EDTA- and DTPA-functionalized silica gel and chitosan adsorbents for the removal of heavy metals from aqueous solutions

Adsorbents functionalized with chelating agents are effective in removal of heavy metals from aqueous solutions. Important properties of such adsorbents are high binding affinity as well as regenerability. In this study, aminopolycarboxylic acid, EDTA and DTPA, were immobilized on the surface of silica gel, chitosan, and their hybrid materials to achieve chelating adsorbents for heavy metals such as Co(II), Ni(II), Cd(II), and Pb(II). New knowledge about the adsorption properties of EDTA- and DTPA-functionalizedadsorbents was obtained. Experimental work showed the effectiveness, regenerability, and stability of the studied adsorbents. Both advantages and disadvantages of the adsorbents were evaluated. For example, the EDTA-functionalized chitosan-silica hybrid materials combined the benefits of the silica gel and chitosan while at the same time diminishing their observed drawbacks. Modeling of adsorption kinetics and isotherms is an important step in design process. Therefore, several kinetic and isotherm models were introduced and applied in this work. Important aspects such as effect of error function, data range, initial guess values, and linearization were discussed and investigated. The selection of the most suitable model was conducted by comparing the experimental and simulated data as well as evaluating the correspondence between the theory behind the model and properties of the adsorbent. In addition, modeling of two-component data was conducted using various extended isotherms. Modeling results for both one- and twocomponent systems supported each other. Finally, application testing of EDTA- and DTPA-functionalized adsorbents was conducted. The most important result was the applicability of DTPA-functionalized silica gel and chitosan in the capturing of Co(II) from its aqueous EDTA-chelate. Moreover, these adsorbents were efficient in various solution matrices. In addition, separation of Ni(II) from Co(II) and Ni(II) and Pb(II) from Co(II) and Cd(II) was observed in two- and multimetal systems. Lastly, prior to their analysis, EDTA- and DTPA-functionalized silica gels were successfully used to preconcentrate metal ions from both pure and salty waters

Uptake of heavy metals by plants from airborne deposition and polluted soils

Selostus: Kasvien raskasmetallien otto ilmasta ja saastuneesta maasta

Arsenic and heavy metal concentrations in agricultural soils in South Savo province

Selostus: Etelä-Savon viljelysmaan arseeni- ja raskasmetallipitoisuudet

Heavy-metal pollution and remediation of forest soil around the Harjavalta Cu-Ni smelter, in SW Finland

Abstract

Energy harvesting methods for wireless sensor nodes in heavy-duty vehicles

The number of autonomous wireless sensor and control nodes has been increasing rapidly during the last decade. Until recently, these wireless nodes have been powered with batteries, which have lead to a short life cycle and high maintenance need. Due to these battery-related problems, new energy sources have been studied to power wireless nodes. One solution is energy harvesting, i.e. extracting energy from the ambient environment. Energy harvesting can provide a long-lasting power source for sensor nodes, with no need for maintenance. In this thesis, various energy harvesting technologies are studied whilst focusing on the theory of each technology and the state-of-the-art solutions of published studies and commercial solutions. In addition to energy harvesting, energy storage and energy management solutions are also studied as a subsystem of a whole energy source solution. Wireless nodes are also used in heavy-duty vehicles. Therefore a reliable, long-lasting and maintenance-free power source is also needed in this kind of environment. A forestry harvester has been used as a case study to study the feasibility of energy harvesting in a forestry harvester’s sliding boom. The energy harvester should be able to produce few milliwatts to power the target system, an independent limit switch.

Pohjakuonan käsittelyn ja hyötykäytön toimintamallin muodostaminen Kotkan Energia Oy:n jätteenpolttolaitokselle

