硫化物矿物溶解度与溶液pH值的关系-贾建业

:1008-0058(2001)03-0241-06硫化物矿物溶解度与溶液pH值的关系贾建业1,兰斌明2,谢先德1,吴大清1,汤艳杰1,王燕3,王建成4(1.,510640;2.,710054;3.,510000;4.,453600):硫化物作为自然界常见的一大类矿物,由于溶解度很小,硫化物对水pH值的影响以及水对它的溶解度影响往往被人们所忽视通过计算常见硫化物矿物的自由能$G0f溶度积Ksp和溶解度S绘制logS)pH曲线,得出硫化物矿物在不同pH值条件下的溶解规律,水溶液的pH值受硫化物矿物的控制;反过来,水溶液的pH值也影响着矿物溶解度的大小此外,对硫化物矿物饱和溶液的缓冲范围缓冲容量和硫化物与溶液pH值相互作用的机理进行了探讨:硫化物;溶解度;pH值;缓冲容量和范围;机理:P578.2:A:2001-01-10:(49872017);;:(1956-),,,,10,,pH,,[1],[2],,[3~5],10,,,[1],,[6],,,,[7]pH,pH,1Ostwald-Fre-undlich:RTMlnS2S1=2RQ(1r2-1r1)(1)S1S2r2r1,M,R-,Qrr1,1r1,RTMlnSrS1=2RQr(2)Srr,,MayKolthoff,,,(2)(1)(2),31320017JOURNALOFCHANGCHUNUNIVERSITYOFSCIENCEANDTECHNOLOGYVol.31No.3Jul.20012Ksp:MmXn(s)Z(mMn+(aq)+nMm-(aq),$G0=m$fG0(Mn+,aq)+n$fG0(Xm-,aq)-$fG0(MmXn,s)MmXn,M+Xm-MmXn,$G0(J#mol-1)Ksp(3):lnKsp=-$G0RT(R=8.314J/K;T=298.15K)(3)$G0Ksp11$G0fKsp(18~15e,100kPa)Table1Freeenergy($G0f)ofsulfidesversussolubilityproductKsp(18~15e,100kPa)$G0f/(kJ#mol-1)KspAg2S(A)-40.676.3@10-501.6@10-49Ag2S(B)-39.52)2.5@10-49Cu2S-86.2992.5@10-484.2@10-48CuS-52.7696.3@10-365.1@10-36FeS-100.776.3@10-183.8@10-18FeS2-106.226.3@10-31)FeS2=Fe2++S2-+S-106.22)4.1@10-19HgS(A)-45.7734.0@10-532.8@10-52HgS(B)-43.6681.6@10-526.6@10-52MnS-218.552.5@10-131.7@10-14PbS-96.7138.0@10-284.5@10-28ZnS-187.492.5@10-221.9@10-22ZnS-200.611.6@10-249.6@10-25As2S3+4H2O=2HAsO2+3H2S-168.612.1@10-221.0@10-40Bi2S3-164.851@10-97)1/2Bi2S3+H2O+H+=BiO++3/2H2S-164.85)2.4@10-23Sb2O3-173.631.6@10-93)1/2Sb2O3+H2O+H+=SbO++3/2H2S-173.638@10-312.2@10-19Sb2O3+4H2O=2HSbO2+3H2S-173.63)6.3@10-40:$G0f,,,1988,274;CRCHandbookofChemistryandPhysics,65th,B222,1984~1985;KspJ.A.,,,,1991.3pHMS,MSZM2++S2-,KD=[M2+][S2-]C2?[MS]C0(4)MS,,:MS(s)ZMS(aq)ZM2++S2-(5)MS(aq)MS,M2+S2-,,[MS]C0,[MS]MSM2+S2-(4)[M2+][S2-]C2?=KD[MS]C0(6),[MS]S0Ksp=[M2+][S2-]C2?=KdS0(7)C01,MSS[M2+][S2-]S02422001,M2+(),():M2+z)))y+OH-M(OH)+z)))y+OH-M(OH)2z)))y+OH-,z)))y+OH-M(OH)n-2nS2-HS-H2S:S2-z)))))))y+OH-(pKa2=12.90)HS-z)))))))y+H+(pKa1=6.97)H2SL,LM2+,M2+S2-DM2+DS2-M2+S2-,,:DM2+=11+Eni=1BOH,i[OH-]i+Emi=1BL,i[L-]i,(8)DS2-=Ka1Ka2[H+]2+[H+]Ka1+Ka1Ka2(9)BOH,iM2+OH-iKa1Ka2H2S,Ka1=1.3@10-7Ka2=7.1@10-15BOH,iM2+LiL,(8)DM2+=11+Eni=1BOH,i[OH-]i(10)M2+,(8)(10)S(mol#L-1);[M2+][S2-]M2+S2-,[M2+]=SDM2+,[S2-]=SDS2-(11)(11)(7)Ksp=SDM2++SDS2-+C2?,(12)S=KspC2?DM2+DS2-(13)M2SS=3Ksp4C3?DM2+DS2-,(14)M2S3S=5Ksp108C5?D2M2+D3S2-(15)25eDebye-H™chel:logC?=-0.509|Z+Z-|I(16)C?;I,I=12EmiZ2i,:mol#kg-1;Z+Z-;mii,:mol#kg-1pH:(a)pH(9)(10)DMn+DS2-;(b)C?