Nanoporous solid-state membranes modified with multi-wall carbon nanotubes with anti-biofouling property

Figures & data

Figure 1 FTIR spectrum of membranes: a: NSSM, b: NSSM-OH, c: NSSM-MWCNT.

Abbreviations: FTIR, Fourier-transform infrared spectroscopy; MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane.

Figure 2 EDAX point data and EDAX image of membrane (A, B) NSSM, (C, D) NSSM-MWCNT which were anodized in aqueous solutions of acid, 100 V and 25°C.

Abbreviations: EDAX, energy dispersive X-ray; MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane.

Figure 3 SEM image of surface and cross-section (A, B) of NSSM and (C, D) NSSM-MWCNT membranes which were anodized in aqueous solutions of acid, 100 V and 25°C.

Abbreviations: MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane; SEM, scanning electron microscopy.

Figure 4 AFM: two-dimensional (A and B) three-dimensional images of NSSM, (C) two-dimensional and (D) three-dimensional images of NSSM-MWCNT (500×500 nm), (E) three-dimensional images of NSSM and (F) NSSM-MWCNT (100×100 nm).

Abbreviations: AFM, atomic force microscopy; MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane.

Figure 5 WCA and SFE of NSSM and NSSM-MWCNT membranes.

Abbreviations: MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane; SFE, surface free energy; WCA, water contact angle.

Figure 6 Surface SEM image of NSSM (A) 5.00 kx, (B) 200 kx, and NSSM-MWCNT (C) 30.00 kx and (D) 50.00 kx after biofilm assay.

Abbreviations: E. coli, Escherichia coli; MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane; SEM, scanning electron microscopy; S. aureus, Staphylococcus aureus.

Figure 7 Results flow cytometry analysis (A) NSSM-E. coli, (B) NSSM-S. aureus, (C) NSSM-MWCNT-E. coli and (D) NSSM-MWCNT- S. aureus.

Abbreviations: PI, propidium iodide; SSC-H, side scatter height.

Figure 8 Percentage of bacterial viability in membrane specimens.

Abbreviations: MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane.

Figure 9 FTIR spectrum of NSSM-MWCNT membrane, which is absorbed by bacteria (1.5×10⁸ CFU/mL).

Abbreviations: FTIR, Fourier-transform infrared spectroscopy; MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane.

Figure 10 SEM images of membrane modified with carbon nanotube before (A) and after coming into contact with bacteria (B) and normal E. coli (C).

Abbreviations: E. coli, Escherichia coli; SEM, scanning electron microscopy.

Figure 11 Pesudo-first-order (A) and pesudo-second-order (B) kinetic models plot for the absorption of E. coli of 1.5×10⁸ CFU/mL.

Abbreviation: E. coli, Escherichia coli.

Figure 12 Isotherm models plot (A) Freundlich and (B) Langmuir for the absorption of E. coli at concentrations of 1.5×10⁸, 10⁷, 10⁶, 10⁵, 10⁴, and 10³ CFU/mL, 13 minutes and flow rate of 0.05 mL/min.

Table 1 The constants of Freundlich and Langmuir models

Freundlich	Langmuir
R^2=0.99	R^2=0.06
n=0.97	Qm=3.3×10^4
Kf=2,047.74	b=0.03

Table 2 Thermodynamic parameters

Initial concentration 1.5×10^8 CFU/mL	Temperature °C	% Removal	ΔG kJ/mol
ΔH=171.54 kJ/mol	5	74.00	−2.97
	10	82.00	−6.12
ΔS=0.63 kJ/mol k	15	97.33	−9.27
	20	99.00	−12.42
	30	99.90	−18.72

Figure S1 The general schematic diagram of the fabrication and modification process of membranes.

Abbreviations: MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane.

Figure S2 Absorption of E. coli on the membranes in dead-end cell.

Abbreviations: E. coli, Escherichia coli; MWCNT, multi-walled carbon nanotube; NSSM, nanoporous solid-state membrane.

Figure S3 Plate count method in absorption studies.

Note: Counting the colonies of concentration (A) 1.5 × 10⁸ and (B) 10⁷.

Table S1 Parameters of acid-base Van Oss method

Liquid	SFT (mN/m)	σ^disperse (mN/m)	Acid (mN/m)	Base (mN/m)
Milli-Q water	72.8	21.8	25.5	25.5
Glycerol	64.0	34.0	3.9	57.4
Formamide	58.0	39.0	23.2	23.2

Abbreviation: SFT, surface free energy.