Mikroaaltoavusteisen MP-AES-menetelmän soveltuvuus Hugger-murskaimella tuotettujen mineraalipartikkeleiden analysoimiseen

Tiivistelmä. Maapallon raaka-ainevarojen kestävään hyödyntämiseen tarvitaan uusia ja innovatiivisia menetelmiä. Kaivos- ja rikastusteollisuudessa käytetyt malmien hienonnusmenetelmät kuluttavat suurimman osan energiasta ja tuottavat eniten jätteitä metallien ja mineraalien arvoketjussa. Myös hienonnustuotteiden ja -jätteiden kemialliset analyysit kuluttavat arvokkaita luonnonvaroja reagenssien ja suojakaasujen muodossa. Tässä opinnäytetyössä tarkastellaan uuden ja innovatiivisen Hugger-murskauksen toimintaperiaatetta. Hugger-murskaus perustuu ”free crushing” -ilmiöön, jossa malminkappaleiden hienonnus tapahtuu niiden sisältämien mineraalien luonnollisia raerajoja pitkin. Tavoitteena on tuottaa mahdollisimman puhtaita mineraalipartikkeleita kuluttamalla mahdollisimman vähän energiaa, vettä ja kemikaaleja. Hugger-murskaustekniikka on nykyisin aktiivisen menetelmäkehityksen kohteena, mutta sen toimintaperiaatteen taustalla olevat fysikaaliset ilmiöt on tunnettu jo 1950-luvulta asti. Tässä opinnäytetyössä tarkastellaan myös mikroaaltoavusteisen hajotuksen, mikroaaltoplasma-atomiemissiospektrometrin (MP-AES) ja röntgenfluoresenssi-spektroskopian (XRF) käyttöä malmien hienonnustuotteiden analyyseissä. Nämä hajotus- ja analyysimenetelmät ovat paitsi nopeita myös edullisia, sillä ne kuluttavat mahdollisimman vähän hajotus- ja analyysireagensseja. Lisäksi MP-AES-menetelmässä käytetyn laitekohtaisen typpigeneraattorin tuottama typpikaasu tekee siitä huomattavasti edullisemman vaihtoehdon muihin plasmaemissiotekniikoihin verrattuna. Opinnäytetyössä osoitetaan edellä mainittujen Hugger-murskaus-, mikroaaltohajotus-, XRF- ja MP-AES-tekniikoiden soveltuvuus rinnakkaiskäyttöön.Applicability of microwave-assisted MP-AES method for the analysis of mineral particles produced by the Hugger crusher. Abstract. New and innovative methods are needed for the sustainable utilisation of the earth’s raw materials. The ore grinding methods used in the mining and beneficiation industry consume most of the energy and produce the most waste in the value chain of metals and minerals. Chemical analyses of comminution products and waste also consume valuable natural resources in the form of reagents and shielding gases. This thesis examines the operating principle of the new and innovative Hugger crushing. Hugger crushing is based on the "free crushing" phenomenon, where ore bodies are crushed along the natural grain boundaries of the minerals they contain. The goal is to produce the purest possible mineral particles by consuming as little energy, water, and chemicals as possible. Hugger crushing technology is currently the subject of active method development, but the physical phenomena underlying its operating principle have been known since the 1950s. This thesis also examines the use of microwave-assisted digestion, microwave plasmaatomic emission spectrometer (MP-AES) and X-ray fluorescence spectroscopy (XRF) in the analysis of ore crushing products. These digestion and analysis methods are not only fast but also inexpensive, as they consume as little digestion and analysis reagents as possible. In addition, the nitrogen gas produced by the device-specific nitrogen generator used in the MP-AES method makes it a significantly more affordable alternative compared to other plasma emission techniques. In this thesis, the suitability of the Hugger crushing, microwave digestion, MP-AES, and XRF techniques for parallel use is demonstrate

Terpenes and fungal biomass in the nest mounds of Formica aquilonia wood ants

AbstractNest mounds of wood ants of the Formica rufa group are built using conifer needles, small branches, other plant materials and soil. Conifer needles contain several mono and sesquiterpenes. Thus, wood ant nests may act as terpene hotspots in conifer forest soils. Some of the terpenes show antifungal activity and may thus cause small-scale heterogeneity in fungal biomass. We compared terpene concentrations and fungal biomass (ergosterol concentration) of nest material of the wood ant Formica aquilonia from the top, core and basement of 14 nest mounds in eastern Finland. Overall, α-pinene, camphene, sabinene, β-pinene, myrcene, limonene, camphor and longifolene were detected the most and were commonly present in all the studied layers. We found that terpene concentrations differed between the sampled nest material layers, being generally highest in the core of the nest and lowest at the basement of the nest. There was no association between the terpene concentration and material moisture. Fungal biomass was highest in the top layer, intermediate in core and lowest in basement; however, it was not negatively associated with terpene concentrations. Fungal biomass in nest mounds was positively associated with moisture and alkalinity. Nest mounds of Formica rufa group wood ants are complex structures with different chemical and microbial properties among its layers.</p

