Evidence map›Paper›PMID 41565859›Full record

ArticleScientific reports2026

Effect of HIFU frequency on gold removal efficiency from e-waste.

Topi Pudas, Axi Holmström, Jere Hyvönen, Tom Sillanpää, Joni Mäkinen, Martin Weber, Kenichiro Mizohata, Antti Kuronen, Tapio Kotiaho, Edward Haeggström and 1 more

Abstract read
In one paragraph

Article in Scientific reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

11 authors.

Topi PudasElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland. topi.pudas@helsinki.fi.
Axi HolmströmElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland.
Jere HyvönenElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland.
Tom SillanpääElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland.
Joni MäkinenElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland.
Martin WeberElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland.
Kenichiro MizohataAccelerator Laboratory, Faculty of Science, University of Helsinki, P.O.B. 43, Helsinki, 00014, Finland.
Antti KuronenAccelerator Laboratory, Faculty of Science, University of Helsinki, P.O.B. 43, Helsinki, 00014, Finland.
Tapio KotiahoDrug Research Program and Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O.B. 56, Helsinki, 00014, Finland.
Edward HaeggströmElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland.
Ari SalmiElectronics Research Laboratory, Faculty of Science, University of Helsinki, P.O.B. 64, Helsinki, 00014, Finland.

Funding

Research Council of Finland 347459
6 · The paper itself

Abstract

The depletion of mineable gold reserves, paired with the increase in demand for electronics, underlines the need for sustainable gold recycling methods. Owing to its high precious metal content, electronic waste (e-waste) is a promising source for gold recovery. Conventional approaches, such as pyro- and hydrometallurgy, remain environmentally taxing, producing harmful emissions and toxic byproducts. This study advances a recently reported ultrasound-based, green technology for recovering gold from discarded printed circuit boards (PCBs). The method uses localized cavitation in water, driven by high-intensity focused ultrasound (HIFU), to mechanically remove gold from PCB edge connectors. In this work, the influence of ultrasound frequency on removal efficiency is investigated using three custom-built HIFU transducers operating at 4.2, 7.3, and 11.8 MHz. Gold removal at 4.2 MHz was found to be 4.6 and 3.8 times more efficient than at 11.8 MHz and 7.3 MHz, respectively. Direct comparison of the erosion marks to the pressure fields revealed that complex frequency-dependent cavitation cloud dynamics are likely responsible for the increase in removal efficiency at the lowest frequency employed. The improved efficiency indicates potential for scale-up, although industrial viability will require further optimization of throughput and thermal management.

Indexed as

CavitationE-waste recyclingHigh-intensity focused ultrasoundSustainable technologyUrban mining

Identifiers

PMID41565859
PMCPMC12830688

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.