You are cordially invited to the URI Chemical Engineering Open Day and Graduate Student Poster Presentations on Wednesday, May 3, 2000.  Attached is the schedule including titles and abstracts of the presentations and posters. In the morning, the Faculty will present their research. Following lunch, graduate students will present posters and meetings with the Faculty and laboratory tours will be available. The presentations will be in the Cherry Auditorium  in the Kirk Technology Center on Upper College Road at the University of Rhode  Island in Kingston, Rhode Island.  We hope you or a colleague can attend. If there are other people who you feel would be interested in attending, please feel free to pass this information onto them. This day is a great opportunity to discover  the research that is being conducted at URI in the Chemical Engineering  department. If you require anymore information, such as directions, do not hesitate to contact me at (401) 874-2707 or by e-mail at rbrown@egr.uri.edu. We would appreciate you informing us of your intent to attend this Open Day by Monday, May 1, so we can plan accordingly for the correct number of attendees. 

I look forward to seeing you on May 3, 2000. 

Sincerely,

Richard Brown, Chair
Chemical Engineering Department
 

9:10-9:30                      Mercedes A. Rivero-Hudec, Associate Professor
                                     “Microbial Populations and Chemical Engineering“

9:30-9:50                     Stanley M. Barnett, Professor 
                                    “Energy, Pollution Prevention, Risk Assessment and Biotechnology:  Industrial
                                     Partners Needed”

9:50-10:10                    Harold Knickle, Associate Dean of Engineering
                                     “International Incubator for Technology and Improving the Performance of Gasoline
                                      Powered Lawn Mowers”

10:10-10:30                   Angelo Lucia, Chester H. Kirk Professor 
                                      “Chemical Process Engineering at the University of Rhode Island”

10:30-10:45                    Refreshments

10:45-11:05                   Vincent C. Rose, Professor
                                      “Innovative Energy Technology Collaborative”

11:05-11:25                    Arijit Bose, Professor
                                       “Nanostructured Materials and Interfaces” 

11:25-11:45                    Donald J. Gray, Associate Professor
                                       “Composite Processing in Low Vacuum Systems”

11:45-12:05                    Otto J. Gregory, Distinguished Engineering Professor
                                        “Semiconductor Strain Gages for Harsh Environments”

12:05-12:25                     Richard Brown, Professor 
                                        “A Non Chromate Conversion Coating to Replace Chromates” 

12:30-1:30 p.m.               Lunch

1:35-3:00                         Poster Session 

3:00-4:30                         Laboratory Tours

Understanding of aquatic microorganisms’ activity in their natural environment is essential to processes such as pollution and its remediation, biocorrosion and biofouling, biogeochemical cycling of elements and genetic exchange and biodegradation.  Our research applies chemical engineering principles to the study of aquatic microbial populations with emphasis on autotrophic and heterotrophic flagellates.

One of our projects examines the effects of heavy-metal exposure on phytoplankton.  Phytoplankton are primary producers and, as such, are at the base of food chain.  Therefore, their exposure to heavy metals could result in impairment of the food chain and metal transfer to higher trophic levels.  Another project focuses on the interaction between bacteria and heterotropic flagellates.  Both microorganisms are among the first to adhere to and form microbial films on submerged surfaces (microbial adhesion and biofilm formation are processes leading to biocorrosion and biofouling).

To study the dynamics of the cell populations, we use a stopped-flow diffusion chamber, which roves well-characterized chemical and cell gradients.  Cell distributions in the chamber are digitally recorded and analysed.  Masss-transfer models are used to quantitatively express results in terms of microorganisms’ parameters analogous to diffusitivites and bulk velocities.
 
 

A brief overview of industrial support projects will be provided.  These include pollution prevention and energy assessments as well as evaluation of risk management plans.

Research on limiting factors for photo-bio and photo-catalytic reactors for environmental cleanup and pharmaceutical, polymer and hydrogen production will be briefly discussed.

