Effect of variations of washing solution chemistry on nanomaterial physicochemical changes in the laundry cycle

Transcription

1 Effect of variations of washing solution chemistry on nanomaterial physicochemical changes in the laundry cycle Denise M. Mitrano* 1, Yadira R. Arroyo 2 and Bernd Nowack 1 1. Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, 914 St. Gallen, Switzerland 2. Empa, Swiss Federal Laboratories for Materials Science and Technology, Electron Microscopy Center, Überlandstrasse 129, 86 Dübendorf, Switzerland *Corresponding Author Supporting Information The supporting information includes 5 figures (Au filtration study, EDX spectra of presented TEM analysis, additional TEMs of Ag ENP in oxi containing detergents, and results from experiments in DI vs tap water). The five tables give information on the laundry detergent chemistry, particle number measured by spicp-ms in various experiments and Ag ultrafiltration results. Further notes on analytical measurements of Ag in washing solutions is provided. Number of Figures: 5 Number of Tables: 5 Additional text included with notes on analysis of Ag in washing solutions

2 Figure S1: Sample 6 nm Au NP distributions measured by spicp-ms from serial filtration studies. Average of three samples; solutions include: panel A) DI Water; B) Grocery Liquid ; C) Grocery Powder Oxi; D) Grocery Powder ; and E) Large Batch using standardized (powder) detergent under the same conditions from Mitrano et. al 214. The efficiency of filters can drop initially because particles can clog up the smaller pore volumes in the filter first (due to natural variation in the filter pore sizes), but when a larger volume of liquid is passed through NPs have relatively higher recovery rates.

3 Counts Pristine Counts Grocery Powder All Purpose Oxi Counts Industrial Liquid Powder Counts Grocery Liquid All Purpose Counts Grocery Powder (AgNO 3 Addition) All Purpose Oxi Figure S2: EDX spectra correlating to Figure 3 in the main text of representative pristine nanomaterials (brown box) and nanoparticulate material found in each detergent after the washing procedure; grocery liquid varieties (blue box), grocery powder varieties (green boxes, both NP and AgNO 3 addition) and industrial detergents (peach box).

4 a b c) d Figure S3: BF and DF STEM images of the Ag ENPs: a) in oxi powder detergent, b) in all propose powder detergent and c and d) in industrial detergent. Approximately 2% of the AgNPs in Oxi Powder are fractured (panel A). Yellow arrows point the fractured particles. They are forming groups with dissolved AgNPs (small particles) and parent particles. In all propose powder detergent (panel b), the fractured AgNps percent is less than oxi powder (around 15%). In industrial detergents, the AgNPs are dissolved or totally fractured (Figure 1c and 1d). Around the AgNPs (Figure 1c) small Ag particles are found (with less contrast), they are fragments from the AgNPs. Fractured nanoparticles are not found in this sample, only fragment of AgNp that can come from the fracturing or the dissolving of the particles.

5 Figure S4: Averaged histograms of triplicate samples analyzed by spicp-ms of the mass equivalent of 7 nm Ag NP addition to grocery powder color and oxi detergents made up in either DI water (panels A and B) or tap water (panels C and D) with a residual chlorine concentration of 1 mg/l. In all panels, the particle size distribution histogram before washing is displayed in orange while the after wash counterpart is displayed in purple. Experiments using the oxi detergent are shaded in grey. Note: particles used in this portion of the study were Au/Ag core/shell particles, with an equivalent silver mass of 7 nm. Since we were focused only on the transformation/dissolution of the silver portion of the particle, we found it a suitable proxy to use the total mass of the acquired pulse as a single particle and observe any changes to the total mass of silver as loss to the outer shell of the particle. While absolute size changes to the particle with these calculations may not be strictly related to the physical changes the particle undergoes, the relative observed trends to any particle size changes are as valid as when using a solid silver particle.

6 Figure S5: EDX spectra correlating to Figure 4 in the main text of representative nanomaterials found in A) color or B) oxi grocery washing powders at time intervals of 1 day (blue trace), 2 days (red trace) and 5 days (green trace).

