Fabric Recycle Polyaniline Water Treatement_SlideShare.pdf

Dumping of spent fabric material has created extra solid wastes for the landfill. Noting this, the present work converted spent fabric material into a new adsorbent for humic acid (HA) removal. Here, a facial sheet mask was used as the model fabric material. The spent facial sheet mask was thoroughly cleaned and modified with polyaniline (PANI) via a facile dip-coating method. Satisfactory of the modification was verified by Fourier transform infrared spectroscopy and scanning electron microscopy analyses. Experimental results showed that the PANI-coated mask outperformed the blank mask in HA removal due to the presence of amine and imine groups in the PANI. Hence, increasing the PANI loading from 1 to 10 g/L significantly improved the HA adsorption from 51.9 ± 0.4 to 83.1 ± 0.21%. Furthermore, the PANI-coated mask showed a pH-dependency in HA removal, with the highest removal achieved at pH 2 (80.5 ± 0.05%) where both adsorption and self-precipitation of HA occur simultaneously. The efficiency dropped to 51.9 ± 0.4% at pH 4 where adsorption plays the dominant role. Model fitting indicated that the adsorption followed the pseudo-second-order model and is explainable by three-stage intraparticle diffusion model. While PANI itself is electrically conductive, the PANI-coated mask is also potential to be used as an electrical conductor.

1. Surface modification of recycled
fabric materials with conductive
polyaniline and its role in
organic matter adsorption
Full Paper Link:
https://link.springer.com/article/10.1007/s13762-021-03757-6

3. Introduction
Polyaniline (PANI)
•Has high electrical conducting properties, high environmental
stability, available at low cost, easy to be synthesized.
•Synthesized by chemical oxidative polymerization.
•Dip-coated onto spent mask for HA removal and electrical
conductivity.

Humic Acid (HA)
•Found in natural waters as a result of decomposition of
plants, animals and microorganisms.
•Consists of carboxylic- and phenolic-OH functional groups.
•Has micelle-like structure.

TEM image of PANI
Molecular structure of HA

4. Problem Statement & Novelty
•Problem 1: Sheet masks are usually disposed after usage, creating more wastes to the environment.
Solution: Coating of PANI on spent masks transforms them into useful water
pollutant removal adsorbents and flexible electrical conductors, while reducing
wastes.

•Problem 2: Dip-coating process enables even coating of the PANI paste, however it
is difficult to control the coating thickness.
Solution: PANI solution was first centrifuged for 20 minutes to ensure the
particles are evenly dispersed before coating.

•Problem 3: HA removal is highly dependent on pH of HA solution.
Solution: HA removal was carried out on pH 2 which involves adsorption and
precipitation, and pH 4 which is purely adsorption.

5. To study the effectiveness of HA removal using PANI-coated
spent masks at different pH, concentrations and time intervals.

To explore the possibility of coating spent masks with PANI
particles using the dip-coating method.

To describe the mechanisms of dip-adsorption process via
kinetic study.

To study the morphology of PANI-coated spent masks via
scanning electron microscope (SEM).

7. Fabrication techniques of PANI paste onto solid substrate
Dip Coating
Drop Casting
Spin Coating

8. Humic Acid Removal Methods
Method Advantages Disadvantages
Adsorption
- Easy to operate.
- Insensitive to toxic
pollutants.
- Does not require use of chemicals.
- High efficiency in pollutant removal.
- Adsorbents require regeneration.
Electrocoagulation
- Low operating and capital costs.
- Consistent and provides reliable result.
- Low maintenance cost.
- The sacrificial anodes need to be
replaced regularly.
- Highly dependant on availability of
electricity.
- Difficult to separate flocs.
Membrane
separation
- Operates at low temperature
- Low energy requirement
- Does not require use of chemicals
- Prone to fouling
- High equipment cost
- High maintenance cost

9. Methodology

10. START
Preparation
of PANI
paste and
HA solution
Coat PANI
onto spent
masks using
dip-coating
method
Removal of HA
at various pH,
concentrations
and time
intervals
Electrical
conductivity
of PANI/HA
masks
Optimization of
adsorption capacity of
PANI-coated mask
using PANI
concentrations of 5 g/L
and 10 g/L
END
Research Flow Chart

11. Step 1: Preparation of Polyaniline Paste
150 mL distilled water
9 mL aniline
10 mL of 9 M HCl
Aniline solution
11 g ammonium persulfate
100 mL distilled water

12. Centrifugation of PANI
The synthesized PANI
solution was centrifuged
for 1 hour at a speed of
3200 rpm
Its supernatant was
disposed to remove
impurities.
The PANI paste was added
with 50 mL distilled water
until obtained a concentrated
PANI solution.

