Bruce D. Honeyman

Colorado School of Mines, Golden, Colorado, United States

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Publications (49)95.69 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study focuses on the effects of fulvic acid (FA) on uranium(VI) sorption kinetics to a silica sand. Using a tritium-labeled FA in batch experiments made it possible to investigate sorption rates over a wide range of environmentally-relevant FA concentrations (0.37-23 mg l-1 TOC). Equilibrium speciation calculations were coupled with an evaluation of U(VI) and FA sorption rates based on characteristic times. This allowed us to suggest plausible sorption mechanisms as a function of solution conditions (e.g., pH, U(VI)/FA/surface site ratios). Our results indicate that U(VI) sorption onto silica sand can be either slower or faster in the presence of FA compared to a ligand-free system. This suggests a shift in the underlying mechanisms of FA effects on U(VI) sorption, from competitive sorption to influences of U(VI)-FA complexes, in the same system. Changes in metal sorption rates depend on the relative concentrations of metals, organic ligands and mineral surface sites. Hence, these results elucidate the sometimes conflicting information in the literature about the influence of organic matter on metal sorption rates. Furthermore, they provide guidance for the selection of appropriate sorption equilibration times for experiments that are designed to determine metal distribution coefficients (Kd values) under equilibrium conditions.
    Environmental Science & Technology 04/2013; · 5.48 Impact Factor
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    ABSTRACT: Upscaling from bench scale systems to field scale systems incorporates physical and chemical heterogeneities from atomistic up to field scales. Heterogeneities of intermediate scale (~10(-1)m) are impossible to incorporate in a bench scale experiment. To transcend these scale discrepancies, this second in a pair of papers presents results from an intermediate scale, 3-D tank experiment completed using five different particle sizes of uranium contaminated sediment from a former uranium mill field site. The external dimensions of the tank were 2.44m×0.61m×0.61m (L×H×W). The five particle sizes were packed in a heterogeneous manner using roughly 11cm cubes. Small groundwater wells were installed for spatial characterization of chemical gradients and flow parameters. An approximately six month long bromide tracer test was used for flow field characterization. Within the flow domain, local uranium breakthrough curves exhibited a wide range of behaviors. However, the global effluent breakthrough curve was smooth, and not unlike breakthrough curves observed in column scale experiments. This paper concludes with an inter-tank comparison of all three experimental systems presented in this pair of papers. Although there is a wide range of chemical and physical variability between the three tanks, major chemical constituent behaviors are often quite similar or even identical.
    Journal of contaminant hydrology 01/2013; · 2.01 Impact Factor
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    ABSTRACT: Intermediate scale tank studies were conducted to examine the effects of physical heterogeneity of aquifer material on uranium desorption and subsequent transport in order to bridge the scaling gap between bench and field scale systems. Uranium contaminated sediment from a former uranium mill field site was packed into two 2-D tanks with internal dimensions of 2.44×1.22×0.076m (tank 1) and 2.44×0.61×0.076m (tank 2). Tank 1 was packed in a physically homogenous manner, and tank 2 was packed with long lenses of high and low conductivities resulting in different flow fields within the tanks. Chemical gradients within the flow domain were altered by temporal changes in influent water chemistry. The uranium source was desorption from the sediment. Despite the physical differences in the flow fields, there were minimal differences in global uranium leaching behavior between the two tanks. The dominant uranium species in both tanks over time and space was Ca(2)UO(2)(CO(3))(3)(0). However, the uranium/alkalinity relationships varied as a function of time in tank 1 and were independent of time in tank 2. After planned stop-flow events, small, short-lived rebounds were observed in tank 1 while no rebound of uranium concentrations was observed in tank 2. Despite appearing to be in local equilibrium with respect to uranium desorption, a previously derived surface complexation model was insufficient to describe uranium partitioning within the flow domain. This is the first in a pair of papers; the companion paper presents an intermediate scale 3-D tank experiment and inter-tank comparisons. For these systems, physical heterogeneity at or above the decimeter scale does not affect global scale uranium desorption and transport. Instead, uranium fluxes are controlled by chemistry dependent desorption patterns induced by changing the influent ionic composition.
