利用膨潤土及硫化物對污泥中重金屬的穩(wěn)定化研究_英文__圖文

1、第 46卷 增 刊 2007年 6月中山大學學報 (自然科學版 ACTA SCIENT IARUM NATU RA L I UM UN I V ERSITAT IS SUNYAT SEN IV o l 46 Sup Jun 2007Study on H eavy M etal Stabilizati on i n Sl udge w ith Bentonite and Sulfi deSUN Yi n g, X U Ran, QI AN Guang ren(Co llege o fEnv ironm enta l and Che m i c al Eng i n eer i n g , Sha

2、nghaiUn i v ersity , Shangha i 200072, Ch i n aAbstrac t :T he stab iliza tion o f heavy me tals i n sludg e w as stud i ed by usi ng bentonite and Sulfi de separa tely . W ith che m i ca l spec i a ti on analysis o f heavy m eta l s and w ith heavy m eta l t ox ic characteristi c l eaching exper i

3、m ent , the app licati on probability of t w o k i nds o fm ate rials i n adsorpti on and stabilizati on of heavy m eta lsw ere stud ied to offe r a new way to trea t heavy m etals e ffecti v ely in t he ag ricu lt u re u tili zati on of sludg e . R esults sho w t hat leach i ng concen trati on of h

4、eavy m eta l s i s decreased to m eet t he standard o f sl udge u tiliza tion in ag ricu lt ure . A nd , the spec i es of heavy me tals are changed too w i th the rati o o f the unsteady spec i es o f heavy m e tals i n s l udge reduced g reatly . Am ong t hese , Benton ite has effecti ve adso rpti

5、ve prope rti es on heavy m eta ls li ke Cd and N , i w hil e p H va l ue ism a i n infl uenc i ng factor on adsorpti on and sodi u m s u lti de has good stab ilizati on prope rti es on heavy me tals li ke Zn , Cu and Cd . W hen 10%sca lesm e d i ca m ent was used , leach i ng concentrati on o f Zn w

6、 as 4 96mg /Lon l y and t he rati o of the unsteady spec ies o f heavy m etals i n sl udge w as reduced by 50%60%.K ey word s :sl udge ; heavy m eta ls ; benton ite ; sulfi deCLC nu m ber :X131 Docum en t code :A Ar ti c le I D :0529 6579(2007 S1 0041 031 Introducti onSe w age sludge conta i n s hea

7、vy m eta ls , such as Zn , Cu and Cd, wh ich can lead to series hea lth prob le m w hen enteri n g i n to food chain . Stabilization is a process of transfor m ing heavy m eta ls fro m po isonous and delete rious m atters to lo w disso lvable , lo w transferable and lo w po isonous ones . Bentonite

8、and Sulfide w ere m i x ed w it h sludge at different sca le separately in f o llo w i n g ex peri m en. t By co m pari n g correspond i n g effec, t the high -effecti v e che m ical stab ilizati o n m ater i a ls w ere f o und out 1-2.2 E xperi m ents2 1 Materi a l s and Sequenti a l Extr acti o n

9、ofHeavy Metal sA k i n d o f i n dustry sl u dge , sa m pled fr o m Tao Pu W aste w ater Treat m en tP lant o f Shangha iw as adopted as experi m ent sa m ple . O ther m a i n m ateri a l inc l u de N a 2S 9H 2O, and Ca bentonite . The tox ic ity of the sludge sa mp les w ere deter m ined at d iffer

10、ent p H va l u es w ith Tox ic Characteristic Leach i n g Procedure prescri b ed by USEPA, The leachate co m ponen ts w ere tested using I C P Em ission Spectro m etr y 3, and the sequenti a l che m ical ex traction o f heavy m e tals w as perfor m ed 4-6 2 2 Heavy M etal S t a bilizati o n Experm i

11、 ent w ith Bentonite and Sulfi d eFour d ifferent sca les (1, 2, 3and 5gra m o f bentonite and four different sca les (2, 5, 10and 15 gra m of Na 2S 9H 2O w ere adopted separate l y , into w hich 100g ra m o f sludge sa m ple w as joined . E ach sa m ple w as fu lly m i x ed and l e ached w ith TCLP

12、 to eval uate the effectiveness of benton ite or sulfi d e i n stabiliza ti o n of heavy m eta ls .3 R esults and D iscussi on3 1 Leachi n g Concentrati o n of Heavy M etal s i n SludgeT ab 1 leach i ng concentration o f heavy m etalw ith TCLP (m g /Lp H Zn Cu N i Cd Cr 2. 8842. 226. 941. 80. 326. 2

13、2 5. 019. 512. 618. 70. 092. 75I n this st u dy , Zn , Cu , N, i Cr and Cd w ere se lected as targeted heavy m eta ls accord i n g to their re la ti v e concentrati o n i n ra w sludge sho w ed i n Tab . 1and收稿日期 :2007 01 10基金項目 :上 海 市 教 委 基 金 資 助 項 目 (04AC101; 長 江 水 環(huán) 境 教 育 部 重 點 實 驗 室 開 放 基 金 資 助

14、項 目 (YRW EF06008:(, 女 , ; E m a ngsh sit h e a ll o w ed leach i n g out fro m agricu ltural used m ateri als .3 2 Heavy M et a l Adsor pti o n w ith Bentonite F ig 1 L eachi ng concentration of heavy m eta ls w ithbentonite F i g 2 A dso rbed quantit y changed w it h p HFig 1show s that leach i n g

