Peat Coated with Iron Oxides

Purification of Metal(loid)-Contaminated Water and Treatment of the Spent Adsorbent

Document identifier: oai:DiVA.org:ltu-76325
Keyword: Engineering and Technology, Adsorption, Avfallsteknik, Landfilling, Hydrothermal carbonisation, Combustion, Metals, Arsenic, Iron-peat, Environmental Engineering, Annan naturresursteknik, Other Environmental Engineering, Miljöledning, Naturresursteknik, Teknik och teknologier, Environmental Management, Waste Science and Technology
Publication year: 2019
Relevant Sustainable Development Goals (SDGs):

The SDG label(s) above have been assigned by OSDG.ai

Abstract:

In Sweden due to the industrial activities, such as wood impregnation, multiple point sources of arsenic (As) contamination in soil and water bodies are scattered over the country. Metals, such as chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), cadmium (Cd) or zinc (Zn) at varying concentrations are usually present as well. Since adsorption is a common method to purify contaminated water, research and development of adsorbents have been actively carried out in the last few decades. However, seldom spent sorbent is safely handled afterwards and often end up in landfill, thus creating new problems and posing new risks to humans and environment.

The aim of this study was to develop a waste-based adsorbent for simultaneous removal of As and associated metals: Cr, Cu and Zn, and to analyse sustainable ways how to manage the spent adsorbent without creating secondary pollution.

In the model system two well-establish adsorbents: Fe oxides (deriving from FeCl₃) and peat (waste-based), were combined and the concept of simultaneous removal of cationic and anionic contaminants was tested in a batch adsorption experiment. Due to Fe coating, removal of As and Cr increased by 80% and 30%, respectively, as compared to non-coated peat. Removal of Cu and Zn was higher (up to 15%) on non-coated peat than on Fe-coated peat. Similar results were obtained in the up-scaled column adsorption experiment, where Fe salt was substituted with a waste-based Fe hydrosol. Within the same pH environment (pH=5), Fe-coated peat effectively adsorbed all four investigated contaminants (As, Cr, Cu and Zn). Non-coated peat was effective for Cr, Cu and Zn. While, Fe oxides (coated on sand) adsorbed only As.

Three management strategies for spent adsorbents, obtained after column adsorption experiment, were investigated in this study. i) Long-term deposit in a landfill was simulated by exposing spent adsorbents to a reducing environment and evaluating metal(loid) leaching. Leaching of As increased manifold (up to 60% in a 200-day experiment) as compared to the standardized batch leaching experiment under oxidizing conditions. It was determined that about one third of As(V) was reduced to As(III), which is more mobile and toxic. ii) Valorisation of the spent adsorbent was attempted through hydrothermal carbonisation. It was expected that obtained hydrochar could be used as a beneficial soil amendment. However, treatment resulted in the process liquid and the hydrochar both having high loads of As, Cu and Zn. Additional treatment of process water and hydrochar imply higher management costs for spent adsorbents. iii) Possibility of thermal destruction was investigated by combusting spent adsorbents. After the treatment volume of the waste (ash) was by 80-85% smaller as compared to spent adsorbents. Combustion at higher temperature (1100 °C vs 850 °C) resulted into a weaker metal(loid) leaching from ashes. Furthermore, co-combustion with calcium (Ca)-rich lime (waste-based) decreased leaching of all four investigated elements, Cr in particular, below the limit values for waste being accepted at landfills for hazardous waste. Therefore, combustion enabled possibility of safe and long-term deposit of As-bearing ashes. At the same time, less As would be circulating in society. 

For the future work, studies that could broaden the spectrum of contaminants targeted by Fe-coated peat would be beneficial. At the same time it is important not only to find alternative utilisation methods for Fe-coated peat, but also investigate other management options for the spent adsorbents.