Membrane systems for desalination, water reuse, energy and environmental applications will be discussed.  Our group is especially interested in forming teams with industry for the purpose of obtaining federal funds.
 
 

NAMI, the Central Automobile and Automobile Engine Scientific Research Institute in Moscow and URI have obtained a grant from the Department of Energy to begin testing of an Aluminum-Air battery.  The battery was developed at NAMI for the drive motor of an electric automobile.  The Al-Air battery provide one of the highest specific energies of any cell with a theoretical value of 2815 Wh/kg.  Real losses lower that value substantially.  The United States and Russia performed extensive work on this battery system especially in the mid 1980’s.  The US essentially discontinued that work shortly after the mid 1980’s while NAMI continued to make improvements.  Testing at URI will attempt to evaluate the latest experiments in Moscow and to recommend further developmental work. 

Improving the Performance of Gasoline Powered Lawn Mowers

Russian Technology is used to reformulate the surface of aluminum lawn mower pistons.  These pistons are now being tested in a five horsepower Briggs and Stratton lawnmower engine.  The reformulation can take place up to 400 micrometers.  Both the skirt and the top surface and the side of the piston undergo treatment.  The treatment decreases the surface thermal conductivity.  This increase in thermal conductivity slows the loss of heat from the combustion chamber and increases the combustion temperature.  The increase in combustion temperature decreases the fuel usage and the exhaust pollutants.  Tests are underway to confirm other results from Russian engines indicating mileage increases up to 20 percent. 
 
 

Chemical process engineering encompasses a number of interrelated skills - mathematical modeling, thermophysical property estimation, an understanding of numerical methods, computer graphics and others.  Various combinations of these skills are often required in equipment design, process simulation and optimization, control system design as well as in other areas of the chemical process industries.  In this presentation, I will give an overview of the process engineering efforts in Chemical Engineering at the University of Rhode Island.  In particular, I will present results from a number of recently funded government and industrial projects that illustrate both the need for the above-mentioned skills and the  value-added attributes of process engineering.  Industrial applications include the development of a general-purpose multiphase flash algorithm for use within the Aspen Plus simulator, the modeling and control system design of  an industrial polymer mixer and the phase equilibrium modeling of environmentally friendly refrigerant/oil mixtures in compressor operations.  I will also briefly discuss the theoretical and practical aspects of some work currently funded by the National Science Foundation.
 
 

An Innovative Energy Technology Collaborative has been established in the College to develop and promote the use of renewable energy sources and encourage energy conservation practices.  This center also will foster communication and collaboration among government agencies, energy providers, and energy customers. 

One focus of the center will be research related to fuel cells and related issues of producing and storing the fuels as well as the energy produced.  This includes developing:
a). new alternative sources of fuels. 
b). methods of supplying and storing these fuels. 
c). improved fuel cell components. 
d). innovative methods of storing the energy produced. 

In the short term methane will be the fuel explored while hydrogen is the long term fuel of choice.

In addition, the collaborative will perform demonstration of renewable energy and energy efficient systems.  Demonstration facilities can be used to acquire further information and serve as a tool for public awareness.  Examples of possible renewable energy systems include, but are not limited to, fuel cells, active and passive solar heating and cooling, heat pumps, photovoltaics,  combined heat and power systems and energy conservation.  Efforts will be made to use off the shelf components and systems with short payback periods. 

Results of this work will be used to promote the adoption of innovative energy technology in local industries.  Areas include working with industries and government agencies to improve energy efficiency in the metal casting and jewelry industries and in waste treatment processes. 

These efforts will use graduate and undergraduate students in research, development and demonstration activities.  Through this endeavor, students will gain development and application experience as well as increased awareness of energy conservation practices and available energy alternatives.
 
