The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)...The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.展开更多
Because of its broad spectrum and high efficiency,the microwave disinfection was used to control the airborne microbial contaminates in VAC system.Some microwave disinfection devices were developed combined with air f...Because of its broad spectrum and high efficiency,the microwave disinfection was used to control the airborne microbial contaminates in VAC system.Some microwave disinfection devices were developed combined with air filter,the design and calculation method was presented,and the disinfection effects on White staphylococcus,Staphylococcus aureus,Bacillus Subtilis,Escherichi coli were measured.The results show that the major influence factors on disinfection effect are microwave power,water-content of filter material,disinfecting duration.After 15 min,the kill ratio is >90%,and the log value is >1.The microwave field is uniform and the kill effect of bacteria on each surface of filter is the same,without statistically significant difference.展开更多
At present microbiological risk are still the most frequent in the food industry and the disinfection is one of the procedures that can be carried out in the general prevention of foodborne infectious diseases. In the...At present microbiological risk are still the most frequent in the food industry and the disinfection is one of the procedures that can be carried out in the general prevention of foodborne infectious diseases. In the industrial process of food transformation the cleaning and disinfection procedures of surfaces and machinery have to be considered an integrate system with food production,a technological aspect that surely affects the finished product quality and safety. First of all to carry out properly these operations it is necessary that the factory and the equipment have been designed and constructed with high standard of hygiene to reduce the risk of contamination and to facilitate the sanitation. The procedures involve several stages which generally include pre-washing with water,cleaning,real disinfection,and a final rinsing with water. In order to assure a right disinfections of surfaces areas and of processing equipment the choice of disinfectant takes on particular importance. Some of the most widely used disinfectants include the hypochlorous acid,the chlorine dioxide and the peroxides like peracetic acid; the latter is widely used in soft drink and mineral water industries. The efficiency of these chemical agents depends on various factors as pH,temperature and the presence of organic substances with which the disinfectants can react to give by-products which can reduce the activity and can present toxicity. The use of hypochlorite may led to the formation of carcinogenic substance such as trialomethanes (THM) while the use of chlorine dioxide may lead to the formation of chlorites and chlorates. The peracetic acid is a good alternative compounds and it doesn’t lead to the formation of carcinogenic by-products. In our researches we evaluated the effectiveness of peracetic acid to inactivate some resistant micro-organism like hepatitis A virus; our results show that in practical application in CIP (cleaning in place) it’s necessary to use concentration of 600～1300mg/L of peracetic acid for 15～ 30min of contact time for an inactivation >99.99%.展开更多
The disinfected bacteria will be a photoreactivation under the irradiation of the sunlight,and the light intensity plays an important role in the bacteria resurrection.The effect of light intensity on photoreactivatio...The disinfected bacteria will be a photoreactivation under the irradiation of the sunlight,and the light intensity plays an important role in the bacteria resurrection.The effect of light intensity on photoreactivation of Escherichia coli(E.coli) and Enterococcus faecalis(E.faecalis) in secondary effluents which were disinfected respectively by pure UV and UV-TiO_2 was investigated.The results show that the disinfection efficiency of UV-TiO_2 is much higher than that of the pure UV disinfection.The photoreactivation rate of E.coli is much higher in pure UV disinfection than in UV-TiO_2 photocatalytic disinfection.Under high light intensity in UV-TiO_2 disinfection,high resurrection rate can be induced.However,a higher resurrection rate can be introduced even under low light intensity in pure UV disinfection alone.Meanwhile,UV-TiO_2 disinfection has a strong inhibition effect on E.faecalis photoreactivation.When the light intensity is lower than 21 μW/cm^2,nearly no resurrection of E.faecalis occurs after 72 h resurrection irradiation,and a little resurrection rate is observed only under a strong photoreactivating light intensity.展开更多
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,...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 thc problem algae reproduction.展开更多
基金supported in part by the National Natural Science Foundation of China(12174366)Fundamental Re-search Funds for the Central Universities(WK3450000005)the Anhui Provincial Natural Science Foundation(2108085MC93).
文摘The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.
基金Supported by China Postdoctoral Science Foundation and Municipal and Environmental Engineering Research Province Key Laboratory Foundation,Shenyang Jianzhu University
文摘Because of its broad spectrum and high efficiency,the microwave disinfection was used to control the airborne microbial contaminates in VAC system.Some microwave disinfection devices were developed combined with air filter,the design and calculation method was presented,and the disinfection effects on White staphylococcus,Staphylococcus aureus,Bacillus Subtilis,Escherichi coli were measured.The results show that the major influence factors on disinfection effect are microwave power,water-content of filter material,disinfecting duration.After 15 min,the kill ratio is >90%,and the log value is >1.The microwave field is uniform and the kill effect of bacteria on each surface of filter is the same,without statistically significant difference.
文摘At present microbiological risk are still the most frequent in the food industry and the disinfection is one of the procedures that can be carried out in the general prevention of foodborne infectious diseases. In the industrial process of food transformation the cleaning and disinfection procedures of surfaces and machinery have to be considered an integrate system with food production,a technological aspect that surely affects the finished product quality and safety. First of all to carry out properly these operations it is necessary that the factory and the equipment have been designed and constructed with high standard of hygiene to reduce the risk of contamination and to facilitate the sanitation. The procedures involve several stages which generally include pre-washing with water,cleaning,real disinfection,and a final rinsing with water. In order to assure a right disinfections of surfaces areas and of processing equipment the choice of disinfectant takes on particular importance. Some of the most widely used disinfectants include the hypochlorous acid,the chlorine dioxide and the peroxides like peracetic acid; the latter is widely used in soft drink and mineral water industries. The efficiency of these chemical agents depends on various factors as pH,temperature and the presence of organic substances with which the disinfectants can react to give by-products which can reduce the activity and can present toxicity. The use of hypochlorite may led to the formation of carcinogenic substance such as trialomethanes (THM) while the use of chlorine dioxide may lead to the formation of chlorites and chlorates. The peracetic acid is a good alternative compounds and it doesn’t lead to the formation of carcinogenic by-products. In our researches we evaluated the effectiveness of peracetic acid to inactivate some resistant micro-organism like hepatitis A virus; our results show that in practical application in CIP (cleaning in place) it’s necessary to use concentration of 600～1300mg/L of peracetic acid for 15～ 30min of contact time for an inactivation >99.99%.
基金Projects(51174090,51168026)supported by the National Natural Science Foundation of China
文摘The disinfected bacteria will be a photoreactivation under the irradiation of the sunlight,and the light intensity plays an important role in the bacteria resurrection.The effect of light intensity on photoreactivation of Escherichia coli(E.coli) and Enterococcus faecalis(E.faecalis) in secondary effluents which were disinfected respectively by pure UV and UV-TiO_2 was investigated.The results show that the disinfection efficiency of UV-TiO_2 is much higher than that of the pure UV disinfection.The photoreactivation rate of E.coli is much higher in pure UV disinfection than in UV-TiO_2 photocatalytic disinfection.Under high light intensity in UV-TiO_2 disinfection,high resurrection rate can be induced.However,a higher resurrection rate can be introduced even under low light intensity in pure UV disinfection alone.Meanwhile,UV-TiO_2 disinfection has a strong inhibition effect on E.faecalis photoreactivation.When the light intensity is lower than 21 μW/cm^2,nearly no resurrection of E.faecalis occurs after 72 h resurrection irradiation,and a little resurrection rate is observed only under a strong photoreactivating light intensity.
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 thc problem algae reproduction.
