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Earth Sciences and Environmental Sciences THESE ARE DIFFERENT TYPE OF LABORATORY. I WILL ATTACH THEIR INSTRUCTION. IN THE INSTRUCTIONS IT SAID 2 PAGES BUT I JUST NEED 1.
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Dept of Chemistry, Earth Sciences and Environmental Sciences
Lab #7: Removal of Water Hardness By Precipitation with Soda Ash
Objective
To determine the optimum dose of soda ash that will remove 50% of calcium hardness from a hard
water sample.
Background
The total hardness of water is defined as the sum of the concentration of cations with more than one
charge, that is the multivalent cations such as Ca2+, Mg2+, Fe2+, Sr2+, Ba2+, Al 3+ . Because of their
geological abundance, calcium and magnesium are the major contributors to hardness in natural waters.
When too many hardness ions are present in water, they may cause undesirable chemical reactions that
interfere with water use. For example, if you live in a region that has hard water, you may notice that
your soap does not lather well. This occurs because Ca2+ and Mg2+ present in the water react with soap
molecules to form an insoluble complex that precipitates out of water (i.e., the black soap scum around
your bathtub).
The effect of this reaction is to remove soap molecules from solution and reduce the soap’s capacity to
solubilize dirt!!
M2+
+
Hardness ion
Na+ -OOC-(CH2)10-CH3 (aq)
Soap
M[OOC-(CH2)10-CH3 ]2
Soap Scum
M =Ca2+, Mg2+
Water hardness can cause more significant problems in residential and industrial water heaters, boilers,
pipes and heat exchange systems. When water containing Ca2+, Mg2+ and bicarbonate (HCO3-) is heated,
calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) may precipitate from solutions.
These precipitates, commonly known as scale, coat the inside of pipes and heater coils, reducing the
efficiency of water flow and heat transfer. They also increase the cost of system operation and
maintenance, so it is easy to see why communities want to remove some of the hardness ions from water
prior to its use. The process of removing hardness from water is called water softening.
Water Softening
Precipitation reactions are commonly used to remove unwanted contaminants from water. Consider a
water supply with too much calcium, Ca2+. One way to remove the Ca2+ ions is to add a source of an
anion (i.e., a negative ion) that will react to form an insoluble solid that will precipitate and fall to the
bottom of the tank. The liquid water on top is relatively free of Ca2+. The anion that is commonly used
in water treatment to remove Ca2+ is CO32-.
Ca 2+ (aq) +
CO3 2- (aq)
CaCO3 (s)
Experimental Materials
1.
2.
3.
4.
5.
6.
7.
8.
Buret
50 mL graduated cylinder
50 mL beakers
Hardness Buffer
0.01M EDTA Titrant
Eriochrome Black T Indicator
Hard Water Sample (Unknown Hardness Concentration)
10000 mg/L Sodium Carbonate (Na2CO3) Solution
Experimental Procedure
1. Determine the hardness of the original water sample according to the hardness test procedure.
2. Pour out 500mL of hard water sample into each of 5 beakers
3. To the first beaker add 0 mL of Na2CO3 solution and mix rapidly for 1 minute (this corresponds to a
Na2CO3 dose of 0 mg/L). This is the control sample.
4. To the second beaker add 2.5 mL of Na2CO3 solution and mix rapidly for 1 minute (this corresponds
to a Na2CO3 dose of 50 mg/L).
5. To the third beaker add 5 mL of Na2CO3 solution and mix rapidly for 1 minute (this corresponds to
a Na2CO3 dose of 100 mg/L).
6. To the fourth beaker add 10 mL of Na2CO3 solution and mix rapidly for 1 minute (this corresponds
to a Na2CO3 dose of 200 mg/L).
7. To the fifth beaker add 20 mL of Na2CO3 solution and mix rapidly for 1 minute (this corresponds to
a Na2CO3 dose of 400 mg/L).