Authors

Alfreda Kasiuliene

Luleå tekniska universitet; Geovetenskap och miljöteknik
Other publications >>

Jurate Kumpiene

Luleå tekniska universitet; Geovetenskap och miljöteknik
Other publications >>

Ivan Carabante

Luleå tekniska universitet; Geovetenskap och miljöteknik
Other publications >>

Prosun Bhattacharya

KTH Royal Institute of Technology, Sustainable Development, Environmental Science and Engineering
Other publications >>

Luke Beesly

James Hutton Institute, United Kingdom
Other publications >>

Documents attached

Click on thumbnail to read

Record metadata

Click to view metadata

	
    header: 
        identifier: oai:DiVA.org:ltu-76325
        datestamp: 2021-04-19T12:56:39Z
        setSpec: SwePub-ltu
    metadata: 
        mods: 
            @attributes: 
                version: 3.7
            recordInfo: 
                recordContentSource: ltu
                recordCreationDate: 2019-10-09
            identifier: 
                978-91-7790-462-5
                978-91-7790-463-2
                http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76325
            titleInfo: 
                @attributes: 
                    lang: eng
                title: Peat Coated with Iron Oxides
                subTitle: Purification of Metal(loid)-Contaminated Water and Treatment of the Spent Adsorbent
            abstract: 
In Sweden due to the industrial activities such as wood impregnation multiple point sources of arsenic (As) contamination in soil and water bodies are scattered over the country. Metals such as chromium (Cr) copper (Cu) lead (Pb) nickel (Ni) cadmium (Cd) or zinc (Zn) at varying concentrations are usually present as well. Since adsorption is a common method to purify contaminated water research and development of adsorbents have been actively carried out in the last few decades. However seldom spent sorbent is safely handled afterwards and often end up in landfill thus creating new problems and posing new risks to humans and environment.
The aim of this study was to develop a waste-based adsorbent for simultaneous removal of As and associated metals: Cr Cu and Zn and to analyse sustainable ways how to manage the spent adsorbent without creating secondary pollution.
In the model system two well-establish adsorbents: Fe oxides (deriving from FeCl3) and peat (waste-based) were combined and the concept of simultaneous removal of cationic and anionic contaminants was tested in a batch adsorption experiment. Due to Fe coating removal of As and Cr increased by 80% and 30% respectively as compared to non-coated peat. Removal of Cu and Zn was higher (up to 15%) on non-coated peat than on Fe-coated peat. Similar results were obtained in the up-scaled column adsorption experiment where Fe salt was substituted with a waste-based Fe hydrosol. Within the same pH environment (pH=5) Fe-coated peat effectively adsorbed all four investigated contaminants (As Cr Cu and Zn). Non-coated peat was effective for Cr Cu and Zn. While Fe oxides (coated on sand) adsorbed only As.
Three management strategies for spent adsorbents obtained after column adsorption experiment were investigated in this study. i) Long-term deposit in a landfill was simulated by exposing spent adsorbents to a reducing environment and evaluating metal(loid) leaching. Leaching of As increased manifold (up to 60% in a 200-day experiment) as compared to the standardized batch leaching experiment under oxidizing conditions. It was determined that about one third of As(V) was reduced to As(III) which is more mobile and toxic. ii) Valorisation of the spent adsorbent was attempted through hydrothermal carbonisation. It was expected that obtained hydrochar could be used as a beneficial soil amendment. However treatment resulted in the process liquid and the hydrochar both having high loads of As Cu and Zn. Additional treatment of process water and hydrochar imply higher management costs for spent adsorbents. iii) Possibility of thermal destruction was investigated by combusting spent adsorbents. After the treatment volume of the waste (ash) was by 80-85% smaller as compared to spent adsorbents. Combustion at higher temperature (1100 °C vs 850 °C) resulted into a weaker metal(loid) leaching from ashes. Furthermore co-combustion with calcium (Ca)-rich lime (waste-based) decreased leaching of all four investigated elements Cr in particular below the limit values for waste being accepted at landfills for hazardous waste. Therefore combustion enabled possibility of safe and long-term deposit of As-bearing ashes. At the same time less As would be circulating in society. 
For the future work studies that could broaden the spectrum of contaminants targeted by Fe-coated peat would be beneficial. At the same time it is important not only to find alternative utilisation methods for Fe-coated peat but also investigate other management options for the spent adsorbents.

