Metal transport parameters in residual soil with different structures percolated by an acidic solution

Transcription

1 Metal tranport parameter in reiual oil wit ifferent tructure percolate by an aciic olution Euaro Pavan Korf, Gláucia. o Santo & Nilo ear onoli Feeral Univerity of io Grane o Sul, Porto Alegre, io Grane o Sul, Brazil afael Tímbola, Antonio Tomé, Pero omingo Marque Prietto Univerity of Pao Funo, Pao Funo, io Grane o Sul, Brazil ABSTAT Aciic an inorganic material in reiual water repreent a common effluent from inutrial activitie uc a mining. Tee effluent impact te environment ue it aciic propertie an te preence of metal. Among te factor tat influence te migration of tee pollutant to uburface te oil tructure eerve furter invetigation. Te objective of ti tuy wa etermine an evaluate te tranport parameter for, Ni, r, Zn, u, Mn an Pb metal in an aci multipecie olution in a reiual oil wit an uniturbe an remoule tructure. olumn tet were conucte to etermine te an k. Upon comparion between te tructure, te reult referring to k an i not ow a ignificant variation. A ignificant increae in te magnitue of value obtaine from te uniturbe tructure wa oberve, an only te value for te r metal i not increae. ESUMEN Materiale ácio e inorgánico en agua reiuale repreentan un efluente común e la activiae inutriale como la minería. Eto efluente impactan al meio ambiente ebio a u propieae ácia y la preencia e metale. Entre lo factore que influyen en la migración e ete contaminante bajo la uperficie, la etructura el uelo merece mayor invetigación. El objetivo e ete etuio fue eterminar lo parámetro e tranporte e, Ni, r, Zn, u, Mn Pb en una olución ácia e múltiple epecie en el uelo reiual con una etructura original inalteraa y outra moificaa. Prueba e columna fueron eca para eterminar y k. Para la etructura, lo reultao e k y no motraron variación ignificativa. Un aumento ignificativo en la magnitu e lo valore obtenio para la etructura moificao fue obervaa, y ólo lo valore para el metal r no aumentaron. INTOUTION Aciic an inorganic material in reiual water repreent a common effluent from inutrial activitie uc a mining (coal an mineral epoit), electroplating, cating an te anling of cemical ubtance in general. Tee effluent, if not well manage, may generate environmental pollution an ave a negative impact on oil, uperficial an unergroun water an ecoytem. Te mining activitie are te inutrial proce tat mot contribute to generation of effluent. Mining generate eriou environmental problem bot in te metal extraction procee an coal extraction becaue it involve te tranport of great volume of oli material, wic are wate generate a a reult of low content of available ore. Uually, te wate are ipoe witout any concern about retaining te percolation of torm water an te conequent generation of leacate wit aciic an inorganic caracteritic, wic i calle aci mine rainage (AM). AM i generate by oxiation a well a by cemical an biological procee aociate wit ulfie ore (e.g. FeS), an it a a ig leac capacity of cemical preent in te tailing. Tee rainage are caracterize by an extremely low ph, a ig electric conuctivity an ig concentration of Al, Fe, Mn, among oter metal at low concentration (, r, u, Ni, Pb, o, Hg), emimetal (A) an everal inorganic contituent. Tee component promote an increae in aciity once tey become part of te yrolyi reaction. (Acterberg et al. 003, Jonon an Hallberg 005, Akcil e Kola 006, Nieto et al. 007, ampaner an Luiz- Silva 009, Equenuin et al., 00) Te metal wen inerte in te environment may caue eriou amage to toxicity in expoe organim, becaue metal may be inerte in te foo cain ue to teir ig mobility. Krina an Govil (008) ave claime tat contamination by metal may lea to bot acute an cronic ig toxicity, perit in an environment, ig mobility an accumulate in organim ue to teir lipoolubility. Aitionally, metal compoun, even in mall amount, may be toxic to plant an animal (iel 00, Lafuente et al. 008). Stuie are neee to provie an unertaning of te control mecanim of AM metallic compoun on te oil, o tey elp in te eciion making proce in relation to te pollutant management an control in contaminate uburface area, wic are to geration environmental problem (Acterberg et al. 003, Jonon an Hallberg 005, Akcil e Kola 006, Kalin et al. 006). Suc tuie oul be conucte wit te objective of monitoring te contamination plume migration an carrie out environmental moel tuie. Aitional tuie migt alo accelerate immobilization an econtamination project or upen uc

