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Separation of textile effluents by polyamide membrane for reuse
Polymer Testing 21 (2002) 539–543 www.elsevier.com/locate/polytest
Product Performance
Separation of textile effluents by polyamide membrane for reuse Hsing-Yuan Yen a, Shyh-Fang Kang a b
a,*
, Mu-Hoe Yang
b
Department of Water Resources and Environmental Engineering, Tamkang University, Taipei, 251 Taiwan, Republic of China Department of Chemical Engineering, Kao Yuan Institute of Technology, Kaohsiung County, 82101 Taiwan, Republic of China Received 6 August 2001; accepted 16 October 2001
Abstract The influence of different operating parameters on the treatment of effluent by polyamide membrane separation for reuse in the textile factory was studied systematically in the temperature range 15–45 °C and applied pressure range 50–200 psi. The results showed that the flux of water increased and solute rejection increased with an increase in applied pressure. The flux of water increased and solute rejection decreased with an increase in temperature. The flux of water decreased and solute rejection increased with an increase in solute concentration in the feed. Moreover, the flux of water was proportional to the applied pressure. The solute rejection was found to be a nonlinear function of the applied pressure and temperature. Comparison of the values of rejection, the separation ability of polyamide membrane decreases in the following order: inorganics⬎organics. The experimental formula developed by Sourirajan (Ind. Ind. Chem. Prod. Des. Dev. 6 (1976) 154) was used for calculating the transport parameters of the polyamide membrane system in this study. 2002 Elsevier Science Ltd. All rights reserved. Keywords: Polyamide membrane; Textile effluent; Reuse
1. Introduction Recently, to cope with ever-increasing energy costs in chemical industrial processes, extensive efforts have been made to replace conventional energy-consuming separation processes with more commercial new processes using membranes [1,2]. Polymeric membrane separation processes are playing an increase role in such applications as water desalination, industrial and municipal wastewater, and bioengineering [3–5]. Too rapid industrial growth causes demand for more and more water in Taiwan. We are now facing a severe water resource shortage crisis. Thus, reuse of wastewater has become increasingly important. The textile industry consumes a considerable amount of water in the manufactur-
* Corresponding author. Tel.: +886-2-2622-0472; fax: +8862-2622-2653. E-mail address: [email protected] (S.F. Kang).
ing process and results in large amounts of wastewater streams of a complex contaminant matrix from the different steps of the dying process [6–9]. Dyestuffs and polyvinyl alcohol are the main sources of biorefractory color and chemical oxygen demand in textile industrial wastewater. Traditional activated sludge and chemical coagulation are intended to treat the textile wastewater to a level that meets the discharge standards required. However, there are organic matter, color, turbidity and inorganic matter remaining in the effluent [10,11]. Thus, the water quality has to be enhanced to a level to meet the reuse standards of the industry. In order to meet the quality for reuse in production for dyeing processes, it is necessary to study further treatments by reverse osmosis membrane separation [12,13]. The aim of this study is to test a polyamide membrane applied to the textile effluents to understand the membrane characteristics needed for various applied processes. This study aims to provide more understanding of the polyamide membrane properties and, in turn, help
0142-9418/02/$ - see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 1 4 2 - 9 4 1 8 ( 0 1 ) 0 0 1 2 1 - 0
540
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
to treat textile effluents by a polymeric membrane separation process for reuse.
2. Experimental 2.1. Sample effluents and reagents Textile effluents were sampled from a textile factory located in southern Taiwan. The effluents had been treated by neutralization, coagulation, activated sludge and sand filter. The effluent used was analysed for quality as follows: pH 6.83; chemical oxygen demand 62.1 mg/l; hardness 160 mg/l; conductivity 2440 µs/cm; color 142 in ADMI unit; and turbidity 9.21 NTU. All analytical chemicals were GR grade, obtained from Merck Co., and used without further purification. 2.2. Permeation experiment The experimental apparatus is shown in Fig. 1. The membrane apparatus, consisting of a 6-litre thermostatic tank, high-pressure pump, membrane module and pressure gauge, was the same as that employed in previous work [14]. The membrane module was made of a stainless steel cell. The disk membrane (polyamide material, Film-Tec TW30-1812-50 cut into a circle of diameter 47 mm) was laid on a porous woven support material. The feed entered the cell perpendicularly to the membrane and the flow was distributed radially. Pressure applied during filtration on this module was 50–200 psi and temperature control was between 15 and 45 °C. The pressure was applied to the upstream side and enough time was allowed for a steady permeation rate to be established.
