The effectiveness of a magnetic ion exchange resin(MIEX) for the treatment of Hongze Lake water in China was evaluated.The kinetics of natural organic matter(NOM) removal at various MIEX doses and contact time,multipl...The effectiveness of a magnetic ion exchange resin(MIEX) for the treatment of Hongze Lake water in China was evaluated.The kinetics of natural organic matter(NOM) removal at various MIEX doses and contact time,multiple-loading experiments,impacts of MIEX prior to coagulation on coagulant demands and the effectiveness of combination of MIEX,pre-chlorination and coagulation were investigated.Kinetic experimental results show that more than 80%UV254 and 67%dissolved organic carbon(DOC) from raw water can be removed by the use of MIEX alone.94%sulfate,69%nitrate and 98%bromide removals are obtained after the first use of MIEX in multiple-loading experiments.It is suggested that MIEX can be loaded up to 1 250 bed volume(BV,volume ratio of tested water to resin) or more without saturation when regarding organics removal as a target. MIEX can remove organics to a greater extend than coagulation and lower the coagulant demand when combining with coagulation. Chlorination experimental results show that MIEX can remove 57%chlorine demand and 77%trihalomethane formation potential(THMFP) for raw water.Pre-chlorination followed by MIEX and coagulation can give additional organic and THMFP removals.The results suggest that MIEX provides a new method to solve the problem algae reproduction.展开更多
Magnetic ion exchange(MIEX) resins have received considerable attention in drinking water treatment due to their fast and efficient removal of dissolved organic carbon(DOC). Two types of mechanisms, i.e., ion exchange...Magnetic ion exchange(MIEX) resins have received considerable attention in drinking water treatment due to their fast and efficient removal of dissolved organic carbon(DOC). Two types of mechanisms, i.e., ion exchange,reversible and irreversible adsorption, may occur during pollutants removal by MIEX. This work examined the removal mechanism of 17α-Ethinylestradiol(EE2) by MIEX. As one of typical estrogen micro-pollutants,EE2 existed as neutral molecule in natural water, and its charge density was close to zero [(0.00000219 ±0.00000015) meq·(μg EE2)^(-1)] based on the potentiometric titration method. However, the removal of EE2 by MIEX was much higher than that of other micro-pollutants previously reported. Multi-cycle adsorptionregeneration experiments and ion exchange stoichiometry analysis were conducted to elucidate the removal mechanism of EE2 by MIEX resin. The results suggested that the main removal mechanism of EE2 by MIEX was ion exchange instead of reversible micro-pore adsorption. The experimental analysis based on Donnan theory indicated that the internal micro-environment of resin beads was alkaline, in the alkaline environment EE2 would be ionized into negatively charged groups. As a result, ion exchange reaction occurred inside the pore of MIEX resin, and the removal process of EE2 by MIEX was dominated by the ion exchange reaction.展开更多
Macroporous weak basic anion exchanger （D301R） was used to remove organic substances from drilling wastewater. The effect of pH, temperature and contact time on adsorption behavior was investigated in batch experime...Macroporous weak basic anion exchanger （D301R） was used to remove organic substances from drilling wastewater. The effect of pH, temperature and contact time on adsorption behavior was investigated in batch experiments, which indicated that the COD （Chemical Oxygen Demand） removal ratio of drilling wastewater was approximately 90%, and the COD of treated wastewater was below 70 mg/L under appropriate operating conditions. A mixed liquor of NaOH and NaCI was selected as desorbent because of its better elution performance. The results of column dynamic adsorption and regeneration showed that the COD of wastewater could be efficiently removed by D301R resin, and the resin was easily regenerated by the selected desorbent.展开更多
基金Project(2008ZX07421-002) supported by the Key National Science and Technology Project of ChinaProject(50638020) supported by the National Natural Science Foundation of China
文摘The effectiveness of a magnetic ion exchange resin(MIEX) for the treatment of Hongze Lake water in China was evaluated.The kinetics of natural organic matter(NOM) removal at various MIEX doses and contact time,multiple-loading experiments,impacts of MIEX prior to coagulation on coagulant demands and the effectiveness of combination of MIEX,pre-chlorination and coagulation were investigated.Kinetic experimental results show that more than 80%UV254 and 67%dissolved organic carbon(DOC) from raw water can be removed by the use of MIEX alone.94%sulfate,69%nitrate and 98%bromide removals are obtained after the first use of MIEX in multiple-loading experiments.It is suggested that MIEX can be loaded up to 1 250 bed volume(BV,volume ratio of tested water to resin) or more without saturation when regarding organics removal as a target. MIEX can remove organics to a greater extend than coagulation and lower the coagulant demand when combining with coagulation. Chlorination experimental results show that MIEX can remove 57%chlorine demand and 77%trihalomethane formation potential(THMFP) for raw water.Pre-chlorination followed by MIEX and coagulation can give additional organic and THMFP removals.The results suggest that MIEX provides a new method to solve the problem algae reproduction.
基金Supported by the National Natural Science Foundation of China(51678408,51478314,51638011)the National Key Research and Development Program of China(2016YFC0400506)+1 种基金the Natural Science Foundation of Tianjin(14JCQNJC09000)the Research Fund of Tianjin Key Laboratory of Aquatic Science and Technology(TJKLASTZD-2016-06)
文摘Magnetic ion exchange(MIEX) resins have received considerable attention in drinking water treatment due to their fast and efficient removal of dissolved organic carbon(DOC). Two types of mechanisms, i.e., ion exchange,reversible and irreversible adsorption, may occur during pollutants removal by MIEX. This work examined the removal mechanism of 17α-Ethinylestradiol(EE2) by MIEX. As one of typical estrogen micro-pollutants,EE2 existed as neutral molecule in natural water, and its charge density was close to zero [(0.00000219 ±0.00000015) meq·(μg EE2)^(-1)] based on the potentiometric titration method. However, the removal of EE2 by MIEX was much higher than that of other micro-pollutants previously reported. Multi-cycle adsorptionregeneration experiments and ion exchange stoichiometry analysis were conducted to elucidate the removal mechanism of EE2 by MIEX resin. The results suggested that the main removal mechanism of EE2 by MIEX was ion exchange instead of reversible micro-pore adsorption. The experimental analysis based on Donnan theory indicated that the internal micro-environment of resin beads was alkaline, in the alkaline environment EE2 would be ionized into negatively charged groups. As a result, ion exchange reaction occurred inside the pore of MIEX resin, and the removal process of EE2 by MIEX was dominated by the ion exchange reaction.
文摘Macroporous weak basic anion exchanger （D301R） was used to remove organic substances from drilling wastewater. The effect of pH, temperature and contact time on adsorption behavior was investigated in batch experiments, which indicated that the COD （Chemical Oxygen Demand） removal ratio of drilling wastewater was approximately 90%, and the COD of treated wastewater was below 70 mg/L under appropriate operating conditions. A mixed liquor of NaOH and NaCI was selected as desorbent because of its better elution performance. The results of column dynamic adsorption and regeneration showed that the COD of wastewater could be efficiently removed by D301R resin, and the resin was easily regenerated by the selected desorbent.
