Supporting information Photo-reduction and Stabilization Capability of Molecular Weight Fractionated Natural Organic Matter in Transformation of Silver Ion to Metallic Nanoparticle 7 8 9 Yongguang Yin 1, Mohai Shen 1, Xiaoxia Zhou 1, Sujuan Yu 1, Jingbo Chao, Jingfu Liu 1*, and Guibin Jiang 1 10 11 1 1 1 1 1 State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10008, China Chemical Metrology and Analytical Science Division, National Institute of Metrology, Beijing 10001, China 1 * Corresponding author: Tel. +8(10)-8919; jfliu@rcees.ac.cn 17 Number of pages: 18 Number of figures: 19 19 Number of tables: S1
Table S1 Molar absorptivity at 80 nm and Ex/Em wavelength and intensity of florescence peak of pristine and M f -NOM. molar absorptivity at 80 nm (1 mol -1 cm -1 OC) pristine >100 kda 0-100 kda 10-0 kda -10 kda < kda 80 100.8 8. 770. 8. 0 Ex/Em (nm) / 0/8 70/8 0/0 /0 0/ peak intensity of florescence 711 918 79 7980 8707 19 S
Table S Dual-mode distribution of AgNPs size in pristine and M f -NOM determined by DLS. Solution conditions: 0. mmol L -1 AgClO, mg L -1 DOC pristine or M f -NOM, mmol L -1 borate buffer (ph 8.0) under simulated sunlight irradiation for 9 h. Size of Peak 1±SD (d. nm) Size of Peak ±SD (d. nm) Pristine NOM 1.9±0.87.7±0. >100 kda M f -NOM.8±1.88.11±0.0 0-100 kda M f -NOM.±1.8.1±0.0 10-0 kda M f -NOM 7.1±.0.±0.17-10 kda M f -NOM.7±10.08.89±0.8 < kda M f -NOM 7.8±0..0±0.78 S
Figure S1. Transmittance of UV-B block film (cut-off wavelength 1 nm), UV Block film (cut- off wavelength 81 nm) and aluminum foil. S
Figure S. The molecular weight distribution of M f -NOM fraction in SRNOM. S
Figure S. Light spectrum from (a) solar simulator (Xe lamp), (b) Hg lamp, and (c) Hg lamp with glass filter. S
Figure S. Transmittance of glass filters to separate nm light from Hg lamp. S7
Figure S. UV-vis spectra of pristine and M f -NOM. Solution conditions: mg L -1 DOC pristine or M f -NOM in mmol L -1 borate buffer (ph 8.0). S8
Figure S. Fluorescence excitation-emission spectra of pristine and M f -NOM. (a) pristine NOM, (b) >100 kda M f -NOM, (c) 0-100 kda M f -NOM, (d) 10-0 kda M f -NOM, (e) -10 kda M f - NOM, and (f) < kda M f -NOM. Solution conditions: mg L -1 DOC pristine or M f -NOM in mmol L -1 borate buffer (ph 8.0). S9
Figure S7. UV-vis spectra of the solution after different irradiation time. (a) pristine NOM, (b) >100 kda M f -NOM, (c) 0-100 kda M f -NOM, (d) 10-0 kda M f -NOM, (e) -10 kda M f - NOM, and (f) < kda M f -NOM. Background absorption of NOM was deducted from the prepared AgNPs solution. Solution conditions: 0. mmol L -1 AgClO, mg L -1 DOC pristine or M f -NOM, mmol L -1 borate buffer (ph 8.0). 7 8 9 S10
Figure S8. TEM images (a and b), SAED (c) and EDS (d) of the photo-induced AgNPs in SRNOM solution. The scale bars are 0 nm ad nm in (a) and (b), respectively. Solution conditions: 0. mmol L -1 AgClO, mg L -1 DOC pristine SRNOM, mmol L -1 borate buffer (ph 8.0). S11
1 Figure S9. TEM images of the photo-induced AgNPs in Mf-NOM solution after 9 h simulated sunlight irradiation. (a) >100 kda Mf-NOM, (b) < kda Mf-NOM. The scale bars are 0 nm in (a) and (b). Solution conditions: 0. mmol L-1 AgClO, mg L-1 DOC Mf-NOM, mmol L-1 borate buffer (ph 8.0). 7 8 9 S1