Fig. 1. The flow chart of permeation testing: (1) feed bank; (2) constant-flow pump; (3) pressure gauge; (4) test cell; (5) permeate; (6) needle valve; (7) concentrate out.
Fig. 2. Effect of applied pressure on the polyamide membrane water flux at different temperatures.
2.3. Chemical analysis The samples were analyzed for COD, color, hardness, conductivity and turbidity in accordance with standard methods [15]. The detection of the ADMI color value was based on the ADMI Trisimulus Filter Method (Method 2120E, Hitachi U-2001). The results were converted to volume flux in liters/m2/h. Percent rejection was calculated according to the equation: % solute rejection=(1⫺Cp/Cf)×100, where Cp is solute concentration in the permeate solution and Cf is solute concentration in the feed solution.
3. Results and discussion The effects of applied pressure on the separation of textile effluents using the polyamide membrane are shown in Figs. 2–4. The experiment was carried out over
Fig. 3. Effect of applied pressure on the polyamide membrane conductivity rejection at different temperatures.
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
Fig. 4. Effect of applied pressure on the polyamide membrane COD rejection at different temperatures.
the temperature range 15–45 °C at an applied pressure of 50–200 psi. As shown in Fig. 2, the water flux increased with an increase in applied pressure. The water flux is proportional to the applied pressure. This phenomenon was similar to most of the reverse osmosis desalination membranes, which have a linear relationship between the water flux and the applied pressure [16]. As shown in Figs. 3 and 4, conductivity rejection and COD rejection increased with an increase in applied pressure. However, conductivity rejection and COD rejection were found to be highly nonlinear functions of the applied pressure. This is similar to most of the reverse osmosis desalination membranes, which have a nonlinear relationship between the solute rejection and the applied pressure. The rejection degree of the polyamide membrane decreases in the order: conductivity⬎COD (that is in the order: inorganics⬎organics). This phenomenon can be explained as being due to the lower selectivity for organics in this polyamide membrane separation process. The effects of temperature on the separation of textile effluents using the polyamide membrane are shown in Figs. 5–7. The experiment was carried out over an applied pressure range of 50–200 psi and at temperatures between 15 and 45 °C. As shown in Fig. 5, the water flux increased with an increase in temperature. These results suggest that the viscosity of water will decrease with increasing temperature, and thus the water flux through the membrane will increase [2]. As shown in Figs. 6 and 7, conductivity rejection and COD rejection decreased with an increase in temperature. This means that the solute permeated through the membrane with the same concentration, which results in solute rejection decrease. The effects of COD feed concentration on the performance of the membrane are shown in Fig. 8. The experiment was carried out at a COD concentration in the feed of 6.2–53.4 mg/l at 25 °C and 100 psi. As shown in Fig. 8, an increase in the COD concentration in the
541
Fig. 5. Effect of temperature on the polyamide membrane water flux at different pressures.
Fig. 6. Effect of temperature on the polyamide membrane conductivity rejection at different pressures.
feed leads to a water flux decrease and the COD rejection increase. The results indicate that when the concentration of the organics in the effluent drops, it can decrease the fouling effect of the membrane and increase the permeate flux. This result is similar to the research of Reimann, who reported that the concentration of COD can promote the permeate flux [17]. The experimental formula developed by Sourirajan [18] was used in the analysis of the water transport through the polyamide membrane. According to these phenomena, the water flux and solute rejection of a membrane are given by the following equations: PR⫽[A·exp(⫺P/Pmax)⫹B](r/m)P
(1)
f⫽aP/(bP⫹1)
(2) 2
where PR is the flux of water (l/m /h); A, B, a and b are
542
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
Fig. 7. Effect of temperature on the polyamide membrane COD rejection at different pressures.
