ACTA CHIMICA SINICA. 5 Zn2Al HTlc PZNC. Studies of the Point of Zero Net Charge and Isoelectric Point of Zn2Al Hydrotalcite2like Compounds

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1 , ACTA CHIMICA SINICA Vol 62, 2004 No 4, Zn2Al a, b Ξ, a a ( a ) ( b ) a Ξ Zn2Al (HTlc), Al/ (Zn + Al) ( x) Zn2Al HTlc (PZNC) ( IEP), PZNC IEP,PZNC IEP ; IEP PZNC,,IEP PZNC, IEP PZNC HTlc IEP PZNC PZNC IEP,,, Studies of the Point of Zero Net Charge and Isoelectric Point of Zn2Al Hydrotalcite2like Compounds LI, Li2Fang a, b HOU, Wan2Guo Ξ, a DAI, Xiao2Nan a LIU, Chun2Xia a ( a Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan ) ( b College of Applied Chemistry and Material Science, Shandong Agriculture University, Tai an ) Abstract A series of Zn2Al hydrotalcite2like compounds ( HTlc) was synthesized by co2precipitation method The structure and chemical composition of the samples were determined by X2ray powder diffraction and automatic X2ray fluorescent spectrometric analysis, respectively The results showed that pure HTlc could be obtained in the range of 0131 x 0152 [ x = n (Al) / n ( Zn + Al) ] The point of zero net charge ( PZNC) and isoelectric point ( IEP) of pure Zn2Al HTlc were measured using potentiometric titration method and electrophoretic method, respectively The results indicated that permanent charge led to shifts in the PZNC and IEP of HTlc samples, and this influence was just the same as that of the cations adsorption on HTlc samples PZNC and IEP all decreased with x or permanent charge density increasing, and IEP values were higher than PZNC values for all samples The difference value ( IEP2PZNC) increased as x value increased, indicating that the difference came from the structure charge of HTlc samples Keywords hydrotalcite2like compound, layered double hydroxide, isoelectric point, the point of zero net charge, potentiometric titration : ( ph, (Point of zero net proton charge, ) - PZNPC, H = 0, ) ( ST ), (Point of zero net charge, PZNC, o = 0) [2] H + OH - ( H ), (Potentiometric titration, PT) PZC ( Intrinsic charge, o ), o = ST + [1] H PT ( ) [3 (Points of zero charge, PZC) PZC,4],, ph PZNC [5], Ξ E2mail : edu cn Received May 19, 2003 ; revised August 10, 2003 ; accepted October 10, 2003 (No )

2 430 Vol 62, 2004 PZNC, PZNC [6] Rikadu D/ MAX 2200PC X ( ) ( Hydrotalcite2like compounds, HTlc) [2,6 PZC,7] HTlc ) ph ; DXD2 (, [8] : [M( II) 1 - x M( III) x 2 ) HTlc (OH) 2 ] x + A n - x/ n mh 2 O,,M( II) M( III) 1 2 [2,A - n, x Zn2Al HTlc,6] - + HTlc M( III), HTlc ( OH - H ) ph PT, m 1 3 PZNC, Mg HTlc ( Mg2 HTlc [11], ph Fe [6], Mg2Fe2Al [7] HTlc) PZNC, HTlc PZNC = 0 ph HTlc IEP PZNC, x PZNC IEP 25,HTlc PZNC PZNC : Mg ( OH) 2 ph PZNC 12, 2FeOOH ph PZNC 714, 2AlO (OH) ph PZNC 717 [9] Mg (OH) 2 ph PZNC x,mg 2 1 Zn2Al HTlc, Mg HTlc, x XRD, 0131 x 0152,,HTlc ph PZNC, ; x < 0131, ZnO ; Mg x > 0152, HTlc, Zn2Al HTlc PZNC Zn Al x [8], ph PZNC, HTlc x ( Isoelectric point, IEP) Mg2Zn2Al Mg2Fe2Al HTlc HTlc, ( ) ph IEP x [12,13] PZNC 1 x HTlc, ( a, c) ( d) ( S) [6] a,iep PZNC ;,IEP nm, c nm PZNC,IEP, PZNC, d nm Zn2Al HTlc,IEP PZNC ;,IEP, PZNC [12],IEP PZNC [10] IEP PZNC IEP 2 2 Zn2Al HTlc IEP 1 2 Zn2Al HTlc PT, 1 ; X ( ) ;phs23c ph ( 2 PT ( Common intersection point, CIP), PT [2,6], CIP ph PZNC 1 1 Zn2Al HTlc, HTlc PZNC Zn2Al HTlc [6] ZnCl 2 ph PZNC 2, AlCl 3,NH 3 H 2 O ph Zn2Al HTlc ph PZNC , [6, ( x ST ),ph PZNC,,7] 1 Zn2Al HTlc Table 1 The chemical formula, lattice parameters, basic spacing and specific surface area of Zn2Al HTlc samples No Chemical formula x a/ nm c/ nm d/ nm S/ (m 2 g - 1 ) 1 Zn 0 48 Al 0 52 (OH) 2 34 Cl Zn 0 59 Al 0 41 (OH) 2 24 Cl Zn 0 63 Al 0 37 (OH) 2 21 Cl Zn 0 65 Al 0 35 (OH) 2 19 Cl Zn 0 69 Al 0 31 (OH) 2 11 Cl

