Juris Burlakovs1, JovitaPilecka2, Inga Grinfelde2, Ruta Ozola-Davidane1
1University of Latvia, Latvia2Latvia University of Life Sciences and Technologies, [email protected]
CLAY MINERALS AND HUMIC SUBSTANCES
AS LANDFILL CLOSURE COVERING MATERIAL CONSTITUENTS: FIRST STUDIES
CLAY
• Crystalline hydrated alumosilicate with cage-likestructure
• High internal and external surface area with a negativecharge neutralized by exchange cations
• Can be suggested as an heavy metal ion removal agentdue to its cost-effectiveness and high efficiency
• Hydrophobization process in order to improve interactionwith low polarity organic molecules
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CLAY APPLICATIONS
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DEVONIAN and TRIASSIC CLAY IN LATVIA
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QUATERNARY CLAY IN LATVIA
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SCOPE OF THE STUDIES
• The aim of the work is to provide alternativesolution for landfill closure by giving theoreticalconsiderations from multidisciplinary knowledge ofenvironmental engineering, chemistry and wastemanagement
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TOPICALITY OF THE RESEARCH• The landfills are systems with pollution and
aftercare period that takes a long time• Humic substances has own unique chemical category
with distinct unique properties, and those might beisolated from the organic mass
• Clay components and humic acids treatment performedto contaminated soil with heavy metals as modelcontaminants has been done previously and might be agood solution
• Modified clay may also capture pharmaceuticals which ishuge leachate problem at landfills
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LITHUANIA
LATVIA
ESTONIA
RU
SSIA
BELARUS
GULF OF RIGA
BALTIC SEA
Triassic clay deposit, dominantly smectite >75%, illite 10-20%, clayey fraction(<0.005 mm) varies ~43 %,
aleirolitic ~40%
Field work Experimentalwork
Analyticalwork
Sorptionkinetics
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Metal ion complex formation with its natural abilityof metal complexation is of unexplored potentialfor landfill coverage in future. The strength of theinteraction among organic ligands and metalsmay be modeled as a function of pH and reactantconcentration (Byrne et al., 2011) andexperimentally proves usefulness of natural claysand humic substances as remediationamendment for contaminated soils in dumps
Field work Experimentalwork
Analyticalwork
Sorptionkinetics
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Illustrative example of enhanced copper stability (a) copper with no humic amendment; (b) copper with
humic amendment
Field work Experimentalwork
Analyticalwork
Sorptionkinetics
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Field work Experimentalwork
Analyticalwork
Sorptionkinetics
Metal ions in the solution as well as the ability of metals to bind with humicacids and clays are calculated according formulas (1) and (2)
Cu+HS=CuHS
where the Cu is the amount of Cu2+ moles in solution and HS – amount of moles of humic acid in the solution, and
(2),
where [Cu] – concentration of hydrated Cu2+ in the solution; Ko - stability constant of complex forming; CuHS – amount of moles, which are included in complexes (Bresnahan, Grant, &Weber, 1978)
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• Scanning Electron Microscopy (SEM)
thin layer of goldand palladium powderion coater (JB-3, Eiko, Japan)
• Fourier transform infrared spectroscopy (FTIR)Perkin Elmer Spectrum BX FT - IR System spectroscope
Field work Experimentalwork
Analyticalwork
Sorptionkinetics
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• Brunauer–Emmett–Teller (BET) testnitrogen multilayer adsorptionMicromeritics instrument:Gemini2360
Field work Experimentalwork
Analyticalwork
Sorptionkinetics
• Powder X-Ray Difractometry(PXRD)
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Field work Experimentalwork
Analyticalresults
Sorptionkinetics
Series of experiments by using humicsubstances have shown promising results for diminishing the content of biologically available Cu and Pb, ingredients might be of good use for using in landfill closure to stop the migration of heavy metal pollution when closed byinnovative fine fraction material mixed withmodified clays
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Field work ExperimentalAnalytical
resultsSorption kinetics
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50 mL of 100 mg L-1 Pb (II) solution – 0.025g sorbent
5, 15, 30, 60, 180, 360, 480 and 1440 minutes
filtered and analyzed for residual lead content by FAAS
Field work Experimental Analyticalwork
Sorptionexperiment
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NOVELTY
• Innovative clay sorbents produced fromlocal resources can be offered for appliedremediation
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• Recent studies have shown that clay minerals and clay-humic acid composites can be natural, low cost andeffective sorbents to remove various pharmaceuticalproducts from environment
• For example, montmorillonite has been used to removepharmaceutical products such as tramadol and doxepine(Thiebault, Guegan, & Boussafir, 2015); kaolinite toremove ofloxacin (Li, Bi, & Chen, 2017); and natural clay(mainly consisting from smectite and kaolinite) to removeibuprofen, naproxen and carbamazepine from aqueoussolutions (Khazri et al., 2017)
Effective at pharmaceuticals hunting
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• Recent studies have shown that clay minerals and clay-humic acid composites can be natural, low cost andeffective sorbents to remove various pharmaceuticalproducts from environment
• For example, montmorillonite has been used to removepharmaceutical products such as tramadol and doxepine(Thiebault, Guegan, & Boussafir, 2015); kaolinite toremove ofloxacin (Li, Bi, & Chen, 2017); and natural clay(mainly consisting from smectite and kaolinite) to removeibuprofen, naproxen and carbamazepine from aqueoussolutions (Khazri et al., 2017)
Summary I
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• The landfill closure process has similarities with environmentalremediation process; however, there are additional componentsrelated whether the capping of contamination includes the need ofsorption, such as water of irrigation or leachate recirculation andtotal produced leachate treatment with innovative materials
• Innovative closure of landfills by capping with landfill mined finefraction material mixed with modified clay with humic substances isone of prospective solutions
• More studies are needed and modelling elaborated in order to findthe right recipe for finding the best constituents to stop leaching ofpollution out of the landfill as well as mitigate greenhouse gasemissions through methane degradation
Summary II
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This study was supported by Project 1.1.1.2/VIAA/3/19/531 “Innovative technologies for stabilization of landfills -diminishing environmental impact and resources potential in frames of circular economy”
and EU ESF Project Nr.8.2.2.0/18/A/010 “Academic Staff Renewal and Continuing Professional Development at the University of Latvia”
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From the Lab to Remedial Decisions...???
Towards more studies…
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