David Dzombak - Academia.edu (original) (raw)

Papers by David Dzombak

Journal of Colloid and Interface Science, 2004

Ferrocyanide (Fe(CN)4−6) adsorption onto γ-alumina (γ-Al2O3(s)) and gibbsite (Al(OH)3(s)) was inv... more Ferrocyanide (Fe(CN)4−6) adsorption onto γ-alumina (γ-Al2O3(s)) and gibbsite (Al(OH)3(s)) was investigated over a wide pH range and at various solid loadings. Batch experiments were performed using 100-ml solutions (I=0.01 M NaCl) dosed with 1.0 mgl−1 Fe(CN)4−6 as CN. Equilibrium adsorption–pH edges were developed for 0.3, 0.6, 1.2, and 2.0 gl−1γ-Al2O3(s) and 25 gl−1 Al(OH)3(s). Ferrocyanide adsorption increased as pH decreased, consistent with the general

Colloids and Surfaces A-physicochemical and Engineering Aspects, 1997

This study examines the effects of pH, electrolyte concentration and solids concentration on the ... more This study examines the effects of pH, electrolyte concentration and solids concentration on the surface charge characteristics, viscosity and stability of concentrated alumina dispersions, and the relationships between these properties of the dispersions. The surface charge properties of various concentrated alumina dispersions were investigated using acid-base titrations. Suspension viscosity and stability were also investigated for selected dispersion concentrations, electrolyte concentrations,

Journal of Construction Engineering and Management-asce, 1996

Journal of Contaminant Hydrology, 1998

This paper presents the results of modelling and experimental investigations of factors affecting... more This paper presents the results of modelling and experimental investigations of factors affecting enhanced transport of hydrophobic organic compounds (HOCs) on colloids in porous media, especially effects of nonequilibrium sorption/desorption. Simulations were performed with a model that considers equilibrium and rate-limited exchange of contaminant between the true dissolved phase, the suspended and attached colloids, and the fixed solid phase as

Colloids and Surfaces A-physicochemical and Engineering Aspects, 1996

Colloid release was observed from packed columns for two natural porous media (sands) and one mod... more Colloid release was observed from packed columns for two natural porous media (sands) and one model system (glass beads with deposited latex colloids). Colloid release was found to occur in all cases when the ionic strength was reduced in columns that were in equilibrium with Na+ ions. Most of the released colloids from the natural porous media were smaller than

Environmental Science & Technology, 1997

... purged with N 2 , capped, and equilibrated on an end-over-end rotator (Fisher Scientific, Pit... more ... purged with N 2 , capped, and equilibrated on an end-over-end rotator (Fisher Scientific, Pittsburgh, PA) for at least 24 h. The aqueous phase in the ... Transport experiments were performed to observe the effects of colloids on the retardation of a contaminant through a ...

Environmental science & technology, Jan 12, 2015

Complex, hypersaline brines-including those coproduced with oil and gas, rejected from desalinati... more Complex, hypersaline brines-including those coproduced with oil and gas, rejected from desalination technologies, or used as working fluids for geothermal electricity generation-could contain critical materials such as the rare earth elements (REE) in valuable concentrations. Accurate quantitation of these analytes in complex, aqueous matrices is necessary for evaluation and implementation of systems aimed at recovering those critical materials. However, most analytical methods for measuring trace metals have not been validated for highly saline and/or chemically complex brines. Here we modified and optimized previously published liquid-liquid extraction (LLE) techniques using bis(2-ethylhexyl) phosphate as the extractant in a heptane diluent, and studied its efficacy for REE recovery as a function of three primary variables: background salinity (as NaCl), concentration of a competing species (here Fe), and concentration of dissolved organic carbon (DOC). Results showed that the mod...

Waste management (New York, N.Y.), 2014

Thirty-one alkaline industrial wastes from a wide range of industrial processes were acquired and... more Thirty-one alkaline industrial wastes from a wide range of industrial processes were acquired and screened for application in an aqueous carbon sequestration process. The wastes were evaluated for their potential to leach polyvalent cations and base species. Following mixing with a simple sodium bicarbonate solution, chemistries of the aqueous and solid phases were analyzed. Experimental results indicated that the most reactive materials were capable of sequestering between 77% and 93% of the available carbon under experimental conditions in four hours. These materials - cement kiln dust, spray dryer absorber ash, and circulating dry scrubber ash - are thus good candidates for detailed, process-oriented studies. Chemical equilibrium modeling indicated that amorphous calcium carbonate is likely responsible for the observed sequestration. High variability and low reactive fractions render many other materials less attractive for further pursuit without considering preprocessing or act...

Geochemical Transactions, 2014

Chemistry, Risk, and Management, 2005

Environmental science & technology, Jan 7, 2014

This study evaluated the feasibility of using three impaired waters - secondary treated municipal... more This study evaluated the feasibility of using three impaired waters - secondary treated municipal wastewater, passively treated abandoned mine drainage (AMD), and effluent from ash sedimentation ponds at power plants - for use as makeup water in recirculating cooling water systems at ...

Environmental Science & Technology, 2003

Chemistry, Risk, and Management, 2005

Water Research, 2004

Changes in water quality over 25 years have been documented for discharges from an extensive netw... more Changes in water quality over 25 years have been documented for discharges from an extensive network of abandoned underground coal mines in the Uniontown Syncline, Fayette County, PA, USA. A baseline study of 136mine discharges in the syncline was conducted in 1974–1975. In 1998–2000, follow-up water flow and quality monitoring was conducted at 21 selected discharges for 2 years to