    Journal of contaminant hydrology 01/2013; · 2.01 Impact Factor
  • Emily K Lesher, Bruce D Honeyman, James F Ranville
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    ABSTRACT: The speciation and transport of uranium (VI) through porous media is highly dependent on solution conditions, the presence of complexing ligands, and the nature of the porous media. The dependency on many variables makes prediction of U transport in bench-scale experiments and in the field difficult. In particular, the identification of colloidal U phases poses a technical challenge. Transport of U in the presence and absence of natural organic matter (Suwannee River humic acid, SRHA) through silica sand and hematite coated silica sand was tested at pH 4 and 5 using static columns, where flow is controlled by gravity and residence time between advective pore volume exchanges can be strictly controlled. The column effluents were characterized by traditional techniques including ICPMS quantification of total [U] and [Fe], TOC analysis of [DOC], and pH analysis, and also by non-traditional techniques: flow field flow fractionation with online ICPMS detection (FlFFF-ICPMS) and specific UV absorbance (SUVA) characterization of effluent fractions. Key results include that the transport of U through the columns was enhanced by pre-equilibration with SRHA, and previously deposited U was remobilized by the addition of SRHA. The advanced techniques yielded important insights on the mechanisms of transport: FlFFF-ICPMS identified a U-SRHA complex as the mobile U species and directly quantified relative amounts of the complex, while specific UV absorbance (SUVA) measurements indicated a composition-based fractionation onto the porous media.
    Geochimica et Cosmochimica Acta 01/2013; · 3.88 Impact Factor
  • B. D. Honeyman, R. M. Tinnacher
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    ABSTRACT: In this study, we investigate changes in the kinetics of uranium(VI) sorption reactions to silica sand due to the presence of fulvic acid, a recalcitrant natural organic matter fraction. On the field scale, local contact times between metal contaminants and bulk mineral phases may often be too short to attain full sorption equilibria. Hence, kinetic limitations for surface reactions need to be included in predictive transport models. Natural organic matter is ubiquitous in the environment and can substantially influence metal sorption and transport behavior in saturated porous media. However, at this point little is known about potential effects of organic matter on metal sorption kinetics. Therefore, we investigated the kinetics of uranium(VI) (U(VI)) sorption onto a pretreated silica sand in the absence and presence of fulvic acid in lab-scale experiments. Furthermore, experimental data were simulated in pseudo-first order kinetic models in order to determine the characteristic times for U(VI) sorption reactions under various chemical conditions. Last, speciation modeling allowed for a qualitative assessment of dominant U(VI) solution species as a function of organic ligand concentrations and pH. Results indicate that U(VI) surface reactions are slowed down in the presence of low concentrations of fulvic acid (0.4 and 4.3 mg/l TOC), at conditions where U(VI)-fulvic acid solution complexes can be neglected. This kinetic behavior can be attributed to the competition of U(VI) and fulvic acid for a limited number of fast-sorbing surface sites. In contrast, metal sorption reactions seem to be faster relative to the binary metal-mineral system at a high FA concentration (26 mg/l TOC) and pH conditions where a substantial fraction of U(VI)-FA solution complexes is expected. In this case, U(VI) and fulvic acid sorption kinetics appear to be very similar, which suggests the formation of ternary U(VI)-FA-surface complexes. Hence, kinetic sorption data indicate a change in the underlying mechanisms of fulvic acid effects on U(VI) sorption behavior depending on the relative concentrations of metals, organic ligands and mineral surface sites. The observed variations in metal sorption kinetics are relevant for lab-scale sorption experiments, which are often designed to determine metal sorption characteristics in the presence and absence of organic matter under equilibrium conditions. Furthermore, in dynamic flow-systems on the field scale, apparent net effects of natural organic matter on metal sorption behavior may in fact be due to a combination of (1) changes in metal sorption affinities and (2) kinetic limitations of metal surface reactions. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
    AGU Fall Meeting Abstracts. 12/2010;
  • Ruth M Tinnacher, Bruce D Honeyman
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    ABSTRACT: Distribution coefficients (K(d) values) describe contaminant partitioning between liquids and solids for linear sorption at equilibrium conditions. If experimentally-determined K(d) values do not represent sorption equilibria, errors are introduced in contaminant transport models. These errors may be further propagated when K(d) values are used to compare contaminant mobility under different chemical solution conditions. Our theoretical analysis based on pseudo-first order sorption kinetics shows that, independent if two systems have the same or different sorption kinetics, relative comparisons of K(d) values and retardation factors are always affected by sorption times under non-equilibrium conditions. The time-frames required for attaining constant K(d) values are not only dependent on kinetic sorption characteristics, but also the equilibrium K(d) values approached. The type of kinetic errors introduced is affected by the specific differences in sorption kinetics and equilibrium K(d) values between the two systems. For systems with the same sorption kinetics, relative increases or decreases in contaminant velocities are always underestimated. In case of different kinetics, either an under- or overestimation of relative differences seems possible. Experimental sorption times should aim to equilibrate the system with the highest K(d) value for systems with comparable kinetics, and the system with the slowest sorption kinetics for different kinetics.
