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Irina Breus, Alexandra Denisova, S ergey Nekljudov, Vladimir Breus

Use of organomodified minerals for sorption of BTX (benzene, toluene, xylene) causing soil and groundwater contamination. Irina Breus, Alexandra Denisova, S ergey Nekljudov, Vladimir Breus. presented by Irina Breus. Kazan State University / Institute of Chemistry.

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Irina Breus, Alexandra Denisova, S ergey Nekljudov, Vladimir Breus

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  1. Use of organomodified minerals for sorption of BTX(benzene, toluene, xylene) causing soil and groundwater contamination Irina Breus, Alexandra Denisova, Sergey Nekljudov, Vladimir Breus presented by Irina Breus Kazan State University / Institute of Chemistry ConSoil 2008, 3-6 June 2008, Milano, Italy

  2. BTX: Subsurface Contamination • 1 BTX group belongs to typicalfuel hydrocarbons found as petroleum derivatives. It is one of the most hazardous groups of non-halogenated volatile organic contaminants (VOCs) detected in both saturated and unsaturated soil zones • 2 Subsurface BTX contamination potentially exists in four phases: • gaseous: BTX vapors in unsaturated zone • solid: liquid BTX adsorbed on soil particles in both saturated and unsaturated zones • aqueous: soluble part of BTX dissolved into pore water in both saturated and unsaturated zones • immiscible (NAPL): primarily in unsaturated zone • 3 Treatment technologies by contaminant group – technologies of BTX remediation form a notable part 4 Potentially applicable remediation technologies to treat BTX include both In Situ and Ex Situ (requiring soil/ground water extraction) treatment technologies ConSoil 2008, 3-6 June 2008, Milano, Italy

