3-trichloro- propane Column 50 & 93 mg/L 1,2,3-TCP was passed through 6 flow through reactive columns containing Fe(0), silica sand & simulated groundwater. End-product propene. Fe(0) enhanced dechlorination. Rate increased in proportion to iron SA to soln. volume ratio. Ratios of 1.16, 3.7, 8 m2/mL gave t1/2 17.6, 6.6, 3 h, respectively. Focht, R.M. & R.W. Gillham. 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:741 (1995)
Fe Review Reactive Walls Gillham founded EnviroMetal Technologies in 1992 to commercialize the reactive wall technology. To Date 5 full-scale in situ treatment zones installed: 2 in commercial sites in CA, 1 in KS, 1 in N Ireland and 1 at Elizabeth City, NC Focht, R.M., et al., Remediation, Summer:81 (1996)
Fe TCE Funnel and-Gate In Sunnyvale CA site, 100% pure granular iron filing wall is 4 ft thick, 40 ft wide and 20 ft deep. TCE levels of 30-68 ppb entering wall reduced to < 0.5 ppb; cDCE of 393-1916 ppb to < 0.5 ppb Focht, R.M., et al., Remediation, Summer:81 (1996)
Fe TCE Funnel and-Gate 1000 foot funnel and gate system installed at industrial facility in Kansas in January 1996 to treat 100 to 400 ppb TCE. Reactive zone 30 to 17' bgs and 3' thick Under optimum conditions, the soil-bentonite slurry wall could be built in 1 or 2 weeks and gate section in one week. Slurry wall, gate, 7900 ton of granular iron = ~$400,000 Focht, R.M., et al., Remediation, Summer:81 (1996)
Fe TCE, cDCE, VC Funnel and-Gate New York facility (1995) treats up to 300 TCE, 500 cDCE, 80 VC (ppb). 12' x 3.5' reactive section flanked by 15' sheet piling on either side. Installed in 10 d. VOC reduced to MCLs within 1.5 feet of travel through reactive media. Cost $250,000 including $30,000 for 45 tons of iron. Focht, R.M., et al., Remediation, Summer:81 (1996)
Permeable treatment barrier CCl4, TCE, CHCl3, Cr(VI), Tc, U In situ Used abiotic reagent sodium dithionite at theHanford site. Biotic reagent/nutrient either citrate or glucose. Compared abiotic & biotic methods for controlling redox potential to reduce solids in unconfined aquifer. Fruchter, J.S., Pacific NW Lab & U. S. DOE. PNL-SA-21731 (1993)
Permeable treatment barrier Velocity measurements Tracer Bromide considered most appropriate tracer. Pilot system (3 long x 3 wide x 5.5m deep) installed 11/1995 at gov. facility in Colorado. Models indic. ~ 60 cm/day (2 ft/day) in reac. zone. Could not detect small tracer. Large targets could disrupt flow; time consuming. Water table calculations not accurate. Heat-pulse velocity meter suspect for directional vectors. In situ velocity probes most promising/easy to use. Focht, R.M., et al., Internat'l Contain. Tech. Conf. & Exhib. St. Petersburg, FL, Feb 9-12, pp. 975 (1997)
Fe Foam As, Se, Mo, U, sulfate, nitrate Batch, Column Batch (1 wk) & column (70 d) using Fe foam and steel wool to compare removal of As, Se, Mo, U, sulfate, and nitrate. Precipiation and removal mechanisms also studied. Batch Fe foam removed 100% Se, 86% nitrate, 100%U, 83% As. Steel wool ~ 80% U, 20% As, 70% nitrate. Neither remove sulfate or Mo. Column conduc. decreased slightly (0.08 steel wool; 0.09 cm/s foam). Reduction/ precip. Se; adsorption As, U. Gallegos, T.J., et al., HSRC/ WERC Joint Conf. on the Environment, May 20, Paper 75 (1997)
Fe, Mg, Ultrasound (US) TCE Batch TCE (20 ppmv) in 3 neck-1 L round bottom reactors, with ultrasound (US) probe inserted in center neck and tip just above 1.0 g Fe or Mg, or 50:50 mix, w/ & w/o ultrasound. Controls only ultrasound, no metal or ultrasound. Higher pH from dechlorination reactions increases deactivation by precipitating metal compounds on active surface.Ultrasound can strip away coorrsion keeping metals active longer. Another benefit is sonication produces H+ ion to stabilize pH. Geiger, C., et al., 211th ACS Meeting. New Orlean, LA, March 24-28, 36:17-18 (1996)