            subject: 
                    @attributes: 
                        lang: eng
                        authority: uka.se
                    topic: 
                        Engineering and Technology
                        Environmental Engineering
                        Environmental Management
                    @attributes: 
                        lang: swe
                        authority: uka.se
                    topic: 
                        Teknik och teknologier
                        Naturresursteknik
                        Miljöledning
                    @attributes: 
                        lang: eng
                        authority: uka.se
                    topic: 
                        Engineering and Technology
                        Environmental Engineering
                        Other Environmental Engineering
                    @attributes: 
                        lang: swe
                        authority: uka.se
                    topic: 
                        Teknik och teknologier
                        Naturresursteknik
                        Annan naturresursteknik
                    @attributes: 
                        lang: eng
                    topic: iron-peat
                    @attributes: 
                        lang: eng
                    topic: adsorption
                    @attributes: 
                        lang: eng
                    topic: arsenic
                    @attributes: 
                        lang: eng
                    topic: metals
                    @attributes: 
                        lang: eng
                    topic: combustion
                    @attributes: 
                        lang: eng
                    topic: hydrothermal carbonisation
                    @attributes: 
                        lang: eng
                    topic: landfilling
                    @attributes: 
                        lang: swe
                        authority: ltu
                    topic: Avfallsteknik
                    genre: Research subject
                    @attributes: 
                        lang: eng
                        authority: ltu
                    topic: Waste Science and Technology
                    genre: Research subject
            language: 
                languageTerm: eng
            genre: 
                publication/doctoral-thesis
                vet
            note: 
                Published
                1
            name: 
                    @attributes: 
                        type: personal
                        authority: ltu
                    namePart: 
                        Kasiuliene
                        Alfreda
                    role: 
                        roleTerm: aut
                    affiliation: 
                        Luleå tekniska universitet
                        Geovetenskap och miljöteknik
                    nameIdentifier: 
                        alfkas
                        0000-0001-5375-8825
                    @attributes: 
                        type: personal
                        authority: ltu
                    namePart: 
                        Kumpiene
                        Jurate
                    role: 
                        roleTerm: ths
                    affiliation: 
                        Luleå tekniska universitet
                        Geovetenskap och miljöteknik
                    nameIdentifier: 
                        juku
                        0000-0002-1442-1573
                    @attributes: 
                        type: personal
                        authority: ltu
                    namePart: 
                        Carabante
                        Ivan
                    role: 
                        roleTerm: ths
                    affiliation: 
                        Luleå tekniska universitet
                        Geovetenskap och miljöteknik
                    nameIdentifier: 
                        ivacar
                        0000-0003-4292-6752
                    @attributes: 
                        type: personal
                    namePart: 
                        Bhattacharya
                        Prosun
                        Professor
                    role: 
                        roleTerm: ths
                    affiliation: KTH Royal Institute of Technology Sustainable Development Environmental Science and Engineering
                    nameIdentifier: 0000-0003-4350-9950
                    @attributes: 
                        type: personal
                    namePart: 
                        Beesly
                        Luke
                        Dr.
                    role: 
                        roleTerm: opn
                    affiliation: James Hutton Institute United Kingdom
            originInfo: 
                dateIssued: 2019
                publisher: Luleå University of Technology
                place: 
                    placeTerm: Luleå
            relatedItem: 
                @attributes: 
                    type: series
                titleInfo: 
                    title: Doctoral thesis / Luleå University of Technology 1 jan 1997 → …
                identifier: 1402-1544
            location: 
                url: http://ltu.diva-portal.org/smash/get/diva2:1359453/FULLTEXT01.pdf
            accessCondition: gratis
            physicalDescription: 
                form: electronic
            typeOfResource: text