8. After 5 minutes have elapsed for each beaker, check the pH of the water with the pH paper.
9. If the pH is less than 9 add drops of 1M NaOH and mix rapidly for about 10 seconds.
10. Check the pH after again.
11. Repeat steps 9-10 until the pH is approximately 9.
12. Once the pH in each beaker is 9 allow the beakers to stand for 20 minutes.
13. Take a 50 mL sample from the top of each beaker and measure the hardness
14. Record your results on the data table
15. Calculate the residual hardness of each sample
Dept of Chemistry, Earth Sciences and Environmental
Sciences
Lab #7: Removal of Water Hardness By Precipitation with Soda Ash
Name: _________________________
DATA SHEET
Dose of Na2CO3
(mg/L)
Volume of EDTA
(mL)
0
(control sample)
18.1
50
18.1
100
17.8
200
10.1
400
3.8
Total Hardness* (mg/L
as CaCO3)
% Hardness Removal
Calculate Total Hardness as follows:
A x B x 1000
Total Hardness (mg/ LasCaCO3) =
Where:
mL SampleUsed
A = mL of 0.01M EDTA titrant used
B = mg CaCO3 equivalent to 1.00 mL EDTA titrant (B = 1 in our case)
mL Sample Used = 50 mL
Calculate % Total Hardness Removal for each samples as follows:
(Total Hardness of ControlSample − Total Hardnessin Sample
% Total Hardness Removal =
Total Hardness of ControlSample Data
Analysis
1. Plot Total Hardness (y-axis) versus Na2CO3 dose (x-axis).
2. Plot % Total Hardness Removal (y-axis) versus Na2CO3 dose (x-axis)
3. Determine the Na2CO3 dose required to remove 50% of the original total water
hardness in the water sample by drawing a line from the 50% removal point to the curve
and then a vertical line down to the x-axis to read the dose the Na2CO3 dose
4. Submit your lab report according to the ENV11 Lab Report Format, including the graph
as a single Microsoft Word or pdf file on your Blackboard course site
Dept of Chemistry, Earth Sciences and Environmental Sciences
ENV11
Lab #8: Using Phytoremediation to Remove Hardness from Water (Pre-Lab)
What is Phytoremediation?
Phytoremediation is the utilization of plants to remove hazardous chemicals from soil and water through
uptake of the hazardous chemicals into the plant roots, leaves, or plant tissue. Research studies have
shown that plants such as water hyacinths (Eichhornia Crassipes) can accumulate metals such as zinc,
cadmium and arsenic. In next week’s lab we will use water hyacinths to remove calcium hardness from
water. The amount of calcium removed from the water will be determined by titrating with standard
EDTA solution.
General Information on Water Hyacinths
Water Hyacinths are floating aquatic plants, native to tropical America. It has shiny light-green, circular
leaves that are 2 to 5 inches wide and attached to inflated stems. The stems have trapped air, and act as
an air bladder providing the Water Hyacinth buoyancy. Water Hyacinths have purple flowers in warm
weather. Figure 1 shows water hyacinths covering a lake.
Figure 1. Water Hyacinths covering a lake
The water Hyacinth roots are feathery and a purple-white color. They usually run from 12 to 18 inches
long and they trail down into the water, providing spawning grounds for fish.
New plants grow from the mother plant and the Water Hyacinth tends to grow in large bunches. Water
Hyacinths reproduce rapidly and are considered the weed of the water world.
Why Use Water Hyacinths for Phytoremediation?
Water Hyacinths are just beginning to be used for Phytoremediation. This use came about for a few
reasons, the first since water hyacinths are so plentiful in nature. People have been trying to remove the
plant from many waterways, spending billions of dollars on doing so. In many cases, this removal is
almost impossible. It has been discovered that water hyacinths quest for nutrients can be turned into a
more useful direction. Water Hyacinth is already being used to clean up wastewater in small-scale sewage
treatment plants. The plants utilize vast amounts of many nutrients, which are poisonous to humans in
these quantities. The water hyacinth has been shown to remove Nitrogen and Phosphorous, as well as
organic chemicals from wastewater. In the process of studying water hyacinths capabilities in sewage
treatment, it has been discovered that this plant removes toxic metals such as zinc, cadmium and arsenic
from water as well. Its ability to remove toxic metals from water is what makes water hyacinths so
appealing for treating water.
How Does Water Hyacinths Remove Metals From Water?