2 proceure for verifying effectivene of natural attenuation procee (for example ee Sarmiento 009). Te migration of pollutant to te uburface i influence by everal factor tat may etermine te movement of metal troug te oil. Tee factor are ecribe by pyical an biopyical-cemical procee, wic are repreente by te teoretical moel own in Eq. (). Te ifferential equation repreent te tranport rate of a pollutant ( / t) in a one-imenional flow (x). Te pyical proce, in general, involve iffuion an mecanical iperion penomena, an one may be preominant over te oter. In Eq. (), te ummation of toe two procee i calle yroynamic iperion ( ). Ti penomenon i caracterize in te iffuive part by molecular iffuion coefficient (*), wic i repreente by te irect relationip between te coefficient iffuion in free olution (o) an a pyical-cemical factor calle tortuoity ( ). In te iperive part of tranport, te penomena are repreente by te mecanical iperion (α) an te percolation pee (v ). Te biopyicocemical procee are relate to te pyical, cemical an biological interaction tat may occur between te oil an te pollutant. In toe procee, te interaction between te environmental conition, te pollutant an te porou meia may caue te elay, acceleration or egraation of pollution. In Eq. (), among te parameter tat govern tee procee, are te itribution coefficient (k ) an te retaration factor ( ), wic are irectly co-relate. Te tranport parameter can be etermine troug laboratory experiment uc a column tet, iffuion tet an batc tet, or te tranport parameter can be etimate accoring to literature ata an by correlation or troug retroanalyi wit analytical or numeric olution (Yong et al. 99, Sackelfor 993, Sarma an ey 004). k t S. e x v. x. k n em que: () *. v ; Te objective of ti tuy wa to etermine an evaluate te tranport parameter of, Ni, r, Zn, u, Mn an Pb metal iolve in a ph multipecie aci olution in a clayey reiual wit uniturbe an remole tructure. Bot oil tructure were evaluate wit te objective of imulating, repectively, te conition of a natural barrier in te fiel a well a a remole conition tat repreent te oil movement procee in mining, by percolation of an aciic an inorganic pollutant from aci mine rainage (AM). EXPEIMENTAL POGAM. Baaltic reiual oil Te oil utilize in te preent reearc wa a baaltic reiual oil ample from te Geotecnical Experimental Site of te Univerity of Pao Funo, locate in te city of Pao Funo, in outern Brazil. Te ample wa obtaine from te B orizon (. m ept). Te mineral caracterization wa relate to te pecific uperficial area (SSA), wic wa preominantly comprie of mineral clay kaolin. Te SSA wa m².g -, an it enable te oil to be caracterize a a material cloe to te range uggete by Mitcell an Soga (005) a well a Yong et al. (99), wo inicate tat oil tat preominantly contain kaolinite ave an SSA witin te range of 0 to 0 m.g -, an Meurer (006), wo inicate tat te SSA wa witin te range of 7 m².g - to 30 m².g -. Te cemical an geotecnical caracterization of te pyical inexe a well a te granulometry of ti oil for te B orizon i own in Table. Te reult inclue obervation of low organic matter content, low E (cation excance capacity), ig clay content an an aciic ph. Table. Geotecnical an cemical oil caracterization of te tuie area. Parameter Value lay (%) 67 Silt (%) 5 San (%) 8 Liquiity limit (%) 53 Platicity limit (%) 4 Platicity inex G.67 Natural moiture (%) 34.6 Natural pecific weigt (kn/m³) 6.30 Voi ratio.9 Saturation egree (%) Poroity (%) 54 ph (H O) 5.00 Organic matter (%) 0.80 T (cmol c /m³).50 Permeability (m/) SSA internal+external (m /g).39 x Pollutant olution Te pollutant olution containe metal wa iolve in itille water wit a ph of.35. Te concentration of metal in te pollutant olution (Table ) wa efine accoring to increaing of te reference value for unergroun water from ETESB (005).

