Using technology to enhance the effectiveness of general chemistry laboratory courses.

Practicing and teaching current chemistry requires the use of computers, yet the focus of undergraduate teaching laboratories for several decades has been using the traditional bench method. This paper makes a case for the pedagogical advantages of using computer-interface systems to perform computer-assisted experiments in general chemistry laboratory courses. We compare data from control group students using traditional bench laboratory procedures and experimental group students using computer-interface laboratory procedures with the software program LabWorks. The results show that conducting laboratory activities using computer-interface procedures can improve student understanding of calorimetry

Removal of aqueous selenium by four aquatic plants.

Several aquatic species were examined as potential phyto-removal agents for selenium in aqueous solutions. Selenium was initially present in concentrations of 0-100 ppm Se (as sodium selenite) in 10% Hoagland’s medium, and aquatic plants were grown in the medium for one week. Four aquatic plants were studied: Cattail (Typha domingensis), duckweed (Lemna obscura), hydrilla (Hydrilla verticillata Royle), and swamp lily (Crinum americanum). Analyses were done by atomic absorption spectrometry using hydride reduction. Four replicates were done for each analysis. Each system was examined for change in fresh weight, percent removal of selenium from solution, and accumulation of selenium in the plant. At selenium concentrations of 100 ppm or less, fairly good to excellent removal was achieved (65 to 100%), depending on the plant. Exposure to concentrations greater than 100 ppm had an inhibitory effect on plant growth, so concentrations less than 100 were studied in more detail. During a one-week period, hydrilla quantitatively removed the selenium, and the fresh weight and dry weights of the plant increased. Other plants were less effective in removal of selenium or were more adversely affected by added selenium

Integrating Basic Analytical Methods and Computer-interface Technology into an Environmental Science Water Quality Lab Improves Student Attitude

The aim of this study was to investigate if integrating basic analytical methods and computer interface technology would result in a positive change in student attitude. Students\u27 self-concept of science knowledge and skills (Capability), opinion towards science (Affect), and perceptions of the value of science (Value) were determined with attitudinal surveys administered in a pre/post test design. Three separate lab modification groups were compared based upon level of integration over three academic semesters. The main findings were student attitude toward science improved with more integratio

PBDE degradation with zero-valent bimetallic systems.

Polybrominated diphenyl ethers (PBDEs) are a group of widely used brominated flame retardants. Due to their extensive use, increasing levels of PBDEs have been found in humans, fish, birds, marine mammals, sediments, house dust, air, and supermarket foods. As a new environmental pollutant, a feasible in-situ remediation method is needed. In situ remediation methods for PCBs have been developed at UCF using palladium/magnesium bimetal created by mechanical alloying. The lessons learned from the PCB work have been applied to PBDEs in this chapter. Several bimetallic systems were examined to determine the rate of debromination of 2,2\u27,4,4\u27- tetrabromodiphenyl ether (BDE-047). In addition, kinetic studies on BDE-047 were conducted with 99% degradation in five hours with 0.8% Mg/Pd. During the first 30 minutes, 80% of the BDE-047 is degraded with diphenyl ether detected as one of the byproducts

Using technology equipment to teach chemistry laboratory exercises in community colleges (Session 2386).

The drive to attract students into science and technology careers at all levels has led to creative programs and efforts across the country. At Hillsborough Community College in Tampa Florida, a new associate in science manufacturing technology degree program focused on high tech manufacturing processes and skills has been developed. The lab facilities include a high-end vacuum technology and systems laboratory. Training on the new equipment was offered to both the technology and science faculty members across the state as part of an NSF ATE grant. As a result of this vacuum system training, science faculty worked with technical faculty to develop several laboratory activities for general college chemistry and organic chemistry laboratories using the vacuum systems. Multiple stations allow the chemistry students to work in small groups as in any traditional chemistry laboratory. Student exposure with multiple chemistry experiments using the vacuum training equipment will provide reinforcement and comfort with the seemingly complicated equipment. The objective of the chemistry activities in the vacuum laboratory are to familiarize students with practical and real-life applications of the chemistry they learn in a pure science class in industrial type settings and to peak their interest in science and technology career paths. An overview of the chemistry demonstrations and experiments using the vacuum technology equipment will be provided in addition to the science student impressions to these alternative laboratories

RDX properties as a guide to remediation.

The history and properties of RDX (cyclotrimethylenetrinitramine, 1,3,5-trinitro-1,3,5-triazine), a popular high explosive are reviewed and considered as a guide to the removal for this material from Florida soils

GC/MS analysis of volatile organic selenium species produced during phytoremediation.

The use of plants and microorganisms that can naturally volatilize selenium and remove it from the soil or water has been studied with promising results. It has been shown that selenium can be removed from soils by plant uptake and accumulation, plant volatilization, and removal in the rhizosphere. Preliminary studies indicated that Hydrilla verticillata Royle removed selenium by means of phytovolatilization. Therefore, studies were conducted to examine the volatile products produced during phytoremediation of selenium by hydrilla. Samples were obtained and analyzed by GC/MS. Organoselenium compounds found were dimethyl selenide, dimethyl diselenide, and diethyl diselenide

Effects of selenium supplementation on four agricultural crops.

Agricultural crops can be used either to remediate selenium-contaminated soils or to increase the daily selenium intake of consumers after soil supplementation using inorganic or organic selenium sources. In this study, four agricultural crops were examined for potential selenium enhancement. Soils containing tomato, strawberry, radish, and lettuce plants were supplemented with either an inorganic or an organic form of selenium. Two different soils, i.e., low Se and high Se containing, were also used. Statistically significant differences in appearance, fruit production, and fresh weights of the fruit produced were studied. Next, the amount of selenium retained in the edible fruits, nonedible plant, and soil for each was analyzed by acid digestion followed by hydride generation atomic absorption analysis. Finally, inhibition effects on the seeds of the agricultural plants were studied. The results show that supplementation with an inorganic form of selenium led to higher retention in the plants, with a maximum of 97.5% retained in the edible portion of lettuce plants

Remediation of selenium contamination by plants and microbes: An annotated bibliography.

An annotated bibliography of recent developments in selenium remediation is given. Although many different approaches are considered, the most important processes concerning selenium removal from contaminated soils and waters appear to be microbial-induced chemical reactions that transform the existing selenium species into volatile compounds and accumulation by certain plants