Fe Chlorinated hydrocarbons Batch, Column 10g 100 mesh iron powder, silica sand, 40 mg/l CaCO3 added to 40 ml hypovials All 14 chlorohydrocarbons, but dichloromethane degraded. 1m2 Fe surface/ml solution: t1/2 values from 0.013 to 20 hr; 5 to 15 orders of magnitude greater than natural abiotic degradation. Gillham, R.W., et al. 33rd Hanford Symp. on Health & the Environ. In Situ Remed., pp. 931 (1994)
Fe Halogenated compounds Batch 10 g 100 mesh iron filings in 40 ml hypovials filled with solution, no headspace, sealed, at 2 rpm. Co for CCl4, HCE, PCE were 1630, 3620, 2250 µg/L, respectively. t1/2 for CCl4, PCE and HCE were 20, 1100 and 13 minutes, respectively. Chloroform, produced by CCl4 was the only breakdown product acuumlating in significant quantities. Gillham, R.W. & S.F. O'Hannesin, IAH Conf., Hamilton, Ontario, May 10-13 (1992)
Zn, stainless steel, Cu, brass, Al
Chlorinated hydrocarbons Batch, Column, Reac. Wall Bordon, Ontario Batch: 10 g stainless steel, Cu, brass, Al, Fe, & Zn in 40 ml hypovials w/ 1,1,1-TCA. Next, Fe w/ halo-aliphatics. Batch/columns used wall material. Constructed Bordon wall by driving sheet piling to form 1.6 m x 5.5 m cell. Reactive material 22% Fe grindings and 78% concrete sand with 348 sampling points installed within wall. Batch: 1st order TCA rates, Steel, brass, Cu low rates; Al better; Zn, Fe rapid (t1/2 100 min.). Fe(0) batch: Highly Cl-organics most rapid. t1/2 0.22 h HCA to 432 h cDCE. Fe mass to solution volume ratio important. Rates decline at pH ~ 9. Batch/column: t1/2 15 h TCE, PCE. In situ wall: Avg. max. conc. downstream of wall ~10% of influent conc. Performance constant over 14-months. Gillham, R.W., et al., HazMat Central Conference. Chicago, Illinois, March 9-11, pp. 440 453 (1993)
Fe Chlorinated hydrocarbons Batch, Column 10g 100 mesh iron powder, silica sand, 40 mg/l CaCO3 added to 40 ml hypovial. Substantial degradation rates in all but dichloromethane. Rates in column independent of velocity and consistent with batch tests. When normalized to 1 m2/mL, t1/2 was from 0.013 to 20 hr. Gillham, R.W. & S.F. O'Hannesin, Ground Water, 32(6):958 (1994)
Fe, Ni/Fe PCE, cDCE, TCE Canister, NJ Fe canister, NJ site treating up to 15 PCE, 1 cDCE, 0.5 mg/L TCE since 11/1994. Initial column used Ni plated Fe, site water. Reactor used comm. plated Ni-Fe 7/96. SA 3.1 m2/g (before plating 1.1 m^2/g). 2nd column comm. Ni-Fe. t1/2 in initial column factor of ten (30 to 3 min, TCE) lower than Fe alone. 1 to 1.5 versus 24 h res. time. Enhanced reactor t1/2 4X > initial column test, but 4X lower than Fe reactor. Longer t1/2 may resulted from inadequacies in commercial plating process. Gillham, R.W., et al., Internat'l Contain. Tech. Conf. & Exhib. St. Petersburg, FL, Feb 9-12, pp. 85 (1997)
Fe TCE Batch Batch 150µm, 370µm mesh Fe & Fe powder in 40 ml ZHEs, TCE in DI water, shaken 150 rpm then analyzed for pH, dissolved Fe and Cl- removal. 2-fold increase in psuedo 1st order rates when Fe SA decreased from 370 µm by factor of 2.5. For Fe SA/ unit volume of soln <1000 m-1, TCE rate constant increased linearly with SA/V ratio. Gotpagar, J., et al., Environ mental Progress, 16:137 (1997)
Fe Cr(VI) Batch Varied Cr(VI), H+, and surface area of iron as well as ionic strength and mixing rate. Rate constant 5.45 x 10^-5 cm-2 min-1 over wide range of conditions. 1.33 mol diss. iron for each mole Cr(VI) reduced. Gould, J. P., Water Res., 16:871 (1982)