    Journal of contaminant hydrology 10/2010; 118(1-2):1-12. · 2.01 Impact Factor
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    ABSTRACT: Models are a mainstay of the environmental sciences; they allow for both deeper understanding of process knowledge and, to a limited extent, predictive capabilities of current day inputs on the future. Mathematical codes have become increasingly complex with explicit inclusion of many processes that could not be accounted for using simpler solving techniques. And yet, for metal/radionuclide transport in subsurface systems, the inclusion of smaller scale processes in a numerical solver do not always lead to better descriptions of larger scale behavior. The reasons for this are many, but included in this review are the following: unknowable conceptual model errors, discrepancy in the scale of model discretization relative to the scale of the chemical/physical process, and omnipresent chemical and physical heterogeneities. Although it is commonly thought that larger, more complex systems require more complex models to gain insight and predictive capability, there is little to no experimental evidence supporting this thought. Indeed, the evidence points to the fact that larger systems can be well described with simple models. To test this thought and to appreciate the incorporation of scaling behaviors into reactive transport modeling, new experiments are needed that are intermediate in scale between the more traditional bench and field scales.
    Environmental Science & Technology 10/2010; 44(21):7996-8007. · 5.48 Impact Factor
  • Emily K Lesher, James F Ranville, Bruce D Honeyman
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    ABSTRACT: The ability to quantify the amount of metals ions that are present as macromolecular, nanoparticulate, or colloid phases is critical for understanding bioavailability and transport as well as performing risk assessments and remediation strategies. Flow field-flow fractionation-inductively coupled plasma mass spectrometry (FI FFF-ICP-MS) is a powerful separation tool that has been previously used to characterize colloidal metals in environmental samples. In this study we examine the degree to which FI FFF-ICP-MS provides quantitative data on uranium speciation by comparing the results to centrifugation followed by filtration. Sorption of uranium to nanoparticulate hematite (approximately 60 nm) was examined over the pH range of 3 to 6. Close agreement was found between the two approaches over the pH range.
    Environmental Science and Technology 08/2009; 43(14):5403-9. · 5.48 Impact Factor
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    ABSTRACT: Batch adsorption experiments and spectroscopic investigations consistently show that aqueous Pu(IV) is quickly removed from solution and becomes incorporated in a brucite or hydroxylated MgO surface to a depth of at least 50 nm, primarily as Pu(IV) within a pH range of 8.5–12.5, and is unaffected by the presence of the organic ligand, citrate. X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS) and Rutherford backscattering spectroscopy (RBS) were used to estimate Pu penetration depth and provide information about its chemical state.