Fig. 8. Effect of COD concentration in feed on the polyamide membrane performance with different applied pressure: (䊐) flux; (䊊) rejection.
Fig. 9.
The relation between (PR/P)(m/r) and exp(⫺P/Pmax).
points and are listed in Table 1. As shown in Table 1, A increased and B decreased with an increase in the temperature. Moreover, according to Eq. (4), a straight line should result from the reciprocal of solute rejection and the reciprocal of applied pressure for the conductivity and COD, respectively. The dependence of reciprocal of solute rejection on the reciprocal of applied pressure at different temperatures for the polyamide membrane is given in Figs. 10 and 11. This illustrates that for these cases a straight line exists between the reciprocal of solute rejection and the reciprocal of applied pressure for the conductivity and COD, respectively, where the slope is 1/a and the intercept is b/a. From this dependence a and b were evaluated by linear regression analysis of the data points and are listed in Table 1. As shown in Table 1, a and b decreased with an increase in the temperature for the conductivity and COD, respectively.
4. Conclusion the membrane characteristics values; P is applied pressure; Pmax is maximum applied pressure; r is density; m is viscosity; and f is solute rejection. Rearrangement of Eqs. (1) and (2) gives: (PR/P)(m/r)⫽A·exp(⫺P/Pmax)⫹B
(3)
1 1 1 b ⫽ · ⫹ f a P a
(4)
According to Eq. (3), a straight line should result from a plot of (PR/P)(m/r) against exp(⫺P/Pmax). The (PR/P)(m/r) dependence on exp(⫺P/Pmax) at different temperatures for polyamide membrane is given in Fig. 9 and illustrates that for these cases a straight line exists between (PR/P)(m/r) and exp(⫺P/Pmax), where the slope is A and the intercept is B. From this dependence A and B were evaluated by linear regression analysis of the data
The influence of different operating parameters on the performance of a polyamide membrane was examined. The effect of temperature and applied pressure on the effluent treatment by RO membrane separation for reuse in the textile factory was studied systematically in the temperature range 15–45 °C and the applied pressure range 50–200 psi. The results showed that the flux of water increased and solute rejection increased with an increase in applied pressure. The flux of water increased and solute rejection decreased with an increase in temperature. The flux of water decreased and solute rejection increased with an increase in solute concentration in the feed. Moreover, the flux of water was proportional to the applied pressure. The solute rejection was found to be a nonlinear function of the applied pressure and temperature. Comparing the values of rejection, the separation ability of the polyamide membrane decreases in the fol-
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
543
Table 1 The experimental parameters determined by using Eqs. (3) and (4) Temp. (°C)
Water flux A
15 25 35 45
⫺0.205 ⫺0.194 ⫺0.127 ⫺0.081
Solute rejection B
0.308 0.299 0.259 0.230
Conductivity
COD
a
b
a
b
30.53 28.07 16.88 11.99
0.31 0.28 0.17 0.12
12.24 10.81 8.35 5.62
0.12 0.11 0.08 0.06
tion of the membrane–solute system. The experimental formula developed by Sourirajan was used to calculate the transport parameters of the polyamide membrane system used in this study. A-values increased and Bvalues decreased with an increase in temperature. avalues and b-values decreased with an increase in temperature for the conductivity and COD, respectively.
References
Fig. 10. Dependence of the reciprocal of conductivity rejection on the reciprocal of applied pressure.
