Personal Research Database

Full Text: J\J Haz Mat69, 53.pdf

Abstract: Hydrochlorofluorocarbons (HCFCs), among the major replacements for chlorofluorocarbons (CFCs) and chlorinated solvents, are now considered to the prime contribution to the stratospheric ozone depletion. This paper reports the adsorption equilibrium of 1,1-dichloro-1-fluoroethane (HCFC-141b) vapor in air streams on the commercial activated carbons PCB and BPL, which were made from coconut shell and bituminous coal, respectively, at 283, 293, 303, and 313 K. The experimental results show that within the experimental conditions, the adsorption capacities of the two adsorbents for HCFC-141b in dry air streams can be well-fitted by the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) adsorption equations. The physical properties of the adsorbents are consistent with the isotherm parameters obtained from the adsorption results. In addition, available experimental data of adsorption breakthrough at 283 K were used in conjunction with the Yoon and Nelson model to generate theoretical breakthrough curves based on the obtained values of parameters. In each case, calculated theoretical breakthrough curves are in agreement with corresponding experimental data. (C) 1999 Elsevier Science B.V. All rights reserved.

Keywords: HCFC-141B, Activated Carbons, Adsorption Isotherm, Breakthrough, CFC Replacements, HCFC 141B, Vapor, Capacities, HCFC-141B, Toxicity, Chloride, VOCs

? Nassar, I.N. and Horton, R. (1999), Transport and fate of volatile organic chemicals in unsaturated, nonisothermal, salty porous media: 1. Theoretical development. Journal of Hazardous Materials, 69 (2), 151-167.

Full Text: 1999\J Haz Mat69, 151.pdf

Abstract: A wide variety of volatile organic chemicals (VOC) have been applied to agricultural land or buried in chemical waste sites. The fate of these chemicals depends upon several mechanisms such as sorption, degradation, and transport in liquid and gaseous phases. Understanding the transport mechanisms affecting the volatile chemicals can lead to better management strategies. A theory describing inorganic solute transport, water and heat transfer, and the fate and transport of VOC in porous media has been developed. This theory includes matric water pressure head, solution osmotic pressure head, gravity pressure head, temperature, inorganic solute concentration, and VOC concentration gradients as driving forces for beat and mass transfer. The effect of surface tension, as a function of VOC concentration and temperature, on the matric water pressure head is included. The VOC can be associated with gas, Liquid, and solid phases of the porous media. The gas and liquid phases are mobile, but the solid phase is immobile. The transfer of VOC across the gas/liquid, liquid/solid, and gas/solid interfaces is included using sorption-equilibrium assumptions at the interfaces. The VOC can degrade. This degradation is described by a first-order decay rate. The theory can be used to predict spatial and temporal variations of water content, temperature, inorganic concentration and the total concentration of VOC within a porous medium. The concentration of VOC in each phase can be predicted also. (C) 1999 Elsevier Science B.V. All rights reserved.

Keywords: Coefficient, Degradation, Development, Evaporation, Flow, Function, Gas-Diffusion, Gradients, Heat and Mass Transfer, Interfaces, Lead, Management, Mass Transfer, Media, Model, Porous Media, Pressure, Rights, Simulation, Soil, Soil, Soil Temperature, Solute Transfer, Solute Transport, Sorption, Spatial, Strategies, Surface, Temperature, Tension, Theory, Total Concentration, Transfer, Transport, Unsaturated Flow, Variations, VOC, Water, Zone

? Nassar, I.N., Ukrainczyk, L. and Horton, R. (1999), Transport and fate of volatile organic chemicals in unsaturated, nonisothermal, salty porous media: 2. Experimental and numerical studies for benzene. Journal of Hazardous Materials, 69 (2), 169-185.

