Supplementary Material

Study on the adsorption of CuFe2O4-loaded corncob biochar for Pb(II)

Tianci Zhao1, Xiaolong Ma2, Hao Cai 1, Zichuan Ma1, * and Huifeng Liang3 *

1 College of Chemistry and Material Science, Normal University, Shijiazhuang 050024, Hebei, PR China; [email protected] (T. Z.); [email protected] (H. C. ); [email protected] (Z. M.) ;

2 School of Environmental Science and Engineering, of Science and Technology, Shijiazhuang 050018, Hebei, PR China; [email protected] (X. M.) ;

3 College of Chemistry and Chemical Engineering, Xingtai University, Xingtai 054001, Hebei, PR China; [email protected] (H. L.) ;

* Correspondence: [email protected] ; [email protected] ;Tel.: +86 311 80787400

Table S1. Texture properties of different samplesa.

Specific surface area Pore volume (cm3·g−1 Pore size Samples (m2·g−1 ) ) (nm) CCBC 17.1 0.039 7.93 CuFe2O4@CCBC(3%) 30.7 0.067 2.57 CuFe2O4@CCBC(5%) 75.0 0.082 2.44 CuFe2O4@CCBC(8%) 60.7 0.057 1.89

a Pore volume was measured at 0.99 of p/p0, pore size was calculated from the absorptive branch by BJH method.

Table S2. Kinetics parameters calculated from intra-particle diffusion model for Pb(II) adsorption onto samples (ki1: mg·g-1·min-1/2, ki2: mg·g-1·min-1/2).

ki1 (mg·g- ki2 (mg·g- samples C1 R2 C2 R2 1·min-1/2) 1·min-1/2) CCBC 1.39 1.09 0.9959 0.83 4.22 0.9166 CuFe2O4@CCBC(5 83.5 113.4 7.61 0.9930 1.84 0.7159 %) 9 4

Table S3. Partition coefficient (PC) for Pb(II) adsorption onto CCBC and CuFe2O4@CCBC(5%).

Sorbe Initial Final Pb(II) Equilibrium Partition nt Pb(II) Remov Concentrati Pb(II) sorption coefficient amples densi Concentra al rate on capacity (mg·g- ty tion (%) (μM) ( mg·g−1) 1·μM-1) (g·L-1) (μM ) 193.1 176.8 8.4 5.06 0.029 289.6 267.4 7.6 6.89 0.026 386.1 358.8 7.1 8.48 0.024 CCBC 0.67 482.6 450.6 6.6 9.95 0.022 579.2 543.2 6.2 11.16 0.020 723.9 687.7 5.0 11.25 0.016 965.2 926.9 4.0 11.50 0.012 482.6 198.7 58.8 88.25 0.444 579.2 239.4 58.7 106.05 0.443 723.9 359.9 50.3 113.15 0.314 CuFe2O4@C 0.67 965.2 575.0 40.4 121.29 0.211 CBC(5%) 1447.9 1043.2 28.0 125.78 0.120 1930.5 1522.2 21.2 126.90 0.083 2413.1 2005.6 16.9 126.98 0.063

2

Table S4. Comparison of the adsorption performance of typical adsorbents for Pb(II).

Adsorption capacities Adsorbent sample Reference (mg·g−1) MnFeOx@CCBC 99.60 [1] Magnetic Douglas fir biochar (MBC) 26.00 [2] Cannabis biochar (CA400) 106.39 [3] A H3PO4-modified biochar (CFCP) 55.42 [4] anaerobic digestion sludge biochar 51.77 [5] (ADSBC600) This CuFe2O4@CCBC(5%) 132.10 study

Table S5. Thermodynamic parameters for the Pb(II) adsorption by CuFe2O4@CCBC and CCBC.

CuFe2O4@CCBC(5%） CCBC ο ο ο Sm ο ο ο Gm Hm Gm Hm Sm （J·mol-1·K- (kJ·mol-1) (kJ·mol-1) (kJ·mol-1) (kJ·mol-1) （J·mol-1·K-1） 1） 303 7.13 41.02 10.89 80.80 K 313 6.65 19.55 41.23 10.39 35.42 79.99 K 323 6.30 41.03 9.29 80.84 K

（a） （b）

（c） （d）

Figure S1. SEM photos of CCBC (a) , CuFe2O4@CCBC (5%) (b) and mappings of Cu (c), Fe (d).

3

¨ CuFe2O4  quartz

CuFe2O4@CCBC(5%) Intensity (a.u.) Intensity

CCBC  ¨ ¨ ¨  ¨ ¨ ¨

10 20 30 40 50 60 70 80 2Theta（degree）

Figure S2. XRD patterns of CuFe2O4@CCBC (5%) and CCBC.