13. Step 2:
Preparation
of Humic
Acid

14. Step 3: Fabrication of PANI onto spent mask
Blank mask
•The 2.5cm x 2.5cm spent mask was soaked in soap water for 3 hours then thoroughly cleaned
with distilled water to remove any impurities.
•1 g/L PANI solution was sonicated for 20 minutes.
•The spent mask was immersed in PANI solution for 30 minutes.
•After that, the PANI-coated mask was taken out and let to dry under the sun until fully dried.

+ PANI
nanoparticles
PANI-coated mask

15. Step 4: Application Process
Effect of pH
•Five 20 mL glass bottles were filled with 50 mg/L HA solution each.
•HA solution in each bottle was adjusted to pH 2, 4, 6, 8 and 10 respectively with addition of 1 M NaOH or 1 M HCl.
•PANI-coated mask was immersed in each HA solution for 1 hour.
•The PANI/HA mask was taken out.
•Residual HA solution was centrifuged for 20 minutes at speed 3200 rpm.
•The centrifuged solution was tested with UV-Vis spectrophotometer to measure HA concentration.

PANI-coated mask Immersed in HA solution
of different pH for 1
hour
After HA removal, residual
HA was centrifuged for 20
minutes.
Concentration of the centrifuged
HA solution was measured with
UV-Vis spectrophotometer.

16. Effect of HA concentration
•Five 20 mL glass bottles were filled with 10
mg/L, 20 mg/L, 30 mg/L, 40 mg/L and 50
mg/L HA solution each of pH 2.
•PANI-coated mask was immersed in each HA
solution for 1 hour.
•The PANI/HA mask was taken out.
•Residual HA solution was centrifuged for 20
minutes at speed 3200 rpm.
•The centrifuged solution was tested with
UV-Vis spectrophotometer to measure HA
concentration.
•These steps were repeated with HA solution
of pH 4.

17. Effect of time interval
•Seven 20 mL glass bottles were filled with 50 mg/L
HA solution each.
•PANI-coated mask was immersed in each HA
solution at different time intervals (5 min, 15 min,
30 min, 45 min, 1 hour, 2 hours, 3 hours).
•The PANI/HA mask was taken out.
•Residual HA solution was centrifuged for 20
minutes at speed 3200 rpm.
•The centrifuged solution was tested with UV-Vis
spectrophotometer to measure HA concentration.

18. Step 5: Test Electrical Conductivity of PANI/HA Mask
•The electrical conductivity of the PANI/HA mask was measured
using a DT-9205A digital multimeter at room temperature.

•The leads were plugged into the appropriate sockets at the
bottom of the multimeter.

•The black lead was plugged into the COM socket while the red
lead was plugged into the V socket.

•PANI/HA mask was clipped onto the lead probes and the power
button was switched on.

•The resistance of PANI/HA mask was determined by turning the
dial along the omega range to detect the resistance value.

20. SEM Analysis
Blank mask 10 g/L PANI-coated mask 1 g/L PANI-coated mask
•Smooth rod-like structures.
•Some are smooth, thick fibres
while some are bundles of
filament fibres.
•Rough PANI layer formed.
•Irregular, heterogeneous surface.
•Deposition of large PANI
agglomerates.
•Provides large surface area for HA
molecules to bind onto.
•Higher saturated with PANI
agglomerates.
•PANI-coated mask becomes thicker.
•Increased surface irregularity of
PANI-coated mask, provides more
binding sites for HA molecules.

21. Effect of pH
pH
Removal percentage (%)
PANI-coated mask Blank mask
2 80.5 66.0
4 51.9 33.1
6 29.4 23.9
8 26.8 13.7
10 18.7 10.2
•HA molecules in aqueous solution are
negatively-charged.
•At low pH, imine and amine groups of PANI
were protonated.
•High HA removal efficiency due to
electrostatic attraction.
•pH 2 involves adsorption and precipitation,
while pH 4 is purely adsorption.

22. Effect of HA concentration
HA
conc.
(mg/L)
Removal percentage (%)
pH 2 pH 4
10 34.1 5.4
20 55.6 23.8
30 71.7 32.6
40 73.7 36.6
50 80.5 51.9
•HA removal percentage in HA concentration of
50 mg/L is highest.
•Has high concentration gradient.
•As concentration increases, adsorption shifts
from initial diffusion-controlled to attachment-
controlled.
•At low concentration, binding sites less
saturated.
•At high concentration, PANI-coated mask
highly saturated with HA molecules and more
competition for binding onto adsorption sites.

23. Effect of time interval Time
(min)
Removal percentage (%)
pH 2 pH 4
5 77.0 25.8
15 79.3 39.2
30 80.0 41.6
45 80.2 46.6
60 80.5 51.9
120 78.6 52.6
180 77.7 52.8
•At initial stage, there are many adsorption sites
available thus adsorption is rapid.
•As more adsorption sites are occupied,
adsorption slows down.
•At pH 2, slight PANI detachment occurs due to
PANI weakly bonded to mask surface.
•HA molecules at pH 2 is spherical shape, has
lower surface area for van der Waals
interaction.

