A. Young A的研究论文

预处理以及阳离子和阴离子对预防的影响•r。Sheikholeslaml°A，I.S。A1-Mutaz B，T。KooA，A。YoungAtel。+61（2）9385-4343;传真+61（2）9385-5966，“电子邮件：r.sheikholeslami@unsw.edu.au.au'Chemical Eng。2001; 2001年3月23日接受，是紫红色水的脱盐的主要顾客之一。它的存在限制了水回收和钥匙词：硅粉;硅粉; ro fouling;倒渗透；倒渗透；脱盐；膜脉；膜脉；水处理。通讯作者的丰富材料。S 0 0 1 1-9 1 6 4（0 1）0 0 2 9 7 -I 84r。Sheikholeslami等 /淡化139（2001）83-952。Background2.1。二氧化硅溶解度，聚合性和沉积物均存在于各种中形式。有避免歧义，讨论的术语2NAA1SI3OS（s.albite） + 2H + + 9H20¢m（1）A12SI205（OH）4（S，Kaolinite） + 4si（OH）4 + 2NA + 2NA + Kaolinite在上述反应Maya12sio 5（OH）4（S，S，S，S，S，S，S，S，S，） Kaolinite)-t- 6H ÷ <=~2AI ÷3(2)+ 2Si(OH)4 + H20Another means of orthosilicic acid generationSiO2(s) + 2H20 ~ Si(OH)4(3)Among all the possible solid states, silica inFor instance, at room temperature and below pH10 times that of quartz. However, it appears thatThe solubility of amorphous silica in pure(monosilisic) acid; above pH of 8, it ionizes and300°C) on silica solubility below pH of 8 isEffects of pressure on silica solubility at R. Sheikholeslami et al. / Desalination 139 (2001) 83-95Wall deposition of amorphous silica can takeAdditional factor to consider is agglomeration.Morphology of scales obtained from RO plants[10] showed that Si was the most abundant2.2. Silica removal by pretreatmentAs mentioned previously, to reduce the extentThe most common method of silica removal fromMg(OH)2 are effective in removing both soluble85[ 13,14], chemical reaction [ 15] or a combinationIn practice, silica removal is usually part of a[ 17,18]. Lime-softening reactions [Eqs. (5)-(11)]Silica is removed by adsorption on theSodium aluminate is a combination of sodiumAlumina, A1203, is an excellent adsorbent for 86R. Sheikholeslami et al. / Desalination 139 (2001) 83-95AhOa precipitate and SiO4 adsorption onto theSodium aluminate also reduces hardness according to Eqs. (14)--(17).In the presence of colloidal silica (unreactiveAluminum atoms can substitute for silicon in2/8 o f valence [22]. The solubility o f the Si-O-SiThe solubility increases in the order K < N a < C a CACO3 $ +H20（4）CA（HCO3）2 +Ca（OH）2 -〜2Caco3 $ +2H20（5）mg（HCO3）2 +Ca（OH）2＃= 9.4）CACO3 $ +MGCO 3 +2H20（6）mgco3 + ca（oh）2＃= 〜o.6）caco3 $ + mg（oh）2 $（7）caso4 + na2co3 -〜caco3 $ + na2so4（8）（9）mgcl2 + ca（oh）2 -4mg（OH）2〜， + CaCl2（10）MGSO4 + Ca（OH）2 - 〜mg（OH）2〜， + Caso〜（11）（12）（13）Na2ai，O4 + mg（HCO3）2+ 4H20- > 2NAHCO3 + mg（OH）2 $ + 2al（OH）3 $（14）Na2a1204 + Ca（HCO3）2 + 2H20-¢2NA2CO3 + Caco 3，I，i， + 2ai（OH）3 $（15）Na2a1204 + Ca（HCO3）2 + 2H20 -¢2NAHCO3 + 2CACO3'J“ + 2AI（OH）3 $（16）Na2a120， + 2CO2 + 4H20 -O 2NAHCO3 + AI（OH）AI3÷+ 3H4SIO4“ - '> NAAISI3OS” [“+ 4H20+ 4H+（18）87R。