3 No 4 :Zn2Al 431 2AlO(OH), 2AlO (OH) ph PZNC 717, 715, Zn(OH) 2 ph PZNC 718 [9] Zn2Al HTlc ph PZNC Zn Al ph PZNC, [6,7,11] Zn Al ph PZNC, Zn/ Al IEP Zn Al IEP ph PZNC, Zn2Al HTlc ph PZNC IEP ph PZNC Zn Al ph PZNC Zn2Al HTlc IEP Zn Al IEP, IEP, Zn2Al HTlc 2 Zn2Al HTlc Table 2 The PZNC and IEP of Zn2Al HTlc No ST / (C m - 2 ) ( OH - H ) PZNC / ph PZNC (mmol g - 1 ) IEP Zn2Al HTlc 2 2 Figure 2 2potential of Zn2Al HTlc sample ph PZNC IEP,pH PZNC IEP, ph PZNC IEP HTlc ph PZNC IEP [10], ST,IEP ph PZNC, IEP ph PZNC References 1 Zn2Al HTlc 2 Figure 1 PT curves of Zn2Al HTlc sample 2 (,,,,,, HTlc PZNC : ST, PZNC OH -, ph PZNC ; ST,OH - HTlc 4 James, R O ; Parks, G A Surf Colloid Sci 1982, 12,, ph PZNC Zn2Al HTlc ph PZNC Zn Al ph PZNC, 5 Kraepiel, A M L ; Keller, K ; Morel, F M M Environ ;ph PZNC Sci Technol 1998, 32, 2829, 6 Hou, W2G ; Su, Y2L ; Sun, D2J ; Zhang, C2G 2 3 A J Colloid Interface Sci 2003, 257, Zn2Al HTlc ph, ph ph IEP, 2 ( x 1 Sposito, G Environ Sci Technol 1998, 32 (19), Hou, W 2G ; Xia, C2Y ; Han, S2H ; Wang, G2T ; Zhang, C2G Acta Chim Sinica 1998, 56, 514 (in Chinese) 1998, 56, 514 ) 3 Sprycha, R J Colloid Interface Sci 1984, 102 (1), 173 ST ), ph PZNC,IEP, Sci 1979, 70 (3), 483 Zn Al ( ) IEP PZNC 10 Shojai, F ; Pettersson, A ; Mgntylg, T A ; Rosenholm, J [14] Zn/ Al IEP, Ceram Int 2000, 26, Langmuir 2001, 17, Li, S2P ; Hou, W2G ; Han, S2H ; Li, L2F ; Zhao, W2 8 Cavani, F ; Trifir, F ; Vaccari, A Catal Today 1991, 11, Yoon, R H ; Salman, T ; Donnay, G J Colloid Interface

4 432 Vol 62, Han, S2H ; Xu, S2P ; Hou, W2G ; Sun, D2J ; Zhang, C2G ; Wang, G2T Chin J Chem 1997, 15 (4), Jiang, P ; Hou, W2G ; Han, S2H ; Hu, J 2F ; Li, D2Q Chem J Chin Univ 2002, 23 (1), 78 (in Chinese) (,,,,,, 2002, 23 (1), 78 ) 13 Li, S 2P ; Hou, W2G ; Jiang, P ; Zhu, W2Q Chin Chem Lett 2002, 13 (8), Parkes, G A Chem Rev 1965, 65, 177 (A ZHAO, X J ; ZHENG, G C )

5 No 4 Graphical Abstract Influence of Crosslinking Degree of Soluble 2 Cyclodextrin Polymer on the Fluorescence of 32 Hydroxy222naphthoic Acid and Its ER Proper2 ties GAO, Zi2Wei ; ZHAO, Xiao2Peng Acta Chimica Sinica 2004, 62 (4), 418 High Resolution NMR Study on Solubilization Behavior of Styrene in CTAB Microemulsion System Six soluble 2cyclodextrin polymers were prepared by the modified method of Renard Using 32hydroxy222naphthoic acid as a fluo2 rescence probe, the relationship between the crosslinking degree of the polymer ( CLD) and the stability of supramolecular complex, the fluorescence properties and electrorheo2 logical properties were investigated, respec2 tively The solubilization of styrene in the O/ W type CTAB/ n2butanol/ water/ styrene mi2 croemulsion systems was investigated by 1 H NMR and 13 C NMR method The re2 SHI, Yuan2Chang ; WU, You2Shi ; LI, Gan2Zuo Acta Chimica Sinica 2004, 62 (4), 424 sults showed that the solubilization site was mainly in the palisade layer of the mi2 croemulsions and less of styrene was locat2 ed in the inner core Meanwhile, due to the steric hindrance effect styrene molecules can be hardly distributed near the N2CH 3 group of CTAB, and the content of styrene was gradually decreased from the outer to inner along the hydrocarbon chain of CTAB Studies of the Point of Zero Net Charge and Isoelectric Point of Zn2Al Hydrotalcite2like Compounds LI, Li2Fang ; HOU, Wan2Guo ; DAI, Xiao2Nan ; LIU, Chun2Xia Acta Chimica Sinica 2004, 62 (4), 429 Photoelectron Spectroscopy ( PES) and Theo2 retical Studies on Bromine Monochloride Expanded photoelectron spectroscopy of bromine monochloride in the low ioniza2 tion energy region shows that the first band is split by spin2orbit coupling into two components which exhibit fine vibra2 tional structure QIAO, Zhi2Min ; SUN, Qiao ; SUN, Shu2Tao ; WANG, Dian2Xun Acta Chimica Sinica 2004, 62 (4), 433