Most of the common metals that are in water are positive ions. Calcium metal dissolved in water has a
+2 charge (Ca2+). One possible theory of a way to remove them would be to put a negatively charged
object into the water and use it to attract the positively charged ions. This is what essentially happens
when we put the roots of the water hyacinth into water polluted with metals. The roots of hyacinths like
many plants have a negative charge to them. When they are placed in water containing metals, the roots
act like a magnet to attract the positively charged metals. The bigger the charge on the metal, the greater
will be the attraction for the roots of the water hyacinth. Therefore a metal like chromium (Cr3+) with a
charge of +3 will have a greater attraction for the roots of the water hyacinth than a metal like zinc (Ca2+)
with a charge of +2.
Critical Thinking Skills Questions
1. What is phytoremediation?
2. What type of plants can be used for phytoremediation?
3. Are there any other toxic chemicals you can think of for which you may use water
hyacinths?
4. What are some apparent advantages of using water hyacinths as a water treatment strategy
in the United States?
5. What are some apparent disadvantages of using water hyacinths as a water/wastewater
treatment strategy in the United States?
Dept of Chemistry, Earth Sciences and Environmental Sciences
ENV11
Lab #8: Using Phytoremediation to Remove Metals from Water
Objectives
The objectives of this lab are to determine the rate at which water hyacinth plants remove total
hardness in the form of calcium metal from a water sample.
Introduction
Phytoremediation is the process of using plants to remove harmful chemicals from the environment. At
Brookhaven National Lab on Long Island, NY, research has shown that plants may be effective in
removing radioactive Strontium and Tritium from groundwater. Water hyacinths have been reported by
numerous researchers to be capable of absorbing and removing metals and nutrients from the water
environment.
The water hyacinth belongs to the pickerelweed family, Pontederiaceae. It’s scientific classification is
Eichhornia Crassipes. Water hyacinth is a plant that grows chiefly in the tropical regions of the world.
It floats on lakes, rivers, and swamps and grows to a height of about 2 feet (61 centimeters) above the
water. The water hyacinth has as many as 38 purple flowers grouped around the top of the stem. Water
hyacinths are a serious environmental problem because they grow so fast. The plants may double in
number every 10 days.
The thick growth of water hyacinths blocks the sunlight, and the roots of the plants use up the oxygen in
the water. In addition, boats cannot travel on waterways that are choked with water hyacinths. Many
scientists are exploring possible uses of water hyacinths. In the early 1970’s, researchers began the
experimental use of the plants to clean up polluted streams. Water hyacinths can absorb many chemicals
including sewage, industrial wastes and metals from the water in which the plants grow. Thus, polluted
water might be purified by passing it through tanks that contain water hyacinths.
MATERIALS
1. Water Hyacinth Plant (available at http://www.lilyblooms.com at a cost of $30/10 plants) 2.
Buret and buret stand
3. 0.01 M EDTA Titrating Solution
4. Eriochrome Black T Indicator (0.2 g in 15 mL of distilled water)
5. Buffer Solution
6. Calcium solution
EXPERIMENTAL PROCEDURE
1.
2.
3.
4.
Obtain 50 mL of the initial calcium solution from the instructor (Time = 0 min sample)
Place 2 liters of calcium solution in the aluminum container
Obtain a water hyacinth plant from the instructor
Place 2 the plant in the aluminum container so that the roots are completely under water.
5. To the Time = 0 min sample (step 1), add 1 mL of buffer solution and swirl to mix
6. Add 2 drops of Eriochrome Black T Indicator (solution will appear wine red in color if calcium is
present) and swirl to mix
7. Titrate slowly with 0.01M EDTA until the solution becomes blue (swirl to mix after each addition).
8. Record the volume of EDTA used.
9. Repeat steps 5 – 9 for solutions removed from the aluminum container at 15 min, 30 min, 60 min,
90 min, 120 min.
