Piirilevyjen koostumuksesta ja kierrätyksestä
Tässä pro gradu -tutkielmassa on perehdytty elektroniikkajätteen ja erityisesti piirilevyjätteen koostumukseen ja kierrätykseen. Useita erilaisia tekniikoita piirilevyjen kierrätykseen on tarkasteltu. Sähkö- ja elektroniikkalaitteiden lyhentynyt käyttöikä synnyttää valtavat määrät e-jätettä. E-jätteen kierrätys on tärkeää niin materiaalien kuin metallien talteen ottamiseksi. Erityisesti jalometallien talteenotto on kiinnostavaa niiden taloudellisen arvon vuoksi. Piirilevyt sisältävät paljon arvokkaita metalleja, mutta ne ovat myös vaarallista jätettä. Piirilevyjen koostumuksen analysointi on erittäin haastavaa monimuotoisesta materiaalista johtuen. Analysointi on kuitenkin tärkeää, jotta vo…
Preconcentration and speciation analysis of mercury : 3D printed metal scavenger-based solid-phase extraction followed by analysis with inductively coupled plasma mass spectrometry
A selective method for preconcentration and determination of methylmercury (MeHg) and inorganic mercury (iHg) in natural water samples at the ng L−1 level has been developed. The method involves adsorption of Hg species into a 3D printed metal scavenger and sequential elution with acidic thiourea solutions before ICP-MS determination. Experimental parameters affecting the preconcentration of MeHg and iHg such as the sample matrix, effect of the flow rate on adsorption, eluent composition, and elution mode have been studied in detail. The obtained method detection limits, considering the preconcentration factors of 42 and 93, were found to be 0.05 ng L−1 and 0.08 ng L−1 for MeHg and iHg, res…
Addition of thiourea and hydrochloric acid: Accurate nanogram level analysis of mercury in humic-rich natural waters by inductively coupled plasma mass spectrometry.
Abstract An analytical method was developed for the direct determination of total mercury in natural waters at low ng L−1 level by inductively coupled plasma mass spectrometry (ICP-MS). The presented method overcomes previously observed problems relating to poor spike recoveries by adding 0.12% thiourea in addition to 3% HCl to all samples and standards. The sample preparation is fast and easy to perform by the developed method since it requires only the addition of HCl and thiourea to the water samples. A very low instrument detection limit (0.4 ng L−1) was obtained without time-consuming preconcentration procedures. The accuracy and precision of the developed method were found excellent b…
Determination of mercury at picogram level in natural waters with inductively coupled plasma mass spectrometry by using 3D printed metal scavengers
The determination of ultra-trace concentrations of Hg in natural water samples via preconcentration using 3D printed metal scavenger technique followed by inductively coupled plasma mass spectrometry (ICP-MS) was developed. The determination of Hg in certified reference material ERM-CA615 (groundwater) was performed with high accuracy and precision resulting in recovery of 100 ± 3% and RSD <2.5%, respectively. Selective laser sintering (SLS) 3D printing was used to fabricate the scavengers using a mixture of polyamide-12 powder with thiol-functionalized silica. The preconcentration procedure is based on the adsorption of Hg on the scavenger and followed by elution of the preconcentrated Hg …