Poly aluminum chloride sulfate(PACS) with different SO 2- 4/Al 3+ mole ratios and bacicity(γ) of 2 0 was synthesized using AlCl 3\56H\-2O, Al\-2(SO\-4)\-3\518H 2O and Na 2CO 3 as raw materials. The effect of SO 2- \-...Poly aluminum chloride sulfate(PACS) with different SO 2- 4/Al 3+ mole ratios and bacicity(γ) of 2 0 was synthesized using AlCl 3\56H\-2O, Al\-2(SO\-4)\-3\518H 2O and Na 2CO 3 as raw materials. The effect of SO 2- \-4/Al 3+ ratio on the performance of PACS for removal of natural organic matter(NOM) with humic rich actual water was examined. It was found that PACS with SO 2- \-4/Al 3+ mole ratio of 0.0664 achieved the best NOM removal results and was selected to investigate its performance in comparison with PAC, FeCl 3 and alum(Al 2 (SO 4) 3·18H 2O). The experimental results showed that the optimum NOM removals were achieved at pH 5.0\_8.2 and the dose of about 5 0 mg/L as Al both for the selected PACS and PAC, at pH 5 0\_6 0 and the dose of about 7 0 mg/L as Fe for FeCl 3, and at pH 5 0\_7 0 and the dose of about 7 0 mg/L as Al for alum, respectively. At the optimum conditions, the selected PACS achieved the best NOM removal result, followed by PAC, FeCl 3, and then alum. The concentration of residual aluminum in treated water by the selected PACS and PAC under the optimum coagulant conditions was approximately 115 μg/L, which can completely comply with the regulated limits.展开更多
Resin adsorption technique with XAD-8 and XAD-4 was used to characterize the raw water from Erlong reservoir in Jilin province of China. The NOM chemical composition sequences of four organic fractions in the raw wate...Resin adsorption technique with XAD-8 and XAD-4 was used to characterize the raw water from Erlong reservoir in Jilin province of China. The NOM chemical composition sequences of four organic fractions in the raw water, from high to low, are fulvic acid （FA） fraction, hydrophilic non-acid （HPINA） fraction, hydrophilic acid （HPIA） fraction, and humic acid （HA） fraction. Experimental results show that FA is the main precursor of THMFP among the four organic fractions. However, HA or hydrophobie acid exhibits the highest chlorination activity in forming THMs. It is also found that the value of FI/DOC or SUVA and the specific THMFP have better positive correlation. It is implied that certain source water has unique nature of NOM and DBPs.展开更多
Natural organic matter (NOM) and particles in source water are responsible for the majority of ultrafiltration (UF) membrane fouling that occurs during drinking water treatment. This study was conducted to (1) underst...Natural organic matter (NOM) and particles in source water are responsible for the majority of ultrafiltration (UF) membrane fouling that occurs during drinking water treatment. This study was conducted to (1) understand the UF membrane fouling phenomena caused by NOM and turbidity-causing particles and (2) investigate the effect of coagulation pretreatment on the alleviation of membrane fouling. In this study, kaolinite and humic acid (HA) were used to simulate the particles and NOM present in source water. The results revealed that the particles contributed to reversible fouling due to cake layer formation on the membrane surface, but that could be effectively reduced by increasing the frequency of physical backwashing. The results of the molecular weight (MW) distribution measurements, resin fractionation, SEM and FTIR analyses showed that HA primarily contributed to irreversible fouling. Taken together, the results of this study imply that the particles and NOM compounds present in source water may have different fouling behavior, and that particles may mitigate the irreversible fouling caused by HA. The addition of coagulant can lead to a higher rate of removal of large-sized hydrophobic compounds. Coagulation pretreatment can improve membrane performance and postpone membrane fouling development effectively, as well as retard the implementation of membrane chemical cleaning.展开更多
Hydrophobic organic contaminants(HOCs)—pyrene,and natural organic matters(NOM)from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’parti...Hydrophobic organic contaminants(HOCs)—pyrene,and natural organic matters(NOM)from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’partition to the NOM in this study.The effects of solution property,NOM characteristics,and modification by ozone preoxidation on pyrene partition to NOM were systematically evaluated.According to the fluorescence quenching method,the partition coefficient K_(oc) of pyrene to NOM was calculated,which was found to have a great relationship with the aromatic structures and hydrophobic functional groups of the NOM.The NOM characteristic modification corresponding to solution property could influence the interactions between the NOM and pyrene.Preozonation could destroy the aromatic or hydrophobic structures of the NOM and decrease K_(oc) of pyrene.展开更多