Sediment trapping - An attempt to monitor temporal variation of microplastic flux rates in aquatic systems

Sediment trapping as a tool to monitor microplastic influx was tested in an urban boreal lake basin. The one-year-long trap monitoring consisted of 5-month and 7-month periods representing growing season and winter season (including the spring flood event), respectively. Sediment accumulation rate (SAR), and organic content were determined, highest SAR - 14.5 g/m(2)/d - was measured during the winter period. Microplastics were extracted from the sediment applying heavy-liquid density separation method and collected under a microscope for further identification with FTIR spectroscopy. PE was identified as the most abundant synthetic polymer type, while PP and PET are also present. The annual microplastic flux rate is 32 400 pieces/m2/ year, and highest accumulation does not coincide with the highest SAR, but occurs during the growing season. Changes in the microplastic accumulation rates are related to seasonal conditions. Highest microplastic concentration with respect to dry sediment weight (10 200 pieces/kg) was observed in a growing season sample, while highest concentration with respect to sediment volume (1800 pieces/l) was observed during winter. This finding underlines the problems related to reporting microplastic concentrations in various units. The results highlight that sediment trap monitoring is an efficient tool for monitoring microplastic accumulation rate in aquatic environments and provides an opportunity to better understand and define processes controlling microplastic accumulation. (C) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND licensePeer reviewe

Size matters more than shape: Ingestion of primary and secondary microplastics by small predators

Experimental studies have shown how microplastics are taken up by various aquatic organisms. Most of these studies have been carried out with small ( 200 μm and ABS > 100 μm) in comparison to primary microplastic beads (90 μm). Our results show that fragments of secondary plastics may end up in the food web but only in small amounts, and that the size of the fragments more than their shape is a crucial nominator influencing the numbers of plastics ingested. Future research aiming to resolve the effects of microplastics in the ecosystems should concentrate on environmentally relevant plastics and concentrations.Peer reviewe

Impact of copper and zinc on the growth of saprotrophic fungi and the production of extracellular enzymes

Peer reviewe

Microplastic concentrations, size distribution, and polymer types in the surface waters of a northern European lake

Practitioner points • Samples were taken with a manta trawl (333 μm) and a pump filtration system (300/100/20 μm) • With pump filtration, small 20–300 μm particles were more common than >300 μm particles • The average concentration of manta trawled samples was 0.27 ± 0.18 (mean ± SD) microplastics/m3 • FTIR analysis revealed PE, PP, PET, and PAN to be the most common polymersWe examined microplastic concentrations, size distributions, and polymer types in surface waters of a northern European dimictic lake. Two sampling methods, a pump sieving water onto filters with different pore sizes (20, 100, and 300 µm) and a common manta trawl (333 µm), were utilized to sample surface water from 12 sites at the vicinity of potential sources for microplastic emissions. The number and polymer types of microplastics in the samples were determined with optical microscopy and μFTIR spectroscopy. The average concentrations were 0.27 ± 0.18 (mean ± SD) microplastics/m3 in manta trawled samples and 1.8 ± 2.3 (>300 μm), 12 ± 17 (100–300 μm) and 155 ± 73 (20–100 μm) microplastics/m3 in pump filtered samples. The majority (64%) of the identified microplastics (n = 168) were fibers, and the rest were fragments. Materials were identified as polymers commonly used in consumer products, such as polyethylene, polypropylene, and polyethylene terephthalate. Microplastic concentrations were high near the discharge pipe of a wastewater treatment plant, harbors, and snow dumping site

Decolorization of six synthetic dyes by fungi

To find out ability of fourteen basidiomycetes and four ascomycetes strains to grow in the presence of synthetic colour dyes and to degrade them, fungi were cultivated on the malt agar plates containing 0.5 g kg-1 dye, either Remazol Brilliant Blue R, Remazol Brilliant Yellow GL, Remazol Brilliant Orange 3 R, Reactive Blue 4, Remazol Brilliant Red F3B or Reactive Black 5. Fungi representing basidiomycetes were Phlebia radiata (FBCC 43), Tremella encephala (FBCC 1145), Dichomitus squalens (FBCC 312), Physisporinus rivulosus (syn. Obba rivulosa, FBCC 939), Cerrena unicolor (FBCC 387), Pleurotus abieticola (FBCC 517), Phanerochaete velutina (FBCC 941), Agrocybe praecox (FBCC 476), Trametes pubescens (FBCC 735), Pleurotus ostreatus (FBCC 498), Fomitopsis pinicola (FBCC 18), Postia placenta (= syn. Rhodonia placenta, FBCC 112), Gloeophyllum trabeum (FBCC 328) and Piptoporus betulinus (FBCC 1191). Ascomycetes belonged to genera Alternaria (HAMBI 3289), Epicoccum (HAMBI 3291), Fusarium (HAMBI 3292) or Chaetomium (HAMBI 3291). The growth rate of P. rivulosus belonged to three highest among the 14 tested basidiomycetes with five dyes, but not in the case of Remazol Brilliant Red F3B containing plates. The growth rate of A. praecox belonged to three lowest among the 14 tested basidiomycetes on Remazol Brilliant Blue R, Remazol Brilliant Yellow GL, Remazol Brilliant Red F3B, Reactive Black 5 and malt agar. The growth rate of Chaetomium sp. was the highest among the four ascomycetes on all tested plates. Decolorization was seen with 7 basidiomycetous strains on Remazol Brilliant Blue R, with 7 basidiomycetes on Remazol Brilliant Orange 3 R, with 8 basidiomycetes on Reactive Blue 4 and 11 basidiomycetes on Reactive Black 5 containing plates. T. encephala did not decolorize any of the tested six dyes. Epicoccum sp. and Chaetomium sp. decolorized Reactive Black 5 dye containing plates. None of the fourteen basidiomycetous or four ascomycetes were able to degrade all the tested six dyes.Peer reviewe