Sheikholeslami等。/ Desafination 139（2001）83-953。实验是在添加（Na2ai204）进行的（na2ai204）进行的（14） - （16）的凝结剂进行的（na2ai204）中进行实验（石灰氧化软化，二氧化硅还原。analysis of water before and after precipitators and before ROParameterBefore precipitatorsAfter precipitatorsBefore ROTotal hardness, mg/I as CaCO3Ca hardness, mg/! as CaCO3Mg hardness, mg/l as CaCO3Total alkalinity, mg/1as CaCO3Temperature, °CTDS, nag ion/lConductivity, IxS/cmChloride, mg ion/1Sulphate, mg ion/lIron, mg ion/1CO:, mg/lSilica, SIO2,mg/1Turbidity, NTU8.170544026515260155020162414000.445927.31.8610.330015514533.36.2272149123633145020152884500.02215602907.07.00.154 88R. Sheikholeslami et al. / Desalination 139 (2001) 83-954. Results and discussionThe membranes used in the plant are B-9DuPont with specifications summarized inTable 3. The chemical treatment utilized in theseLime softening and high pH levels affect theTable 4 shows the pH and silica content of three4.1. Laboratory testsBatch tests were carded out to determine theTable 5 summarizes the range o f experimentation.Table 5Range of experimentationParameterSiO2, ppmCa hardness, ppm as CaCO3Mg hardness, ppm as CaCO3Table 3Specifications of membrane modules used in the plantAverage recovery85%Salt rejection87-92%Operating pressure range 2415-2760 kPa(34O--400 psig)Operating temperature0-40°C (32-104°F)4-11Average cleaning interval 1.5 yearsModule arrangement4:2:1Range200--6005.5-9.5100--6250-1004.1.1. Effect o f p HThe effect of pH on silica polymerization rate380ppm (360-400ppm) was investigated andTotal polymerization time, which is the time forTable 4Variation ofpH and silica in the plantSample locationSilica content, mg/LRaw water before coolingRaw water after coolingAfter precipitatorAfter pri. acidification7.038.0110.256.586.978.0210.236.486.978.0110.36.1425.827.16.956.6026.027.36.956.7026.027.27.06.60 89R. Sheikholeslami et al. I Desalination 139 (2001) 83-95Currently, this is the pH range of operation forThe rate of silica polymerization drops to a5.5. These results correspond well with theoretical explanation. At pH of 9.5, the solution isHowever, this would cause particulate fouling ofThe equilibrium concentration of silica for140ppm while for5.5 ...是各种阳离子的作用一个d一个离子存在于二氧化硅聚合中的水中。通常，有一个拆除的预要阶段作为二氧化硅作为可能在交流呼吸淡化步骤。了解大多数主要阳离子的影响非常重要一个d一个离子o... 淡化139（2001）