3 Table. oncentration of metal inerte in te column. Metal ETESB (mg.l - ) Increaing Inerte oncentration (mg.l - ) Ni r Pb Zn 5 0 u.5 5 Mn Moling of tet ample Eac ample wa taken from te fiel in it uniturbe form an in te ape of a cubic block wit a 30 cm ege from te B orizon of te oil. In te laboratory, te cylinrical tet ample (TS) were mole wit an uniturbe an remole tructure. Te remole tet ample a approximately te ame enity an natural moiture a te uniturbe ample. Te iameter of te tet ample wa 5 cm, an te eigt of te ample were variable. Table 3 an 4 ow te pyical inexe for te tet ample wit uniturbe an remole tructure, repectively. Table 3. Pyical inexe of te tet ample wit an uniturbe tructure. TS w (%) H (cm) (cm) (g.cm -3 ) e n Vv (cm³) *w = moiture content; H Heigt; iameter; - pecific ma, e voi ratio; n poroity; Vv voi volume. Table 4. Pyical inexe of tet ample wit a remole tructure. TS w (%) H (cm) (cm) (g.cm -3 ) e n Vv (cm³) equivalent to te fiel value..4 Proceing te pollutant olution A multipecie pollutant olution wa mae by iluting a A multipecie pollutant olution wa mae by iluting a tanar olution of,000 mg.l- from eac metal iolve in itille water. After te ilution, te ph wa correcte wit yroclorie aci (Hl) until it reace.35, wic wa one to imulate te mot critical aci mine rainage conition..5 olumn tet Te column tet reprouce te tranport of a pollutant troug te oil an allowe for a etermination of pyical an biopyical-cemical tranport parameter. Te tet wa conucte wit equipment prouce accoring to te ASTM (995). Te tet conite of two tep, te firt wa te itille water percolation until flow teay tate, were te yraulic conuctivity wa etermine. In te econ tage wa carrie out te percolation of te pollutant olution. For eac tructure, tree tet ample were tete imultaneouly. After percolating te pollutant olution troug te oil, te liqui wa collecte in ifferent percolate volume an tete time. Te metal concentration in eac collecte ample wa etermine troug analyi wit an atomic aborption pectropotometer at te UPF oil analyi laboratory. After etermining metal preent in te percolate effluent from te tet ample, it wa poible to obtain te breaktroug curve for eac tet an pollutant. Te breaktroug curve give te number of percolate pore (percolate volume/voi volume V perc /V v ) or te percolation time (t) along te x axi, an te pollutant relative concentration (percolate effluent concentration/initial concentration - / o ) i given along te y axi. Te mean yraulic conuctivity reult of te ample wa 3,7.0-4 cm/..6 etermination of tranport parameter in te column tet Ogata an Bank(96) evelope a one-imenional analytical olution () for Eq. by comparing te flow in omogenou an aturate oil (Sackelfor, 995) uing bot initial an bounary conition: (x,0) = 0 for x 0; (0,t) = o for t 0; (,t)/ (t) = 0 for t 0. Eq. () ow te analytical olution for a reactive olute for te occurrence of elay biopyical-cemical procee. In te equation, / o i te ratio between meaure percolate effluent concentration an te initial concentration, erfc i a function of te upplementary error, i te elay factor, L i te one-imenional flow itance given by te eigt of te tet ample, v i te percolation pee, t i te time of te tet, an i te yroynamic iperion coefficient. To etermine te parameter, a teoretical curve wa ajute at experimental tranport curve (breaktroug) from column tet by te Ogata an Bank olution Eq.. To generate a teoretical curve, te / o value were foun by etabliing ifferent time range

