Leaching of metals from paint and rubber particles

Posavec, Damir

4. term

Environmental Engineering, Master

2018

2018-06-01

17

Små partikler af gummi og antifouling-bundmaling (marine belægninger, der forhindrer organismer i at sætte sig på skrog) kan frigive metaller som zink (Zn) og kobber (Cu) til vand, hvilket er forbundet med miljøtoksicitet. Vi udførte udvaskningsforsøg for at se, hvordan partikelstørrelse, mængden af materiale i vandet og varigheden påvirker hastigheden, hvormed metaller frigives. Fire gummityper og tre malinger blev testet i tre størrelsesintervaller (1–2 mm, 200–500 μm og 40–80 μm). Partiklerne blev omrørt i ultrarent (Milli-Q) vand i 72 timer eller længere ved en lav koncentration (0,52 mg pr. mL) og, i nogle forsøg, ved en højere koncentration (5,22 mg pr. mL). For at sammenholde frigivelsen med det, der findes i materialerne, opløste vi gummi- og malingprøverne for at måle deres samlede metalindhold og brugte dette til at anslå, hvor lang tid det vil tage at udvaske 50% af det indeholdte zink. Vi brugte også mikroskopi til at bekræfte partikelstørrelser, beregnede specifikt overfladeareal (overfladeareal pr. masse) og undersøgte, hvordan det hænger sammen med hastigheden af metaloverførsel fra partikler til vand.

Small particles of rubber and antifouling paint (marine coatings that prevent organisms from attaching to hulls) can release metals such as zinc (Zn) and copper (Cu) into water, and these metals are linked to environmental toxicity. We carried out leaching tests to see how particle size, the amount of material in the water, and exposure time affect the rate at which metals are released. Four rubber materials and three paints were tested in three particle-size ranges (1–2 mm, 200–500 μm, and 40–80 μm). Particles were stirred in ultrapure (Milli-Q) water for 72 hours or longer at a low concentration (0.52 mg per mL) and, for some tests, at a higher concentration (5.22 mg per mL). To compare release with what is present in the materials, we digested the rubber and paint samples to measure their total metal content and used this to estimate how long it would take for 50% of the contained zinc to leach. We also used microscopy to verify particle sizes, calculated specific surface area (surface area per mass), and examined how it correlates with the rate of metal mass transfer from particles to water.

[This abstract was generated with the help of AI]

Microplastic ; Leaching ; Zinc ; Digestion ; Specific surface area ; Environment ; Copper ; Metals ; Rubber ; Paint

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