Full Text: 1999\J Haz Mat69, 169.pdf

Abstract: Simultaneous transport in soil of heat, water, potassium chloride, and benzene was studied experimentally and numerically. A laboratory experiment permitted observation of temperature, water content, chloride concentration and benzene concentration distributions in soil. A numerical model based upon newly developed transport theory was used to simulate the observed data. Transport of benzene in soils was simulated numerically under isothermal and nonisothermal conditions. Simulated results for benzene were compared with experimental data. Experiments were conducted in sealed aluminum columns (0.05-m I.D. and 0.20-m length) with sterilized salinized unsaturated Fayette soil. The soil had initial water content of 0.22 m(3)/m(3) and initial inorganic solute concentration of 0.20 mol/kg. Benzene was injected at one end of each soil column (top end) to provide 143 g/m³ benzene in the upper 0.01 m portion. The isothermal soil columns were set in an incubator at 29°C. The nonisothermal experiment had upper and lower boundary temperatures of 34 and 21°C, respectively. Isothermal and nonisothermal experiments each lasted for seven days. A numerical model based upon heat and mass transfer theory was used to predict transient soil temperature, water content, and inorganic and organic chemical distributions. Both predicted and measured final temperatures showed linear distributions. In the non isothermal study, water moved from the hot region toward the cold region, and inorganic solute accumulated in the hot region. Benzene redistributed along the soil column for both isothermal and nonisothermal conditions. Total concentration of benzene in the cold region under nonisothermal conditions was larger than the concentration of benzene in the hot region. On the other hand, the concentration of total benzene was approximately uniform along the soil column under isothermal conditions. For isothermal conditions, the benzene concentration by volume in the three phases followed the order: liquid > solid > gas. The results of this study indicated that transport models need to include the effect of temperature and temperature gradient to describe the movement of volatile chemicals in soils. (C) 1999 Elsevier Science B.V. All rights reserved.

Keywords: Adsorption, Aluminum, Benzene, Column, Diffusion, Experiments, Heat and Mass Transfer, Incubator, Isothermal, Mass Transfer, Media, Model, Models, Moisture, Need, Numerical Model, Observation, Porous Media, Potassium, Region, Rights, Simulation, Soil, Soil, Soil Column, Soil Temperature, Soils, Solute Transport, Temperature, Theory, Transfer, Transport, Unsaturated Flow, Water

Wu, F.C., Tseng, R.L. and Juang, R.S. (1999), Pore structure and adsorption performance of the activated carbons prepared from plum kernels. Journal of Hazardous Materials, 69 (3), 287-302.

Full Text: J\J Haz Mat69, 287.pdf

Abstract: According to iodine number, amount of Methylene Blue adsorption, the BET specific surface area, and the yield, the conditions for preparing activated carbons as adsorbents from plum kernels were optimized. The activation temperature and time tested were in the ranges 750-900C and 1-4 h, respectively. Adsorption isotherms of two commercial dyes and phenol from water on such activated carbons were measured at 30C. It was shown that the optimal activation temperature and time depended on the molar mass of the solutes, and all equilibrium isotherms could be fitted by the Langmuir equation. The experimental results indicated that the prepared activated carbons were economically promising for adsorption removal of dyes and phenol, in contrast to other commercial adsorbents. (C) 1999 Elsevier Science B.V. All rights reserved.

Keywords: Aqueous-Solutions, Fly-Ash, Equilibrium, Removal, Adsorbents, Dyestuffs, Cost, Sorption, Waste, Activated Carbons, Preparation, Plum Kernels, Adsorption Isotherms, Dyes, Phenol

? Lin, S.H. and Huang, C.Y. (1999), Adsorption of BTEX from aqueous solution by macroreticular resins. Journal of Hazardous Materials, 70 (1-2), 21-37.

Full Text: 1999\J Haz Mat70, 21.pdf

Abstract: Theoretical and experimental investigations were conducted on the adsorption of benzene, toluene, ethylbenzene and xylene (BTEX) by macroreticular resins. A mass transfer model based on the squared-driving force principle is presented for describing the BTEX transfer between the aqueous and solid phases. Also proposed is a theoretical model for describing the BTEX breakthrough curves of the adsorption column. While the mass transfer model involves only an overall mass transfer coefficient, the column adsorption model has two model parameters. Those parameters are conveniently estimated using the observed mass transfer and breakthrough data. The predictions using the proposed models were found to compare well with the experimental data of batch and column BTEX adsorption tests. (C) 1999 Elsevier Science B.V. All rights reserved.

Keywords: Adsorption, Adsorption Model, Aqueous Solution, Batch, Benzene, Breakthrough, Breakthrough Curves, BTEX, BTEX Adsorption, Column, Column Adsorption, Column Adsorption Model, Ethylbenzene, Force, Kinetics, Macroreticular Resin, Macroreticular Resins, Mass Transfer, Mass Transfer Coefficient, Mass Transfer Model, Model, Models, Phenol, Resins, Rights, Sorption, Theoretical Model, Toluene, Transfer, Wet Air Oxidation

? Arafat, H.A., Hebatpuria, V.M., Rho, H.S., Pinto, N.G., Bishop, P.L. and Buchanan, R.C. (1999), Immobilization of phenol in cement-based solidified/stabilized hazardous wastes using regenerated activated carbon: role of carbon. Journal of Hazardous Materials, 70 (3), 139-156.

