Contaminant transport in ground water is an important environmental process that
affects a host of natural systems. Transport of contaminants is affected by many
processes, including aqueous complexation, adsorption, and redox reactions. One of the
most important components of an aquifer that controls transport is iron-oxide. In this
study, the...
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...
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...