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Cactus Goo: Research that Stuck

with a High School Chemistry

Teacher

Lisa C. PeakeChemistry Teacher at Wesley Chapel High School

The School District of Pasco County, FloridaRET Teacher at the University of South Florida

Chemical Engineering DepartmentUnder the Direction of Dr. Norma Alcantar and Dr. Alessandro Anzalone

Presentation Outline

Background Information on Research Project Project Title: Design and optimization of natural-based

process for removing/reducing contaminants in water.

Classroom Application

Personal Application

Questions

Research Motivation

Aluminum sulfate, ferric chloride and polymers are

typically used in wastewater and water treatment.

A natural alternative that behaves similarly to the

currently used flocculants is the mucilage from the

common cactus plant.

The goal is to build a device that can be used by low-

income households to clean their water supply. This

water supply comes from rivers or underground wells

where heavy metal content is high due to volcanic

soil.

Research Background

Communities in Latin America

already use mucilage from cactus

plants to reduce turbidity and

hardness in their water supply [1].

Cactus: Opuntia ficus indica, has

green, thick, long pads the shape of

tennis rackets. They grow

abundantly and are inexpensive.

Research Background

What is Mucilage?

A thick, gum-like substance

made of proteins,

monosaccharides and

polysaccharides.

Has the potential to precipitate ions, bacteria and

particles [2].

A gum that has special surface active characteristics,

allowing it to reduce surface tension.

Research Objectives

Extract and Purify the Nopal Mucilage.

Determine the Properties of the Mucilage.

Measure the Surface Active Properties.

Compare the Efficiency and Effectiveness of each

Type of Coagulant to Separate Ions, Heavy Metalsand Bacteria from Drinking Water.

Analyze Mucilage Recycling Properties.

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Research Conclusions

Higher yields of mucilage can be obtained

through:

Selection of appropriate starting materials

Simple procedural modifications

(ie. heating, centrifuging)

Highly viscous samples appear to have a

higher mucilage content

Steam pretreatment method (Cardenas)

produced highest yield of mucilage

Classroom Applications

Project Specific Applications:

Design of Standards-Based Lesson Plans

To introduce chemistry students to water and

wastewater treatment systems

To introduce the analytical and regulatory issues

associated with the use and management of water

resources

To teach precipitation reactions and solubility rules.

Cross-curricular integration with Biology,

Environmental Science, and Government.

Classroom Applications

http://www.eng.usf.edu/rnr/ret2002.htm

Classroom Applications

General Applications:

Guest Speakers at Wesley Chapel High School from

the University of South Floridas Engineering

Department

Increased Credibility when Advising Students

towards Engineering Degrees

Research Experience supports inquiry-based learning

in the classroom. Lab activities need to be student-

designed and centered.

Personal Application

Equipped me with real-life applications to motivate

my students

Increased my confidence as a High School

Chemistry Teacher

Caused inquiry to be a fundamental theme of mypersonal teaching philosophy

Jump-started my desire to start my Masters Degree

in Chemistry Curriculum and Instruction at the

University of South Florida I will finish in August

2006!

References

1. Saenz C, Sepulveda E, and Matsushiro B, Opuntia spp mucilages: a

functional component with industrial perspectives. Journal of Arid

Environments, in press.

2. Benson L, The Cacti of the United States and Canada, 1982: Stanford

University Press.

3. Medina-Torres et al., Rheological properties of the mucilage gum

(Opuntia ficus indica), 2000.

4. Cardenas, Arguelles, and Goycollea, On the Possible Role of Opuntia

ficus-indica Mucilage in Lime Motar Performance in the Protection of

Historical Buildings, 1998.

5. D. McGarvie, H. Parolis, The Mucilage of Opuntia ficus-indica. 1979

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Acknowledgements

I would like to thank the following people:

Dr. Carlos Smith from the University of South Florida for

the opportunity to participate in the RET program, as well

as educational and financial support.

Dr. Norma Alcantar and Dr. Alessandro Anzalone for the

guidance and assistance.

Wayne Jenne and Claire Duggan at Northeastern

University for Coordinating this NSF RET Presentation

National Science Foundation for sponsoring the program.

Cactus Goo:

Research that Stuck

with a High School

Chemistry Teacher