Fig. 11. Dependence of the reciprocal of COD rejection on the reciprocal of applied pressure.
lowing order: inorganics⬎organics. This phenomenon can be explained as being due to the molecular interac-
[1] M.H. Yang, T.J. Chu, Polym. Test. 12 (1) (1993) 3. [2] T.J. Chu, M.H. Yang, J. Chem. Eng. Jpn 25 (6) (1992) 660. [3] M.H. Yang, T.J. Chu, Sep. Sci. Technol. 28 (6) (1993) 1315. [4] M.H. Yang, J. Polym. Eng. 19 (5) (1999) 371. [5] M.H. Yang, Polym. Test. 14 (5) (1995) 415. [6] S.F. Kang, C.H. Liao, H.P. Hung, J. Hazard. Mater. B65 (1999) 317. [7] A. Rozzi, M. Antonelli, M. Arcari, Water Sci. Technol. 40 (4-5) (1999) 409. [8] S.F. Kang, H.M. Chang, Water Sci. Technol. 36 (1997) 215. [9] P.C. Vendevivere, R. Bianchi, W. Verstraete, J. Chem. Technol. Biotechnol. 72 (1998) 289. [10] C. Galindo, A. Kalt, Dyes Pigments 42 (3) (1999) 199. [11] C.H. Liao, M.D. Gurol, Environ. Sci. Technol. 29 (1995) 3007. [12] M.H. Yang, M.T. Su, C.S. Chen, T.H. Wu, Monthly J. Taipower’s Eng. 615 (1999) 74. [13] M.H. Yang, J. Technol. 12 (3) (1997) 471. [14] M.H. Yang, T.J. Chu, Polym. Test. 12 (2) (1993) 97. [15] American Public Health Association, American Water Works Association, Water Environmental Federation, Standard Methods for the Examination of Water and Wastewater, 19th ed., Washington, DC, USA, 1995. [16] K. Koyama, M. Okada, M. Nishimura, J. Appl. Polym. Sci. 27 (1982) 2783. [17] W. Reimann, Desalination 109 (1997) 51. [18] S. Sourirajan, Ind. Ind. Chem. Prod. Des. Dev. 6 (1) (1967) 154.
Product Performance
Separation of textile effluents by polyamide membrane for reuse Hsing-Yuan Yen a, Shyh-Fang Kang a b
a,*
, Mu-Hoe Yang
b
Department of Water Resources and Environmental Engineering, Tamkang University, Taipei, 251 Taiwan, Republic of China Department of Chemical Engineering, Kao Yuan Institute of Technology, Kaohsiung County, 82101 Taiwan, Republic of China Received 6 August 2001; accepted 16 October 2001
Abstract The influence of different operating parameters on the treatment of effluent by polyamide membrane separation for reuse in the textile factory was studied systematically in the temperature range 15–45 °C and applied pressure range 50–200 psi. The results showed that the flux of water increased and solute rejection increased with an increase in applied pressure. The flux of water increased and solute rejection decreased with an increase in temperature. The flux of water decreased and solute rejection increased with an increase in solute concentration in the feed. Moreover, the flux of water was proportional to the applied pressure. The solute rejection was found to be a nonlinear function of the applied pressure and temperature. Comparison of the values of rejection, the separation ability of polyamide membrane decreases in the following order: inorganics⬎organics. The experimental formula developed by Sourirajan (Ind. Ind. Chem. Prod. Des. Dev. 6 (1976) 154) was used for calculating the transport parameters of the polyamide membrane system in this study. 2002 Elsevier Science Ltd. All rights reserved. Keywords: Polyamide membrane; Textile effluent; Reuse
1. Introduction Recently, to cope with ever-increasing energy costs in chemical industrial processes, extensive efforts have been made to replace conventional energy-consuming separation processes with more commercial new processes using membranes [1,2]. Polymeric membrane separation processes are playing an increase role in such applications as water desalination, industrial and municipal wastewater, and bioengineering [3–5]. Too rapid industrial growth causes demand for more and more water in Taiwan. We are now facing a severe water resource shortage crisis. Thus, reuse of wastewater has become increasingly important. The textile industry consumes a considerable amount of water in the manufactur-
* Corresponding author. Tel.: +886-2-2622-0472; fax: +8862-2622-2653. E-mail address: [email protected] (S.F. Kang).
