Study On Methods Of Determination And Degradation Of Chloro-methylbenzotriazole

Under the background of the vigorous development of China's industry,a large number of renew water treatment products have emerged.Chloro-methylbenzotriazole(Chloro-TTA)that own excellent inhibition effect as a new type of copper corrosion inhibitor has great potential for development.It replaces the previously used copper corrosion inhibitors and has been widely used abroad,whereas it isn't widely used in China.In order to determine its content in water and how to degrade the residual in the environment Chloro-TTA conducted this studyThe ultraviolet spectrophotometric method for the determination of Chloro-TTA in the solution was established.The effects of pH,temperature and interfering ions on themeasurement results were explored.The precision and detection limit of the method were tested.The results show that the measurement results are different under different acid and alkali conditions.The maximum absorption wavelength of the acidic environment(pH is about 4)is 268 nm,and the maximum absorption wavelength of the alkaline environment(pH is about 10)is 278 nm,while the measurement results are not affected by temperature and interfering ions.The detection limit of this method is 0.0548mg/L,the relative standard deviation in the precision experiment is 1.2%,and the average recovery rate is between 91%and 101%,indicating that the UV spectrophotometry is suitable for the determination of Chloro-TTA.A fluorescence spectrophotometric method for the determination of Chloro-TTA in the solution was established.The effects of pH,temperature and interfering ions on the measurement results were explored,and related experiments were carried out on the precision and detection limit.The results show that the maximum emission wavelength is 370 nm in an acidic environment(pH is about 4)and 338 nm in an alkaline environment(pH is about 10).Before each measurement,the pH of the solution needs to be adjusted to a suitable condition.What the measurement result show is the phenomenon appears to be low with the rise of temperature.In a solution containing interfering ions,the measurement result fluctuates irregularly due to the presence of interfering ions.Through precision,spike recovery and detection limit experiments,the detection limit of fluorescence spectrophotometry is lower as 0.0054mg/L,the relative standard deviation in precision experiments is 0.5%,and the average recovery rate is between 86%-95%This means that fluorescence spectrophotometry is also suitable for the determination of Chloro-TTA.Chloro-TTA was degraded by irradiation with ultraviolet light(UV,254 nn),ultraviolet light combined with hydrogen peroxide(H2O2)and ultraviolet light combined with sodium persulfate(PDS)to determine the optimal dosage of oxidant quantity,and explored the effects of the initial pH and the interfering substances of the solution.And comparing the differences of degradation methods to remove Chloro-TTA.Degradation of 10mg/L Chloro-TTA by UV irradiation alone showed that the degradation efficiency could reach about 90%after 120 minutes of reaction.Introducing 8 mg/L H2O2,the degradation rate can reach more than 95%after 15min reaction time.When changing the pH of the solution,the degradation efficiency isn't disturbded.The presence of Cl-,SO42-,NO3-,HCO3-doesn't affect degradation efficiency.After introducing 100 mg/L PDS,the time required for the degradation efficiency to reach above 95%is 90 min.After changing the pH of the solution,it doesn't affect the degradation efficiency.The presence of Cl-and NO3-hinders the degradation efficiency of UV/PDS,but he presence of HCO3-promotes its degradation.At the same time,adding free radical scavenger-ethanol to the UV/PDS system to preliminary explore the contribution of free radicals to degradation The result show that the presence of ethanol reduces the removal rate of Chloro-TTA,but some Chloro-TTA is still oxidized decomposed.It is preliminarily believed that the activated PDS has a direct oxidation effect on Chloro-TTA,or there are other degradation mechanisms.The use of oxidant H2O2 or PDS alone has no degradation effect on Chloro-TTA.The above experiments show that the UV photocatalytic oxidation technology can effectively remove the remaining Chloro-TTA in the environment.Among them,the UV/H2O2 degradation system uses less reagent.And the reaction time is short.In addition,the degradation efficiency is high.In order to compare the degradation performance of different copper corrosion inhibitors,degradation experiments were also conducted on methylbenzotriazole(TTA),which is widely used in China.Degradation of 10 mg/L TTA by UV irradiation alone and UV/H2O2 combination was found:after UV irradiation alone for 120 min,the degradation efficiency of TTA can only reach 65%.After the introduction of H2O2,after reaction in 30 min,the degradation rate of TTA was only 68%.When the reaction was extended for 120 min,the degradation efficiency of TTA reached only 78%.This indicates that Chloro-TTA is more easily degraded than TTA.