estimation of the concentration of phosphate in laundry effluent sample by using visible...

ESTIMATION OF THE CONCENTRATION OF PHOSPHATE IN LAUNDRY EFFLUENT SAMPLE BY

USING VISIBLE SPECTROPHOTOMETER

Submitted by: Sadia Rahat

TABLE OF CONTENTS

SPECTROPHOTOMETRY...............................................................................................................................1

PROBLEM.....................................................................................................................................................1

APPLICATION OF SPECTROPHOTOMETRY....................................................................................................1

UV-visible spectrophotometer................................................................................................................1

IR spectrophotometer.............................................................................................................................2

PHOSPHATE (PO4-3)......................................................................................................................................2

NATURAL OCCURRENCE..........................................................................................................................3

SOURCES OF PHOSPHATE............................................................................................................................3

PERMISSIBLE STANDARDS OF PHOSPHATES IN DIFFERENT WATER BODIES................................................4

PRINCIPLE....................................................................................................................................................4

PROCEDURE.................................................................................................................................................4

SAMPLING...............................................................................................................................................4

REGEANT PREPARATION..........................................................................................................................4

STOCK SOLUTION-1000ppm KH2PO4........................................................................................................5

STANDARD SOLUTIONS...........................................................................................................................5

PROCEDURE.................................................................................................................................................7

CALCULATIONS............................................................................................................................................8

ENVIRONMENTAL IMPACTS OF PHOSPHATES.............................................................................................9

PHOSPHATES IMPACTS ON HUMANS......................................................................................................9

PHOSPHATES IMPACTS ON WILDLIFE......................................................................................................9

AQUATIC SPECIES LOSS........................................................................................................................9

PHOSPHATES IMPACTS ON PLANTS.......................................................................................................10

REFERENCES..............................................................................................................................................10

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SPECTROPHOTOMETRYSpectrophotometry is a method to measure how much a chemical substance absorbs light by

measuring the intensity of light as a beam of light passes through sample solution. The basic

principle is that each compound absorbs or transmits light over a certain range of wavelength.

This measurement can also be used to measure the amount of a known chemical substance.

Spectrophotometry is one of the most useful methods of quantitative analysis in various fields

such as chemistry, physics, biochemistry, material and chemical engineering and clinical

applications.

PROBLEM ESTIMATION OF THE CONCENTRATION OF PHOSPHATES, IN THE LAUNDRY

EFFLUENT SAMPLE BY USING SPECTROPHOTOMETER

APPLICATION OF SPECTROPHOTOMETRY

Spectrophotometry is widely used for quantitative analysis in various areas (e.g., chemistry,

physics, biology, biochemistry, material and chemical engineering, clinical applications,

industrial applications, etc). Any application that deals with chemical substances or materials

can use this technique. In biochemistry, for example, it is used to determine enzyme-catalyzed

reactions. In clinical applications, it is used to examine blood or tissues for clinical diagnosis.

There are also several variations of the spectrophotometry such as atomic absorption

spectrophotometry and atomic emission spectrophotometry.

A spectrophotometer is an instrument that measures the amount of photons (the intensity of

light) absorbed after it passes through sample solution. With the spectrophotometer, the

amount of a known chemical substance (concentrations) can also be determined by measuring

the intensity of light detected. Depending on the range of wavelength of light source, it can be

classified into different types such as:

UV-visible

spectrophotometer

It uses light over the ultraviolet range (185 - 400 nm) and

visible range (400 - 700 nm) of electromagnetic radiation

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spectrum.

IR

spectrophotometer

It uses light over the infrared range (700 - 15000 nm) of

electromagnetic radiation spectrum.