 

Recent research in our group is focused on  (i)self-assembly of surfactant aggregates and their exploitation for nanostructured materials synthesis (ii) development of a flow-through device for colloidal magnetic affinity separations and (iii) developing a robust strategy for modeling processes that contain dynamic contact lines. 

Progress in each of these areas will be reviewed, with a special emphasis on how these results can be applied to problems of practical importance. 
 
 

The treatment of metals and plastics may be in the form of coating, etching, deposition, cleaning, stripping, plating, adhesion, dissolving filtering and many other types of processes throughout the manufacturing industries.  Unless the process is required to be carried out in a negative gage pressure environment, an enclosed low vacuum system is not considered mainly because of the additional capital cost required for the process. In many cases however, vacuum systems can prove to be much more efficient, flexible, and environmentally friendly while having an overall life cycle costs savings.  A number of fields operating equipment designs and research processes being evaluated in the Chemical Engineering Department will be discussed with emphasis placed on overall costs and process efficiency.
 
 

A robust thin film strain gage has been developed for both static and dynamic strain measurement at temperatures approaching 1500C.  These thin film sensors are ideally suited for in-situ strain measurement in harsh environments such as those encountered inside a gas turbine engine. The sensors are non-intrusive, having dimensions considerably less than the boundary layer thickness and thus, do not adversely affect the gas flow path through the engine and are robust enough to withstand the high “g” loadings associated with rotating components.  Results of recent laboratory tests here at URI in conjunction with extensive high temperature-high frequency, dynamic testing at  NASA have shown that these strain gages can meet most of the current demands of high performance aerospace applications.  Specifically, static strain tests have been performed at URI to determine piezoresistive response at temperatures as high as 1450C, which is considerably higher than the current state of the art high temperature strain gages.  Also, high frequency dynamic strain tests were performed at 2000Hz and 500 ?? to simulate conditions that would be encountered during high cycle fatigue.  For this purpose, thin film sensors based on alloys of indium-tin-oxide were deposited directly onto specially prepared Inconel 718 constant strain beams that were subsequently cycled for 1 hour at temperatures ranging from room temperature up to 700C.  These results indicated that not only did these sensors survive the severe testing conditions but that they were sensitive enough to isolate possible causes of high cycle fatigue, which is the leading cause of failure in high performance propulsion engines.
 
 

Chromate conversion coatings for corrosion resistance and adhesive bonding treatments are environmentally unfriendly.  In this research the protection mechanism used by chromates was investigated. From an understanding of this mechanism a non-chromate alternative conversion coating was designed. One requirement of the new coating process is that it follows the same processing route as present chromate conversion coating. This was successfully achieved. Electrochemical testing indicates that the new,  non chromate coating equals chromate conversion coating in corrosion protection for aluminum alloys such as Al 2024, a copper bearing alloy.  Data will be presented in this talk comparing the non chromate alternative to chromate for a range of alloys.
 

A flow-through hybrid magnetic field gradient device was developed for the recovery of cadmium from waste solution using extractant-coated magnetic particles. The device utilizes an axially-rotating horizontal glass tube, with four axially located repeating hybrid magnetic units. Each magnetic unit consists of an alternating current solenoid surrounding the chamber followed by four azimuthally distributed permanent magnets that rotate with the chamber. 

Experiments were carried out on a feed system consisting 10mg/L of cadmium solution using polymeric coated ferromagnetic particles with an absorbed layer of bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) and di-(2-ethylhexyl) phosphoric acid (D2EHPA). The result demonstrated that cadmium recovery was improved using the device over the conventional techniques (solvent extraction). This enhancement was attributed by repeated introduction of fresh magnetic particles to the supernatant leaving the stages. 

It is to be recalled (Ghebremeskel and Bose, Separation Science and Technology, 1999) that the same device was used for separation of model system feed mixture consisting biotinylated latex beads (targets) and non-functionalized latex beads (non-targets). Streptavidin labeled magnetic particles were used as the separation vehicles. The removal of cadmium experimental result coupled with previous results from model system experiment will be the focus of our poster presentation.
 
