Supplementary Information

Facile synthesis of highly efficient and recyclable magnetic solid acid from biomasswaste

Wu-Jun Liu, Ke Tian, Hong Jiang*Han-Qing Yu

Department of Chemistry, University of Science and Technology of China, Hefei 230026,China

Corresponding author:

Dr. Hong Jiang

Fax: +86-551-3607482; E-mail:

The following (Tables S1-S3, and Figures S1-S9) is included as additional Supplementary Informationfor this paper

Table S1. The Texture Feature (Surface Area, Pore Volume and Size ) of the Solid Acids

MPC-SO3H / PC-SO3H
Single point surface area (m2 g-1) / 294.0 / 6.6
BET surface area (m2 g-1) / 296.4 / 6.9
t-Plot micropore area (m2 g-1) / 208.5 / 0.3
t-plot external surface area (m2 g-1) / 87.9 / 6.6
total pore volume (cm³ g-1) / 0.14 / 0.01
t-Plot micropore volume (cm³ g-1) / 0.09 / 2.2×10-4
average pore size (nm) / 5.7 / 6.5

Table S2. The elemental composition, SO3H contents and total acid sites of the solid acid

MPC-SO3H / PC-SO3H
Elemental composition (wt.%)
C / 60.9 / 70.4
S / 5.6 / 3.1
Fe / 2.4 / 0.1
O a / 31.1 / 26.4
SO3H contents (mmol g-1) / 1.75 / 0.97
Total acid sites (mmol g-1) / 2.57 / 1.26
a by difference: O = 100 – C – S – Fe

Table S3. Analysis of the main elements in the XPS survey spectra of the fresh and 5 times reused MPC-SO3H catalysts (At.% = atom%)

Fresh MPC-SO3H / 5 times reused MPC-SO3H
Peak B.E. (eV) / At. % / Peak B.E. (eV) / At. %
C 1s / 284.8 / 70.83 / 284.8 / 74.06
O 1s / 533.0 / 26.58 / 532.3 / 23.57
S 2p / 169.1 / 1.32 / 168.9 / 1.23
Fe 2p / 711.9 / 1.27 / 713.0 / 1.14

Fig. S1. Comparison of the pore size distribution of the MPC-SO3H and PC-SO3H. The average pore diameters obtained by the Barrett-Joyner-Halend (BJH) method were 5.7 and 6.5 nm for the MPC-SO3H and PC-SO3H, respectively.

Fig. S2. XPS spectrum of the PC before sulfonation.

Fig. S3. FTIR spectra of the MPC-SO3H. The bands at wavenumber of ~3500 and 1131 cm-1 were attributed to the stretching and bending of OH group, respectively. The peaks at wavenumber of 1399 and 1057 cm-1 were assigned to the stretching of C-S and S=O (in SO3H group), respectively, suggesting that the SO3H groups were successfully introduced to the carbon matrix of the MPC-SO3H. Another small band at ~2700 cm-1 is attributed to an overtone of the bending of OH···O linked by a strong hydrogen bond, suggesting that some SO3H were contiguous.

Fig. S4. The conversion of xylose and yield of furfural as function of time

Fig. S5. The conversion of sucrose and yield of hydrolysis products (glucose and fructose) as function of time.

Fig. S6.(a) Separation of the fresh catalyst from the reaction mixture using an external magnet, and (b) Separation of the 5 times reused catalyst from the reaction mixture using an external magnet.

Fig. S7. SEM image of the MPC-SO3H catalyst after five times reused.

Fig. S8. (a) XPS survey spectra of the fresh and 5 times reused MPC-SO3H. (b) C 1s spectrum of the 5 times reused MPC-SO3H and (c) S 2p spectrum of the 5 times reused MPC-SO3H.

Fig. S9. Thermogravimetric analysis of the magnetic solid acid in a nitrogen flow at a heating rate of 10 K min-1 from room temperature to 1273 K.As the TGA results show (red and blue curves), first weight loss was found at temperature from ~300 to 400 K, which involved the volatilization of moisture. Another weight loss peak was observed at temperature from 430 to 590 K, in which the SO3H groups were decomposed to H2O and SO2. Corresponding to the TGA results, there were two endothermic peaks found in the heat flow curve, which were attributed to decalescence in the water release and SO3H group decomposition process, respectively.