24. SEM Analysis of PANI/HA Mask
•HA fibres are long, thin and curved.
•They are interconnected to form long, thin strands.
•The rough, irregular surface of PANI agglomerates provide
good binding sites for HA molecules.
•There is less PANI on the mask surface after HA removal due
to PANI detachment.

25. Electrical Conductivity of PANI/HA Mask
•A multimeter was used to measure the resistance of
PANI/HA masks.
•But there was no reading and resistance of PANI/HA masks
could not be measured.
•When concentration of PANI coating increased to 81.7 g/L,
resistance reading recorded 2.89 Ω, but this value kept
fluctuating and resistance could not be determined.


Possible reasons

•Concentration of 1 g/L PANI coating was too little.
•The surface of the spent mask is too porous, hence
electricity could not flow properly.

27. Objective Conclusion
To study the effectiveness of HA removal using different
PANI-coated spent masks at different pHs, concentrations
and time intervals.
•Effect of pH : Both pH 2 and pH 4 are good for HA
removal.
- PANI-coated mask : pH 2 is 80.5 %, pH 4 is 51.9%
- Blank mask : pH 2 is 66.0 %, pH 4 is 33.1%

•Effect of HA concentration : HA removal percentage is
highest in 50 mg/L HA solution.

•Effect of time interval : HA removal increases with
increasing time.
- HA of pH 2 reached equilibrium after 1
hour. But PANI detached after 1 hour.
- HA of pH 4 reached equilibrium after 3
hours.
To explore the possibility of coating spent masks with PANI
particles using the dip-coating method.
•PANI was successfully coated onto the spent masks as
can be seen in the SEM images. The spent masks were
coated with dark green PANI.

28. Objective Conclusion
To describe the mechanisms of dip-adsorption process via
kinetic study.
•HA removal percentage increases with increasing time.
•At initial stage, there are many adsorption sites
available thus adsorption is rapid.
•As more adsorption sites are occupied, adsorption
slows down until equilibrium is attained.
To study morphology of the PANI-coated spent masks via
scanning electron microscope.
•SEM images showed deposition of PANI agglomerates.
•A rough PANI layer is formed on the surface of spent
mask.
•HA molecules exists as long, thin stranded which are
interconnected.








PANI-coated mask PANI/HA mask

29. •Abdolahi, A. et al. (2012) ‘Synthesis of uniform polyaniline nanofibers through interfacial polymerization’, Materials, 5(8), pp. 1487–1494.
•Abu-Thabit, N. Y. and Makhlouf, A. S. H. (2016) 'Smart Textile Supercapacitors Coated with Conducting Polymers for Energy Storage
Applications', Industrial Applications for Intelligent Polymers and Coatings, 437–477.doi:10.1007/978-3-319-26893-4_21
•Ariffin, N. et al. (2017) ‘Review on Adsorption of Heavy Metal in Wastewater by Using Geopolymer’, 01023.
•Bhadra, S., Singha, N. K. and Khastgir, D. (2007) ‘Electrochemical Synthesis of Polyaniline and Its Comparison with Chemically Synthesized
Polyaniline’, 104(January 2006), pp. 1900–1904. doi: 10.1002/app.
•Guo, B. et al. (2013) ‘Chemical Engineering and Processing : Process Intensification Research on the preparation technology of polyaniline
nanofiber based on high gravity chemical oxidative polymerization’, Chemical Engineering & Processing: Process Intensification. Elsevier B.V.,
70, pp. 1–8. doi: 10.1016/j.cep.2013.05.013.
•Husin, M. R. et al. (2017) ‘Fourier transforms infrared spectroscopy and X-ray diffraction investigation of recycled polypropylene/polyaniline
blends’, Chemical Engineering Transactions, 56, pp. 1015–1020. doi: 10.3303/CET1756170.
•Itoi, H. et al. (2017) ‘Electrochemical synthesis of polyaniline in the micropores of activated carbon for high-performance electrochemical
capacitors’, Chemical Communications, 53(22), pp. 3201–3204. doi: 10.1039/c6cc08822h.
•Wang, J. et al. (2012) ‘Efficient removal of humic acid in aqueous solution using polyaniline adsorbent’, Desalination and Water Treatment, 40(1–
3), pp. 92–99. doi: 10.1080/19443994.2012.671153.
•Wang, J. et al. (2014) ‘Removal of humic acid from aqueous solution by magnetically separable polyaniline: Adsorption behavior and mechanism’,
Journal of Colloid and Interface Science. Elsevier Inc., 430, pp. 140–146. doi: 10.1016/j.jcis.2014.05.046.
•Zhao, Y. et al. (2017) ‘Hydrophobic polystyrene / electro-spun polyaniline coatings for corrosion protection’, Synthetic Metals. Elsevier,
234(November), pp. 166–174. doi: 10.1016/j.synthmet.2017.11.005.

30. Full Paper Link:
https://link.springer.com/article/10.1007/s13762-021-03757-6