7 Table S1: Solution chemistries of the laundry detergents Washing Solution Chemistries All Purpose Wt % Wt % Water n-alkyl(c1-13)benzolsufonic acid Alkyl(C12-14) diglykoletherfulfate, Na-salt Alkyl(C12-18) carbonic acid Oxoalcohol(C13-15) polyetheylenglycolether (7EO) Sodium hydroxide ,2-Propyleneglycol Cumene sulphonate, K-Na-salt 2.. Trisodiumsulfate dihydrate Polycarboxylate, Na-salt.5.5 Protease.49 <.1 Alpha-Amaylase <.1 <.1 Enzymes <.1 <.1 Cellulase. <.1 Sodium borohydrate Chloro-2-methyl-4-isothiazolin-3-on +2- Methyl-4-isothiazonlin-3-on Grocery Store Liquid Detergents <.1 <.1 Modified Polystyrol-Dispersion.2.2 Scents.6.6 ants <.1 <.1 Grocery Store Powder Detergetns All Purpose Oxi Wt % Wt % Wt % Sodium sulfate Sodium carbonate Sodium carbonate peroxide 6 13 Sodium-alluminim silicate (Zeolite A) Sodium silicate Sodium methyl 2-sulphooctadecanoate and soldium 1-methoxy-1-oxohexadecane-2- sulphonate Tetraacethylethylenediamine Oxoalcohol (C13-15) polyethyleneglycolthether (7EO) Alkyl (C1-16) sulfate, sodium salt Fatty acids and oils Benzosulfonic acid, C1-13Alkylderivative, sodium salt Carboxymethyl cellulase, sodium salt Sodium carbonate, colorant Scent Disodium-4,4-bis((4-anilino-6-morpholin- 1,3,5-triazine-2-yl)amino) stilbene-2,2- disulfonate.3 Sodium hydroxide Phthalimidoperoxyhexane acid.2 Hydroxythan-1,1-diphosphonic acid, sodium salt Polydimethylsiloxane Copolymer wth 1-Vinylmidazol and 1-Vinyl- 2-pyrrolidine.7.76 Enzyme Mix (Protease, Amylase, Cellulase).5 <.1.1 Industrial detergents. Powder Liquid wt% wt% Sodium percarbonate 56.1 Tetraacethylethylenediamine 25 Phthalimidoperoxyhexane acid 2%

8 Table S2: Measured ph and chloride levels of the washing solutions. Background chloride concentrations were below the instrumental detection limit. Washing Solution Name ph Chloride (mg/l) Grocery Store Liquid Grocery Store All Purpose Grocery Store Powder Grocery Store Powder All Purpose Grocery Store Powder Oxi Industrial Powder Industrial Liquid Table S3: 6 nm Au particle number measured by spicp-ms in one data collection time period (two minutes). Solution Solution Fraction Average Particle # STDEV Total solution DI H2O.45 micron filtrate micron filtrate Total solution Grocery Liquid.45 micron filtrate micron filtrate Raw solution Grocery Powder Oxi.45 micron filtrate micron filtrate 61 4 Total solution Grocery Powder.45 micron filtrate micron filtrate 42 5 Total solution Large Batch (EC.45 micron filtrate Test Detergent).1 micron filtrate 79 66

9 Table S4: Concentration of dissolved Ag recovered from the addition of 8 µg/l NP addition or 25 µg/l AgNO 3 addition to various detergents. Analyte Avg Ultrafiltrate Sample Composition (ppb) Avg RSD NP Powder All Purpose Powder Oxi Powder Liquid All Purpose Liquid Industrial Liquid Industrial Powde ION Powder All Purpose Powder Oxi Powder As an analytical note, recovery of total Ag in the washing solutions was mixed, often with less silver recovered than added to the solutions (results not shown). Even with sample acidification before storage, Ag adhered to particulate mater in the solution, settled and was not analyzed. Any Ag ions which were added directly or indirectly through dissolution of the particles was also affected in this way as we note all ionic addition of Ag does not appear in the ultrafiltrate fraction of the analysis. The only exception to this was the industrial washing liquid, which had by far the lowest ph and highest oxidant concentration, where nearly all of the Ag recovered was in the dissolved form. To improve total analysis results, it would be recommended to either i) analyze samples directly after washing to avoid prolonged exposure time of the Ag to particulate matter, thus reducing the possibility of adhesion to the non-dissolvable solid material and settling and/or ii) if a longer storage time is necessary, dilute the wash solution directly after the experiment to reduce the concentration of remaining particulate in the solution. Table S5: Average number of particles observed in a given analysis time allotment of spicp-ms. Detergent Wash Stage Particle Number STDEV Grocery Liquid Before Wash After Wash Grocery Liquid All Purpose Before Wash After Wash Grocery Powder Before Wash After Wash Grocery Powder All Purpose Before Wash After Wash Grocery Powder Oxi Before Wash After Wash Industrial Liquid Before Wash After Wash Industrial Powder Before Wash After Wash