Practical 6 - Testing dissolvability of chitosan in 15% v/v acetic acid (Comparison of with Ultrasonication and without)

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Practical 5

Week 10 & 11

Teammates Present: Shawn and Nelly

Written By Shawn

It has been found that ultrasonication is not effective in improving the dissolvability of chitosan compared to the traditional method of using stirring using a stir bar at 200RPM being the only viarable. The results are shown below.

Exp 1 - Traditional(200RPM)

Run

Weight of Filter paper (g)

Weight of Dried filter paper + Chitosan (g)

Weight of undissolved chitosan (g)

Original Mass of Chitosan used (g)

1

1.3647

1.7678

0.4031

0.5032

2

1.3595

1.4586

0.0991

0.5019

3

1.3593

1.3536

-0.0057

0.5007

4

1.3724

1.6753

0.3029

0.5007

5

1.3369

1.6578

0.3209

0.5011

Average Mass of undissolved chitosan = 0.2815g

Run 3 is excluded due to the negative weight of undissolved chitosan calculated. This may be due to loss of filter paper during filtration from acetic acid reacting with filter paper or inaccurate readings from the weighing balance.


Exp 2 (Ultrasonicated)

Run

Weight of Filter paper (g)

Weight of Dried filter paper + Chitosan (g)

Weight of undissolved chitosan (g)

Original Mass of Chitosan used (g)

1

1.3580

2.9242

1.5662

0.5049

2

1.3480

3.5301

2.1821

0.5023

3

1.4664

1.8278

0.3614

0.5018

4

1.3673

3.0653

1.698

0.5037

5

1.4222

3.3526

1.9304

0.5012

Average mass of undissolved chitosan = 1.5476g


1.4 depicts experiment 1 run 4, 1.5 depicts experiment 1 run 5, 2.4 depicts experiment 2 run 4, 2.5depicts experiment 2 run 5.

Based on the results obtained, it can be shown that the traditional stirring method is superior to the ultrasonication method.

Overview

Goals

  • Determine Chitosan’s ability to dissolve in Water with the assistance of Acetic Acid (AA).

  • Data Collection of Chitosan’s ability to dissolve in Water with the assistance of Acetic Acid (AA). 

  • Find out what cause the clumping when AA is added into acetic acid 


Objectives

  • Test for various factors affecting solubility of Chitosan

    • Factors include

      • Temperature

      • Concentration of Acetic Acid (SAFETY CONCERN!!, WEAR 3 GLOVES & DO NOT TOUCH ANY SURFACES WHEN HANDLING AA)

      • Stirring Speed

  • To formulate a work procedure for future ease of replication


Background info

Referring to the report done by the previous group and a trial done during the replication of the previous group’s FYP set-up, we found that Chitin takes a very long time to dissolve, even in the presence of concentrated sulfuric acid (H2SO4). Chitosan too, took quite some time to partially dissolve in the acetic acid solution, leaving a heterogeneous mixture. The m/v ratio used for Chitosan to Solvent was rather small at 1:10. Specifically, 1g of Chitosan mixed with 10ml of 1%v/v Acetic Acid. From our literature review and observations during the practical session, there was a clear need for improvement of solute dissolution in order to make it more commercially viable and upscalable.


Thus, after doing literature review, we propose to run a dissolution experiment to find the most effective solute-solvent mixture with the intent of comparing results to produce a recipe for future electrolyte preparation. With many factors in mind, we decided to focus on changing several variables we think that might affect the solubility critically. 


Design of experiment (DOE) 

Several possible factors identified that we think might critically affect the dissolution of Chitin are the solute-solvent mixture itself, the concentration of the solvents and temperature. To keep the design simple, we kept each factor at two levels (low, high). The factors and their levels are listed down below. 


Variables (Low and High): 


Variable

Low

High

Type of dissolving

Traditional (Stirring RPM: 200)

Ultrasonication


Fixed Parameters:


Parameter

Quantity

Chitosan

0.5g

Volume of AA used (15% v/v)

10mL

Volume of DI water used

90mL




Apparatus preparation list


No.

Equipment

Quantity/Volume

Remarks

1

Stopwatch

1


2

Weigh Scale 

1


3

50mL beaker

4


4

500mL beaker

5


5

100mL measuring cylinder

2


6

10mL glass measuring cylinder

1


7

Filter Paper 

12


8

Sieve

1


9

Filter Funnel

2


10

Hot Plate + Stir bar + Magnet stick

1


11

Weighing Boat

-


12

Thermometer

1


13

100mL Volumetric Flask

2


14

Glass funnel

1



No.

