Study on the hydrolysis2polymerization process of aluminum in polyaluminum silicate chloride ( PASC) flocculant

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1 Acta Scientiae Circumstantiae Vol. 25,No. 11 Nov., 2005,,,. (PASC) 2 [J ].,2005,25 (11) : GAO Baoyu, LIU Lili, ZHOU Weizhi, et al. Study on the hydrolysis2polymerization process of aluminum in polyaluminum silicate chloride (PASC) flocculant [J ]. Acta Scientiae Circumstantiae,2005,25 (11) : (PASC) 2 3,,,,, : : : :, (210 mol L - 1 ) SiΠAl ( PASC). Al2 Ferron, 2.,Al2Ferron A t = A 0 + A 1 [1 - exp ( - k b1 t ] + A 2 [ - exp ( - k b2 t) ] ; PASC,, 2. PASC Al, PASC SiΠAl. : (PASC) ; ; ; : (2005) :X70315 :A Study on the hydrolysis2polymerization process of aluminum in polyaluminum silicate chloride ( PASC) flocculant GAO Baoyu 3, LIU Lili, ZHOU Weizhi, YUE Qinyan, LI Qian School of Environmental Science and Engineering, Shandong University, Jiπnan Received 10 March 2005 ; received in revised form 9 September 2005 ; accepted 15 September 2005 Abstract : Using NaAlO 2 as basification agent, the high2concentration (about 210 mol L - 1 ) flocculants polyaluminum silicate chloride (PASC) with different SiΠAl molar ratio were prepared by feeding the alkali slowly. The species distribution and transformation were detected by Ferron timed complexation spectrophotometry. And the hydrolysis2polymerization process of aluminum in PASC solution was investigated by NaOH titration method. And the interaction between hydrolyzed aluminum species and polysilicic acid in PASC were studied by IR measurements. It was found that the kinetics curve of Al2Ferron timed complexation accorded with A t = A 0 + A 1 [1 - exp ( - k b1 t ] + A 2 [ - exp ( - k b2 t) ] equation. It was also found that there were interactions between polysilicic aid and hydrolyzed aluminum species in PASC, and these interactions could partially affect the hydrolysis2polymerization processes and the aluminum species distribution. The aluminum species could change from low polymer into high polymers easily when NaAlO 2 was used as basification agent. The higher the SiΠAl ratio was, the more the polymerize aluminum species were. Keywords:the high2concentration flocculant polyaluminum silicate chloride ( PASC) ; hydrolysis2polymerization process of aluminum; infrared spectrum;aluminum species, (Shu et al., 2001).,,,,, (Polyaluminum chloride, PAC) (Marina et al., 1997). PAC, ( Gao et al., 2002). Al 13 (80 % ) PAC,, PAC ( 015 mol L - 1 ),. : (No. 2004BS08002) : (1961 ),,,E2mail : edu. cn, Tel : ; 3 ( ) Foundation item :Shandong Provincial Science Fund for Distinguished Young Scholars(No. 2004BS08002) Biography : GAO Baoyu(1961 ), male, professor, E2mail : edu. cn, Tel : ; 3 Corresponding author

2 11 : (PASC) Perry (2001) NaAlO 2 ( B,OH - ΠAl ), NaAlO 2,,, B ( 2. 0 mol L - 1 ) (Perry et al., 2001)., ( 2. 0 mol L - 1 ), 2. SiΠAl (2. 0 mol L - 1 ) (PASC),, 2,, PASC. 1 ( Experiments) 111 :20SX 7821A DZKW2C UV ( ) ZD22. : (A. R. ) (A. R. ) (,C. P. ) PAC 20 ( r min - 1 ), ( 24 % Al 2 O 3 ) AlCl 3 ( 811 % Al 2 O 3 ) B 115, (80 5) 015 h,, PAC. PAC 24 h, PASC, ( r min - 1 ) (SiO 2 4 % 8 %,Na 2 OΠSiO 2 = ) ( 24 % Al 2 O 3 ) (, ), AlCl 3 ( 811 % Al 2 O 3 ).,, SiΠAl PASC PAC ref 20 ( r min - 1 ), AlCl 3 ( 015 % Al 2 O 3 ) B 115, (80 5) 015 h, 24 h, 0110 mol L - 1 et al., 2003), 0110 mol L - 1 PAC ref (Lionel PAC ref Al ( ) 2 2 mol L - 1 PAC PASC Table 1 Characteristics of different flocculants SiΠAl (Al T )Π(mol L - 1 ) B ph PAC PASC PASC PASC PASC PASC PASC PAC ref Al2Ferron ( Feng et al1, 1993) 10 ml Ferron 50 ml, 30 L 011 mol L ml Ferron,. 60 s UV22450, 7200 s (Jean et al., 1999), ml (01010 mol L - 1 ) Al mol L - 1 NaOH, 0101 ml min - 1, ph OH - ΠAl ( OH - ) PASC 20SX FT2IR, 2 cm - 1, 60, cm - 1. PASC 60,, KBr. 2 ( Results) 211 Al2Ferron 1 Al2Ferron 7200 s. Al2Ferron Ferron 2,, PAC Al a,al b,al c 3. Al a, Ferron 60 s