Fe, Pd/Fe PCB Batch HCl treated Fe particles (< 10µm). K2PdCl6 w/ Fe powder (0.05% w/w Pd). 20 ppm PCB (1 mL Aroclor 1260 or 1254), methanol/ water/acetone (1:3:1) w/ 0.05% w/w Pd/Fe in vial, amb. temp., capped, shaken. 1 µL samples. Rapid (few min.) dechlorination on Pd/Fe surface to biphenyl. Rate depend on amount Pd/Fe, % w/w of Pd0 on Fe, & % v/v water. Pd/Fe surface can be used repeatedly if acid-washed after 3 to 4 uses. Grittini, C., et al., EST, 29:2898-2900 (1995)
Fe(0), surfactant TCE, PCB Batch, Column TCE batch ZHEs: 20.9 40-mesh Fe & Pd(.05%)-Fe, 100 mL TCE (2mg/L), surfactant (2%, 4%), cosolvent (2%), 30 rpm. PCBs in 5-mL vials, 2.9 100-200-mesh Fe-Pd(0.1%). Columns wet-packed w/ Fe or Fe-Pd, sampled after >10 PV at various levels, times, rates. Batch Pd-Fe: t1/2 TCE ~27.4; PCB ~100 to ~500 min (as surfactant increased). Columns: TCE and PCBs degrade at enhanced rate t1/2 ~1.5 and 6 min due to increased solid to solution ratio. Fe-Pd filings applicable for ex-situ treatment of TCE and PCBs in surfactant solutions generated during surfactant flushing. Gu, B., et al., Internat'l Contain. Tech. Conf. & Exhib. St. Petersburg, FL, Feb 9-12, pp. 760-766 (1997)
Cu Dioxin, Furans Batch Heat mixtures with Cu to enhance catalyzing reactions to degrade dioxins and other compounds. Cu catalyzed degradation of PCDD, PCDF, 7 other chlorinated aromatics at low temp. similar to first observation using fly ash. Hagenmaier, H., et al., ES&T, 21:1085 (1987)
Fe TCE Batch 1.5-2.0 g of elemental iron per 100 ml aq sample containing 0.02 mmoles TCE (25ppm); maintained pH. With and without citric acid, pH 5.8: rate 5.37 h-1 & 0.85 h-1; t1/2 7.74 & 48.9 min., resp. Citric acid chelating ligand for Fe2+. Haitko, D.A.& S.S. Baghel, 209th National ACS Meeting, Anaheim, CA, 35:807 (1995)
Fe CO2 Batch, Column Determine that C1 to C5 hydrocarbons are formed by the reduction of aqueous CO2 by Fe(0) and product, have ASF distribution. Pretreat iron with H2 increased hydrocarbon conc. 140 h untreated Fe 3.8 ±1.2µg/L vs. 7.9±2.4 µg/L using hydrogenation. Indicate absorbed H is a reactant in reduction of aqueous CO2. Hardy, L.I. & R.W. Gillham. 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:724 (1995)
Fe Hydrocarbon (HC) formation Batch Reduction of aqueous CO2 by Fe(0). Reaction mechanism proposed for electroreduction of aqueous CO2 with Ni electrodes, Fe. Anderson-Schulz-Flory (ASF) distrib. 10 HCs & C5 products ASF distrib. w/ hydrophobics sorbed to Fe. Fe supply e-s & catalyst promote formation/ growth of HC chains. H2O also reactant. Desorption HCs may be rate-limiting step. Hardy, L.I. & R.W. Gillham, ES&T, 30:57-65 (1996)
Fe, Sulfur CCl4 Batch Determine if adding sulfur enhances degradation of CCl4 by iron. Sulphur (sulfate, organosulphonic acid, sulfides & pyrite) accel erated Fe induced degradation of CCl4 under aerobic conditions. Harms, S., et al. 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:825 (1995)
Fe, Sulfur TCE, PCE Batch 2 grades Fe, TCE and PCE. Lab grade Fe filings, 420 µm, sulfur >180 ppm. Extra pure Fe, at a particle size of 6 to 9 µm and S content of 22.1 ppb. Lab grade Fe resulted in ethyne, ethene, ethane in 24 h. Extra pure unreactive after 1 mo. despite high SA, but fast production of ethyne, ethene, ethane after adding sodium hydrogen sulfide. Hassan, S.M., et al, 209th National ACS Meeting, Anaheim, CA, April 2-7, 35:735 (1995)

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.