In visible spectrophotometry, the absorption or the transmission of a certain substance can be

determined by the observed color. For instance, a solution sample that absorbs light over all

visible ranges (i.e., transmits none of visible wavelengths) appears black in theory. On the other

hand, if all visible wavelengths are transmitted (i.e., absorbs nothing), the solution sample

appears white. If a solution sample absorbs red light (~700 nm), it appears green because green

is the complementary color of red. Visible spectrophotometers, in practice, use a prism to

narrow down a certain range of wavelength (to filter out other wavelengths) so that the

particular beam of light is passed through a solution sample.

A detailed process diagram of UV/Visible spectrophotometer is shown below:

PHOSPHATE (PO4-3)

Phosphate is an inorganic polyatomic ion whose molecular form is a negatively charged group

of one phosphorus and four oxygen atoms (Manahan, 2004). Phosphate comprises 99 percent

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http://www.eoearth.org/article/Oxygen

http://www.eoearth.org/article/Phosphorus

http://www.eoearth.org/article/Molecule

of all naturally occurring phosphorus in the Earth crust and surface waters. Phosphate occurs

naturally in the Earth crust in a variety of mineral formations in rock; it is also found in dissolved

form in most water bodies, and is an essential part of living organisms, as a necessary part of all

DNA, along with other cellular occurrences (Holt et al., 1970).

NATURAL OCCURRENCE

Phosphorus occurs naturally in rocks and other mineral deposits. During the natural process of

weathering, the rocks gradually release the phosphorus as phosphate ions which are soluble in

water and the mineralize phosphate compounds breakdown.

In nature, phosphates exist in three forms i.e., orthophosphate, metaphosphate (or

polyphosphate) and organically bound phosphate. These forms of phosphate occur in living and

decaying plant and animal remains, as free ions or weakly chemically bounded in aqueous

systems, chemically bonded to sediments and soils, or as mineralized compounds in soil, rocks,

and sediments.

SOURCES OF PHOSPHATE

Phosphates are present naturally in soils and rocks and are required for plant growth and soil

health. Phosphorus despite being the eleventh most abundant element in earth’s crust is

deficient in most soils and is applied to soils in the form of phosphate fertilizers (Jeer, 1997).

Phosphates become a problem once they leach from soil or are discharged in natural water

bodies in the form of human and animal wastes (i.e., sewage) and industrial wastes in both

agricultural and urban settings (Sanjay et al., 1997).

Hence, anthropogenic sources of phosphate include:

Agricultural run-off from crops

Sewage from animal feedlots

Effluent from pulp and paper industry

Water from vegetable and fruit processing

Effluent from chemical and fertilizer manufacturing

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http://www.eoearth.org/article/DNA

http://www.eoearth.org/article/Organism

Grey water resulting from use of detergents at domestic and industrial level (Dowd &

Huertos, 2008).

PERMISSIBLE STANDARDS OF PHOSPHATES IN DIFFERENT WATER BODIES

US-EPA

Natural water stream 0.05-0.10 mg/L

Public sewer 2mg/L

(EPA, Waste Water Treatment Standard, 2001)

Jamaican National Sewage Effluent Standards

Industrial effluents 4mg/L

(Jamaican National Sewage Effluent Standards, 2009)

South African Bureau of Standards

Industrial effluents 1mg/L

(South African Bureau of Standards, 2008)

Draft Jamaica National Ambient Water Quality Standard,

Marine Water

Phosphate 0.001-0.3 mg/L

(Jamaica National Ambient Water Quality Standard, 2009)

Safe Drinking Water Act

rivers and streams 0.1 mg/L

(Safe Drinking Water Act, 2004)

PRINCIPLE

The amount of electromagnetic radiation in the visible region of the spectrum absorbed by a

colored solution is often directly proportional to the concentration of the colored species as

defined by the Beer-Lambert Law. By allowing a substance to bind with color forming

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chromogens, its concentration can be found as the intensity of colored solutions is measured

using spectrophotometer.

PROCEDURE

SAMPLING

Prepared laundry effluent Samples were collected from CEES analytical laboratory.