3 ;Al b s Ferron, ;Al c = Al T - (Al a + Al b ),, 7200 s Ferron ( Feng et al., 1993). 1 Al2Ferron (11PAC,21PASC 01025,31PASC 01050, 41PASC 01100,51PASC 01200,61PAC ref ) Fig. 1 The kinetics curve of Al2Ferron timed complexation ( 11PAC, 21PASC 01025, 31PASC 01050, 41PASC 01100, 51PASC 01200, 61PAC ref ) 1,PASC Al2Ferron,,. PASC PAC, PAC, PASC PAC,. PAC ref 7200 s PAC PASC, PASC, PAC ref Al a PASC Al b PASC,.,Al b 2Ferron Π. Al b,, Jardine (1986) Al b k b 2, Al b1 Al b2 k b1 k b2. Al2Ferron :,A t A t = A 0 + A 1 [1 - exp ( - k b1 t) ] + A 2 [1 - exp ( - k b2 t) ] (1) t Ferron Al (cm - 1 ) ; t (s) ; A 0 Al a Ferron (cm - 1 ) ; A 1 A 2 Al b1,al b2 Ferron (cm - 1 ) ; k b1 k b2 Al b1 Al b2 (min - 1 ). Origin,, 2. 2 Table 2 The constant of kinetics curve A 0 A 1 A 2 k b1 k b2 R 2 PAC ref PAC PASC PASC PASC PASC , (1) 2 3, k b1 k b2, Al b1 Al b2 Ferron. 2 y 1 = A 1 [1 - exp ( - k b1 t) ] y 2 = A 1 [1 - exp ( - k b2 t) ], Al b1 Al b2 Ferron ( 2). 22a Al b1. Al b1, Ferron. PAC PAC ref PASC,,. 3, PAC ref > PAC > PASC, PASC, SiΠAl. 22b Al b2. Al b2. Al b1,al b2 Ferron (Luan et al., 1997). PAC PASC. 22a Al b2 : PAC > PASC > PAC ref,, k b2. Ferron PAC ref Al a Al b Al c % % 4138 %. PAC PASC 3, SiΠAl = 0

4 11 : (PASC) Al b1 Al b2 Ferron (11PASC 01025,21PASC 01050,31PASC 01100,41PASC 01200,51PAC,61PAC ref ) Fig. 2 The complexation curve of Al b1 2Ferron and Al b2 2Ferron(11PASC 01025,21PASC 01050,31PASC 01100,41PASC 01200,51PAC,61PAC ref ) PAC., NaAlO 2. PAC PASC PAC ref, Al b PAC ref %,Al c PAC ref 4138 %. NaAlO mol L - 1, PAC Al b, SiΠAl, PASC Al b, Al b1.,al b1 Al b, Al b2, Al b. Al a,,al c SiΠ Al. NaAlO 2 PAC PASC, Al Al b, Al b, Al Al, Al a,, 3 Ferron PAC PASC Fig. 3 The distribution of Al species in different samples 212 Al ( ) 2, SiΠAl PASC, 4. 42a 3 AlCl 3 PAC PAC ref 4 PASC Al( ) (11AlCl 3, 21PAC, 31PAC ref, 41PASC 01025, 51PASC 01100, 61PASC ) Fig. 4 The titration curves of Al ( ) solution with alkali addition in PAC and PASC (11PAC ref, 21PAC, 31AlCl 3, 41PASC 01025, 51PASC 01100, 61PASC )

