Marilyn Barger

Permeability of electrolytes through a flat RO membrane in a direct osmosis study

Abstract A direct osmosis study was carried out using several 1:1 and 2:1 electrolytes, which diffused in a RO TFC membrane. The solute permeability DSMKS/δ has been calculated using the preferential sorption capillary flow model. It was found that to some extent the ions maintain their hydration in the membrane and the permeation is a function of the hydrated radii rather than crystal ionic radii. Moreover, a linear dependence was found between electrolyte permeability through the membrane and their average diffusivity in infinite dilute solution. The relatively low permeation of 2:1 chloride salts was attributed to the interaction with the membrane surface charge.

FOULING PREDICTION IN REVERSE OSMOSIS PROCESSES

In recent years, membrane separation processes have successfully established footholds in all areas of chemical separations. Semipermeable membranes are now enhancing and even replacing long-time standard techniques such as distillation and solvent extraction (1). They are also being used in the preparation of purified chemical and biological products as well as the treatment and recovery of many industrial waste streams (2, 3). Many of these recent technological advances follow from successful research begun in the 1950s to desalinate seawater using synthetic membranes in reverse osmosis processes. While other methods to desalinate seawater have proven too unreliable or too expensive, the use of reverse osmosis in the production of potable water has steadily increased (4). Despite its growing popularity and improved technology, reverse osmosis, RO, along with all membrane separation processes continues to be plagued with one persistent problem. The problem is membrane fouling (5). Eyecamp has defined this broad term as the following:

Mass transfer in RO TFC membranes: dependence on the salt physical and thermodynamic parameters

Abstract The objectives ofthis research were to determine the importance ofparameters such as ionic size, ionic hydrated size, diffusivity in solution, enthalpy of hydration ΔH and relative Gibbs (free) energy ΔΔG on the salt permeation coefficient DK/δ in a RO TFC membrane. The experimental apparatus consisted of a commercial RO water maker and an in-line sensors system, which allows data acquisition on a continuous base for temperature, pH, conductivity, flow rates, and operating pressure. The solutions investigated were monovalent and divalent chlorides. Each feed solution was tested at 0.1 M. A preferential-sorption capillary-flow model PSCF was used in data evaluation. It was found that salt diffusivity, hydrated radii, enthalpy and entropy of hydration exert the controlling effect on the membrane selective transport, and any of them can be used in a comparative estimation of DK/δ. The relative Gibbs energy emerged as a parameter which can fully characterize the membrane selectivity and permits the prediction of DM for a certain salt in a certain membrane.

Work in progress - developing an integrated mathematics, science and engineering curriculum for elementary school

As the fact that effective and efficient engineering education does not begin at the University becomes more universally acknowledged, it is becoming more apparent that the fundamental aspects of engineering must be presented in the high school curriculum, should be inserted into middle school, and could be introduced into elementary school environment. This work-in-progress describes the initial activities of a 4-year commitment to develop an elementary school curriculum that integrates mathematics, science, and engineering components into all aspects of the curriculum in all grade levels for a new public school in Pinellas County Florida, Douglas L. Jamerson, Jr. Elementary School. Over

The high school technology initiative: a novel approach to encourage students to follow science and technology career paths

1.7 million has been secured from the US Department of Education to support the inception, development, implementation, and assessment of the curriculum as a demonstration project. First year activities include integrating the Jamerson design process throughout the entire school, faculty professional development, and initiation of the curriculum development

Reverse osmosis (“RO”) membrane system incorporating function of flow channel spacer

High school students are frequently unable to associate fundamental math and science curricular materials with the operation of the numerous high technology components that they encounter on a daily basis. We present a new approach to adapt and incorporate high technology content materials into typical state-mandated secondary education curricula. Our goal is to interest the students in following science and technology career paths by exposing them to interesting technology concepts throughout their coursework in high school or community college. Working with secondary and community college faculty, effective multimedia-based modular materials are being developed to act as a resource in the preparation of lessons in mathematics, physical science, chemistry, and physics. The development and dissemination of the modules is being funded by a grant from the NSF Advanced Technology Education division. The first module is titled Problem Solving and at present it is being adopted in schools in our central Florida region as well as in selected states. The underlying technology topics presented in the PSM are based on semiconductor manufacturing. Topic areas within the module are divided among the eight tenets of problem solving, significant figures, errors precision and accuracy, unit conversion, and scientific notation. The structure of the modules provides teachers with easy access to pre-prepared power point presentations, student worksheets, quizzes, video materials, and other content that they may find useful in their courses. They are free use the materials as is or to adapt and modify the materials as appropriate for their courses. An interesting aspect of the dissemination activities of this program is the apparent requirement that teachers be provided with workshop trainings to assist them in adopting and using the materials. This workshop structure includes a short course on semiconductor manufacturing technology that builds a level of confidence to enable the teacher to present the content material with a level of comfort required in their classrooms. In this work we present the module structure and components, examples of the user group workshop materials and the semiconductor manufacturing technology content. We will also briefly discuss the national dissemination activities.