 

Although template-directed mineralization in equilibrium surfactant phases have proved versatile approaches to access novel materials processing order on the nanometer scale, nano-particle processing using non-equilibrium structures such as disks or evolutional small vesicles as templating phase to direct the deposition have not been explored.  Template-directed synthesis of nanoparticles on non-equilibrium structures might offer new alternatives to conventional synthetic strategies.  In the present work, the synthesis of nanoparticles of iron hydroxide by precipitating on the non-equilibrium structures, including disks and tiny vesicles of 10~20 nm in diameter, during micelle-to-vesicle transition has been attempted. TEM is used to explore the morphology and size of products. Microanalysis confirmed the formation of iron particles. The difference between particles produced by template-directed synthesis and from precipitates formed in bulk solution in the absence of disks and vesicles is examined. 
 
 

In preparation for Space Station experiments focused towards developing the correct boundary conditions for modeling dynamic wetting processes, the engineering team needs tolerance limits for several of its design parameters such as smoothness of solid surfaces, velocity control and vibration. Fabrication of equipment that satisfies these tolerance limits is critical towards obtaining high quality data so that the required physics can be extracted from the experiments. We use numerical simulations as a fast and efficient tool to obtain these tolerance limits. The Galerkin Finite Element Method code is used to solve for velocity and pressure fields as well as free surface location for the experimental configuration. Design parameters are changed directly in the simulations, and their effects quantified.  These simulations can potentially save large expenditures for the design team involved in the dynamic wetting experiments.
 
 

The determination of the correct number of equilibrium phases and their corresponding compositions at fixed temperature and pressure (TP flash) is studied.  The novel aspects of this work center around unique initialization strategies and Successive Quadratic Programming (SQP) enhancements that include the use of 1) only binary tangent plane analyses, 2) the determination of all partially miscible binary pairs and a dominant immiscible pair, 3) novel relative solubility calculations based on component activities and double tangency separation, 4) least squares solutions to compute phase fraction estimates, and 5) a variety of algorithmic features that dynamically trap difficulties such as compositions well below machine accuracy and trivial and collapsed solutions.  The overall algorithmic framework is one based on using a combination of binary tangent plane analyses, bubble point calculations and dimensionless Gibbs free energy minimizations.  Binary tangent plane analyses are used to identify all immiscible or partially miscible binary pairs and to avoid dimensionality difficulties associated with locating all stationary points in the tangent plane distance function in the full composition space.  The proposed approach consists of solving a sequence of subproblems (i.e., LE, LLE, VLLE, ...) until the global minimum dimensionless Gibbs free energy (G/RT) is found.  Maximum information from binary tangent plane analyses and previously solved subproblems are used to generate initial values for the next subproblem.  The concept of relative solubilities is introduced and used to initialize phase compositions in all LLE calculations (i.e., phase split or flash).  All completely miscible component relative solubilities are calculated using component activities while those for immiscible or partially miscible components are initialized using double tangency separation.  Phase fractions are initialized using a least-square solution to the set of component mass balances.  All subproblems are formulated in terms of component flows and solved using a full space SQP method using a modified Broyden-Fletcher-Goldfarb-Shanno (BFGS) update of the Lagrangian Hessian matrix.  The proposed algorithm was tested within the Aspen Plus process simulator using a variety of physical properties options.  Twenty seven multicomponent mixtures including some four-phase (VLLLE) emulsion polymerization problems were used to test the proposed algorithm.  All problems were easily solved and clearly demonstrate the capabilities of the present Multiphase TP Flash Model.
 
 

Process simulation involves the mathematical modeling of a process and subsequent determination of one or more solutions to the corresponding model equations.  The presence of singular points can drastically alter the performance of numerical methods for solving chemical process model equations and, as a result, commonly used computational tools such as Newton's method, trust region (or dogleg) strategies and other equation-solving techniques can exhibit periodic/aperiodic behavior, slow convergence, or divergence.  Moreover, when norm reduction is used, iterates can get trapped at singular points that are local minima in the least-squares function. 