    Journal of Alloys and Compounds 06/2009; · 2.73 Impact Factor
  • Emily K. Lesher, James F. Ranville, Bruce D. Honeyman
    Geochmica et Cosmochimica Acta 06/2009;
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    ABSTRACT: Relatively recently, inorganic colloids have been invoked to reconcile the apparent contradictions between expectations based on classical dissolved-phase Pu transport and field observations of "enhanced" Pu mobility (Kersting et al. Nature 1999, 397, 56-59). A new paradigm for Pu transport is mobilization and transport via biologically produced ligands. This study for the first time reports a new finding of Pu being transported, at sub-pM concentrations, by a cutin-like natural substance containing siderophore-like moieties and virtually all mobile Pu. Most likely, Pu is complexed by chelating groups derived from siderophores that are covalently bound to a backbone of cutin-derived soil degradation products, thus revealing the history of initial exposure to Pu. Features such as amphiphilicity and small size make this macromolecule an ideal collector for actinides and other metals and a vector for their dispersal. Cross-linking to the hydrophobic domains (e.g., by polysaccharides) gives this macromolecule high mobility and a means of enhancing Pu transport. This finding provides a new mechanism for Pu transport through environmental systems that would not have been predicted by Pu transport models.
    Environmental Science and Technology 12/2008; 42(22):8211-7. · 5.48 Impact Factor
  • Ruth M. Tinnacher, Bruce D. Honeyman
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    ABSTRACT: In this paper we propose a new modeling concept for the prediction of the chemical conversion of reducible species as a function of reductant concentration in sodium borohydride reduction reactions. This concept is applicable to organic compounds of unknown reactive group concentrations, such as mixtures of organic or colloidal materials. In addition to the prediction of chemical conversion, the calculation of model fitting parameters also provides values for an “apparent, conditional equilibrium constant” and an effective reactive group concentration. These models are derived on the basis of simple chemical principles and a chemical equilibrium assumption. The model-fitting parameters can be easily determined with standard mathematical software. Nevertheless, these models capture the overall behavior of the chemical reduction reaction sufficiently well for accurate predictive needs. This modeling concept can be applied in two possible ways. First, model predictions allow the transfer of experimental chemical conversion data to new, similar target compounds, assuming that the necessary requirements are fulfilled. This leads to shorter time-frames required for process development. Second, these models can be applied as heuristic tools in order to test the feasibility of a proposed overall reaction mechanism and/or effective reactive group concentration.
    Organic Process Research & Development - ORG PROCESS RES DEV. 05/2008; 12(3).
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    Radiochimica Acta - RADIOCHIM ACTA. 01/2008; 96:739-745.
  • Ruth M. Harper, Cetin Kantar, Bruce D. Honeyman
    Radiochimica Acta - RADIOCHIM ACTA. 01/2008; 96:753-762.
  • Ruth M Tinnacher, Bruce D Honeyman
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    ABSTRACT: In this paper, we describe a new method for labeling NOM with the radioisotope tritium (3H) using fulvic acid (FA) as the target NOM fraction. During labeling, FA ketone groups are chemically reduced with tritiated sodium borohydride (NaBH4), while the chemical functionality of the carboxyl and phenol groups is preserved. The labeling procedure was optimized in efficiency experiments that determined the excess concentration of tritiated NaBH4 required for optimum reduction conditions. The chemical characterization of the labeled FA product using FTIR and 1H NMR spectral analysis confirms the proposed reaction mechanism and rules out any significant amounts of impurities or undesirable side reactions. Results from size exclusion chromatography indicate thatthe tritium label is distributed uniformly over the whole molecular size range of FA and that it is stable over time and under various pH conditions. Potential differences in FA sorption behavior onto mineral surfaces due to labeling were excluded based on experimental data. This method produces NOM of high specific activity (e.g., 1.9 mCi mg(-1) FA); this permits the tracing of FA at a detection limit of 0.3 microg L(-1) FA.
    Environmental Science and Technology 11/2007; 41(19):6776-82. · 5.48 Impact Factor
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    Yuji Arai, P B Moran, B D Honeyman, J A Davis
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    ABSTRACT: Np(V) surface speciation on hematite surfaces at pH 7-9 under pC2 = 10(-3.45) atm was investigated using X-ray absorption spectroscopy (XAS). In situ XAS analyses suggest that bis-carbonato inner-sphere and tris-carbonato outer-sphere ternary surface species coexist at the hematite-water interface at pH 7-8.8, and the fraction of outer-sphere species gradually increases from 27 to 54% with increasing pH from 7 to 8.8. The results suggest that the heretofore unknown Np(V)-carbonato ternary surface species may be important in predicting the fate and transport of Np(V) in the subsurface environment down gradient of high-level nuclear waste respositories.