Microplastic concentrations, size distribution, and polymer types in the surface waters of a northern European lake

Practitioner points • Samples were taken with a manta trawl (333 μm) and a pump filtration system (300/100/20 μm) • With pump filtration, small 20–300 μm particles were more common than >300 μm particles • The average concentration of manta trawled samples was 0.27 ± 0.18 (mean ± SD) microplastics/m3 • FTIR analysis revealed PE, PP, PET, and PAN to be the most common polymersWe examined microplastic concentrations, size distributions, and polymer types in surface waters of a northern European dimictic lake. Two sampling methods, a pump sieving water onto filters with different pore sizes (20, 100, and 300 µm) and a common manta trawl (333 µm), were utilized to sample surface water from 12 sites at the vicinity of potential sources for microplastic emissions. The number and polymer types of microplastics in the samples were determined with optical microscopy and μFTIR spectroscopy. The average concentrations were 0.27 ± 0.18 (mean ± SD) microplastics/m3 in manta trawled samples and 1.8 ± 2.3 (>300 μm), 12 ± 17 (100–300 μm) and 155 ± 73 (20–100 μm) microplastics/m3 in pump filtered samples. The majority (64%) of the identified microplastics (n = 168) were fibers, and the rest were fragments. Materials were identified as polymers commonly used in consumer products, such as polyethylene, polypropylene, and polyethylene terephthalate. Microplastic concentrations were high near the discharge pipe of a wastewater treatment plant, harbors, and snow dumping site

Sediment trapping – An attempt to monitor temporal variation of microplastic flux rates in aquatic systems

ediment trapping as a tool to monitor microplastic influx was tested in an urban boreal lake basin. The one-year-long trap monitoring consisted of 5-month and 7-month periods representing growing season and winter season (including the spring flood event), respectively. Sediment accumulation rate (SAR), and organic content were determined, highest SAR – 14.5 g/m2/d – was measured during the winter period. Microplastics were extracted from the sediment applying heavy-liquid density separation method and collected under a microscope for further identification with FTIR spectroscopy. PE was identified as the most abundant synthetic polymer type, while PP and PET are also present. The annual microplastic flux rate is 32 400 pieces/m2/year, and highest accumulation does not coincide with the highest SAR, but occurs during the growing season. Changes in the microplastic accumulation rates are related to seasonal conditions. Highest microplastic concentration with respect to dry sediment weight (10 200 pieces/kg) was observed in a growing season sample, while highest concentration with respect to sediment volume (1800 pieces/l) was observed during winter. This finding underlines the problems related to reporting microplastic concentrations in various units. The results highlight that sediment trap monitoring is an efficient tool for monitoring microplastic accumulation rate in aquatic environments and provides an opportunity to better understand and define processes controlling microplastic accumulation.</p

Sediment trapping as a method for monitoring microplastic flux rates and deposition at aquatic environments

Microplastics are reported from wide range of aquatic environments with concentrations up to thousands of particles per kilogram of sediment. Due to a lack of temporal control, evaluation of the influx rate of microplastic pollution is not enabled. However, understanding the annual flux rate of microplastics to the aquatic environments is a crucial aspect for environmental monitoring and for risk assessment. A sediment trap method is widely applied in aquatic sedimentary studies in order to measure sedimentation rates and understand sedimentation processes. We have tested near-bottom sediment trap method in lacustrine and estuary environments, at central and coastal Finland, for measuring and quantifying the microplastic influx rate during one year. Near-bottom sediment traps with two collector tubes and known surface area, fixed one meter from the bottom, collect all particles that are about to accumulate on the basin floor of the water body. Controlled temporal interval of trap maintenance enables calculation and determination of local microplastic influx rate i.e. number of accumulating particles per time per surface area. The test results are very promising. Near-bottom sediment traps can be used for long term monitoring in order to gain a deeper understanding of the microplastic transport and sedimentation processes, confirm and compare the feasibility and efficiency of different environmental conservation methods, setting threshold values for microplastic influx, and supervising that the defined target conditions are met.</p