In this study, a simple and efficient online preconcentration method based on headspace in-tube microextraction was used to simultaneously extract and preconcentrate small amounts of six trichlorophenols in aqueous samples. After extraction, the analytes were quantified by capillary electrophoresis and using the calibration curve of standard solutions. The effect of effective factors on the extraction process such as the pH of the donor phase, the type of the acceptor phase, the temperature and time of extraction, and the addition of organic solvent to the donor phase were investigated and optimized. Under optimal conditions, the linear dynamic range for the proposed technique was 15 to 1000 nM with a correlation coefficient of 0.99, and relative standard deviations were obtained with seven repetitions of the experiment and a concentration of 500 nM of analytes in the range of 4.78-7.63%. The detection limit of the method was 5-6 nM. The preconcentration factor for six trichlorophenols was obtained in the range of 310 to 661 times. Finally, this method was used to preconcentrate and measure six trichlorophenols in environmental water samples. The relative recoveries for the spiked samples were within the 82-92% range, indicating good accuracies and the absence of matrix effects.

Introduction: Several reports have indicated that chlorophenols are toxic chemicals and recalcitrant to biodegradation. Advanced oxidative processes (AOPs) are one of the most effective processes for degradation of persistent compounds. Since the mineralization of recalcitrant compounds by AOPs often requires long reaction time and strong dose of oxidant, combination of this process with biological one is considered as one efficient and economic method. Methods: In this work treatment of 2,4,6 TCP wastewater by Fenton's is oxidation in batch reactor and combination of Fenton reaction with activated sludge for removal of TCP in continues mode were studied. Results: Initial concentration of 2,4,6 TCP was 0.6 mM and in pH = 3, [H2O2] =1.8 mM [Fe2+] = 0.6 mM 99% of TCP was degraded in first minute after the reaction was started COD analysis indicated that TCP did not mineralize because COD reduction was only < 37%. Chloride ion increasing from 0 mg/L to 40mg/L, PH decreasing from 3 to 2.74 and UV215 absorbance decreasing from 3.2 to 0.6 indicated that generated intermediates toxicity reduced and biodegradability enhanced. Pilot study of Fenton's oxidation / activated sludge integration for treatment of 2,4,6 TCP wastewater showed that intermediates in effluent from Fenton reactor (operating at [H2O2] / [Fe2+] =3, [H2O2] / [TCP]=3, pH=3, reaction Time = 1hr [TCP]0 = 120 mg/L aqu COD @ 150 mg/L). Degraded by Activated sludge process and COD reduction were ~ 75%. Increasing of aeration Time from 6 hr to 18 hr has no significant effect on removal efficiency (p=0.005). Increasing of concentration of TCP has no significant effect on removal efficiency (p=0.005). Increasing of glucose into the aeration tank caused that COD removal efficiency increased from 75% to 92%. Conclusion: Results from this study indicated that Fenton’s oxidation process is an effective method for biodegradability Enhancement of 2,4,6 TCP and generated intermediates from Fenton’s oxidation of 2,4,6 TCP are easily Biodegradable compounds.