Analysis Of Zeolites Using X Ray Diffraction Biology Essay

Published:

Zeolites are groups of compounds which produce water when they are heated. They have a three-dimensional crystalline structure which contains oxygen, aluminium and silicon. Zeolites are commonly used to purify water and extra nitrogen from air hence increasing the amount of oxygen content there is in the atmosphere

Zeolites contain small pores or cavities in its structure which enable them to act as good host molecules. This allows it to exchange cations such as Na+, K+, Ca2+ in its pores. This unique property allows many applications of Zeolites some of which are; removing ammonium ions from waste streams, treatment of sewages, controlling bad odour, use as catalysts and use in agriculture.

There are channels within the molecule which screen molecules which are of a certain size. Any molecule which is too large to pass through the channel at the given parameters are excluded, hence this forms a 'molecular sieve'.

Lady using a tablet
Lady using a tablet

Professional

Essay Writers

Lady Using Tablet

Get your grade
or your money back

using our Essay Writing Service!

Essay Writing Service

Aim: The aim of this experiment was to analyse and indentify the structures of Zeolites using Xray powder diffraction [2]

Experimental

The x-ray powder diffraction pattern for Zeolites X and Y were collected using the same procedure.

Sample preparation

The Zeolite sample was crushed to powder in a pestal and mortar. The resulting mixture was then sieved to make sure the powder was of regular grain size. The sample holder was cleaned and dried using water followed by methanol. The powdered zeolite was poured into the sample holder (covering the indentation). A microscope slide was drawn across the surface of the powder so that it formed a smooth surface.

Data collection

The sample holder was placed in the sample changer of the Brucka D8 diffractometer and then locked into place (push and then hold). The door is then closed. The PC is used to control the diffractometer. The XRD wizard is opened on the computer and this sets the parameters for data. The range was set between 5-40 (this is normal).The step size = 0.04 (the smaller the step size the more accurate the data).Time per step = 2 seconds. This showed it is going to take 29 minutes to complete the cycle. The file was then saved and closed.

Now the XRD commander was opened and then Clicked on 'jobs' > 'create jobs'. The Zeolite X was placed in position 1. And Zeolite Y was placed in position 2. The parameter file was opened again and a raw file was generated (this must be called the same name as the sample ID). The instrument was started and began to collect data.

Data Analysis

Even though the sample was powder it is still a crystalline sample as it has order to it, it is not amorphous. The powder pattern gave peaks. Once the data had been collected the data evaluation programme EVA was used to process the data. The peak list was obtained and imported to Excel. Plots of the two experimental patterns were also obtained.

Results & discussion

2-Theta °

Theta °

Theta 2

Sin2 Theta °

Ratio

Common Multiplier

Miller Index

a

6.276

3.138

0.002999581

0.002999577

1

3

1

1

1

24.37971879

10.122

5.061

0.007802386

0.007802306

2.601135887

8

2

2

0

24.37971879

11.89

5.945

0.010766101

0.010765893

3.589137536

11

3

1

1

24.37971879

13.555

6.7775

0.013992451

0.013991994

4.664656341

14

3

2

1

24.37971879

15.599

7.7995

0.018530548

0.018529487

6.177367552

19

3

3

1

24.37971879

18.568

9.284

0.026255784

0.026252768

8.752157757

26

5

1

0

24.37971879

20.245

10.1225

0.031212626

0.031207558

10.40398756

31

4

3

2

24.37971879

22.664

11.332

0.03911721

0.039107234

13.03758469

39

6

1

1

24.37971879

23.521

11.7605

0.04213144

0.042118977

14.04164066

42

5

4

1

24.37971879

26.863

13.4315

0.054954564

0.054926908

18.31155343

55

6

4

2

24.37971879

29.426

14.713

0.065941255

0.065893477

21.96759232

66

8

1

1

24.37971879

30.49

15.245

0.070796142

0.070737017

23.58233378

71

8

2

2

24.37971879

31.148

15.574

0.073884796

0.073817592

24.60933672

74

7

5

0

24.37971879

32.201

16.1005

0.078964786

0.078882748

26.29796054

79

8

3

2

24.37971879

33.823

16.9115

0.082653663

0.082559585

27.52374578

83

9

1

1

24.37971879

Zeolite X

2-Theta °

Theta °

Theta2

Sin2 Theta °

Ratio

Common Ratio

Miller Index

a

Lady using a tablet
Lady using a tablet

Comprehensive

Writing Services

Lady Using Tablet

Plagiarism-free
Always on Time

Marked to Standard

Order Now

6.209

3.1045

0.002935878

0.002935874

1

3

1

1

1

24.64279438

10.155

5.0775

0.007853344

0.007853263

2.674931688

8

2

2

0

24.64279438

11.874

5.937

0.010737145

0.010736939

3.657152317

11

3

1

1

24.64279438

15.642

7.821

0.018632851

0.018631773

6.34624358

19

3

3

1

24.64279438

18.706

9.353

0.026647508

0.026644355

9.075441569

27

5

1

1

24.64279438

20.375

10.1875

0.031614767

0.0316095

10.76663997

32

5

2

2

24.64279438

22.786

11.393

0.039539478

0.039529176

13.46419286

40

6

2

0

24.64279438

23.643

11.8215

0.042569633

0.042556777

14.49543628

43

5

3

3

24.64279438

25.015

12.5075

0.047653605

0.047635571

16.22534483

49

7

0

0

24.64279438

25.769

12.8845

0.050569642

0.050548091

17.21738999

52

6

4

0

24.64279438

27.062

13.531

0.055771782

0.055742874

18.98680611

57

7

2

2

24.64279438

27.78

13.89

0.058770478

0.058736652

20.00652917

59

7

3

1

24.43258711

29.624

14.812

0.066831644

0.066781904

22.74685506

68

8

2

0

24.64279438

30.72

15.36

0.071868266

0.071806415

24.45827388

73

8

3

0

24.64279438

31.412

15.706

0.075142549

0.075071854

25.57052852

77

8

3

2

24.64279438

Zeolite Y

Looking at the data generated, the structure of Zeolites X and Y are both Faujasites (FAU). This can be confirmed by comparing the experimental cell dimensions for zeolite X and zeolite Y which are 24.379 and 24.643 Amstrongs respectively, with the literature value of 24.3 [3]

Faujasites contain large cavities which are perpendicular to one another. The cavities contain cages which are connected through hexagonal prisms. Faujasites are used for catalytic cracking which are convert petroleum crude fractions (with high boiling points) to more valuable products such as gasoline and diesel.

Because there is no 7 present as a value in the common multiplier column, this verifies that both Zeolites X and Y are face centred molecules.

Conclusion

In order for the structure of the unknown compounds to be determined accurately, the unit cell dimensions must also be determined accurately and hence finely ground powder must be used.

In this experiment we have established that the values calculated signify that both molecules are face centred and are both Faujasites. However the experimental values differ slightly from the literature values and this can be because of a number of reasons. The sample may not have been ground into fine particles, it may not have been mixed thoroughly or it can also be because there are experimental errors from the machinery or other apparatus. Also there may be some reading errors which cause the results to be inaccurate. In future it is important to ensure that all apparatus is cleaned thoroughly before use and that attention to the smallest detail is paid to ensure better results are obtained.