ing process and results in large amounts of wastewater streams of a complex contaminant matrix from the different steps of the dying process [6–9]. Dyestuffs and polyvinyl alcohol are the main sources of biorefractory color and chemical oxygen demand in textile industrial wastewater. Traditional activated sludge and chemical coagulation are intended to treat the textile wastewater to a level that meets the discharge standards required. However, there are organic matter, color, turbidity and inorganic matter remaining in the effluent [10,11]. Thus, the water quality has to be enhanced to a level to meet the reuse standards of the industry. In order to meet the quality for reuse in production for dyeing processes, it is necessary to study further treatments by reverse osmosis membrane separation [12,13]. The aim of this study is to test a polyamide membrane applied to the textile effluents to understand the membrane characteristics needed for various applied processes. This study aims to provide more understanding of the polyamide membrane properties and, in turn, help
0142-9418/02/$ - see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S 0 1 4 2 - 9 4 1 8 ( 0 1 ) 0 0 1 2 1 - 0
540
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
to treat textile effluents by a polymeric membrane separation process for reuse.
2. Experimental 2.1. Sample effluents and reagents Textile effluents were sampled from a textile factory located in southern Taiwan. The effluents had been treated by neutralization, coagulation, activated sludge and sand filter. The effluent used was analysed for quality as follows: pH 6.83; chemical oxygen demand 62.1 mg/l; hardness 160 mg/l; conductivity 2440 µs/cm; color 142 in ADMI unit; and turbidity 9.21 NTU. All analytical chemicals were GR grade, obtained from Merck Co., and used without further purification. 2.2. Permeation experiment The experimental apparatus is shown in Fig. 1. The membrane apparatus, consisting of a 6-litre thermostatic tank, high-pressure pump, membrane module and pressure gauge, was the same as that employed in previous work [14]. The membrane module was made of a stainless steel cell. The disk membrane (polyamide material, Film-Tec TW30-1812-50 cut into a circle of diameter 47 mm) was laid on a porous woven support material. The feed entered the cell perpendicularly to the membrane and the flow was distributed radially. Pressure applied during filtration on this module was 50–200 psi and temperature control was between 15 and 45 °C. The pressure was applied to the upstream side and enough time was allowed for a steady permeation rate to be established.
Fig. 1. The flow chart of permeation testing: (1) feed bank; (2) constant-flow pump; (3) pressure gauge; (4) test cell; (5) permeate; (6) needle valve; (7) concentrate out.
Fig. 2. Effect of applied pressure on the polyamide membrane water flux at different temperatures.
2.3. Chemical analysis The samples were analyzed for COD, color, hardness, conductivity and turbidity in accordance with standard methods [15]. The detection of the ADMI color value was based on the ADMI Trisimulus Filter Method (Method 2120E, Hitachi U-2001). The results were converted to volume flux in liters/m2/h. Percent rejection was calculated according to the equation: % solute rejection=(1⫺Cp/Cf)×100, where Cp is solute concentration in the permeate solution and Cf is solute concentration in the feed solution.
3. Results and discussion The effects of applied pressure on the separation of textile effluents using the polyamide membrane are shown in Figs. 2–4. The experiment was carried out over
Fig. 3. Effect of applied pressure on the polyamide membrane conductivity rejection at different temperatures.
