An apparatus and procedure are described for investigating
selective adsorption from a binary vapor mixture as a function of
pressure. The technique measures both total mass adsorption and
adsorbed-phase composition.
Development of the method is outlined. Possible sources of
error are analyzed and are found to be either nonexistent or...
The selective adsorption from a series of binary solutions on an
organoclay complex has been studied in relation to the gelling ability
of this organoclay. Adsorption isotherms were obtained for a series
of polar organic solvents in toluene. The isotherms were of the usual
"S" or "U" type depending upon...
Sepsis is a blood infection caused by circulating pathogens and cell wall fragments that affects over 1 million patients per year in the United States. When bacterial cell membranes are lysed by antibiotics, cell wall fragments containing lipopolysaccharides (LPS) are released. As a result, the capture of LPS is critical...
A multiple stage crosscurrent packed column suitable for gas-liquid
mass transfer was constructed and operated. The absorption
column consisted of a rectangular box constructed of plexiglass and
metal. Deflection baffles were positioned at regular intervals on
opposite sides of a central packed section to divert the gas phase
into the...
At present the adsorption kinetic of ions by soil particles is considered to be a surface reaction. When the transport of solutes in soils is described using the one-dimensional flow equation, it becomes a serious problem that lateral diffusion of ions from the bulk solution towards the soil surfaces is...
A multi-stage, crosscurrent column, packed with Pall rings, was
employed for oxygen absorption from an oxygen-rich air phase by
contacting with water. Mass transfer data were collected for the
column using 6 and 12 baffles and employing a partial gas phase recycle.
Data were also collected from a countercurrent column...
The performance of a multiple stage crosscurrent tower packed
with Pall rings was characterized with and without a recycle loop on
the gas stream. The column used 12 baffles. The absorption system
studied was the transfer of oxygen from an oxygen-enriched air stream
into a water stream which is a...
Batch sorption tests were conducted using 3,4-DCP and cellulose triacetate as the sorbate/sorbent pair. Sorbate concentrations
in the liquid were sampled with time and analyzed by electron
capture detector gas chromatography. Sorption was found to be a two
stage process characterized by a rapid initial uptake followed by a
extended...
Ellipsometry was used to study the effects of surface energetics
and temperature on the equilibrium adsorptive behavior exhibited by
β-lactoglobulin. β-Lactoglobulin isotherms at 25, 37, and 55°C were
constructed for this purpose. The surfaces of acrylic, polycarbonate,
polyester, glass, and #304 stainless steel were contacted with protein
solutions of varying...
The adsorption equilibrium and kinetic behavior exhibited
by β-lactoglobulin at silanized silicon surfaces of varying
hydrophobicity were examined using ellipsometry. Adsorption
equilibrium results were used to construct adsorption
isotherms; the adsorbed mass of β-lactoglobulin was observed
to increase with increasing surface hydrophobicity, within a
defined range of hydrophobicity. Adsorption kinetics...
Surface tension kinetics exhibited by selected stability mutants of T4 lysozyme at the air-water interface were monitored with DuNoüy tensiometry. Mutant lysozymes were produced by substitution of isoleucine at position 3 with cysteine, leucine, tryptophan and glycine. Each substitution resulted in an altered structural stability quantified by a change in...
The adsorption kinetics exhibited by selected charge mutants of T4 lysozyme at
silanized silica surfaces were monitored with in situ ellipsometry. Mutant lysozymes were
produced by substitution of lysine (Lys) with glutamic acid (Glu). Each substitution
resulted in a decrease in the net charge of the protein by 2 units....
A large rainfall simulator was used to study infiltration on six
soil plots. Water content and capillary pressure were measured during
steady rainfall at rates less than required to produce runoff. The
equipment and procedures used to make these measurements are discussed.
Water content and capillary pressure data obtained as...
In this research, the interfacial behavior of Trichoderma reesei CBHI and Thermomonospora fusca E₅ cellulases were studied at synthetic surfaces. For this purpose, colloidal silica and polystyrene particles were used to prepare cellulase-particle suspensions that were analyzed by several solution-phase techniques. These included circular dichroism spectroscopy, size exclusion chromatography and...
The formation of solution and solid complexes with heavy metals
will partially determine their mobility and plant availability in soil
systems. Experiments were initiated to determine the effect of pH,
adsorbent and initial metal concentrations, and the presence of water
soluble ligands on the adsorption of Cd and Cu by...
