Study On The Effect Of Algal Toxin On The Production Of Detoxicated By-Products

In the northern summer lakes and reservoirs are prone to the occurrence of"water bloom"events,the root cause is that eutrophication of water has caused large-scale algae blooms in water.Algal toxin?MCs?produced by algae is a representative refractory substance,which has the characteristics of stable structure,not easy to degrade,and three?carcinogenic,teratogenic and mutagenic?.Slightly polluted water treatment at home and abroad of algal method generally used such as coagulation,sedimentation,filtration process to remove algae in the water,in order to reduce the MCs because of the metabolism of algae on human health threat,but these methods are difficult to remove the MCs of existing in water and other aspects.This paper,based on the current research status of the MCs,remove the MCs in the water,adopt pretreatment by liquid chlorine,ClO₂ and NaClO slightly polluted water treatment with algae,respectively,comparing three kinds of the most commonly used in MCs removal effect of the oxidant and cost analysis.ClO₂ in the preoxidation process does not produce trihalomethanes?THMs?and has been widely concerned,this paper studies the ClO₂ oxidation MC-LR chemical kinetics,actual conditions,a reservoir water in changchun determine MCs degradation in water to meet the world health organization?WHO?under the drinking water safety standards(including 1 g/L of CT values.First,three kinds of preoxidants,namely liquid chlorine,ClO₂ and NaCl O,were studied.The results showed that the optimal dosage was 1.5mg/L,0.4mg/L,and2.0mg/L respectively,which could remove 58.3%,79.5%and 70.3%MCs respectively in water,while the algae cells were at the breaking point.In addition,the concentration of the pre-oxidizing agent was increased,and the K ions in the algal cells were drained,the cells were inactivated and lysed,and the concentration of MCs in the water was increased.Trichloromethane,monobromo dichloromethane,dichloroacetonitrile and trichloroacetonitrile were detected in the water body after pretreatment with liquid chlorine.No THMs was detected in the water after ClO₂treatment,only dichloroacetonitrile was detected.Dibromochloromethane and trichloroacetonitrile were detected in water bodies treated with NaCl O.Secondly,the effect of pH on DBPs was studied.Under acidic conditions,it is beneficial to HANs generation;Under alkaline conditions,it is beneficial to the generation of THMs.Then,ClO₂ oxidation Mc-lr dynamics was studied.The reaction series of Mc-lr and Cl O2 were determined by experiment,and the total reaction series was grade 2.In the pH=7.5,the reaction temperature is 25?,MC-LR ClO₂ oxidation reaction rate constant k=264.00 L/?mol,min?.The effects of temperature and pH on the reaction rate constant k were also investigated.The experiment shows that with the increase of temperature,k increases and the reaction rate accelerates.The pH has an effect on the chemical reaction rate,and the more acidic the reaction rate is,the reaction rate constant of pH=5.0 is 297.3L/?mol·min?.The reaction rate constant at pH=7.5 was 264.0l/?mol·min?;The reaction rate constant at pH=9.0 is 254.1L/?mol·min?.The average activation energy is Ea=21 kilojoules per mole.Finally,in the study of ClO₂ treatment of the actual algae micropollution water body,the CT value of ClO₂ was 137.1 mgminl-1 and the CT value of Cl O₂ was positively correlated with the initial concentration of MC-LR when the concentration of 5.76 mu g/L MC-LR was reduced to below 1.Study in this paper,adopting oxidizer can effectively remove the water in the MCs,the outbreak of the northern summer"bloom"event management and drinking water safety in production to provide the theoretical basis,have important practical significance.