  3. ISTC #2419: Use of Natural Sorbents for Prevention of Groundwater Contamination by Hydrocarbons RFNC-VNIIEF / Kazan State University • Method of Increasing Soil Barrier Functions Against Hydrocarbon Contamination • (Record of Invention, ISTC File # 372) • 1localZCM was proved to be promising for GW protection from HC contamination in soils with relative high SOM content • 2 Due to high water retention ability ZCM inserted into the upper soil layer creates there a barrier which prevents downward migration of petroleum HC in a soil soil ZCM BTX Zeolite-clay containing material (ZCM): CLP 12%, SMT 20%,Tatarsky-Shatrashansky deposit, Russia PREVENTION of GW contamination BTX BTX groundwater groundwater REMEDIATION of GW contamination Cost ~ $70 /ton 3 In addition to the Project task, • High sorption capacity of ZCM towards HC was revealed • Thus, a new possibility of environmental application of modified ZCM - for clean-up (remediation) of GW already contaminated by HC was discussed • 4In this connection, some additional experiments were carried out ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  4. OUTLINE • Use of Mineral Sorbents in GW Remediation Technologies towardsBTX • Use of Surfactant-modified Zeolites (NM, USA) for BTX sorption • Experimental • BTX Sorption by Natural Minerals • BTX Sorption by Organo-Modified Minerals • Summary and Conclusions • Research Opportunities ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  5. BTX: Use of Mineral Sorbents in Groundwater Remediation Technologies • 1 AmongIn Situ remediation Technologies most commonly used to treat BTX in groundwater Passive/Reactive Treatment Wallsseem to be one of the most promising: barriers allowing water passage while causing degradation or removal of contaminants • 2 As holders for such walls, porous and superfine natural zeolite- and clay- containing minerals(ZCM) are used: • high sorption capacity • environmental safety • low cost • 3 However in moistened (water) environments ZCM sorption activity towards organic contaminants essentially decreases and to give them water-proof properties, organomodification of minerals is practiced • 4 Forming a Treatment Walls such organomodified minerals can simultaneously sorb not only inorganic (cations, anions) but also organic contaminants like BTX The formation of a layer of organomodifier on zeolite surface (after Bowman, 2003) ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  6. OUTLINE • Use of Mineral Sorbents in GW Remediation Technologies towardsBTX • Use of Surfactant-modified Zeolites (NM, USA) for BTX sorption • Experimental • BTX Sorption by Natural Minerals • BTX Sorption by Organo-Modified Minerals • Summary and Conclusions • Research Opportunities ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  7. Surfactant-modified Zeolites (St.Cloud deposit, New Mexico, USA) • 1 As organomodifiers for mineral sorbents, various Cationic Surfactants (the salts of quaternary amines RR’R’’R’’’N+Hal-) are mostly used: • good holding on a mineral sorbent surface • high sorption capacity of an organomodified sorbent U.S. Natural zeolites (Z) (Ca, Na2, K2)(Al6 SiO) •24H2O • 2 Such organomodified sorbents based on Natural High-grade Zeolites and cationic surfactant Hexadecyltrimethylammonium bromide were proposed in U.S. for GW cleaning (Rob Bowman, New Mexico Tech, USA, 2000) Cost~$ 130 /ton Hexadecyltrimethylammonium bromide(HDTMA+)C16H33N+(CH3)3 $ 7500 /ton • Surfactant-modified zeolites (SMZ) • $500 /ton • 3 However, they did not get any wide application in practice so far because of high cost ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  8. OUTLINE • Use of Mineral Sorbents in GW Remediation Technologies towardsBTX • Use of Surfactant-modified Zeolites (NM, USA) for BTX sorption • Experimental • BTX Sorption by Natural Minerals • BTX Sorption by Organo-Modified Minerals • Summary and Conclusions • Research Opportunities ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  9. Experimental ELECTROPNEUMATIC VALVE SPLITTER FUSED SILICA COLUMN VIAL WITH SAMPLE THERMOSTATE • 1 Sorption activity of ZCM, both natural and organomodified as compared to high-grade zeolite (Z) provided from U.S. under different moisture conditions towards benzene, toluene and p-xylene was investigated ZCM Z (U.S.) • Zeolite 12%, Smectite 20% • Cost ~ $ 70/ton Zeolite 74%, Smectite 5% Cost ~ $ 130/ton Approximation of isotherms: MGAB equation 2 Static headspace gas-chromatographic analysis with the original device for sample inlet Measurement of sorption isotherms of volatile organic substances I.Breus, A.Mishchenko, K.Potashev, V.Breus // Coll. and Surf. A., 276 (2006), N1-3, 122–133 ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  10. OUTLINE • Use of Mineral Sorbents in GW Remediation Technologies towardsBTX • Use of Surfactant-modified Zeolites (NM, USA) for BTX sorption • Experimental • BTX Sorption by Natural Minerals, ZCM and Z • BTX Sorption by Organo-Modified Minerals • Summary and Conclusions • Research Opportunities ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  11. BTX Sorption by Natural Minerals RH=100% RH=0% Benzene sorption on naturalsorbents,oven-dry and watersaturated ■ZCM■Z■Byclyansky clay■Koshakovskyclay Vs increase • 1/ Sorption values of benzene on dry (RH 0%) non-modified ZCM were essentially higher then that on Z due to significant amount of clay minerals (up to 20 %) in ZCM but less then on two bentonite clays • 2/ But the hydration (RH 100%) called hard decreasing benzene sorption, especially on Z • Natural ZCM is more active sorbent for benzene as compared to Z and Vs sensitivity to sorbent moisture as affected by clay content ConSoil 2008, 3-6 June 2008, Milano, Italy

  12. The comparison and selectivity of BTX Sorption by Zeolite Containing Minerals Z ZCM BTXsorption on naturaloven-dry zeolite-containing sorbents,ZCMand Z ■Benzene■Toluene■p-Xylene 1 The same conclusion, about higher sorption activity of ZCM was made in regard to all three studied hydrocarbons • 2/ Among three HC, benzene sorption was a little higher on dry non-modified minerals, ZCM and Z, but in the whole the comparison of BTX sorption values showed a very low selectivity of sorbates • 3/ This reveals the main role of surface sorption and the absence of sorption in zeolite's micropores for both studied sorbents • The absence of BTX selectivity was registered also for hydrated minerals but their sorption values were too small to discuss differences ConSoil 2008, 3-6 June 2008, Milano, Italy

