Interest in the development of inorganic polymerized coagulants is growing; however, there are only limited studies on the synthesis of polytitanium coagulants, which are expected to exhibit improved coagulation effic...Interest in the development of inorganic polymerized coagulants is growing; however, there are only limited studies on the synthesis of polytitanium coagulants, which are expected to exhibit improved coagulation efficiency with better floc properties. This study presents the synthesis of polytitanium sulfate（PTS） for potential application in water purification,followed by characterization of PTS flocs and titanium species detection. Stable PTS solutions were successfully synthesized and standard jar tests were conducted to evaluate their coagulation efficiency. Electrospray ionization time-of-flight mass spectrometry（ESI-TOF-MS） speciation analysis revealed that a variety of mononuclear and polynuclear complexes were formed in PTS solution, indicating the polymeric nature of the synthesized coagulant. Floc characteristics were studied through on-line monitoring of floc size using a laser diffraction particle size analyzer. Results showed that PTS had a comparable or in some cases even higher organic matter and particulate removal efficiency than Ti（SO4）2.The effluent p H after PTS coagulation significantly improved toward desirable values closer to neutral p H. Properties of flocs formed by PTS were significantly improved in terms of floc size, growth rate and structure. This study showed that PTS could be an efficient and promising coagulant for water purification, with the additional benefit that its coagulated sludge can be used to recover valuable TiO2 nanoparticles for various commercial applications.展开更多
Titanium-based coagulation has proved to be effective for algae-laden micro-polluted water purification processes.However,the influence of algae inclusion in surface water treatment by titanium coagulation is barely r...Titanium-based coagulation has proved to be effective for algae-laden micro-polluted water purification processes.However,the influence of algae inclusion in surface water treatment by titanium coagulation is barely reported.This study reports the influence of both Microcystis aeruginosa and Microcystis wesenbergii in surface water during polytitanium coagulation.Jar tests were performed to evaluate coagulation performance using both algae-free(controlled)and algae-laden water samples,and floc properties were studied using a laser diffraction particle size analyzer for online monitoring.Results show that polytitanium coagulation can be highly effective in algae separation,removing up to 98%from surface water.Additionally,the presence of algae enhanced organic matter removal by up to 30%compared to controlled water containing only organic matter.Polytitanium coagulation achieved significant removal of fluorescent organic materials and organic matter with a wide range of molecular weight distribution(693–4945 Da)even in the presence of algae species in surface water.The presence of algae cells and/or algal organic matter is likely to function as an additional coagulant or flocculation aid,assisting polytitanium coagulation through adsorption and bridging effects.Although the dominant coagulation mechanisms with polytitanium coagulant were influenced by the coagulant dosage and initial solution pH,algae species in surface water could enhance the charge neutralization capability of the polytitanium coagulant.Algae-rich flocs were also more prone to breakage with strength factors approximately 10%lower than those of algae-free flocs.Loose structure of the flocs will require careful handling of the flocs during coagulation-sedimentation-filtration processes.展开更多
Application of ceramic membrane(CM)with outstanding characteristics,such as high flux and chemical-resistance,is inevitably restricted by membrane fouling.Coagulation was an economical and effective technology for mem...Application of ceramic membrane(CM)with outstanding characteristics,such as high flux and chemical-resistance,is inevitably restricted by membrane fouling.Coagulation was an economical and effective technology for membrane fouling control.This study investigated the filtration performance of ceramic membrane enhanced by the emerging titanium-based coagulant(polytitanium chloride,PTC).Particular attention was paid to the simulation of ceramic membrane fouling using four widely used mathematical models.Results show that filtration of the PTC-coagulated effluent using flat-sheet ceramic membrane achieved the removal of organic matter up to 78.0%.Permeate flux of ceramic membrane filtration reached 600 L/(m2$h),which was 10-fold higher than that observed with conventional polyaluminum chloride(PAC)case.For PTC,fouling of the ceramic membrane was attributed to the formation of cake layer,whereas for PAC,standard filtration/intermediate filtration(blocking of membrane pores)was also a key fouling mechanism.To sum up,cross-flow filtration with flat-sheet ceramic membranes could be significantly enhanced by titanium-based coagulation to produce both high-quality filtrate and high-permeation flux.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51278283 and 51508308)the China Postdoctoral Science Foundation(Nos.2014M560557 and2015T80722)+1 种基金the Tai Shan Scholar Foundation(No.ts201511003)Hong Kong Scholars Program