Figure S10. UV-vis spectra of the solution after 9 h simulated sunlight irradiation at different ph. (a) pristine NOM, (b) >100 kda M f -NOM, (c) 0-100 kda M f -NOM, (d) 10-0 kda M f - NOM, (e) -10 kda M f -NOM, and (f) < kda M f -NOM. Background absorption of NOM was deducted from the prepared AgNPs solution. Solution conditions: 0. mmol L -1 AgClO, mg L -1 DOC pristine or M f -NOM, mmol L -1 borate buffer. 7 8 9 S1
Figure S11. TEM images of the photo-induced AgNPs in < kda M f -NOM solution at different ph after 9 h simulated sunlight irradiation. (a) ph 7., (b) ph 8.0. The scale bars are 100 nm. Solution conditions: 0. mmol L -1 AgClO, mg L -1 DOC < kda M f -NOM, mmol L -1 borate buffer. S1
Figure S1. Effect of Ag + concentration on the formation of AgNPs in the presence of pristine or M f -NOM under simulated sunlight irradiation. (a) pristine NOM, (b) >100 kda M f -NOM, (c) 0-100 kda M f -NOM, (d) 10-0 kda M f -NOM, (e) -10 kda M f -NOM, and (f) < kda M f -NOM. The absorbance was the maximum absorbance at ~00 nm. Background absorption of NOM was deducted from the prepared AgNPs solution. Solution conditions: mg L -1 DOC pristine or M f -NOM, mmol L -1 borate buffer (ph 8.0). 7 8 S1
Figure S1. Time-evolution of UV-vis spectra of pristine and M f -NOM under simulated sunlight. (a) pristine NOM, (b) >100 kda M f -NOM, (c) 0-100 kda M f -NOM, (d) 10-0 kda M f -NOM, (e) -10 kda M f -NOM, and (f) < kda M f -NOM. Solution conditions: mg L -1 DOC pristine or M f -NOM in mmol L -1 borate buffer (ph 8.0). 7 S1
Figure S1. Effect of NOM concentration on the formation of AgNPs from Ag + in the presence of pristine or M f -NOM under simulated sunlight irradiation. The absorbance was the maximum absorbance at ~00 nm. Background absorption of NOM was deducted from the prepared AgNPs solution. Solution conditions: 0. mmol L -1 AgClO, mmol L -1 borate buffer (ph 8.0). 7 S17
Figure S1. UV-vis spectra of the solution after h nm irradiation. Background absorption of NOM was deducted from the prepared AgNPs solution. Solution conditions: 0. mmol L -1 AgClO, 0 mg L -1 DOC M f -NOM, mmol L -1 borate buffer (ph 8.0)..0..0. >100 kda M f -NOM 0-100 kda M f -NOM 10-0 kda M f -NOM -10 kda M f -NOM < kda M f -NOM Abs.0 1. 1.0 0. 0.0 00 00 00 00 00 700 800 Wavelength (nm) S18
7 Figure S1. Effect of light quality on the formation of AgNPs from Ag + in the presence of pristine or M f -NOM under simulated sunlight irradiation. (a) pristine NOM, (b) >100 kda M f - NOM, (c) 0-100 kda M f -NOM, (d) 10-0 kda M f -NOM, (e) -10 kda M f -NOM, and (f) < kda M f -NOM. The absorbance was the maximum absorbance at ~00 nm. Background absorption of NOM was deducted from the prepared AgNPs solution. Solution conditions: 0. mmol L -1 AgClO, mg L -1 DOC pristine or M f -NOM, mmol L -1 borate buffer (ph 8.0). 8 9 S19
Figure S17. UV-vis spectra of NOM solution in the absence or presence of Ca + (10 mg L -1 ). Solution conditions: 0. mmol L -1 AgClO, mg L -1 DOC pristine or M f -NOM, mmol L -1 borate buffer (ph 8.0). S0
Figure S18. Heating-induced Reduction of Ag + to AgNPs in pristine and M f -NOM solution at and 0 C. (a) C, and (b) 0 C. The absorbance was the maximum absorbance at ~00 nm. Background absorption of NOM was deducted from the prepared AgNPs solution. Solution conditions: 0. mmol L -1 AgClO and mg L -1 DOC pristine and M f -NOM in mmol L -1 borate buffer (ph 8.0). 7 8 S1
1 Figure S19. TEM images of the photo-induced AgNPs in Mf-NOM solution at 0 C. (a) >100 kda Mf-NOM, (b) < kda Mf-NOM. The scale bars are 0. µm. Solution conditions: 0. mmol L-1 AgClO and mg L-1 DOC Mf-NOM in mmol L-1 borate buffer (ph 8.0). 7 S