REGEANT PREPARATION

We have carefully added 35ml sulfuric acid in 250ml distilled water. This is 2.5 molar sulfuric

acid solution. Then we took 10g ammonium molybdate and add it into 250ml distilled water. To

make 10 molar ascorbic acid solution, we carefully took 4.4g of ascorbic acid and add it into 250

ml distilled water. Finally we mixed up all three separately prepared solution, it gives us light

blue solution color.

We have prepared our reagent by carefully mixing 125ml sulfuric acid, 37.5ml ammonium

molybdate solution and 75ml ascorbic acid prepared solution.

STOCK SOLUTION-1000ppm KH2PO4

We have prepared stock solution of KH2PO4 by adding 4.39g of KH2PO4 in one liter distilled

water. This is our 1000ppm stock solution of KH2PO4

Molecular weight of KH2PO4 = 136.09

Molecular weight of P = 31

= 136.09/31 = 4.39 g/L

STANDARD SOLUTIONS

We have prepared dilutions to make standard solution of 10ppm, 20ppm, 40ppm, 60ppm,

80ppm, and 100ppm.

10ppm STANDARD SOLUTION

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We used the dilution formula to find out the volume, in order to prepare 10ppm standard

solution by using 1000ppm stock solution.

C1.V1=C2.V2

1000ppm.V1=10ppm.100ml

V1=1ml

We carefully took 1ml solution from stock solution and add it in 100ml flask and make the

volume up to the mark by adding distilled water in it. This is 10ppm standard solution of KH2PO4.




C1.V1=C2.V2


V1=2ml






C1.V1=C2.V2


V1=4ml




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C1.V1=C2.V2


V1=2ml






C1.V1=C2.V2


V1=2ml






C1.V1=C2.V2

1000ppm.V1=100ppm.100ml

V1=2ml


volume up to the mark by adding distilled water in it. This is 100ppm standard solution of

KH2PO4.

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PROCEDURE

a. Take 125ml H2SO4 solution, 37.5ml ammonium molybdate solution and 75ml of ascorbic

acid solution and mix them. This will be the reagent.

b. Dissolve 4.39g of potassium di-hydrogen phosphate (KH2PO4) in some amount of distilled

water and raise the volume up to 1000ml in a volumetric flask. This will be 1000ppm stock

solution.

c. From the stock solution make dilutions of 10ppm, 20ppm, 40ppm, 60ppm, 80ppm and

100ppm by formula C1V1=C2V2

d. To make 20ppm dilution, take 2ml from stock solution and add 98ml distilled water.

Likewise other dilutions are made.

e. Add 8ml of prepared reagent in all dilutions and in sample.

f. Calibrate the visible spectrophotometer by distilled water and set absorbance at zero. The

wavelength of instrument is set at 880nm. Then check the absorbance of all solutions by

visible spectrophotometer.

g. Plot the graph of absorbance against concentration. From the graph check the

concentration of sample.

CALCULATIONS

Concentration (ppm) AbsorbanceDistilled water 0

Sample 1.409

10 0.747

20 1.501

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40 1.533

60 1.626

80 1.763

100 1.812

RESULTSo, our laundry detergent sample contain about 41 ppm phosphate concentration on 1.409 absorbance.

ENVIRONMENTAL IMPACTS OF PHOSPHATES

Excessive dumping of phosphates into streams, lakes or rivers can cause drastic changes in

water quality. Phosphate supports the growth of plants, including algae. When too much

phosphate is present, excessive amounts of algae and phytoplankton can develop known as

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eutrophication. This may lead to undesirable water quality impacts including reductions in

aquatic life, poor taste and odors in drinking water

Algal blooms block out sunlight and cause oxygen imbalances in a body of water .Lack of oxygen

in water can kill other organisms and make the water unsuitable for humans, livestock and

wildlife (Filippelli, 2004).

PHOSPHATES IMPACTS ON HUMANS

Increased phosphate levels in water bodies’ results in excessive plant and algae growth on

surface water. This crowded growth may make swimming or boating difficult, increases

water treatment costs and impacts tourism and property values (Holt et al., 1970).