文摘Interest in the development of inorganic polymerized coagulants is growing; however, there are only limited studies on the synthesis of polytitanium coagulants, which are expected to exhibit improved coagulation efficiency with better floc properties. This study presents the synthesis of polytitanium sulfate（PTS） for potential application in water purification,followed by characterization of PTS flocs and titanium species detection. Stable PTS solutions were successfully synthesized and standard jar tests were conducted to evaluate their coagulation efficiency. Electrospray ionization time-of-flight mass spectrometry（ESI-TOF-MS） speciation analysis revealed that a variety of mononuclear and polynuclear complexes were formed in PTS solution, indicating the polymeric nature of the synthesized coagulant. Floc characteristics were studied through on-line monitoring of floc size using a laser diffraction particle size analyzer. Results showed that PTS had a comparable or in some cases even higher organic matter and particulate removal efficiency than Ti（SO4）2.The effluent p H after PTS coagulation significantly improved toward desirable values closer to neutral p H. Properties of flocs formed by PTS were significantly improved in terms of floc size, growth rate and structure. This study showed that PTS could be an efficient and promising coagulant for water purification, with the additional benefit that its coagulated sludge can be used to recover valuable TiO2 nanoparticles for various commercial applications.
基金This work was supported by grants from the National Natural Science Foundation of China(Grant No.51978311)the Shandong Provincial Natural Science Foundation,China(No.ZR2019BEE044).
文摘Titanium-based coagulation has proved to be effective for algae-laden micro-polluted water purification processes.However,the influence of algae inclusion in surface water treatment by titanium coagulation is barely reported.This study reports the influence of both Microcystis aeruginosa and Microcystis wesenbergii in surface water during polytitanium coagulation.Jar tests were performed to evaluate coagulation performance using both algae-free(controlled)and algae-laden water samples,and floc properties were studied using a laser diffraction particle size analyzer for online monitoring.Results show that polytitanium coagulation can be highly effective in algae separation,removing up to 98%from surface water.Additionally,the presence of algae enhanced organic matter removal by up to 30%compared to controlled water containing only organic matter.Polytitanium coagulation achieved significant removal of fluorescent organic materials and organic matter with a wide range of molecular weight distribution(693–4945 Da)even in the presence of algae species in surface water.The presence of algae cells and/or algal organic matter is likely to function as an additional coagulant or flocculation aid,assisting polytitanium coagulation through adsorption and bridging effects.Although the dominant coagulation mechanisms with polytitanium coagulant were influenced by the coagulant dosage and initial solution pH,algae species in surface water could enhance the charge neutralization capability of the polytitanium coagulant.Algae-rich flocs were also more prone to breakage with strength factors approximately 10%lower than those of algae-free flocs.Loose structure of the flocs will require careful handling of the flocs during coagulation-sedimentation-filtration processes.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51978311)Taishan Scholars Young Experts Program(China)(No.tsqn202103080)Shandong Provincial Natural Science Foundation,China(No.ZR2019BEE044).
文摘Application of ceramic membrane(CM)with outstanding characteristics,such as high flux and chemical-resistance,is inevitably restricted by membrane fouling.Coagulation was an economical and effective technology for membrane fouling control.This study investigated the filtration performance of ceramic membrane enhanced by the emerging titanium-based coagulant(polytitanium chloride,PTC).Particular attention was paid to the simulation of ceramic membrane fouling using four widely used mathematical models.Results show that filtration of the PTC-coagulated effluent using flat-sheet ceramic membrane achieved the removal of organic matter up to 78.0%.Permeate flux of ceramic membrane filtration reached 600 L/(m2$h),which was 10-fold higher than that observed with conventional polyaluminum chloride(PAC)case.For PTC,fouling of the ceramic membrane was attributed to the formation of cake layer,whereas for PAC,standard filtration/intermediate filtration(blocking of membrane pores)was also a key fouling mechanism.To sum up,cross-flow filtration with flat-sheet ceramic membranes could be significantly enhanced by titanium-based coagulation to produce both high-quality filtrate and high-permeation flux.