  13. OUTLINE • Use of Mineral Sorbents in GW Remediation Technologies towardsBTX • Use of Surfactant-modified Zeolites (NM, USA) for BTX sorption • Experimental • BTX Sorption by Natural Minerals • BTX Sorption by Organo-Modified Minerals • Summary and Conclusions • Research Opportunities ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  14. Organomodification of minerals by HDTMA andDDP Hexadecyltrimethylammonium bromide(HDTMA+)C16H33 N+(CH3)3 M.m.284.5$7500 /ton ZCM Z SMZCM SMZ 4/ and with those on Z modified by HDTMA compared • 3/ Isotherms of BTX sorption on ZCM modifiedby HDTMA and DDP were determined SMZCM Dodecylpyridinium bromide (DDP+) C12H25 N+C5H5M.m248.3 $10500/ton Kinetics of a surfactant sorption on ZCM Isotherm of a surfactant sorption on ZCM • 1/ After modification was completed, for each surfactant equilibrium time for its sorption on ZCM was determined • 2/ then, sorption isotherms of surfactants on ZCM were obtained ConSoil 2008, 3-6 June 2008, Milano, Italy

  15. Benzene Sorption by HDTMA-Modified Zeolite Containing Minerals: SMZCM vs SMZ SMZCMvsZCM SMZCMvsSMZ Benzene sorption on ●ZCM and ● SMZCM, ●●oven-dried, and oohydrated Benzene sorption on ●SMZCM and ●SMZ, ●●oven-dried, and oohydrated (The shape of isotherms points at the large contributionof mechanism of partitioning into HDTMA phase in sorption on organomodified sorbents) 1 Benzene sorption isotherms on zeolite containing minerals modified by HDTMA: • Effect of ZCM modification by HDTMA: • 2/ Organomodification of ZCM resulted in significant increase of its sorption capacity, as for dry as especially for hydrated samples • Comparison of organomodified sorbents: • 3/This effect was so higher (100% for dry ZCM) in comparison to Z (20%) that even the hydrated SMZCM demonstrated higher sorption capacity (2 times as higher) in comparison with dry SMZ • 4/ Both natural and HDTMA-modified ZCMs are more active sorbents towards BTX as compared to Z ConSoil 2008, 3-6 June 2008, Milano, Italy

  16. Benzene Sorption by ZCM modified by HDTMA and DDP HDTMA DDP • DDP in comparison • to HDTMA: • Smaller volume of hydrophobic phase of a molecule (C12 vs C16) • Less flexibility owing to more rigid molecular structure (aromatic ring) • More expensive (appr. 1.5 times) Benzene sorption on SMZCM (ZCM modified by HDTMA) ●oven-dried, and ohydrated Benzene sorption on SMZCM (ZCM modified by DDP) ●oven-dried, and ohydrated RH=0% RH=100% 1 Modification with HDTMA was more advantageous than that with DDP: 2 HDTMA-modified ZCM absorbed benzene essentially better under both dry (1.6 times) and especially hydrated (4 times) conditions ConSoil 2008, 3-6 June 2008, Milano, Italy

  17. OUTLINE • Use of Mineral Sorbents in GW Remediation Technologies towardsBTX • Use of Surfactant-modified Zeolites (NM, USA) for BTX sorption • Experimental • BTX Sorption by Natural Minerals • BTX Sorption by Organo-Modified Minerals • Summary and Conclusions • Research Opportunities ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  18. Summary and Conclusions 1. Natural ZCM are cost effective and possesses high sorption capacity towards BTX due to high clay mineral content and good permeability due to zeolites; however the hydration causes hard decreasing BTX sorption(15 times as less) 2. Sorption capacity of ZCM modified by cationic surfactans, Hexadecyltrimethylammonium bromide and Dodecylpyridinium bromide, is essentially higher(hydrated SMZCM, resp. 17 and 5 times as higher). Here HDTMA-modified ZCM is preferable because of higher sorption capacity and less cost 3. Mechanism of BTX sorption on natural ZCM realizes almost completely as a surface sorption while for organomodified ZCM the contribution of BTX partitioning into hydrophobic phase of an organic modifier is more preferential 4. Effectiveness of environmental use of organomodified ZCM as a sorption barrier against BTX depends on: - SORBENT features (mineral composition; ECEC; pore structure). Here clays provide high sorption capacity and zeolites good permeability - ORGANIC SURFACTANT' chemical nature and structure. Among two cationic surfactants HDTMA is better in regard to both sorption capacity and cost - ORGANIC SURFACTANT' LOADING; hereby the optimum between the maximum of loading and cost of surfactant should be chosen ConSoil 2008, 3-6 June 2008, Milano, Italy