The reaction of F, often a component of industrial
wastes and phosphatic fertilizers, with soil was studied
with regard to sorption reactions and resultant changes in
solution composition. Sodium fluoride solutions (0.0 to
2.5 mmol/L F) were equilibrated with ten soils for 24h.
The soil extract solutions were analyzed for...
A Langmuir sorption model incorporating a second step of
irreversible absorption was applied to a model soil system. The column
was packed with cellulose triacetate; pulse and step input tests with
3,4-dichlorophenol were performed; the effluent concentration was
measured by electron capture detector gas chromatography and sorption
rate constants were...
Electric fields due to adsorbates on a metal surface are studied experimentally with Rydberg atoms as probes. A beam of lithium Rydberg atoms, produced by an oven in a high-vacuum system, passes within 3μm of the surface of a metal mesh having 6μm square openings. Rydberg states with principal quantum...
Chromium and its compounds are widely used by modern industries, resulting in large quantities of this element being discharged into the environment. To remove chromium from contaminated soils and ground water, it is necessary to predict chemical and physical processes that control the rate of reactions and transport of chromium...
A mathematical model was developed to predict the absorption
rate of a slightly soluble gas entrained by a plunging liquid jet. The
single parameter of the model, the transfer factor, TF, was defined
as the summation of the product of the mass transfer coefficient and
interfacial area over all the...
Experiments were conducted to study the effect of pore size
distribution on the diffusion of 2, 4-Dichlorophenoxyacetic acid (carbon-
14) through water saturated porous media. Eight size fractions of
glass beads were used representing the porous media. It was found
that as the average particle radius, and hence pore radius,...
Characterizing the hydrophobicity of nanoparticles can help us understand their fate and transport in the environment, as well as how nanoparticles may interact with biological systems. However, contact angle and partition coefficient have limitations in measuring the hydrophobicity of nanoparticles, thus promising methods to measuring the hydrophobicity of nanoparticles are...
The effect of pH and ionic strength on the equilibrium adsorptive
behavior of β-lactoglobulin onto hydrophobic and hydrophilic
silicon surfaces was studied using ellipsometry. Plots of amount
adsorbed (μg protein/cm²) as a function of protein concentration
(mg/ml) exhibited attainment of plateau values beyond a protein
concentration of 0.250 mg/ml. At...
Nisin, an amphiphilic, antimicrobial peptide, has been shown to integrate into the hydrophobic inner region of poly(ethylene oxide) (PEO) brush layers; however, the presence of integrated nisin may compromise the protein repulsive character of the PEO layer. In particular, the introduction of fibrinogen to nisin-loaded brush layers has been observed...
Several potential sorbent materials containing iron oxides were prepared and evaluated for potential to remove divalent metals from waste waters. These included a ferrihydrite-coated sand, maghemite incorporated in Dowex[Trademark] ion exchange resin, gothite and two thermally activated ferrihydrites. Attempts to prepare sorbents from steel shot by coating with ferrihydrite or...
In this study the enzymatic activity of adsorbed Thermomonospora fusca E₅ and Trichoderma reesei CBHI cellulases were investigated using fluorescence techniques. In particular, cellulases were allowed to contact hydrophobic polystyrene surfaces under conditions of different solution concentrations, and adsorption times. Each of these variables is known to have a potential...
Chitosan has been proposed as a "natural" coagulating agent to solve wastewater problems. The main hindrance in this commercial chitosan application has been its low cost effectiveness. The hypothesis in our research is that chitosan complexes with natural polyanions is more effective than chitosan alone, particularly in recovering low concentration...
Adsorption kinetic data recorded for α-lactalbumin, β-casein, β-lactoglobulin, bovine serum albumin and lysozyme at silianized silica surfaces of low and high hydrophobicity, along with a simple model for adsorption and surfactant-mediated elution of protein, were used to analyze the removal of each protein by sodium dodecylsulfate (SDS) and dodecyltrimethylammonium bromide...
Studies were undertaken of the adsorption of chlorinated phenols from aqueous solution on granular activated carbon (Filtrasorb-400, 30x40 mesh). Single-component equilibrium adsorption data on the eight compounds in two concentration ranges at pH 7.0 fit the Langmuir equation better than the Freundlich equation. The adsorptive capacities at pH 7.0 increase...