0000000000442077
AUTHOR
Siiri Perämäki
showing 16 related works from this author
Dry chlorination of spent nickel metal hydride battery waste for water leaching of battery metals and rare earth elements
2022
An efficient leaching process was developed for nickel, cobalt, and the rare earth elements (REEs) from spent nickel metal hydride (NiMH) battery waste. The process involves dry chlorination with ammonium chloride in low temperature to produce water-soluble chlorinated compounds, followed by simple water leaching. The factors affecting the conversion and solubilization were studied, including the amount of ammonium chloride, residence time and temperature in dry chlorination, and solid to liquid ratio, time and temperature in water leaching. As a result, the dry chlorination process was found to produce ammonium and chloride containing products, depending on the temperature of the process: …
Iron and pH regulating the photochemical mineralization of dissolved organic carbon
2017
Solar radiation mineralizes dissolved organic matter (DOM) to dissolved inorganic carbon through photochemical reactions (DIC photoproduction) that are influenced by iron (Fe) and pH. This study addressed as to what extent Fe contributes to the optical properties of the chromophoric DOM (CDOM) and DIC photoproduction at different pH values. We created the associations of Fe and DOM (Fe-DOM) that cover the range of loadings of Fe on DOM and pH values found in freshwaters. The introduced Fe enhanced the light absorption by CDOM independent of pH. Simulated solar irradiation decreased the light absorption by CDOM (i.e., caused photobleaching). Fe raised the rate of photobleaching and steepened…
Preconcentration and speciation analysis of mercury : 3D printed metal scavenger-based solid-phase extraction followed by analysis with inductively c…
2021
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 ma…
2020
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
2019
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 …
Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanopart…
2022
The advancement of analytical methods for nanoparticle measurements is critical both for the growing industrial exploitation of engineered nanoparticles and for developing robust strategies to understand and control the concentration of nanomaterials in humans and the environment. For high value nanoparticles, the measurement of nanoparticle number concentration in a liquid directly impacts the ability to assess the scale and reproducibility of the production process, it allows optimisation of efficiency and supports regulatory compliance. This measurement is also useful to monitor and control the intentional or accidental release of engineered nanoparticles into the environment at the produc…
Method development for determination and recovery of rare earth elements from industrial fly ash
2014
Rare earth elements (REE) are important in numerous high technology applications and in addition their supply risk is high, which gives rise to studying new sources for rare earth elements. Rare earth element concentrations in industrial fly ash samples collected from Finnish power plants, using a mixture of peat and biomass as a fuel, have been determined. Two sample pre-treatment methods, ultrasound- and microwave-assisted acid digestions, have been applied to fly ash samples. Measurement conditions for inductively coupled plasma-optical emission spectrometry (ICP–OES) have been optimized to reach robust plasma conditions and the reliability of the analysis has been investigated by using …
Occurrence and recovery potential of rare earth elements in Finnish peat and biomass combustion fly ash
2019
Rare earth elements (REEs) are highly important in the modern society as a result of their wide use in various fields of industry. Their high supply risk and increase in demand has led to classification as critical materials, and consequently, new resources for REEs are being prospected widely. Coal fly ash has been suggested as a possible secondary resource for REEs, but very little information is available regarding REE occurrence in biomass or peat derived fly ash. In this paper, fly ash samples from commercial power plants using peat and biomass as fuel were studied for REEs. The average concentration of REEs was 530 ppm, with up to 920 ppm in one fly ash. Five out of seven fly ashes we…
Optimization of instrumental parameters for improving sensitivity of single particle inductively-coupled plasma mass spectrometry analysis of gold
2021
Single particle inductively-coupled plasma mass spectrometry (spICP-MS) is a promising technique for analysis of engineered nanoparticles, whose utilization has increased substantially over the past years. Optimization of instrumental conditions is, however, crucial to improve the sensitivity and precision of nanoparticle (NP) detection. In this study, the influence of ICP-MS instrumental parameters (nebulizer gas flow, plasma radiofrequency-power and sampling depth) on the signal intensity of gold in spICP-MS was evaluated using dispersions of Au NPs and a solution of dissolved gold. The interaction effects of the main factors were found to have a significant effect on the signal intensity…
Solid phase extraction materials as a key for improving the accuracy of silver nanoparticle characterization with single-particle inductively coupled…
2022
