Fig 1.
The K/S values of BC-COF bio-leather at 440 nm with varied extraction liquor ratios (Extraction conditions: Coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min).
Fig 2.
The K/S values of BC-COF bio-leather at 440 nm with varied dyeing temperature from 40°C to 80°C (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 30 min).
Fig 3.
The K/S values of BC-COF bio-leather at 440 nm with varied dyeing time from 30 min to 5 h (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C).
Fig 4.
The percent change in the residual color strength of BC-COF bio-leather (a) pre-mordanted with AlK(SO4)2, CuSO4, and FeSO4; (b) meta-mordanted with AlK(SO4)2, CuSO4, and FeSO4; (c) post-mordanted with AlK(SO4)2, CuSO4, and FeSO4 (Extraction conditions: liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; Dyeing conditions: fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min).
Fig 5.
FT-IR spectra of original BC and BC-COF bio-leather (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4).
Table 1.
Characteristics of peaks of original BC and BC-COF bio-leather (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4).
Fig 6.
XRD diffraction patterns of original BC and BC-COF bio-leather (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4).
Table 2.
The degree of crystallinity (%) of original BC and BC-COF bio-leather (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4).
Fig 7.
SEM images of a, b original BC; c, d BC-COF bio-leather at 10,000 and 20,000x magnification, respectively, with a scale bar of 1 μm (Extraction conditions: liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; Dyeing conditions: fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4).
Table 3.
BET surface areas and pore diameters of original BC and BC-COF bio-leather (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4).
Fig 8.
Dye adsorption rate (%) of BC-COF bio-leather with varied treatment time and concentration of the methylene blue solution (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4; dye adsorption conditions: Fabric-to-liquor ratio of 1:200 (w/v), 25°C).
Table 4.
Maximum dye adsorption rate (%) for various BC derived adsorbents for methylene blue dye adsorption.
Fig 9.
Dye adsorption rate (%) of BC-COF bio-leather with varied adsorption temperature (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4; dye adsorption conditions: 50 mg/L of methylene blue solution with a fabric-to-liquor ratio of 1:200 (w/v), 30 min).
Fig 10.
Dye adsorption rate (%) of BC-COF bio-leather with varied pH level of the methylene blue solution (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4; dye adsorption conditions: 50 mg/L of methylene blue solution with a fabric-to-liquor ratio of 1:200 (w/v), 25°C, 30 min).
Fig 11.
Zeta potential (mV) of BC-COF bio-leather with varied pH level (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4; dye adsorption conditions: 50 mg/L of methylene blue solution with a fabric-to-liquor ratio of 1:200 (w/v), 25°C, 30 min).
Fig 12.
Dye adsorption rate (%) of BC-COF bio-leather with repeated dye adsorption trials (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4; dye adsorption conditions: 50 mg/L of methylene blue solution with a fabric-to-liquor ratio of 1:200 (w/v), pH 6, 25°C, 30 min).
Fig 13.
Dye adsorption rate (%) of original BC and BC-COF bio-leather (Extraction conditions: Liquor ratio of 1:10 (w/v), coffee at an amount of 200 wt% BC, 90°C, 1 h; dyeing conditions: Fabric-to-liquor ratio of 1:10 (w/v), 70°C, 30 min, meta-mordanting with 1% of FeSO4; dye adsorption conditions: 50 mg/L of methylene blue solution with a fabric-to-liquor ratio of 1:200 (w/v), pH 6, 25°C, 30 min).