Students at Bronx Community
Phytoremediation Experiment
College/CUNY
performing
the
Lab #8: Using Phytoremediation to Remove Metals from Water
Name: ______________________
Data
Table 1. Laboratory Data Sheet
Time (min)
Volume EDTA Used (mL)
0
14.52
15
13.72
30
12.44
60
11.18
90
9.94
120
7.34
Total Hardness * (mg/L
as CaCO3)
Calculate Total Hardness as follows
𝐴 𝑥 𝐵 𝑥 1000
𝑇𝑜𝑡𝑎𝑙 𝐻𝑎𝑟𝑑𝑛𝑒𝑠𝑠 (𝑚𝑔/𝐿 𝑎𝑠 𝐶𝑎𝐶𝑂3) = 𝑚𝐿
𝑆𝑎𝑚𝑝𝑙𝑒 𝑈𝑠𝑒𝑑
Where:
A = mL of 0.01M EDTA titrant used
B = mg CaCO3 equivalent to 1.00 mL EDTA titrant (B = 1 in our case)
mL Sample Used = 50 mL
Data Analysis
1. Using Microsoft Excel, plot the concentration of Total Hardness (y-axis)
versus time (x-axis)
2. Add a linear trendline to the graph and record the value of the slope (the
mg
value of the slope is the rate of Total Hardness Removal in
Lx min
3. Submit your lab report reports using the ENV11 lab report format on your
Blackboard course site
Dept of Chemistry, Earth Sciences and Environmental Sciences
ENV11
Spring ‘20
Climate Change Simulation Assignment
This lab uses a robust model of the carbon cycle to give you an intuitive sense for how
carbon circulates through the atmosphere, biosphere, oceans, and crust. This model is
similar to ones presented by the Intergovernmental Panel on Climate Change. It allows
you to experiment with how human input to the cycle might change global outcomes to
the year 2100 and beyond. One particularly relevant human impact is the increase in
atmospheric carbo dioxide (CO2 levels). Between the years 1850 and 2015, atmospheric
concentrations have risen from 290 parts per million (ppm) to over 400 ppm – a level
higher than any known on Earth in more than 30 million years. See the graph below from
the BCC greenhouse gas monitor atop Meister Hall which shows that the atmospheric
carbon Dioxide is definitely above 400 ppm levels. The second graph shows how
increasing carbon dioxide levels (black line) leads to increasing atmospheric temperature
(red line) from ice core samples collected from Antarctica.
Using the simulator, you will experiment with the human factors that contribute to this
rise and explore how different fossil fuel use and deforestation might affect the
concentrations of the greenhouse gas CO2.
Procedure Seasons/Climate Simulation Assignment
1. Copy the following link for the simulation model and open in a different tab on your
internet
browser:
https://test-learnermedia.pantheonsite.io/wp-
content/interactive/envsci/carbon/carbon.html
2. The data for the simulation model for a Deforestation Rate of 1GT and a Fossil
Fuels Use of 2% has already been recorded in your data Table 1 and Table 2.
3. Keeping the Net Deforestation Rate at 1 GT change the fossil fuel use to 2.5%,
2.8%, 3.0%, 3.2%, 3.4%, 3.6%, 3.8% and 1.5% making sure to press the Run Decade
button after each change and record the ppm CO2 in and corresponding year in the
Table 1 below.
4. Keeping the Fossil Fuel Use constant at 2% change the Net Deforestation Rate to
1.4 GT, 1.8 GT, 2.2 GT, 2.6 GT, 3.0 GT, 3.6 GT, 4.0 GT and 0.5 GT making sure to
press the Run Decade button after each change and record the ppm CO2 and
corresponding year in the Table 2 below.
5. Write a 1 page summary (Times New Roman, 12 pt Font, Double Space) explaining
what the data in Tables 1 and Table 2 is telling YOU.
6. Submit the table and the two paragraphs as a single Microsoft Word or pdf
document in the appropriate folder on your Blackboard course site by the deadline
given by your class instructor.
Dept of Chemistry, Earth Sciences and Environmental Sciences
ENV11
Climate Change Simulation Assignment
Name: ______________________
Table 1 – Effect of Fossil Fuel Use on CO2 (Change Fossil Use –Keep Deforestation Same)
Year
Change in Fossil Fuel Use
(%)
Net Deforestation Rate per Yr
(GT)
2010
2
1
2020
2.5
1
2030
2.8
1
2040
3.0
1
2050
3.2
1
2060
3.4
1
2060
3.6
1
2070
3.8
1
2080
0.5
1
CO2
(ppm)
Table 2 – Effect of Deforestation on CO2 (Change Deforestation –Keep Fossil Use Same)
Year
Change in Fossil Fuel Use
(%)
Net Deforestation Rate per Yr
(GT)
2010
2
1
2020
2
1.4
2030
2
1.8
2040
2
2.2
2050
2
2.6
2060
2
3.0
CO2
(ppm)
2060
2
3.4
2070
2
4.0
2080
2
0.5
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Tags:
fossil fuels
deforestation rates
carbon dioxide concentration
forested land
growth of populations
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