If too much phosphate is present in drinking water, it can cause health problems, such as

kidney damage and osteoporosis.

The creation of these large amounts of cyanobacteria in the water due to high level of

phosphates can cause health effects in humans, with symptoms of upset stomach, vomiting,

diarrhea, cramps, skin rash, allergy reactions, eye and ear irritation and flu-like symptoms.

Over time, ingestion of cyanotoxins can cause liver damage, liver cancer, neurological

symptoms and even death (Ritz & Jahn, 1980).

PHOSPHATES IMPACTS ON WILDLIFE

AQUATIC SPECIES LOSS

Phosphate imbalance causes excess algae blooms. Bacteria eat the algae when it

decomposes. A blue-green cyanobacteria alga can also be present. It poisons fish and

mammals (Vince & Valiela, 1973).

Shallow water plants will grow excessively. An entire lake or river can fill with

vegetation. This excessive growth prevents the sun from penetrating to the lower

plants, and the vegetation dies. Dead phytoplankton and macrophytes settle to the

bottom. This decaying process uses up all the dissolvable oxygen that fish and plants at

the lower levels need because the decomposition of so much plant matter depletes the

oxygen in the water (Lee & Jones, 1986).

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Food Problems for Larger Animals

The decline of fish population affects availability of food source for other mammals

along the food chain. Fish-stock-dependent mammals begin to decline in number (Dowd

& Huertos, 2008).

PHOSPHATES IMPACTS ON PLANTS

In plants, phosphate stimulates root growth and helps prevent disease. Phosphates in soil do

not negatively affect plant growth but on the contrary are beneficial and are applied in the form

of phosphate fertilizers. Phosphates become an environmental problem when it leaches from

soil to water bodies and cause excessive enrichment resulting in a disturbed ecosystem leading

to death of fish (Crutchfield, 1978).

REFERENCES

1) APHA. 1992. Standard methods for the examination of water and wastewater. (18th ed.).

American Public Health Association: Washington, DC.

2) USEPA. 1983. Methods for chemical analysis of water and wastes (2nd ed). Method 365.2.

U.S. Environmental Protection Agency: Washington DC.

3) Crutchfield, M. M. (1978). Organic builders: A review of worldwide efforts to find organic

replacements for detergent phosphates. Journal of The American Oil Chemists Society.

doi:10.1007/BF02673391

4) Dowd, B. M., & Huertos, M. L. (2008). Agricultural nonpoint source water pollution policy:

The case of California's Central Coast. Agriculture Ecosystems & Environment.

doi:10.1016/j.agee.2008.05.014

5) Filippelli, G. M. (2002). The Global Phosphorus Cycle. Reviews in Mineralogy &

Geochemistry. doi:10.2138/rmg.2002.48.10

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6) Holt, R. F., Timmons, D. R., & Latterell, J. J. (1970). Accumulation of phosphates in water.

Journal of Agricultural and Food Chemistry. doi:10.1021/jf60171a004

7) International Workshop on Phosphate and Other Minerals, M., Ritz, E., & Jahn, H. (1980).

Phosphate and minerals in health and disease. New York: Plenum Press.

8) Jeer, Sanjay, et al. (1997). “Nonpoint Source Pollution: A Handbook for Local Government,

Washington, D.C (476th ed.). American Planning Association.

9) Lee, G. F., & Jones, R. A. (1986). Detergent phosphate bans and eutrophication.

Environmental Science & Technology. doi:10.1021/es00146a003

10) Manahan, S. (2004). Environmental Chemistry, 8th Edition. CRC. ISBN: 1566706335

11) Vince, S., &Valiela, I. (1973). The effects of ammonium and phosphate enrichments on

clorophylla , pigment ratio and species composition of phytoplankton of Vineyard Sound.

Marine Biology. doi:10.1007/BF00355422

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