Supporting Information

Transcription

1 Supporting Information Online Size and Element Analysis of Aerosol Particles Released from Thermal Treatment of Wood Samples Impregnated with Different Salts Adrian Hess*,a,b, Mohamed Tarik a, Debora Foppiano a,b, Philip Edinger a,b, Christian Ludwig* a,b. a PSI Paul Scherrer Institut, CH 5232 Villigen PSI, Switzerland b EPFL École Polytechnique Fédérale de Lausanne, CH Lausanne, Switzerland. Preparation of the solutions used to impregnate the sawdust batches The weight of each sawdust batch, before the impregnation, was m Wood 2 g. The amount of copper(ii) sulfate pentahydrate (CuSO 4 5H 2 O; puriss. p.a., cryst. > 99 %, from Fluka), used for the CuSO 4 impregnation, was m CuSO mg. With the molar masses of Cu and CuSO 4 5H 2 O, M Cu g mol 1 and M CuSO g mol 1, the Cu concentration in the impregnated sawdust was: c Cu m Cu M m CuSO4 Cu M CuSO % m CuSO4 + m Wood The copper(ii) chloride dihydrate (CuCl 2 2H 2 O; p.a., from Merck) amount, used for the CuSO 4 impregnation, was m CuCl mg. With the molar mass of CuCl 2 2H 2 O, M CuCl g mol 1, the Cu concentration in the sawdust batch became: c Cu m Cu M m CuCl2 Cu M CuCl % m CuCl2 + m Wood S1

2 The potassium chloride (KCl) amount in the CuSO 4 -KCl impregnated sawdust batch was chosen such that a molar ratio of Cl:Cu 4:1 was achieved. With the molar mass of KCl, M KCl g mol 1, the desired concentration was therewith: c KCl c Cu 4 M KCl M Cu % The amounts of KCl (KCl; puriss. p.a., > 99.5 %, from Fluka) and CuSO 4 5H 2 O, used in the mixed CuSO 4 5H 2 O-KCl impregnation, were m KCl 28.9 mg and m CuSO4 24. mg resulting in the desired concentrations: c KCl m KCl c Cu m Cu m KCl m KCl + m CuSO4 + m Wood M m CuSO4 Cu M CuSO4 m KCl + m CuSO4 + m Wood %.3.3 % To impregnate a sawdust batch with only KCl, but with the same concentration as in the mixed sample, m KCl mg were used. The resulting KCl concentration was then: c KCl m KCl m KCl m KCl + m Wood % Procedure to adjust all flows of the RDD-SMPS-ICPMS instrumentation 1. Pull off the sheath gas tube from the DMA inlet, adjust the sheath gas flow, Q Sheath 3. L min 1, and reconnect the tube. 2. Pull off the sample inlet tube from the aerosol neutralizer at the DMA inlet, adjust the polydisperse aerosol flow, Q poly.6 L min 1, by tuning the dilution Ar flow, Q dil Ar, and reconnect the tube. 3. Connect the flow calibrator at the monodisperse DMA outlet and adjust the total monodisperse flow, Q mono,tot.6 L min 1, by tuning the excess flow, Q Excess. S2

3 4. Insert the flow calibrator between the two T-pieces at the DMA outlet and adjust the CPC fraction of the monodisperse aerosol, Q mono,cpc.18 L min 1, by tuning the CPC air flow, Q air,cpc. 5. Check and fine-adjust the monodisperse ICPMS flow, Q mono,icp.4 L min 1, by finetuning the excess flow, Q Excess, if necessary. Analysis of the natural sawdust and the residues from the TGA experiments The elements which were found in the wet chemistry sawdust analysis are listed in Table S1. The results from the final analysis of all TGA sample residues are compiled in Table S2. These values allow appraising the results from the aerosol experiments. The remaining K was in the same order of magnitude for all samples except the CuSO 4 -KCl impregnated pellet, where a substantially higher K amount was found in the residue. This supports the supposition, mentioned in the main article, that the CuSO 4 was impeding the KCl evaporation and therewith the K release. The remaining Cu quantities detected in all residues from the samples impregnated with cupric salts are close to the added Cu amounts, considering a certain error, caused by the procedure of removing the residues from the crucibles and digesting them in acid, before measuring the concentration by ICPMS and calculating the listed amount. Therewith the Cu was mainly found in the residues in all cases. No Cl was found in the residues. This is consistent with the RDD-SMPS-ICPMS data. Table S1. Element analysis of the non-treated sawdust Potassium (K) Magnesium (Mg) Sodium (Na) Copper (Cu) 1327 ± ± ±.5 1. ±.1 All numbers are given in [μg g 1 ]. S3

4 Table S2. Element analysis of sample residues Added K Remaining K Added Cu Remaining Cu Added Cl Remaining Cl Natural <.1 - <.1 KCl < <.1 CuSO <.1 CuCl <.1 CuSO 4 -KCl <.1 All numbers are given in [mg]. Thermodynamic equilibrium calculations Figure S1. HSC calculation of the thermodynamic equilibrium of CuSO 4, undergoing a temperature increase from 25 to 64 C under slightly reducing conditions, in the presence of water, at an absolute pressure of 1. bar. The input compounds, considered for the calculation, were:.1 mol N 2 6 mol H 2 2 mol CuSO 4 Temperature / C S4

5 Figure S2. HSC calculation of the thermodynamic equilibrium of CuSO 4, undergoing a temperature increase from 25 to C under highly reducing conditions, in the presence of water, at an absolute pressure of 1. bar. The input compounds, considered for the calculation, were:.1 mol N 2 mol H 2 1 mol CuSO 4 5H 2 O Temperature / C Figure S3. HSC calculation of the thermodynamic equilibrium of CuCl 2, undergoing a temperature increase from 25 to C under oxidizing conditions, at an absolute pressure of 1. bar. The input compounds, considered for the calculation, were:,.1 mol N 2 mol O 2 1 mol CuCl 2 2H 2 O Temperature / C S5

6 CuSO4-KCl size distribution and element maps e Figure S4. Particle-size-related ICPMS mass intensity on m/z 39, given in cps, representing the K release during the TGA experiment with the CuSO4-KCl-impregnated sample Figure S5. Particle-size-related ICPMS mass intensity on m/z 23, given in cps, representing the Na release during the TGA experiment with the CuSO4-KCl-impregnated sample. S6

7 e6 1e Figure S6. Particle-size-related ICPMS mass intensity on m/z 35, given in cps, representing the Cl release during the TGA experiment with the CuSO4-KCl impregnated sample NaN Figure S7. Particle size related ICPMS mass intensity on m/z 63, given in cps, representing the Cu release during the TGA experiment with the CuSO4-KCl impregnated sample. S7