    Environmental Science and Technology 07/2007; 41(11):3940-4. · 5.48 Impact Factor
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    ABSTRACT: The long-term mobility of actinides in groundwaters is important for siting nuclear waste facilities and managing waste-rock piles at uranium mines. Dissolved organic carbon (DOC) may influence the mobility of uranium, but few field-based studies have been undertaken to examine this in typical groundwaters. In addition, few techniques are available to isolate DOC and directly quantify the metals complexed to it. Determination of U-organic matter association constants from analysis of field-collected samples compliments laboratory measurements, and these constants are needed for accurate transport calculations. The partitioning of U to DOC in a clay-rich aquitard was investigated in 10 groundwater samples collected between 2 and 30 m depths at one test site. A positive correlation was observed between the DOC (4-132 mg/L) and U concentrations (20-603 microg/L). The association of U and DOC was examined directly using on-line coupling of Asymmetrical Flow Field-Flow Fractionation (AsFlFFF) with UV absorbance (UVA) and inductively coupled plasma-mass spectrometer (ICP-MS) detectors. This method has the advantages of utilizing very small sample volumes (20-50 microL) as well as giving molecular weight information on U-organic matter complexes. AsFlFFF-UVA results showed that 47-98% of the DOC (4-136 mg C/L) was recovered in the AsFlFFF analysis, of which 25-64% occurred in the resolvable peak. This peak corresponded to a weight-average molecular weight of about 900-1400 Daltons (Da). In all cases, AsFlFFF-ICP-MS suggested that<or=2% of the U, likely present as U(VI), was complexed with the DOC. This result was in good agreement with the U speciation modeling performed on the sample taken from the 2.3 m depth, which predicted approximately 3% DOC-complexed U. This good agreement suggests that the AsFlFFF-ICP-MS method may be very useful for determining U-organic matter association in small volume samples. Because the pH (7.0-8.1) and carbonate concentrations of these waters are typical of many groundwaters, these data suggested that facilitated transport of U by DOC may be limited in its importance in many groundwater systems.
    Journal of Contaminant Hydrology 06/2007; 91(3-4):233-46. · 2.89 Impact Factor
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    ABSTRACT: The focus of the project is the development of scientifically defensible approaches for upscaling reactive transport models (RTM) through a detailed understanding of U(VI) desorption across several spatial scales: bench-, intermediate-, and field-scales. The central hypothesis of the project is that the development of this methodology will lead to a scientifically defensible approach for conceptual model development for multicomponent RTM at contaminated DOE sites, leading to predictive transport simulations with reduced uncertainty.
  • Linda A. Figueroa, Bruce D. Honeyman, James F. Ranville
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    ABSTRACT: The chemical composition of the water and sediment affects the extent that uranium is immobilized in a microbially active environment. This paper summarizes an integrated framework of coupled microbial and chemical reactions in uranium bioremediation. The research is aimed at improving selection, design and operation of uranium biotreatment systems that use natural organic material to support the microbial consortium. Highlights of experimental and modeling efforts are presented.
    01/2006: pages 183-190;
  • Cetin Kantar, Bruce D. Honeyman
    Journal of Environmental Engineering-asce - J ENVIRON ENG-ASCE. 01/2006; 132(2).

Publication Stats

1k Citations
95.69 Total Impact Points


  • 1996–2013
    • Colorado School of Mines
      • Department of Civil and Environmental Engineering
      Golden, Colorado, United States
  • 2010
    • Lawrence Livermore National Laboratory
      Livermore, California, United States
    • Sandia National Laboratories
      Albuquerque, New Mexico, United States
  • 2008
    • Texas A&M University - Galveston
      • Department of Marine Biology
      Galveston, Texas, United States
  • 1988
    • University of Washington Seattle
      • Department of Oceanography
      Seattle, WA, United States