5 , OH -,OH - ΠAl,pH. (1. 5 < OH - ΠAl < 2. 7), PAC ref OH - ΠAl2pH,PAC.,., OH - ΠAl > 2. 55,PAC ref, OH - ΠAl > 2. 6, PAC, AlCl 3, OH - ΠAl > 2. 7,. AlCl 3 OH - ΠAl. PAC PAC ref, Na 2 CO 3 PAC ref OH - ΠAl NaAlO 2 PAC. 42b, ph (OH - ΠAl = 115 ) SiΠAl,, NaOH, ph,., SiΠAl. PAC OH - ΠAl = 216, PASC OH - ΠAl = 2175, PASC PASC OH - ΠAl = 218 OH - ΠAl = , 3 : cm - 1 PASC PAC OH - OH -, 2530 cm - 1 O Al,1630 cm - 1 ( Farmer et al., 1974)., cm - 1 Al O Al,613 cm - 1 A1 OH. 5 (a :11 PAC, 21 PAC ref, b :11 PAC, 21 PASC 01025, 31 PASC 01100, 41 PASC ) Fig. 5 The infrared spectra of different samples(a :11 PAC, 21 PAC ref, b :11 PAC, 21 PASC 01025, 31 PASC 01100, 41 PASC ) 52a,PAC 2530 cm - 1 PAC ref, 1630 cm - 1 PAC ref. PAC PAC ref, O Al, Al b, Ferron Al. 52b,PASC PAC 840 cm - 1. PASC,. (Chen et al., 2002), SiΠAl,. 3 ( Discussion), PASC SiΠAl Al. Al2Ferron,, NaAlO 2 PAC PASC PAC ref Al b, Al b Al b1 Al b2,pac PASC PAC ref Al b1, Al b2., NaAlO 2 Al.

6 11 : (PASC) PASC,Al b1,al b2. PASC,., PASC Al b1. Al b1,.,,, Al b (Luan et al., 1997)., OH - ΠAl Al b2 (Luan et al., 1997)., NaAlO 2 PAC PASC (OH - ΠAl = 1. 5) Al b, OH - ΠAl,Al Al b2. SiΠAl,PASC.. 4 ( Conclusions) 1) Al2Ferron : A t = A 0 + A 1 [1 - exp ( - k b1 t) ] + A 2 [1 - exp ( - k b2 t) ], SiΠAl, k b1, k b2. 2) Al ( ) 2, NaAlO 2 PAC PASC B = 1. 5 Al b, OH - ΠAl,Al Al b2. 3) 840 cm - 1, SiΠAl PASC. ( References) : Chen W N,Zhong H P, Yang J, et al Analysis of IR spectrum and crystal morphology of polyalumina2silica chlorid ( PASC) prepared by various method[j ]. Chemical Research and Application,14 (1) :73 75 (in Chinese) Farmer V C The Infrared Spectra of Minerals [ M ]. London : Mineralogical Society, Feng L,Luan Z K, Tang H X The Study on Speciation Analysis Methods for Hydrolysis Polymerization of Aluminum[J ]. Environmental Chemistry,12 (5) : (in Chinese) Gao B Y, Hahn H H, Hoffmann E Evaluation of Aluminum2Silicate Polymer Composite as a Coagulant for Water Treatment [ J ]. Research,36 : Water Jardine F M, Zelazny L W Mononuc lear and palynuclear aluminum speciation through differential kinetic reactions with ferron[j ]. Soil Soc Am J,50 : Jean P B, Carmel J Influence of sulfate andπor silicate present in partially prehydrolyzed Al ( ) flocculants on Al ( ) speciation in diluted solutions,a :Physicoxhem[J ]. Eng Aspects,155 : Lionel Allouche, Francis Taulelle Conversion of Al 13 Keggin e into Al 30 : a reaction controlled by aluminum monomers [ J ]. Chemistry Communications,6 : Inorganic Luan Z K Study on the Theory and Application of Inoganic Polymer Flocculate Polyaluminum Chloride [ D ]. Beijing : Research Center for Eco2Environmental Science, Chinese Academy of Sciences,50 70 (in Chinese) Marina C K,John E D, Gary W V Low2cost polymeric aluminum coagulant[j ]. J Environ Eng,123 (9), Perry C C,Shafran KL The Systematic Study of Aluminum Speciation in Medium Concentrated Aqueous Solution [ J ]. J Inorganic Biochemistry,87 : Shu X W, Zheng H L Advances in Cationic Organic Flocculant [J ]. Modem Chemical Industry, 21 (10) : (in Chinese) :,,, [J ].,14 (1) :73 75,, [J ].,12 (5) : [D]. :,50 70, [J ]., 21 (10) :72 76