Full Text: 1999\J Haz Mat70, 139.pdf

Abstract: The use of regenerated activated carbon as an immobilizing additive for phenol in solidification/stabilization (S/S) processes was investigated. The adsorption capacity of regenerated cai bon was compared to that of the virgin form and was found to be very close. The effects of pH and Ca(OH), concentration within the S/S monolith on the adsorption process were also examined. Kinetic tests were performed to evaluate the adsorption of phenol on different forms of F400 carbon, including the regenerated form. Kinetic tests were performed in aqueous solutions as well as in liquid-sand mixtures. Tn both cases, it was found that phenol adsorption on F400 carbon was fairly fast, More than 60% of the equilibrium adsorption amount could be achieved within the first hour for aqueous solutions. For sand-solution kinetics, it was found that 1% carbon (based on dry sand weight) was capable of achieving more than 95% removal of the initial amount of phenol present in solution (1000 and 5000 ppm). Fourier transform infrared (FT-IR) spectroscopy and X-fay mapping tests indicated a homogenous mixing of the carbon into the cement matrix. The carbon was also found to enhance the hydration of cement, which was retarded by the existence of phenol. (C) 1999 Elsevier Science B.V. All rights reserved.

Keywords: Achieved, Activated Carbon, Adsorption, Adsorption Capacity, Adsorption Process, Aqueous Solutions, Capacity, Carbon, Cement, Equilibrium, FT-IR, FTIR, Immobilization, Kinetic, Kinetics, Mapping, Mixtures, Organics, pH, Phenol, Phenol Adsorption, Process, Regenerated Activated Carbon, Removal, Rights, Sand, Solidification, Solidification, Stabilization, Stabilization

Juang, R.S. and Shiau, J.Y. (1999), Adsorption isotherms of phenols from water onto macroreticular resins. Journal of Hazardous Materials, 70 (3), 171-183.

Full Text: J\J Haz Mat70, 171.pdf

Abstract: The amounts of equilibrium adsorption of phenol and 4-chlorophenol from water on non-ionic macroreticular resins were measured in the temperature range 288-318 K, It was shown that the isotherm data could not be fit by any conventional two- or three-parameter equation including the Langmuir, Freundlich, BET, and Redlich-Peterson equations over the entire range of concentration (1-32 molm^-3). They were well fit by combined BET equation or its modified form with the Freundlich or Langmuir equation, depending on the types of solutes and the resins. Such different fitting results could be related to the solute-resin interactions owing to the relatively wide pore size distribution of the resins. The effect of temperature on adsorption equilibrium was also discussed. (C) 1999 Elsevier Science B.V. All rights reserved.

Keywords: Aqueous-Solution, Acid Dye, Sorption, Adsorbents, Equilibrium, Organics, Phenol, 4-Chlorophenol, Macroreticular Resins, Adsorption, Isotherm Analysis

Stam, G.J., Bottelberghs, P.H., Post, J.G. and Bos, H.G. (2000), PROTEUS, a technical and management model for aquatic risk assessment of industrial spills. Journal of Hazardous Materials, 71 (1-3), 439-448.

Full Text: J\J Haz Mat71, 439.pdf

Abstract: The assessment of risks to the aquatic environment related to industrial installations is a priority in environmental pollution control in the Netherlands. Major accidents to the surface water such as the Sandoz incident, but also the high number of smaller accidents that occur every year has invoked the need for an effective method to assess these risks. Two different models have been used in this field in the Netherlands over several years. These two software applications, VERIS and RISAM were developed from two different perspectives: VERIS from the perspective of supplying major accidents related information in the safety report. RISAM form the perspective of controlling risks for both smaller and larger facilities that may pollute surface waters through accidents, Both systems comprised particular strong points: VERlS considers safety management aspects in the assessment, RISAM considers differences in surface water vulnerability and involves quantitative probabilities in the assessment. It was decided to integrate both methods and maintain these strong points in the resulting method. This paper describes the new integrated risk assessment method that now has been developed in a concerted effort between the Ministry of Transport, Public Works and Water Management, the Ministry of Housing, Spatial Planning and Environment, and the National Institute for Public Health and Environment. It also describes the essential elements of the computer program PROTEUS that is based on the new method and that makes the assessment of aquatic risks for industrial activities an easy task, partly due to the automatic generation of the assessment report. (C) 2000 Elsevier Science B.V. All rights reserved.