60 0.012 CuFe2O4@CCBC(5%) CuFe2O4@CCBC(5%) 50 CuFe2O4@CCBC(8%) (a) (b) 0.010 CuFe2O4@CCBC(8%)

） CuFe2O4@CCBC(3%) -1 CuFe O @CCBC(3%)

g 2 4  CCBC 3 40 ） CCBC

-1 0.008 cm （ nm  -1

30 g  0.006 3 cm

20 （ 0.004 Volume Absorted 10 dV/dD 0.002

0 0.000

0.0 0.3 0.6 0.9 0 2 4 6 8 10 12 14 16 18 20 （ ） Pore Diameter（nm） Relative presure P/P0

Figure S3. Nitrogen adsorption/desorption isotherms (a) and pore-size distribution diagram (b) of the samples.

CuFe2O4@CCBC(5%) 1.5 CCBC

1.0

0.5 ΔpH

0.0 1 3 5 7 9 11

pH0 -0.5

Figure S4. pH drift curves of the samples. 4

2.0 8

5% CuFe O @CCBC 5% CuFe2O4@CCBC 2 4 7 (b) (a) CCBC CCBC 1.5 6 ） ) 5 1.0 mg/g

（ 4 ） t min·g/mg q - e （ t

q 3 0.5 q t/ （

log 2

0.0 1

0 -0.5 0 10 20 30 40 50 60 0 10 20 30 40 50 60 Time (min) Time (min)

Figure S5. (a) Adsorption kinetics fitted with the pseudo-first-order model of Pb(II), (b) Adsorption kinetics fitted with the pseudo-second-order model of Pb(II). Initial Pb(II) concentration of 500 g·L-1 and 30±1 ℃.

160

5%CuFe2O4@CCBC 140 CCBC

120

100 ） -1 80

mg·g 60 （ t q 40

20

0

1 2 3 4 5 6 7 8 t1/2(min1/2)

Figure S6. Intraparticle diffusion plot of the Pb(II) adsorption. Initial Pb(II) concentration of 500 g·L-1 and 30±1 ℃.

5

3.5 16

3.0 (b) (a) 14 2.5 12 ）

） 2.0

g/L 10 g/L （

e （

e 1.5 /q

e 8 /q c

e 50℃ c 50℃ 40℃ 1.0 40℃ 6 30℃ 30℃ Fitted by Langmuir Fitted by Langmuir 0.5 4

0.0 0 100 200 300 400 0 20 40 60 80 100 120 140 160 180 200 220 ce（mg/L） ce（mg/L）

2.8

4.9 (c) 2.6 (d)

2.4

e 4.8 e q

q 2.2 ln ln

2.0

4.7 50℃ 50℃ 40℃ 1.8 30℃ 40℃ Fitted by Freundlich 30℃ Fitted by Freundlich 1.6 4.6 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 3.5 4.0 4.5 5.0 5.5 lnc lnce e

Figure S7. (a) Langmuir and (c) Freundlich isotherm models fitted onto the Pb(II) adsorption for CuFe2O4@CCBC(5%); (b) Langmuir and (d) Freundlich isotherm models fitted onto the Pb(II) adsorption for CCBC. (Contact time = 24 h, pH = 5.0.).

140

120

100 ） -1 g 

-1 mg 80 0 mol·L -1 （

e 0.01 mol·L q 0.1 mol·L-1

60

40

1 2 3 4 5 6 7 pH

Figure S8. Influence of pH and ion strength on Pb(II) sorption.

6

-OH -COOH ）

% CuFe2O4@CCBC(5%)-Pb （

-OH Transmission

CuFe2O4@CCBC(5%)

4000 3500 3000 2500 2000 1500 1000 500 （ -1） Wavenumber cm

Figure S9. FTIR Spectra of the CuFe2O4@CCBC(5%) and CuFe2O4@CCBC(5%)-Pb.

Supplementary Materials References

1. Zhao, T.C.; Zhou, S.Z.; Ma, X.L.; Ma, Z.C. Study on the adsorption of Pb2+ by MnFeOx -loaded corncob biochar. Acta Scientiae Circumstantiae. 2019, 39,2997-3009. 2. Karunanayake, A. G.; Todd, O. A.; Crowley, M.; Ricchetti, L.; Pittman, C. U.; Anderson, R.; Mohan, D.; Mlsna, T., Lead and cadmium remediation using magnetized and nonmagnetized biochar from Douglas fir. Biochem. Eng. J. 2018, 331, 480-491. 3. Omidi, A. H.; Cheraghi, M.; Lorestani, B.; Sobhanardakani, S.; Jafari, A., Biochar obtained from cinnamon and cannabis as effective adsorbents for removal of lead ions from water. Environ. Sci. Pollut. Res. 2019, 26, (27), 27905-27914. 4. Chen, H.; Li, W.; Wang, J.; Xu, H.; Liu, Y.; Zhang, Z.; Li, Y.; Zhang, Y., Adsorption of cadmium and lead ions by phosphoric acid-modified biochar generated from chicken feather: Selective adsorption and influence of dissolved organic matter. Bioresour. Technol. 2019, 292, 121948. 5. Ho, W. C. J.; Tay, Q.; Qi, H.; Huang, Z.; Li, J.; Chen, Z., Photocatalytic and Adsorption Performances of Faceted Cuprous Oxide (Cu(2)O) Particles for the Removal of Methyl Orange (MO) from Aqueous Media. Molecules. 2017, 22, 677.

7