=1(c)KspDMn+DS2-(13)(14)(15)S0;(d)S0miI,I(16)C?,(c)S11logSpHFig.1TherelationshipbetweensolubilitylogSandpH1.;2.;3.;4.;5.;6.;7.;8.;9.;10.;11.;12.KsppH=1~12S,1,pH,;MS,pH[6,S2-H2SH2S0.1mol#L-1(),,S0,pH(pHU1.6),,,pH=5Cr6+Fe1-xS,,,pH2433:pH4MSM2SM2S3pHM+M2+M3+,Mn+,S2-H2O,:[H+]+[HS-]+[H2S]=[OH-]+Eni=1i[M(OH)i](17)MSM2SM2S3,[H+][HS-][H2S][M(OH)],[H+]+S(DHS-+2DH2S)=[OH-]+SEni=1iDM(OH)i,(18)[H+]+S(DHS-+2DH2S)=[OH-]+2SEni=1iDM(OH)i,(19)[H+]+3S(DHS-+2DH2S)=[OH-]+2SEni=1iDM(OH)i(20),DH2S=[H+]2[H+]2+[H+]Ka1+Ka1Ka2,DHS=Ka1[H+][H+]2+[H+]Ka1+Ka1Ka2,DM(OH)i=BOH,j[OH-]j1+Eni=1BOH,j[OH-]j(9)(10)(13)(16)(18),MS:(a)pH0=7.0pH,S0;(b)S0(17),pH1;(c)pH1S1;(d),pH,(9)(10)(13)(16)(19)(9)(10)(13)(16)(20),M2SM2S3(2)2,pH,,pHpH,,,pH,,,pH2pH(18~25e100kPa)Table2SulfidesolubilityandpHvalueofsaturationsolu-tion(18~25e,100kPa)S/(g#L-1)¹ºpH8.4@10-14)1@10-130.000330.00620.00490.00001)0.00470.000860.00690.000660.00050.000180.001752.48@10-15)1.19@10-152.55@10-150.00616)0.00001)0.006239.4@10-7))2.48@10-130.000180.001752.5@10-122.9@10-124.7@10-121.7@10-122.2@10-41.3@10-41.4@10-162.0@10-163.8@10-32.7@10-85.3@10-64.7@10-7)1.7@10-101.4@10-67.007.007.007.008.227.987.007.009.537.007.167.01)7.006.98:¹CRCHandbookofChemistryandPhysics,65th,1984-1985;ºSeidell,SolubilitiesofInorganicandMetalOrganicCompinds,3th,1994.,,,,,,,(1),5(Mn+)(S2-),:BT=BH++BOH-+(ln10)Emk=1#ckEnkj=1Ej-1i=0(j-i)2DHjBkDHiBk(21)BT;BH+BOH-H+OH-;ckk(),mol#L-1;nkk();DHjBk[H+],k()HjBk,DHjBk=K(k)nk-j[H+]i/Enki=0K(k)nk-j[H+]i2442001,K(k)nk-1knk(21)(2)2FeSFig.2ThebuffercapacityofFeSversussolutionpHvalue1.Fe2+();2.S2-2,pH3~6,,,,,pH6,,,-,pH[8]Kh(Ka),:[M(H2O)p]n++2H2OZ[M(OH)2(H2Op-2)(n-2)++2H3O+(22)K11K12,B11B12,:B11=K11,B12=K11#K12K11K12;Kh,Kh,,,pH,pH[9]pH,pHcrit,()OH-pHipHcrit,pH,H+;pHipHcrit,pH,H+,pHcrit,pHzpcRHpH(point-of-zerocharge)pHPZC(RCC),pH=pHPZC,R0Davis(1990)RHpHpHPZNPC(point-of-zero-net-protoncharge)pHPPZC(pristinepoint-of-zerocharge)H+OH-pHPZNPC,RCC=0,R0=RHpHPPZC,,[10~14]7(1)$GÀf,15Ksp,Ksp(2)MSM2SM2S3,S,logS-pH(3)pH,pH,,pH(4),pH=3~6,(5)pH2453:pH:[1].[J].,1999,73(3):243-249.[2].[J].,1992,11(3):85-90.[3]JEANGE,BANCROFTGM.Heavymetaladsorp-tionbysulphidemineralsurface[J].GeochimCos-mochimActa,1986,50(7):1455-1463.[4]BROWNJR,BANCROFTGM,etal.Mercuryre-movalfromwaterbyironsulphideminerals:AnESCAstudy[J].EnvironSciTechnol,1979,13(6):1142-1145.[5]HYLANDMM,JEAMGE,BANCROFTGM.XPSandAESstudiesofHg(Ò)sorptionanddesorp-tionreactiononsulfideminerals[J].GeochimCos-mochimActa,1990,54(7):1957-1967.[6]HELGESONHC.Predictionofthethermodynamicpropertiesofelectrolytesattemperature[A].In:RickardD,WickmanFW,eds.Chemistryandgeo-chemistryofsolutionsathightemperaturesandpres-sur