Tavoitteena tässä diplomityössä oli selvittää Kotkan Energia Oy:n jätteenpolttolaitoksen toiminnassa syntyvän pohjakuonan hyötykäyttömahdollisuuksia ja kustannuksiltaan järkevin tapa käsitellä pohjakuona. Tarkasteltavia vaihtoehtoja hyötykäytön osalta olivat erilaiset maarakennustyöt sekä kaatopaikkojen peittäminen. Hyötykäyttövaihtoehdoille vaihtoehtoisena ratkaisuna tutkittiin kaatopaikkasijoituksen kannattavuutta. Pohjakuonan käyttöä maarakentamisessa, jätetäyttöjen peitemaina sekä pohjakuonan loppusijoitusta kaatopaikoille säätelee lainsäädäntö. Valtioneuvoston asetuksessa kaatopaikoista on määritelty loppusijoitettaville jakeille liukoisuus raja-arvot, joiden mukaisesti jätteet sijoitetaan joko pysyvän jätteen, tavanomaisen jätteen tai ongelmajätteen kaatopaikoille. Jätetäyttöjen peitemateriaalina käytettävän jakeen on myös täytettävä kyseisen kaatopaikkaluokan liukoisuusraja-arvot. Maarakennusasetus antaa puolestaan liukoisuus- ja pitoisuusraja-arvot maarakennuksessa hyödynnettäville jakeille. Pohjakuonan hyötykäyttö vaatii kuitenkin aina ympäristöluvan. Hyötyvoimalan pohjakuonasta tehtyjen analyysien perusteella voidaan todeta, että käsiteltyä pohjakuonaa olisi mahdollista käyttää esimerkiksi kenttien ja kaatopaikkojen pohjarakenteissa sekä kaatopaikoilla jätetäyttöjen peitemaina. Pohjakuonan hyödyntäminen kaukolämpötöiden maarakennuksessa vaatii vielä lisätutkimuksia putkien korroosioriskin osalta. Diplomityön tuloksena kehitettiin toimintamalli, jonka avulla Kotkan Energia Oy:n on mahdollista säästää kuonan käsittelyn ja hyötykäytön kustannuksissa. Kustannuksiltaan parhaaksi vaihtoehdoksi osoittautui kuonan käsittely omalla biopolttoaineiden välivarastolla sekä käsitellyn pohjakuonan hyödyntäminen välivaraston pohjarakenteissa. 

Sorption of metal ions to wood, pulp and bark materials

Ett huvudmål med denna avhandling var att erhålla ny information om växelverkan mellan metalljoner i vattenfas och träbaserade material såsom olika pappersmassor, ved och bark. Material av gran, tall och björk har studerats. En ny känslig kolonnkromatografisk metod utvecklades för bestämning av affinitetsordningar för 17 olika metalljoner. Av dessa bands trevärt järn och de mycket toxiska tungmetallerna bly, koppar och kadmium starkast till de studerade materialen. Växelverkan i dessa tvåfas system sker som jonbyte, huvudsakligen via komplexbildning av metalljoner till funktionella grupper i den fasta fasen. Vattenfasens pH är den viktigaste parametern som bestämmer totala halten av metalljoner som binds till materialen. Resultatet i denna avhandling kan delvis betraktas som grundforskning. En ny kunskap om metalljoners förekomst och kemiska reaktioner i dessa system är även av stor ekonomisk och ekologisk, betydelse, när man strävar till allt mera slutna system i moderna massafabriker. Avhandlingen visar också att trädbark har stor potential för biosorption av tungmetaller t.ex. från avfallsvatten. Trädbark har nästan lika stor bindningskapacitet som dyra syntetiska jonbytare.

Heavy Duty ilmarenkaiden hinnasto

kuv., 12 x 14 cm

Heavy Duty Speed Wagon

kuv., 10 x 23 cm

Electrochemical Treatment of Wastewaters

Electrocoagulation is a process in which wastewater is treated under electrical current. Coagulant is formed during the process through the metal anode dissolution to respective ions which react with hydroxyl ions released in cathode. These metal hydroxides form complexes with pollutant ions. Pollutants are removed among metal hydroxide precipitates. This study was concentrated on describing chemistry and device structures in which electrochemical treatment operations are based on. Studied pollutants were nitrogen compounds, sulphate, trivalent and pentavalent arsenic, heavy metals, phosphate, fluoride, chloride, and bromide. In experimental part, removal of ammonium, nitrate, and sulphate during electrochemical treatment was studied separately. Main objective of this study was to find suitable metal plate material for ammonium, nitrate, and sulphate removal, respectively. Also other parameters such as pH of solution, concentration of pollutant and sodium chloride, and current density were optimized. According to this study the most suitable material for ammonium and sulphate removal by electrochemical treatment was stainless steel. Respectively, iron was the optimum material for nitrate removal. Rise in the pH of solution at the final stage of electrochemical treatment of ammonium, nitrate, and sulphate was detected. Conductivities of solutions decreased during ammonium removal in electrochemical processes. When nitrate and sulphate were removed electrochemically conductivities of solutions increased. Concentrations of residual metals in electrochemically treated solutions were not significant. Based on this study electrochemical treatment processes are recommended to be used in treatment of industrial wastewaters. Treatment conditions should be optimized for each wastewater matrix.