  19. Effects of Surfactants and Minerals on BenzeneSorption by Organomodified Minerals The reported data justify that sorption capacities of organomodified minerals are very different for various mineral holders, organomodifiers and their loadings as well Effect of loading of a Surfactant on sorption: ●HDTMA on bentonite 1 ●HDTMA on bentonite 2 ●HDTMA on zeolite B ●BTEA on bentonite 1 ● BTEA on bentonite 2 Effect of type of Surfactant and Mineral on benzene sorption: ●Sorption on various minerals modified by Surfactant A ●Sorption on various minerals modified by Surfactant B ●Sorption on Mineral A modified by different surfactants ConSoil 2008, 3-6 June 2008, Milano, Italy

  20. Research Opportunities • The main task - cheapening organomodified sorbents while conserving their high sorption activity to hydrocarbons • There aretwo possible waysto achieve that: • to find optimal surfactant' loadings together with high sorption capacities - in case of surfactant modified sorbents • to replace expensive surfactants with cheaper (oligomer and polymer) organomodifiers • Plan: • 1. Modification of natural mineral sorbents (zeolites, clays, and their mixtures) by various cationic surfactants: • kinetics of organomodification • isotherms of sorption of surfactants on mineral holders • preparation of organomodified sorbents • 2. Study of sorption of organic pollutants on organomodified minerals: • under different moisture • for various hydrocarbons, aromatic and aliphatic • 3. Evaluation of stability of obtained organomodified minerals • 4. Search of new (oligomer and polymer) organomodifiers and study of hydrocarbon sorption on prepared organomodified sorbents • Realization of this plan will help to elaborate active and cost effective sorption barriers against groundwater contamination by aromatic and aliphatic hydrocarbons, using local natural raw material and effective organomodifiers ConSoil 2008, 3-6 June 2008, Milano, Italy

  21. ConSoil 2008, 3-6 June 2008, Milano, Italy ConSoil 2008, 3-6 June 2008, Milano, Italy

  22. The Influence of Surfactant Content in Organomodified Minerals on Sorption of Aromatic Hydrocarbons (P/P0=0,4)

  23. Method of Increasing Soil Barrier Functions Against Hydrocarbon Contamination Record of Invention, ISTC File # 372) ZCM is promising for GW protection from hydrophobic OC (HOC)contamination in soils with relative high organic matter content. Due to high water retention ability ZCM inserted into the upper soil layer creates there a barrier which prevents downward migration of petroleum HC in soils. • The creation of a barrier preventing downward migration of HOC in a soil / subsoilby inserting into the subsoil natural mineral and organic sorbents with high water retention ability followed by soil wetting up to the field capacity • The created sorption-capillary barrier blocks the downward migration of HOC into the lower soil layers and groundwater but remains permeable for water and water solutions • Advantages : • high retention efficiency to HOC • preservation of soil / subsoil water-physical properties • low cost • environmental safety • The effective HOCimmobilization is achieved owing to two simultaneous effects : • the increase of hydraulic resistance of a water-saturated soil media towards filtration of HOC due to the sorbents • the essentially higher sorption capacity of inserting organic sorbents towards HOC as compared to soil / subsoil itself Soil/ZCM 1-5%, ZCM Particle fineness 2 mm

  24. ZCM organomodification • Make a mixture of ZCM sample with Surfactant’ solution in distilled water • Do organo-modification (water-phase sorption of Surfactant on a Mineral holder as exchange of cations): • intermix the mixture mentioned above at 25 C during a day • Centrifuge the reaction mixture and segregate SMZCM precipitate • Calculate Surfactant’ content in SMZCM, on the basis of its residual concentration in solution (determined by spetrophotomertry – in case of DDP, or with help of CN elemental analysis after incineration – in case of HDTMA)

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