4 /o (t), te eigt of te tet ample (or te flow itance along x (L)), te percolation pee (v ) an te parameter. Te parameter wa obtaine from a meto given by Sackelfor (995), wic efine te area above te tranport curve a a value correponing to. ( x, t) 0 erfc exp vl L v t t erfc L v t t () Te k coefficient wa obtaine uing a linear relationip between te ma aborbe by a unit of oli ma an te concentration of te ubtance in te olution wen te oil i aturate, wic wa etermine after equilibrium wa reace. Te parameter k wa etermine accoring to Equation 3, were: i te elay factor, ρ i te pecific oil ry ma, an n i te poroity of te tet ample [30]. k n 3 ESULTS AN ISUSSION (3) Figure ow a example wic wa ue for ajutment an etermination of. Table 5, 6 an 7 ow te parameter obtaine for te tete metal wit wit uniturbe an remole tructure at a ph of S T T (min) E xperimental Analytic al Figure. Example curve ue for ajutment an etermination of. Table 5. Parameter obtaine for tete metal, Ni, r TS Ni r k k k TS TS TS Average TS TS TS Average cm³/g. Table 6. Parameter obtaine for tete metal u, Zn TS u Zn k k TS TS TS Average TS TS TS Average Table 7. Parameter obtaine for tete metal Mn, Pb TS Mn Pb k k TS TS TS Average TS TS TS Average oncerning te magnitue of parameter k an, imilar value relate to te cange in te tete tructure were oberve for te, Ni, u an Zn metal. Te Mn an Pb metal owe iger k an value for te uniturbe tructure, an only r a iger parameter value for te remole tructure. For metal Mn, Pb an r, te beaviour between te k an value relate to te tructure agree wit te fining of ei an Inyang (000) an aniel (993), wo ave reporte tat te iturbance of a remole tructure influence te mobility of pollutant in oil. However, microtructural an cemical tuie oul be conucte for better unertaning. Wit repect to te metal retention equence, wic wa oberve troug te parameter k an, te following prevalence orer wa oberve for te remole tructure: r>pb>u>>ni>zn>mn. For te uniturbe tructure, te following prevalence orer wa oberve: Pb>Ni>u>r>>Zn> Mn. Te affinity orer a a imilar beavior for Zn an Pb metal, wic agree wit te affinity orer obtaine by Soare (004) from everal oil in te tate of São Paulo, Brazil. Nacente et al.

5 (007) claime tat Pb, r an u metal ave reuce mobility in oil a compare to Zn, Mn, Ni an metal, wic wa confirme by te reult of ti tuy (except for Ni, wic owe lower mobility uniturbe tructure). elative to te kaolinite clay mineral, wic wa preominant in te tuy oil, Yong et al. (99) an ota (00) foun te following preference erie for ph value of 3.5 to 6: Pb>a>u>Mg>Zn>. Similar reult were obtaine in te current tuy. Vega (006) imulate te concentration of a contaminating olution at 5 mg.l -, wic i cloe to mot of te concentration employe in te preent tuy, in oil wit 90.6% kaolinite an % clay. Te autor obtaine k value for (4.9 cm 3.g - ), Ni (9.5 cm 3.g - ), r (7.3 cm 3.g - ), u (5.0 cm 3.g - ), Zn (6.5 cm 3.g - ) an Pb (57.9 cm 3.g - ). Te value reporte by Vega (006) are imilar to te one foun in te preent tuy. 4 ONLUSION oncerning te comparion between te ifferent tructure, te reult referring to k an i not ow a ignificant variation for, Ni, u an Zn. For metal Mn, Pb an r tere wa a variation, but microtructural an cemical tuie oul be conucte for better unertaning. Te metal retention equence for te remole