This work is concerned with the convergence of Newton’s method and traditional and complex domain trust region methods in regions containing singular points that are either local minima and saddle points of the least squares function.  It is shown that Newton’s method behaves periodically while traditional dogleg strategies exhibit slow convergence and terminate at singular points. Complex domain trust region methods, on the other hand, converge quickly and reliably to singular points using quadratic acceleration and subsequently to (nearby) solutions using eigendecomposition.  Single variable nonlinear equations such as the Statistical Associating Fluid Theory (SAFT) equation of state are used to illustrate the challenges and resolutions of simulation in singular regions.
 
 

In process simulation, one of the most difficult tasks is solving a mathematical model, which is composed of a system of nonlinear equations with presence of singular points.  For decades, much effort has been devoted to both theoretical research and numerical algorithm development for solving nonlinear equations.  However, in both chemical engineering and applied mathematics, little attention has been paid to understanding the effects of singular points on the numerical performance of equation-solving methods.  In our opinion, studying singularity and its impact on equation-solving will help develop more efficient and robust numerical algorithms for solving large systems of nonlinear equations and uncover the relationship between singular points and multiple solutions within a model. 

Some of recent developments in both theoretical analysis and numerical algorithm implementation will be demonstrated with VT flash calculation and a two-stage distillation problem.
 
 

In today’s cleaning industry companies have been forced to change their current cleaning processes.  Governmental regulations have continued to become more stringent on usage of specific cleaning agents because of their environmental harmfulness.  These companies must seek alternative processes, equipment and cleaning agents that are accepted by the Environmental Protection Agency.

Currently most part and equipment manufacturers have relied on traditional cleaning methods that utilize single and multiphase solvent cleaning.  These traditional methods have been used for many years and have not required any changes or modifications.  Over the past decade many of the traditional cleaning solvents have been limited to or banned from their continued use, leaving the manufacturer to find a safer and more environmentally safe cleaning media.

Solvent manufacturers have had to derive new cleaning agents and numerous chemical blends to replace the traditional solvents for non-regulated cleaning applications.  The part and equipment manufacturer now has to decide which new cleaning media is the most effective and cost efficient for their needs.  The part and equipment manufacturer currently has to rely on the solvent manufacturer for guidance in selecting the proper replacement.  Unfortunately solvent manufacturer’s are sales driven and can easily persuade the part and equipment manufacturer into selecting the least effective and high cost application to make a sale. 

By developing a scientific model with the understanding of the laws of science, part and equipment manufacturers will no longer have to rely on the solvent manufacturer when making their selection for the correct replacement.  Using thermodynamic methods a solvent screening process can be created to model each new cleaning agent or chemical blend before the part and equipment manufacturer makes a capital investment for the company’s future.  This model can prevent the part and equipment manufacturer from making a costly mistake on a poor investment as a result of being misdirected by a bias opinion and/or recommendation.

The model can also be used for designing chemical co-solvent mixtures.  Co-solvent mixtures are being researched to help reduce manufacturing processing steps by completing multiple cleaning operations for multiple contaminants in a single process step.  The model analyzes the thermodynamic interaction of the components aiding the user to help determine the required co-solvent components and the mixtures molar composition. 
 