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
Fig. 4. Effect of applied pressure on the polyamide membrane COD rejection at different temperatures.
the temperature range 15–45 °C at an applied pressure of 50–200 psi. As shown in Fig. 2, the water flux increased with an increase in applied pressure. The water flux is proportional to the applied pressure. This phenomenon was similar to most of the reverse osmosis desalination membranes, which have a linear relationship between the water flux and the applied pressure [16]. As shown in Figs. 3 and 4, conductivity rejection and COD rejection increased with an increase in applied pressure. However, conductivity rejection and COD rejection were found to be highly nonlinear functions of the applied pressure. This is similar to most of the reverse osmosis desalination membranes, which have a nonlinear relationship between the solute rejection and the applied pressure. The rejection degree of the polyamide membrane decreases in the order: conductivity⬎COD (that is in the order: inorganics⬎organics). This phenomenon can be explained as being due to the lower selectivity for organics in this polyamide membrane separation process. The effects of temperature on the separation of textile effluents using the polyamide membrane are shown in Figs. 5–7. The experiment was carried out over an applied pressure range of 50–200 psi and at temperatures between 15 and 45 °C. As shown in Fig. 5, the water flux increased with an increase in temperature. These results suggest that the viscosity of water will decrease with increasing temperature, and thus the water flux through the membrane will increase [2]. As shown in Figs. 6 and 7, conductivity rejection and COD rejection decreased with an increase in temperature. This means that the solute permeated through the membrane with the same concentration, which results in solute rejection decrease. The effects of COD feed concentration on the performance of the membrane are shown in Fig. 8. The experiment was carried out at a COD concentration in the feed of 6.2–53.4 mg/l at 25 °C and 100 psi. As shown in Fig. 8, an increase in the COD concentration in the
541
Fig. 5. Effect of temperature on the polyamide membrane water flux at different pressures.
Fig. 6. Effect of temperature on the polyamide membrane conductivity rejection at different pressures.
feed leads to a water flux decrease and the COD rejection increase. The results indicate that when the concentration of the organics in the effluent drops, it can decrease the fouling effect of the membrane and increase the permeate flux. This result is similar to the research of Reimann, who reported that the concentration of COD can promote the permeate flux [17]. The experimental formula developed by Sourirajan [18] was used in the analysis of the water transport through the polyamide membrane. According to these phenomena, the water flux and solute rejection of a membrane are given by the following equations: PR⫽[A·exp(⫺P/Pmax)⫹B](r/m)P
(1)
f⫽aP/(bP⫹1)
(2) 2
where PR is the flux of water (l/m /h); A, B, a and b are
542
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
Fig. 7. Effect of temperature on the polyamide membrane COD rejection at different pressures.
Fig. 8. Effect of COD concentration in feed on the polyamide membrane performance with different applied pressure: (䊐) flux; (䊊) rejection.
Fig. 9.
The relation between (PR/P)(m/r) and exp(⫺P/Pmax).
points and are listed in Table 1. As shown in Table 1, A increased and B decreased with an increase in the temperature. Moreover, according to Eq. (4), a straight line should result from the reciprocal of solute rejection and the reciprocal of applied pressure for the conductivity and COD, respectively. The dependence of reciprocal of solute rejection on the reciprocal of applied pressure at different temperatures for the polyamide membrane is given in Figs. 10 and 11. This illustrates that for these cases a straight line exists between the reciprocal of solute rejection and the reciprocal of applied pressure for the conductivity and COD, respectively, where the slope is 1/a and the intercept is b/a. From this dependence a and b were evaluated by linear regression analysis of the data points and are listed in Table 1. As shown in Table 1, a and b decreased with an increase in the temperature for the conductivity and COD, respectively.