an uniturbe tructure, repectively were r>pb>u>>ni>zn>mn an Pb>Ni>u>r>>Zn> Mn, wic alo agree wit everal tuie relate to metal mobility in oil. AKNOWLEGEMENTS Te autor wi to expre teir gratitue to Brazilian eearc ouncil (NPq/MT) for te financial upport to te reearc group (proce 30300/005-7, 3053/008-0, /009-0, 30869/007-3). EFEENES Acterberg, E.P, Braungart,.B. an Millwar, G.E Metal beaviour in an etuary pollute by aci mine rainage: te role of particulate matter. Env. Pol. (): Akcil, A. an Kola, S Aci Mine rainage (AM): caue, treatment an cae tuie. J. leaner Pro. 4 (-3): American Society for Teting an Material ASTM Stanar Tet Meto for leacing oli material in a olumn, Pilaelpia. ampaner, V.P. an Luiz-Silva, W Pyical an cemical procee in aci mine rainage of coal mining in outern Brazil. Quím. Nova. 3 (): ompania e Tecnologia em Saneamento Ambiental eteb, irection eciion number , 005, internet, ttp:// ore_005.pf, 8/06/008. (in Portuguee). ota, P.O.S. 00. Avaliação em laboratório, o tranporte e contaminante no olo o aterro anitário e Sauípe/Ba, M.Sc., Tei, Pontifical atolic Univerity of io e Janeiro, io e Janeiro, Brazil, 68 p. (in Portuguee). aniel.e. lay liner in: aniel,.e. Geotecnical pratictice for wate ipoal, apman & Hall, Lonon, iel, L. Van er Lelie, N., an Batiaen, L. 00. New evelopment in treatment of eavy metal contaminate oil. Env. Sci & Bio/Tec. : Equeenuin, S.M., Tripaty, S., Saoo, P.K. an Panigrai M.K. 00. Hyrogeocemical caracteritic of aci mine rainage an water pollutionat Makum oalfiel, Inia. J. Geoc. Exp. 8 p. Jonon,.B. an Hallberg, K.B Aci mine rainage remeiation option: review. Sci. total Env. 338 (-): 3-4. Kalin, M., Fyon, A. an Weeler, W Te cemitry of conventional an alternative treatment ytem for te neutralization of aci mine rainage. Sci. Total Env. 366 (-3): Krina, A.K. an Govil, P.K Aement of eavy metal contamination in oil aroun Manali inutrial area, ennai, Soutern Inia. Env. Geol. 54: Lafuente, A.L., González,., Quintana, A, Vázquez, J.. an omero, A Mobility of eavy metal in poorly evelope carbonate oil in te Meiterranean region. Geoerma. 45: Meurer, E.J Funamental of Soil emitry. 3r. e. Evangraf, Porto Alegre (Brazil), 90 p. (in Portuguee). Mitcell, J. K. an Soga, K Funamental of Soil Beavior, 3r e., Jon Wiley & Son Inc, New York. Moncaa, M.P.H Etuo em laboratório e caracterítica e colapo e tranporte e oluto aociaa à infiltração e licor cáutico em um olo laterítico, MSc., Tei, Pontifical atolic Univerity of io e Janeiro, io e Janeiro, Brazil, 9 p. (in Portuguee). Nacente,., Ernani, L.P., Silva, P.S. an Azeveo, I emoval of Heavy Metal wit te Ue of oal, Proceing VI EGEO, ecife (Brazil), 007. (in Portuguee) Nieto, J.M., Sarmiento, A.M., Olía, M., anova,.., iba, I., Kalman, J. an elvall, T.A Aci mine rainage pollution in te Tinto an Oiel river (Iberian Pyrite Belt, SW Spain) an bioavailability of te tranporte metal to te Huelva Etuary. Env. Int. 33: Ogata, A.; Bank,.B. A Solution of te ifferential Equation of Longituinal iperion in Porou Meia, US Geological Survey, Profeional Paper No. 4-A, 96. ei, L. N. an Inyang, H. I Geoenvironmental Enginnering: Principle an Application, Marcel ekker, New York, 494 p. Sarmiento, A.M., Olía, M., Nieto, J.M., ánova,.. an elgao J Natural attenuation procee in two water reervoir receiving aci mine rainage, Sci. Total Env., 407 (6):

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