15、 concentrati o n o f heavym etals w ere decreased at pH 5 0. The adsorption of Cd and N i w ith benton ite w as decreased obv iousl y when 5gra m o f ben ton ite w as added i n sl u dge , wh ile that o fCd and N iw as decreased to 0 07m g /Land 8 76m g /Lre specti v e l y . W hereas , the adsorption

16、 o f Zn and Cu w ere not obv i o us at p H 5 0. The adsorpti o n o f heavy m eta ls w it h bentonite w as not obv ious at pH 2 88too .E ffect o f pH value ranged fro m 3 0to 7 0on the adsorption o f t h e heavy m eta ls added w ith bentonite w as i n vesti g ated in the experi m en. t Fig 2show s t

17、h at i n creases i n pH i n the leach i n g solution w ill lead to an i n crease of adsorbed quantity o f the Cu ion . A dsor bed quantity o fCd , N i and Zn changed obv i o usly at p H val ue ranged fro m 5 0to 7 0. The adsor pti o n o f Cr w as si m ilar w ith Cu. I n genera, l the range o f p H v

18、a l u e fro m 5 0to 7 0w as preferab le for adsorpti o n o f heavy m eta ls added w ith bentonite . The adsorption characteristic w as not reflected by the curve i n F i g 2because i n so lublehydrox ides w ill be for m ed at higher p H. Because H +has str ong co m petition at lo w er p H, t h e ads

19、orption o f heavy m eta ls added w ith benton ite w as no t obv ious at p H 2 88.3 3 Heavy M et a l S tabili z ati o n w ith Sulfi deF i g 3 l eaching concentration o fH eavy m eta lw ith sulfideF i g 4 Changes o f F racti onati on of heavy m eta l sI n this experi m en, t N a 2S 9H 2O w as used to

20、stab ilize heavy m etal ions in sludge . Fig 3sho w s that leach i n g concentration of H eavy m eta l w as decreased obv iousl y at p H 2 88. W hen 10g ra m o fN a 2S 9H 2O w as added i n sludge , leach i n g concentration o f Zn , Cu and cd w ere 4 96m g /L,9 65mg /and 0 11mg /Lre specti v e l y .

21、 The l e aching concentati o n o f N i d i d no t de crease obv i o usl y . W hen 15gra m of N a 2S 9H 2O w as added , leaching concentration o fN i re m a i n ed at 30 86m g /L.Fractionati o n analysis of three k i n ds of heavy m et als i n sl u dge after and before stabilizati o n w as reflected

22、i n F i g 4. Content of Zn i n exchangeable fraction, bound to carbonates fracti o n , and bound to iron m anganese ox ides fraction accounted f o r 2 31%, 21 3%and 6 15%respecti v ely before stab ilizati o n, w h ile the pro porti o n w as changed to 0 91%, 10 4%and 3 21%after stab ilization. The f

23、or m er three k i n ds of fractions w ere unstable fracti o ns and the others w ere stable frac ti o ns . C onten t o f Zn i n unstab le fraction is decreased by 50%60%after stabilization .I n conc l u si o n , Fractionation of heavy m eta ls i n sl u dge after and before stab ilizati o n is basica

24、lly consist entw ith results of l e aching concentration , wh ile content of heavy m eta ls decreases i n unstab le fraction and i n creases i n stable fracti o n .4 Concl usi onso is lstabilization w ere discussed in the paper . H eavy m eta l absorption added w ith bentonite is infl u enced by the

25、 surface properties of th is adsorptive m ateria, l wh ile sul fi d e has che m ica l reacti o ns w ith heavy m eta l ions to for m i n so luble substances .(2 Bentonite has excellent adsorptive properties on heavy m etals li k e Cd and N i i n neutral c ircum stance . Th is m ethod is restricted i

26、n lo w er p H c ircum stance .(3 H eavy m etal stabilizati o n w ith su lfide is a ki n d of effecti v e m ethod , by decreasing the leaching concentration of heavy m eta ls to m eet t h e standard o f sl u dge utilization i n agriculture . W hen 1015gra m o f reagentw as used , leach i n g concentr

27、ati o n o f Zn w as 34m g /Lonly . the ra ti o of the unsteady spec iati o n o f heavy m eta ls i n sl u dge reduces greatl y wh ile that of sta b le speciati o n i n creases after stabilization . R eferences :1 EDW ARDS R, R EBEDEA I , LEPP NW, et a. l A n i nvestigati on i nto the m echan is m by

28、wh i ch synt hetic zeolites reduce l abil e m e tal J.Env i ron m enta lG eochem istry and H ea lth , 1999, 21:157-173.2 LOTH E N BAC H B , KREBS R, FVRRER G,e t a. lI mmob ili zati on o f cad m iu m and zi nc i n so il by AL mont m o rill on i te and g rave l sl udge J.European Journal ofSo il Sc i

29、 ence , 1998, 49:141-148.3 T est m ethods for eva l uati ng so li d w aste M.U S EPA, 1990.4 TESSIER A, C AM PBELL PG C , B i sson M.Sequen ti a lextraction procedure for t he speciati on o f particu l a te trace me tals J.A na l ytical Che m i stry , 1979, 51(7:844-851.5 S OUM IA A, MOHAM ED H, GEORGES M,et a. l Sequentia l ex trac ti on of heavy m eta l s dur i ng composti ng of se w age sl udge J.Che m osphere , 2005, 59:801-810.6 M A II I , ARAM BAKK I I , GARC I A R,et a. l Eval