The accurate characterization of silver nanoparticles (Ag NPs) in environmental samples is crucial for understanding the potential impact of these materials on the environment and human health. Single-particle inductively coupled plasma mass spectrometry (spICP-MS) is one of the few techniques available for quantifying NPs at environmentally relevant concentrations. However, the spICP-MS detection of Ag NPs can be interfered with coexisting dissolved analyte causing high background signals, which mask NP signals leading to a significant bias in NP characterization. In this paper, a simple sample pre-treatment procedure for efficient removal of dissolved silver in natural waters is proposed …
Separation of palladium and silver from E-waste leachate : effect of nitric acid concentration on adsorption to Thiol scavenger
2022
The development of recovery techniques for metals present in low concentrations in E-waste, such as silver and palladium, is important from the aspect of the circular economy. Adsorption of palladium and silver was studied in detail in a batch process with silica-based Thiol scavenger from nitric acid leachate of waste printed circuit boards (PCBs). High adsorption efficiencies of Pd(II) and Ag(I), >97%, were reached in nitric acid concentrations below 3 mol L−1. At higher acid concentrations, adsorption efficiency of Ag(I) decreased drastically which enables the separation of Ag(I) and Pd(II) based on nitric acid concentration in sample solution. Pd(II) and Ag(I) followed pseudo 2nd order …
Alkyl-Substituted Aminobis(phosphonates)Efficient Precipitating Agents for Rare Earth Elements, Thorium, and Uranium in Aqueous Solutions
2021
The efficient and environmentally sustainable separation process for rare earth elements (REE), especially for adjacent lanthanoids, remains a challenge due to the chemical similarity of REEs. Tetravalent actinoids, thorium, and traces of uranium are also present in concentrates of REEs, making their separation relevant. This study reports six simple water-soluble aminobis(phosphonate) ligands, RN[CH2P(O)(OH)2]2 (1 R = CH2CH3, 2 R = (CH2)2CH3, 3 R = (CH2)3CH3, 4 R = (CH2)4CH3, 5 R = (CH2)5CH3, 6 R = CH2CH(C2H5)(CH2)3CH3) as precipitating agents for REEs, Th, and U, as well as gives insight into the coordination modes of the utilized ligands with REEs at the molecular level. Aminobis(phospho…
Effective Recovery Process of Copper from Waste Printed Circuit Boards Utilizing Recycling of Leachate
2020
AbstractThis study presents an optimized leaching and electrowinning process for the recovery of copper from waste printed circuit boards including studies of chemical consumption and recirculation of leachate. Optimization of leaching was performed using response surface methodology in diluted sulfuric acid and hydrogen peroxide media. Optimum leaching conditions for copper were found by using 3.6 mol L−1 sulfuric acid, 6 vol.% hydrogen peroxide, pulp density of 75 g L−1 with 186 min leaching time at 20°C resulting in complete leaching of copper followed by over 92% recovery and purity of 99.9% in the electrowinning. Study of chemical consumption showed total decomposition of hydrogen pero…
Alkyl-Substituted Aminobis(phosphonates) : Efficient Precipitating Agents for Rare Earth Elements, Thorium, and Uranium in Aqueous Solutions
2021
The efficient and environmentally sustainable separation process for rare earth elements (REE), especially for adjacent lanthanoids, remains a challenge due to the chemical similarity of REEs. Tetravalent actinoids, thorium, and traces of uranium are also present in concentrates of REEs, making their separation relevant. This study reports six simple water-soluble aminobis(phosphonate) ligands, RN[CH2P(O)(OH)2]2 (1 R = CH2CH3, 2 R = (CH2)2CH3, 3 R = (CH2)3CH3, 4 R = (CH2)4CH3, 5 R = (CH2)5CH3, 6 R = CH2CH(C2H5)(CH2)3CH3) as precipitating agents for REEs, Th, and U, as well as gives insight into the coordination modes of the utilized ligands with REEs at the molecular level. Aminobis(phospho…
Acetic acid leaching of neodymium magnets and iron separation by simple oxidative precipitation
2022
Neodymium-iron-boron (NdFeB) has become the most prominent permanent magnet alloy, with a wide variety of applications and an ever-increasing demand. Their recycling is important for securing the supply of critical raw materials used in their manufacturing. The use of organic acids such as acetic acid has been of recent interest for the recycling of waste NdFeB magnets. Despite achieving good leaching efficiencies, the published literature has not properly investigated the effects of key factors influencing the acetic acid leaching process and their respective interactions, which has lead to conflicting findings as to what conditions are optimal. The present work goes to show that no such o…
Application of 3D printed scavengers for improving the accuracy of single-particle inductively coupled plasma mass spectrometry analyses of silver na…
2023
The determination of silver nanoparticles (Ag NPs) with single-particle inductively coupled plasma mass spectrometry can be severely interfered with coexisting dissolved silver causing high background signals, which can lead to inaccurate quantification of NP size and particle concentration. In this paper, chemically active and reusable 3D printed scavengers are applied for highly efficient dissolved silver removal in Ag NP dispersions, allowing more accurate determination of particle concentration and size. Selective laser sintering was used for constructing the porous 3D scavengers constituting of polystyrene used as a supporting material and ion-exchange material SiliaBond Tosic acid (TA…