Chemical

Quantity/Volume

Remarks

1

15% Acetic acid

100mL







Chemical preparation work procedure (PERFORM ALL STEPS IN FUME HOOD)

 

Steps for Ultrasonication: 

  1. Fill the water until the metal basket is fully immersed

  2. Heat up 90ml of water on the hotplate till it reached 60DC

  3. Place it into the ultrasonicator 

  4.  





Preparation of 15% Acetic Acid in 100mL 

* 1% acetic v/v means 1ml acetic acid dissolve in 99ml DI water 


Step no.

Procedure 

Remarks

1

Get the following equipment in the fume hood: 

DI water spray bottle x1

Green spill tray x1

50mL beaker x2

Plastic pipette x2

10mL measuring cylinder x1

100mL volumetric flask x1

Glass funnel x1



2

Prepare all measuring cylinders and apparatus in a green spill tray in the fume hood. Then, retrieve the 100% Acetic Acid with 3 nitrile gloves (safety).


3

Pour about 15mL of acetic acid into a 50mL beaker.


4

Measure 15mL of acetic acid using a 10mL measuring cylinder.


5

Pour 15mL acetic acid into the 100mL volumetric flask with the assistance of a glass funnel.


6

Fill 100mL volumetric flask with DI water till the line and swirl.




Procedure for Chitosan Dissolvability in Level 1 Test parameters [15% 60oC 200RPM]

Step No. 

Procedure 

1

Prepare 0.5 g of Chitosan in a weighing boat & 90mL of DI water in a 500mL beaker using 100mL measuring cylinder.

2

Prepare 10mL of 15% Acetic acid in a 50ml beaker.

3

Place 500mL beaker (containing 90mL DI) water on a hotplate and turn on heat to 50°C with a thermometer and stirrer. Set it to 100 RPM.

4

Once the DI water is at 50°C, pour 0.5g chitosan into a 50mL beaker.

5

Pour contents of 50mL beaker into 500mL beaker.

6

Leave mixture for 30 minutes

7

Refer to Vacuum Filtration Procedure for filtration and drying steps

8

Repeat experiment 3 times & record findings


Record your observation seen: 

  • Are there lots of chunks? 

  • The consistency of the solution? 

  • The colour of the solution? 

  • Does time play a part for better mixing/dissolving of chitosan with acetic acid?


Procedure for Chitosan Dissolvability in Level 2 Test parameters [15% 60oC, Ultrasonication]

Step No. 

Procedure 

1

Prepare 0.5 g of Chitosan in a weighing boat & 90mL of DI water in a 500mL beaker using 100mL measuring cylinder. Preheat ultrasonicator

2

Prepare 10mL of 15% Acetic acid in a 50ml beaker.

3

Place 500mL beaker (containing 90mL DI) water on a hotplate and turn on heat to 60°C with a thermometer and stirrer. Set it to 200 RPM.

4

Once the DI water is at 60°C, start the ultrasonicator and place the 500mL beaker into the ultrasonicator, then pour 0.5g chitosan into a 50mL beaker.

5

Pour contents of 50mL beaker into 500mL beaker.

6

Leave mixture for 30 minutes

7

Refer to Vacuum Filtration Procedure for filtration and drying steps

8

Repeat experiment 3 times & record findings


Record your observation seen: 

  • Are there lots of chunks? 

  • The consistency of the solution? 

  • The colour of the solution?


Vacuum Filtration Procedure
Instruments Required


Item Name

Quantity

Vacuum Pump

1

Buchner Funnel

1

Side-arm filtration Flask

1

Rubber Adapter

1

DI Water

-

Filter paper (Size 1)

4

Oven tray (wrapped in aluminum foil)

1


Procedures:

  1. Start MEMMERT oven dryer and set the following parameters

    1. Temperature: 50oC

    2. Fan Speed: 100%

    3. Flap:80%

  2. Connect the Vacuum Pump to the Side-arm filtration flask

  3. Attach the Rubber adapted to the side-arm filtration flask then the buchner funnel

    1. Ensure longer side of funnel tip is facing the vacuum 

  1. Weight then place 4 filter paper & rinse with Di water

  2. Start Vacuum pump and check for leakages on filter paper

  3. If there is not leakages, slowly pour chitosan solution onto filter paper

  4. After chitosan is filtered, slowly pour 100mL of DI water to rinse any additional residue acetic acid.

  5. Place filter paper on oven tray & bake for 60minutes or until dry

  6. Weigh dried filter paper with undissolved chitosan


Tips
Use a piece of aluminum foil to prevent heat loss during preheating of ultrasonicator machine.

While vacuum filtrating, use a glass rod to assist with pouring of chitosan mixture.


Picture of drying chitosan on filter paper.


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