Research On Degradation Of CTAB And Remediation Of Slight CTAB Polluted Water

Consumption of surfactant increase greatly as the development of industry, large amount of surfactant polluted water was disposal in the environment,results in contanmination and potential risk.Cationic surfactant such as quaternary ammonium salt is toxic persistent organic pollutants, it's able to inhitit the degradation of other contamination.As as result, researh on the degradation has important significance.In this thesis, the degradation of cetyl trimethyl ammonium bromide (CTAB) by different method was studies.First, degradation of CTAB by Fenton process was studied. influencing factors such as, dosage of H₂O₂, pH value,concentration of Fe²⁺ were also investigated. The optimal conditions when the concentration of CTAB is 20mg·L^-1 were as follows: H₂O₂ dosage 8 mg·L^-1, Fe²⁺20 mg·L^-1,pH value 3.5. CHOOH was detected in the degradation product.Under the optimal condition, CTAB was primary but not finaley degradated becouse of low H₂O₂ dosage.Second, degradation of CTAB by Fe³⁺/UV photocatalysis was studied. Results shown that the degradation of CTAB by Fe³⁺/UV photocatalysis was psedo-first order kineitc.The first order reaction rate constant k was influenced by Fe³⁺,CTAB concentration, pH, temperature and other ions the solution, vared from0-0.18 min^-1when the initial of CTAB was 20 mg·L^-1 and temperature is 25℃.when is concentration of Fe³⁺ is 7 mg·L^-1, k reached the maxmum, and decreased when the concentration of Fe³⁺ above 7 mg·L^-1.CHOO^-,CH₃COO^-,CH₃CH₂COO^-, NO₂^- was detected in the degradation produts by IC ion chromatography, assumed degradation passway was discussed based on the products.CTAB can be finally degradation in a certain reaction time.Finaly, degradation of CTAB in sea water and simulated red tide was studied, the hydrolysis of CTAB in dark sea water under processed slowly,at 25℃and 40℃percent hydrolysis reached only 2.25 and 18.25, respectively. With exsit of light, under the above conditaion percent hydrolysis reached 32.8% and 45.8%, respectively.In the simulated red tide environment, CTAB was able to degradate rapidly, when the dosage of CTAB was 40 mg·L^-1, no CTAB was detected in 72h, which means CTAB is an efficiential and easy-degradated algaecide.