 

The marine biota is exposed to heavy metal residues of industrial and agricultural processes.  The impact that these metals can have on phytoplankton are of particular interest because phytoplankton, as primary producers, represent the first link in the food chain and are able to transfer the metal to higher trophic levels. 
This study aims to examine the effects of cadmium (Cd), a heavy metal considered to be non-essential for living organisms, on phytoplankton. 
The effects of toxic substances, including heavy metals such as Cd, are often observed in terms of the physiological changes of the organisms and their growth, reproduction, and survival.  However, impairment on other activities that can affect the survival of the organism may also arise from exposure to the metal.  Parallel to the studies of Cd bioaccumulation and its effect on the growth rate, the motility of control and Cd-exposed cells will be measured and compared.  For dinoflagellates, members of the phytoplankton community, swimming activity has great significance because they depend on it for their migration up and down in the water column. Additional information regarding the effects of Cd, therefore, will be obtained from observations of the motility of the organisms.  A stopped-flow diffusion chamber, previously used to measure bacterial chemotaxis and motility, is currently being tested to observe and quantify the swimming activity of dinoflagellates.

The presentation will provide information regarding the significance of the studies, a description of the experimental setup and analysis, and some preliminary results.
 
 

Deterioration of concrete structures due to steel corrosion is a matter of considerable concern as the repairing of those structures proved to be a costly procedure. One approach to minimize this effect is by reinforcing the concrete structures with randomly distributed polymer fibers. There is an increasing worldwide interest in utilizing the fiber reinforced concrete structures for civil infrastructure applications. However these fiber reinforced concrete structures have been shown to suffer from degradation when exposed to marine environment.  The specific problem is surface blistering. This reduces the adhesive bond strength and causes delamination of the composite. The bonding between the fibers and the concrete has to be good and the plastic has to withstand the changing environment of freeze and thaw as well as high pH of 12.5 when new down to pH 6.5 when saturated with sodium chloride. With these brand new materials, little is known about the effect of fiber percentage on fracture properties under hot and cold conditions and when saturated with seawater. One of the objectives of this research is to study the Freeze-thaw durability of the fiber reinforced concrete structures under different conditions of marine environment. 
 
 

A new non-chromate conversion coating has been developed at the University of Rhode Island. The process is similar in function to existing chromates so no changes in equipment will be required by companies. Corrosion testing by potentiodynamic scans for a series of aluminum alloys indicates that the URI conversion coating is as good at protecting the alloys from corrosion in seawater as chromates. Data will be presented and applications discussed in the poster.
 
 

Chromate coatings used on aluminum alloys provide excellent corrosion resistance and paint adhesion properties that are commonly used in the aerospace industry. Unfortunately, chromate coatings are confirmed human carcinogens. There are alternative conversion coatings to chromates, but they cannot reproduce chromate coating’s excellent corrosion protection properties. Alternative corrosion protective coatings are being researched to replace chromate coatings, eliminating the associated health risks while trying to maintain the excellent corrosion resistance properties.
In a recent study, a locally developed conversion coating at the University of Rhode Island has shown similar anticorrosive properties as chromate coatings. Added benefit of the University of Rhode Island coating is that it has much higher permissible exposure limits.

Specific to this research is the effect of the University of Rhode Island conversion coating on the adhesive bonding and apparent shear strength of single lap-joint adhesively bonded metal specimens.  The shear strengths of the adhesives on the three sets of conversion coated aluminum alloys will be compared.

To test the effects of a hostile environment on adhesive bonding, samples will be subjected to 5% Sodium Chloride solution in a salt spray cabinet.  Baseline testing of samples not exposed to the salt spray cabinet will completed for comparison.  Samples will be exposed to the hostile environment in 250-hour increments ultimately reaching 1000 hours.  Single-lap joint testing will be completed for each exposure period and compared to determine the effectiveness of the adhesive bonding over long periods of time.
 
 

High temperature resistance strain gages based on indium-tin oxide (ITO) are being developed for both static and dynamic strain measurements at temperatures approaching 1200?C, to meet future material requirements in advanced aerospace structures and propulsion systems. The sensors are non-intrusive and robust enough to withstand the high “g” loading associated with rotating components.  Typical gage thickness is considerably less than the boundary layer thickness, and thus does not adversely affect the gas flow path through engine. Dynamic strain experiments indicate that this oxide semiconductor is well suited for such application where the strain information above 1000 0C in oxidizing ambient is required. However, ITO exhibits relatively large temperature coefficient of resistance (TCR). A self-compensated ITO strain gage has been developed, a mathematical model was also developed using this approach to establish design rules for the self-compensated circuitry, the overall TCR can be balanced to achieve the desired characteristics.
 