Keywords: Industrial Hazards, Aquatic Risk, Risk Assessment, Risk Model, Risk Management, Quantitative Risk Analysis, Hazards

Wey, M.Y., Yan, M.H. and Chen, J.C. (2000), Treatment of hazardous sorbents generated from the adsorption of heavy metals during incineration. Journal of Hazardous Materials, 73 (1), 19-37.

Full Text: J\J Haz Mat73, 19.pdf

Abstract: The emission of heavy metals during waste incineration Can be effectively reduced through the practice of employing non-toxic sorbents. These sorbents can react with toxic metals at high temperatures and create metal binding between them by various physical and chemical mechanisms. After the adsorption process, the used sorbents, which contain heavy metals, need to be desorbed to reduce their potential environmental hazards or provide reusable sorbents for economical aspect. The sorbent’s adsorption efficiency is affected by different operating conditions and waste elemental compositions during incineration, which, in turn, affect their desorption characteristics. However, the effects of operating condition and waste elemental composition on the stability of heavy metals in the sorbents and the desorption efficiencies have been little studied. This study investigates the desorption characteristics of heavy metals (Cr, Pb, Cu, and Cd) from the hazardous sorbents with different extracting reagents (H₂O, HCl, EDTA, and Na₂S₂O₅). The hazardous sorbents were generated under different adsorption time and various input waste elemental compositions during incineration process.

Keywords: Soil, Lead, Removal, Adsorption, Sorbent, Extracting Agents, HCl, EDTA, Na₂S₂O₅

Wu, F.C., Tseng, R.L. and Juang, R.S. (2000), Comparative adsorption of metal and dye on flake- and bead-types of chitosans prepared from fishery wastes. Journal of Hazardous Materials, 73 (1), 63-75.

Full Text: J\J Haz Mat73, 63.pdf

Abstract: The adsorption capacities and rates of Cu(II) and a commercial reactive dye RR222 on flake- and bead-types of chitosans prepared from three fishery wastes (shrimp, crab, and lobster shells) were compared at 30^°C. It was shown that all equilibrium isotherms could be well fitted by the Langmuir equation. The adsorption capacity of Cu(II) on flake-and bead-types of chitosans appeared to be comparable, but the adsorption capacity of RR222 on bead type was much larger than that on flake type by a factor of 2.0-3.8. The rates of dye adsorption on both types of chitosans indicated different controlling mechanisms. In addition, the bead type of chitosans exhibited a greater rate compared to the flake type.

Keywords: Aqueous-Solutions, Removal, Adsorbents, Dyestuffs, Equilibrium, Sorption, Chitin, Cost, Derivatives, Kinetics, Fishery Wastes, Chitosan, Flake, Bead, Comparative Adsorption, Metal, Dye

? Sher, M.I., Arbuckle, W.B. and Shen, Z.Y. (2000), Oxygen uptake rate inhibition with PACT^TM sludge. Journal of Hazardous Materials, 73 (2), 129-142.

Full Text: 2000\J Haz Mat73, 129.pdf

Abstract: Oxygen uptake rate (OUR) experiments were performed with sludge from six laboratory-scale, continuously fed, activated sludge and PACT^TM reactors (sludge ages of 4-, 8-, and 12-days) to evaluate the sludge’s resistance to inhibitory compounds, Three inhibitory compounds with varied ability to sorb on activated carbon were tested: 3,5-dichlorophenol (3,5-DCP, strongly adsorbed), phenol (moderately adsorbed), and zinc (poorly adsorbed). The inhibitory compound concentration that reduced the unacclimated sludge’s specific oxygen uptake 50% from its maximum rate was determined (IC50). For the organic compounds, PACT^TM sludge resisted acute inhibition better for all sludge ages; sorption studies indicate that phenol sorbed onto the PACT^TM sludge could account for the IC50 difference at the higher sludge ages. With 3,5-DCP, the 4- and 8-day-old PACT and activated sludge solids sorbed similar amounts of 3,5-DCP at concentrations near the IC50 values, yet the PACT^TM sludge exhibited higher IC50 values; biomass differences may have accounted for the improved resistance to inhibition. With the poorly adsorbed zinc, no difference in IC50 or sorption was noted with the 4-day-old sludge. For the 12-day-old sludge, the PACT^TM sludge was much more resistant to zinc exposure, with changes in the biomass rather than sorption on carbon the apparent reason. (C) 2000 Elsevier Science B.V. All rights reserved.