4. Conclusion the membrane characteristics values; P is applied pressure; Pmax is maximum applied pressure; r is density; m is viscosity; and f is solute rejection. Rearrangement of Eqs. (1) and (2) gives: (PR/P)(m/r)⫽A·exp(⫺P/Pmax)⫹B
(3)
1 1 1 b ⫽ · ⫹ f a P a
(4)
According to Eq. (3), a straight line should result from a plot of (PR/P)(m/r) against exp(⫺P/Pmax). The (PR/P)(m/r) dependence on exp(⫺P/Pmax) at different temperatures for polyamide membrane is given in Fig. 9 and illustrates that for these cases a straight line exists between (PR/P)(m/r) and exp(⫺P/Pmax), where the slope is A and the intercept is B. From this dependence A and B were evaluated by linear regression analysis of the data
The influence of different operating parameters on the performance of a polyamide membrane was examined. The effect of temperature and applied pressure on the effluent treatment by RO membrane separation for reuse in the textile factory was studied systematically in the temperature range 15–45 °C and the applied pressure range 50–200 psi. The results showed that the flux of water increased and solute rejection increased with an increase in applied pressure. The flux of water increased and solute rejection decreased with an increase in temperature. The flux of water decreased and solute rejection increased with an increase in solute concentration in the feed. Moreover, the flux of water was proportional to the applied pressure. The solute rejection was found to be a nonlinear function of the applied pressure and temperature. Comparing the values of rejection, the separation ability of the polyamide membrane decreases in the fol-
H.-Y. Yen et al. / Polymer Testing 21 (2002) 539–543
543
Table 1 The experimental parameters determined by using Eqs. (3) and (4) Temp. (°C)
Water flux A
15 25 35 45
⫺0.205 ⫺0.194 ⫺0.127 ⫺0.081
Solute rejection B
0.308 0.299 0.259 0.230
Conductivity
COD
a
b
a
b
30.53 28.07 16.88 11.99
0.31 0.28 0.17 0.12
12.24 10.81 8.35 5.62
0.12 0.11 0.08 0.06
tion of the membrane–solute system. The experimental formula developed by Sourirajan was used to calculate the transport parameters of the polyamide membrane system used in this study. A-values increased and Bvalues decreased with an increase in temperature. avalues and b-values decreased with an increase in temperature for the conductivity and COD, respectively.
References
Fig. 10. Dependence of the reciprocal of conductivity rejection on the reciprocal of applied pressure.
Fig. 11. Dependence of the reciprocal of COD rejection on the reciprocal of applied pressure.
lowing order: inorganics⬎organics. This phenomenon can be explained as being due to the molecular interac-
[1] M.H. Yang, T.J. Chu, Polym. Test. 12 (1) (1993) 3. [2] T.J. Chu, M.H. Yang, J. Chem. Eng. Jpn 25 (6) (1992) 660. [3] M.H. Yang, T.J. Chu, Sep. Sci. Technol. 28 (6) (1993) 1315. [4] M.H. Yang, J. Polym. Eng. 19 (5) (1999) 371. [5] M.H. Yang, Polym. Test. 14 (5) (1995) 415. [6] S.F. Kang, C.H. Liao, H.P. Hung, J. Hazard. Mater. B65 (1999) 317. [7] A. Rozzi, M. Antonelli, M. Arcari, Water Sci. Technol. 40 (4-5) (1999) 409. [8] S.F. Kang, H.M. Chang, Water Sci. Technol. 36 (1997) 215. [9] P.C. Vendevivere, R. Bianchi, W. Verstraete, J. Chem. Technol. Biotechnol. 72 (1998) 289. [10] C. Galindo, A. Kalt, Dyes Pigments 42 (3) (1999) 199. [11] C.H. Liao, M.D. Gurol, Environ. Sci. Technol. 29 (1995) 3007. [12] M.H. Yang, M.T. Su, C.S. Chen, T.H. Wu, Monthly J. Taipower’s Eng. 615 (1999) 74. [13] M.H. Yang, J. Technol. 12 (3) (1997) 471. [14] M.H. Yang, T.J. Chu, Polym. Test. 12 (2) (1993) 97. [15] American Public Health Association, American Water Works Association, Water Environmental Federation, Standard Methods for the Examination of Water and Wastewater, 19th ed., Washington, DC, USA, 1995. [16] K. Koyama, M. Okada, M. Nishimura, J. Appl. Polym. Sci. 27 (1982) 2783. [17] W. Reimann, Desalination 109 (1997) 51. [18] S. Sourirajan, Ind. Ind. Chem. Prod. Des. Dev. 6 (1) (1967) 154.