文摘Poly aluminum chloride sulfate(PACS) with different SO 2- 4/Al 3+ mole ratios and bacicity(γ) of 2 0 was synthesized using AlCl 3\56H\-2O, Al\-2(SO\-4)\-3\518H 2O and Na 2CO 3 as raw materials. The effect of SO 2- \-4/Al 3+ ratio on the performance of PACS for removal of natural organic matter(NOM) with humic rich actual water was examined. It was found that PACS with SO 2- \-4/Al 3+ mole ratio of 0.0664 achieved the best NOM removal results and was selected to investigate its performance in comparison with PAC, FeCl 3 and alum(Al 2 (SO 4) 3·18H 2O). The experimental results showed that the optimum NOM removals were achieved at pH 5.0\_8.2 and the dose of about 5 0 mg/L as Al both for the selected PACS and PAC, at pH 5 0\_6 0 and the dose of about 7 0 mg/L as Fe for FeCl 3, and at pH 5 0\_7 0 and the dose of about 7 0 mg/L as Al for alum, respectively. At the optimum conditions, the selected PACS achieved the best NOM removal result, followed by PAC, FeCl 3, and then alum. The concentration of residual aluminum in treated water by the selected PACS and PAC under the optimum coagulant conditions was approximately 115 μg/L, which can completely comply with the regulated limits.
基金Sponsored by the Key Project of Jilin Provincial Science &Technology Program (Grant No.20070409)
文摘Resin adsorption technique with XAD-8 and XAD-4 was used to characterize the raw water from Erlong reservoir in Jilin province of China. The NOM chemical composition sequences of four organic fractions in the raw water, from high to low, are fulvic acid （FA） fraction, hydrophilic non-acid （HPINA） fraction, hydrophilic acid （HPIA） fraction, and humic acid （HA） fraction. Experimental results show that FA is the main precursor of THMFP among the four organic fractions. However, HA or hydrophobie acid exhibits the highest chlorination activity in forming THMs. It is also found that the value of FI/DOC or SUVA and the specific THMFP have better positive correlation. It is implied that certain source water has unique nature of NOM and DBPs.
基金supported by the National Eleventh Five-Year Scientific and Technical Support Plans Project (2006BAD01B03)
文摘Natural organic matter (NOM) and particles in source water are responsible for the majority of ultrafiltration (UF) membrane fouling that occurs during drinking water treatment. This study was conducted to (1) understand the UF membrane fouling phenomena caused by NOM and turbidity-causing particles and (2) investigate the effect of coagulation pretreatment on the alleviation of membrane fouling. In this study, kaolinite and humic acid (HA) were used to simulate the particles and NOM present in source water. The results revealed that the particles contributed to reversible fouling due to cake layer formation on the membrane surface, but that could be effectively reduced by increasing the frequency of physical backwashing. The results of the molecular weight (MW) distribution measurements, resin fractionation, SEM and FTIR analyses showed that HA primarily contributed to irreversible fouling. Taken together, the results of this study imply that the particles and NOM compounds present in source water may have different fouling behavior, and that particles may mitigate the irreversible fouling caused by HA. The addition of coagulant can lead to a higher rate of removal of large-sized hydrophobic compounds. Coagulation pretreatment can improve membrane performance and postpone membrane fouling development effectively, as well as retard the implementation of membrane chemical cleaning.
基金This work was supported by the National Basic Research Program of China(973 Program)(Grant No.2004CB418505).
文摘Hydrophobic organic contaminants(HOCs)—pyrene,and natural organic matters(NOM)from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’partition to the NOM in this study.The effects of solution property,NOM characteristics,and modification by ozone preoxidation on pyrene partition to NOM were systematically evaluated.According to the fluorescence quenching method,the partition coefficient K_(oc) of pyrene to NOM was calculated,which was found to have a great relationship with the aromatic structures and hydrophobic functional groups of the NOM.The NOM characteristic modification corresponding to solution property could influence the interactions between the NOM and pyrene.Preozonation could destroy the aromatic or hydrophobic structures of the NOM and decrease K_(oc) of pyrene.