预处理以及阳离子和阴离子对预防的影响•r。Sheikholeslaml°A*，I.S。A1-Mutaz B，T。KooA，A。YoungAtel。+61（2）9385-4343;传真+61（2）9385-5966，“电子邮件：r.sheikholeslami@unsw.edu.au.au'Chemical Eng。2001; 2001年3月23日接受，是紫红色水的脱盐的主要顾客之一。它的存在限制了水回收和钥匙词：硅粉;硅粉; ro fouling;倒渗透；倒渗透；脱盐；膜脉；膜脉；水处理。*通讯作者的丰富材料。S 0 0 1 1-9 1 6 4（0 1）0 0 2 9 7 -I 84r。Sheikholeslami等 /淡化139（2001）83-952。Background2.1。二氧化硅溶解度，聚合性和沉积物均存在于各种中形式。有避免歧义，讨论的术语2NAA1SI3OS（s.albite） + 2H + + 9H20¢m（1）A12SI205（OH）4（S，Kaolinite） + 4si（OH）4 + 2NA + 2NA + Kaolinite在上述反应Maya12sio 5（OH）4（S，S，S，S，S，S，S，S，S，） Kaolinite)-t- 6H ÷ <=~2AI ÷3(2)+ 2Si(OH)4 + H20Another means of orthosilicic acid generationSiO2(s) + 2H20 ~ Si(OH)4(3)Among all the possible solid states, silica inFor instance, at room temperature and below pH10 times that of quartz. However, it appears thatThe solubility of amorphous silica in pure(monosilisic) acid; above pH of 8, it ionizes and300°C) on silica solubility below pH of 8 isEffects of pressure on silica solubility at R. Sheikholeslami et al. / Desalination 139 (2001) 83-95Wall deposition of amorphous silica can takeAdditional factor to consider is agglomeration.Morphology of scales obtained from RO plants[10] showed that Si was the most abundant2.2. Silica removal by pretreatmentAs mentioned previously, to reduce the extentThe most common method of silica removal fromMg(OH)2 are effective in removing both soluble85[ 13,14], chemical reaction [ 15] or a combinationIn practice, silica removal is usually part of a[ 17,18]. Lime-softening reactions [Eqs. (5)-(11)]Silica is removed by adsorption on theSodium aluminate is a combination of sodiumAlumina, A1203, is an excellent adsorbent for 86R. Sheikholeslami et al. / Desalination 139 (2001) 83-95AhOa precipitate and SiO4 adsorption onto theSodium aluminate also reduces hardness according to Eqs. (14)--(17).In the presence of colloidal silica (unreactiveAluminum atoms can substitute for silicon in2/8 o f valence [22]. The solubility o f the Si-O-SiThe solubility increases in the order K < N a < C a CACO3 $ +H20（4）CA（HCO3）2 +Ca（OH）2 -〜2Caco3 $ +2H20（5）mg（HCO3）2 +Ca（OH）2＃= 9.4）CACO3 $ +MGCO 3 +2H20（6）mgco3 + ca（oh）2＃= 〜o.6）caco3 $ + mg（oh）2 $（7）caso4 + na2co3 -〜caco3 $ + na2so4（8）（9）mgcl2 + ca（oh）2 -4mg（OH）2〜， + CaCl2（10）MGSO4 + Ca（OH）2 - 〜mg（OH）2〜， + Caso〜（11）（12）（13）Na2ai，O4 + mg（HCO3）2+ 4H20- > 2NAHCO3 + mg（OH）2 $ + 2al（OH）3 $（14）Na2a1204 + Ca（HCO3）2 + 2H20-¢2NA2CO3 + Caco 3，I，i， + 2ai（OH）3 $（15）Na2a1204 + Ca（HCO3）2 + 2H20 -¢2NAHCO3 + 2CACO3'J“ + 2AI（OH）3 $（16）Na2a120， + 2CO2 + 4H20 -O 2NAHCO3 + AI（OH）AI3÷+ 3H4SIO4“ - '> NAAISI3OS” [“+ 4H20+ 4H+（18）87R。Sheikholeslami等。/ Desafination 139（2001）83-953。实验是在添加（Na2ai204）进行的（na2ai204）进行的（14） - （16）的凝结剂进行的（na2ai204）中进行实验（石灰氧化软化，二氧化硅还原。analysis of water before and after precipitators and before ROParameterBefore precipitatorsAfter precipitatorsBefore ROTotal hardness, mg/I as CaCO3Ca hardness, mg/! as CaCO3Mg hardness, mg/l as CaCO3Total alkalinity, mg/1as CaCO3Temperature, °CTDS, nag ion/lConductivity, IxS/cmChloride, mg ion/1Sulphate, mg ion/lIron, mg ion/1CO:, mg/lSilica, SIO2,mg/1Turbidity, NTU8.170544026515260155020162414000.445927.31.8610.330015514533.36.2272149123633145020152884500.02215602907.07.00.154 88R. Sheikholeslami et al. / Desalination 139 (2001) 83-954. Results and discussionThe membranes used in the plant are B-9DuPont with specifications summarized inTable 3. The chemical treatment utilized in theseLime softening and high pH levels affect theTable 4 shows the pH and silica content of three4.1. Laboratory testsBatch tests were carded out to determine theTable 5 summarizes the range o f experimentation.Table 5Range of experimentationParameterSiO2, ppmCa hardness, ppm as CaCO3Mg hardness, ppm as CaCO3Table 3Specifications of membrane modules used in the plantAverage recovery85%Salt rejection87-92%Operating pressure range 2415-2760 kPa(34O--400 psig)Operating temperature0-40°C (32-104°F)4-11Average cleaning interval 1.5 yearsModule arrangement4:2:1Range200--6005.5-9.5100--6250-1004.1.1. Effect o f p HThe effect of pH on silica polymerization rate380ppm (360-400ppm) was investigated andTotal polymerization time, which is the time forTable 4Variation ofpH and silica in the plantSample locationSilica content, mg/LRaw water before coolingRaw water after coolingAfter precipitatorAfter pri. acidification7.038.0110.256.586.978.0210.236.486.978.0110.36.1425.827.16.956.6026.027.36.956.7026.027.27.06.60 89R. Sheikholeslami et al. I Desalination 139 (2001) 83-95Currently, this is the pH range of operation forThe rate of silica polymerization drops to a5.5. These results correspond well with theoretical explanation. At pH of 9.5, the solution isHowever, this would cause particulate fouling ofThe equilibrium concentration of silica for140ppm while for5.5

...是各种阳离子的作用一个d一个离子存在于二氧化硅聚合中的水中。通常，有一个拆除的预要阶段作为二氧化硅作为可能在交流呼吸淡化步骤。了解大多数主要阳离子的影响非常重要一个d一个离子o...

淡化139（2001）

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