Keywords: 3,5-Dichlorophenol, Ability, Activated Carbon, Activated Sludge, Activated-Sludge, Adsorption, Biomass, Carbon, Changes, Degradation, Difference, Experiments, Exposure, Inhibition, Organic Compounds, PACT^TM, Phenol, Resistance, Rights, Sludge, Sorption, Values, Zinc

? Benitez, F.J., Beltran-Heredia, J., Peres, J.A. and Dominguez, J.R. (2000), Kinetics of p-hydroxybenzoic acid photodecomposition and ozonation in a batch reactor. Journal of Hazardous Materials, 73 (2), 161-178.

Full Text: 2000\J Haz Mat73, 161.pdf

Abstract: The decomposition of p-hydroxybenzoic acid, an important pollutant present in the wastewaters of the olive oil industry, has been carried out by a direct photolysis provided by a polychromatic UV radiation source, and by ozone. In both processes, the conversions obtained as a function of the operating variables (temperature, pH and ozone partial pressure in the ozonation process) are reported. In order to evaluate the radiation flow rate absorbed by the solutions in the photochemical process, the Line Source Spherical Emission Model is used. The application of this model to the experimental results provides the determination of the reaction quantum yields which values ranged between 8.62 and 81.43 l/einstein. In the ozonation process, the film theory allows to establish that the absorption process takes place in the fast and pseudo-first-order regime and the reaction is overall second-order, first-order with respect to both reactants, ozone and p-hydroxybenzoic acid. The rate constants are evaluated and vary between 0.1810⁵ and 29.910⁵ l/mol s depending on the temperature and pH.

Keywords: Absorption, Application, Batch, Batch Reactor, Decomposition, Experimental, First Order, Flow, Function, Kinetics, Model, Ozonation, Ozone, P-Hydroxybenzoic Acid Degradation, pH, Photolysis, Pressure, Pseudo First Order, Pseudo-First-Order, Quantum Yields, Radiation, Rate Constants, Second Order, Second-Order, Solutions, Source, Temperature, Theory, UV, UV Radiation, Wastewaters

? Gunnison, D., Zappi, M.E., Teeter, C., Pennington, J.C. and Bajpai, R. (2000), Attenuation mechanisms of N-nitrosodimethylamine at an operating intercept and treat groundwater remediation system. Journal of Hazardous Materials, 73 (2), 179-197.

Full Text: 2000\J Haz Mat73, 179.pdf

Abstract: The North Boundary Containment System (NBCS), an intercept-and-treat system, was established at Rocky Mountain Arsenal (RMA), Commerce City, CO, to remove low-level organic contaminants from a groundwater plume exiting RMA to the north and northwest. N-nitrosodimethylamine (NDMA) was detected in groundwater collected from the dewatering and recharge zones of the NBCS system. Concern over the fate of NDMA, in terms of potentially exiting the boundaries of the arsenal, prompted an investigation to evaluate potential attenuation mechanisms for NDMA within the alluvial aquifer system and within the NBCS itself. Groundwater, soil, and granular activated carbon (GAC) samples were taken from key locations in the NBCS system. Soil and GAC samples were assayed for sorption kinetics and for adsorption and desorption properties using C-14-labeled NDMA. NDMA biodegradation experiments were conducted by following (CO₂)-C-14 evolution from C-14-labeled NDMA in soils and GAC samples under aerobic and anaerobic conditions. The sorptive capacity of the site soils for NDMA was insignificant. Furthermore, the adsorption of the NDMA by the soil was almost completely reversible. Evaluation of the degradation potential of the native microbial consortia indicated a high level of NDMA mineralization when measured using bench-scale microcosms. The native consortia had capability to mineralize the NDMA under both aerobic and anaerobic incubations, indicating facultative characteristics. Testing of the local groundwater chemistry revealed that the area of the aquifer of interest was microaerobic and neutral in pH. These conditions were optimal for NDMA removal. While sorption was insignificant. degradation was a significant attenuation mechanism, which may be the reason that no NDMA has migrated off-site. This gives rise to the potential or a long-term sink for attenuating NDMA within the recharge zone of the treatment system. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Aerobic, Anaerobic, Biodegradation, Boundaries, Capacity, Carbon, Co, Contaminants, Degradation, Desorption, Evolution, Experiments, GAC, Granular Activated Carbon, Groundwater, Groundwater Remediation, Key, Kinetics, Mechanism, Microcosms, Mineralization, N-Nitrosodimethylamine, Natural Attenuation, NDMA, Organic Contaminants, pH, Remediation, Removal, Rights, Samples, Soil, Soils, Sorption, Sorption Kinetics, Treatment

? Marhaba, T.F. and Pu, Y. (2000), Rapid delineation of humic and non-humic organic matter fractions in water. Journal of Hazardous Materials,