 

Molecular hydrogen is a non-polluting fuel that may play a role in the future energy economy. Photobiological H2 production processes use whole cells of photosynthetic bacteria, cyanobacteria or green algae for solar H2 production. Anoxygenic photosynthetic bacteria particularly the purple nonsulfur bacteria, are very efficient organism for H2 production. Hydrogen production could be combined with organic waste treatment.

Desirable properties like durability and resistance to degradation have made plastic materials an integral part of contemporary life. The standard plastics formulation used today include polyolefins, polyesters and polyurethanes, all of which are petroleum based and non-degradable. In addition hazardous chemicals are needed for their production as well as their disposal. The environment problem means that there is an increased for biopolymer. The most useful of all the microbiology derived biodegradable plastics are the poly-hydroxy-butyrates (PHB). PHB stays flexible from sub-zero temperature to 130, and completely breaks down into water and carbon dioxide in a few months. It is degraded by a wide variety of microorganism flouring in the soil.

My effort has been aimed to find a microorganism capable of producing the hydrogen and biopolymer by the bioreactor, to find the optimal conditions and the best photobioreactor for production.

Four kinds of bacterium: anaerobic bacteria, photosynthetic bacteria and green algae are used for the hydrogen production. Most of research works are related to two kinds of microorganism. Rhodobacter Sphaeroodes RV, Synechococcus sp. (Cyanobacteria). The efficiency of hydrogen production depends on environmental parameters, such as light, ambient aerobicity, medium flow rate and type of photobioreactor etc. 

A thermophilic cyanobacteria, Synechoccous sp. accumulates PHB at more than 20% of cell dry at under nitrogen – starved conditions. The meophilic Synechocous PCC 7942 is transformed with the genes encoding PHB – synthetic enzymes from Alcaligenes eutrophus.  Combinations of various and nitrogen substration also is used for PHB accumulation and H2 evolution by photosynthetic bacteria Rhodobacter spheroids strain RV.  The cells evolved hydrogen on lactate, pyruvate-glutamate media. An increased in pH caused a decrease in H2 production and increase in PHB accumulation on lactate under nitrogen-deprived condition.
 
 

Recently a large number of companies have replaced chlorinated solvents with aqueous cleaners based upon environmental and fiscal reasoning.  The diminutive effectiveness of these aqueous cleaners has a greater dependency on increased contaminant concentration.  Recycling the cleaning solution becomes important to achieve environmental and economic targets. 

Membrane technologies offer effective processes to increase the life of aqueous cleaners, yet there is no definitive unified approach.  This research will concentrate on the development of a hybrid recycling system of nanofiltration and ultrafiltration or reverse osmosis and ultrafiltration for an aqueous countercurrent degreaser.  The model would investigate the possible benefits of reversing the ‘practiced order’ of separation, which is characterized by decreased pore size.  It is hypothesized that a lower overall pressure drop would occur, therefore reducing the pump load, producing a more energy efficient system.  Membrane-type specific fluid mechanics are of great importance to the realization of this system where as it is hypothesized that reversing the order of membranes would necessitate a tubular flow patterned membrane.

Analysis of membrane morphology, such as the foulant or gel microstructure, is also a significant component of this study.  Observing capillary ultrafiltration and tubular nanofiltration verse historically modeled flat sheet membranes with Scanning Electron Micrograph (SEM) or Atomic Force Micrograph (AFM) is expected to reveal insight into the mechanisms that will facilitate the type of membranes chosen for this application as well as serving as a guide for other application-system selections.