Determination Of Organic Halogens In Textile Dyeing And Finishing Auxiliaries By High Temperature Combustion Pyrolysis-ion Chromatography

The hazard substances contained in textile dyeing and finishing auxiliaries are the main source of textile pollution,which has been concerned and valued by all sectors of society.Textile dyeing and finishing auxiliaries have a wide variety and complex components,often contain many organic halogen components,some of which are toxic and harmful,such as perfluorooctanoic acid(PFOA),chlorophenol,chlorinated benzene,short chain chlorinated paraffins(SCCPs),polybrominated diphenyl ethers(PBDEs),etc.At present,many laws and regulations on the prohibition of halogenated hazardous substances have been promulgated at home and abroad,and the corresponding determination methods or standards have been promulgated and implemented.There are many standards established by commonly used determination methods such as gas chromatography-mass spectrometry(GC-MS)and high performance liquid chromatography(HPLC),and each standard is usually only for the determination of single or several specific organic halogen compounds,which is increasingly difficult to meet the actual demand.For this reason,the industry uses organic halogen indicators such as tox and AOX to test and evaluate the environment or products.In this thesis,the organic halogens in textile dyeing and finishing auxiliaries are absorbed by activated carbon,and then converted into inorganic halogens by high temperature combustion pyrolysis technology,which were determination by ion chromatography after that step.Based on the above content,a high temperature combustion pyrolysis-ion chromatography method has been developed to determine the content of organic fluorine,organic chlorine,and organic bromine in textile dyeing and finishing auxiliaries.Fluorobenzoic acid,chlorobenzoic acid and bromobenzoic acid were used as indicator materials in this thesis.Firstly,the adsorption characteristics of typical organic halogens on activated carbon were studied,which laid a theoretical foundation for the sample pretreatment methods for the determination of organic halogens in textile dyeing and finishing auxiliaries;Afterwards,the pretreatment methods of activated carbon particle and activated carbon fiber,column adsorption method,oscillation adsorption method and ultrasonic adsorption method for organic halogen were compared;The parameters of high temperature combustion pyrolysis(pyrolysis temperature,oxygen flow rate and concentration of absorption solution)and ion chromatography were optimized.Finally,after conducted a methodological investigation,the method is applied to the determination of organic halogens in textile dyeing and finishing auxiliaries actual samples.The results show that the adsorption of organic halogens on activated carbon is an exothermic process based on physical adsorption,low temperature is conducive to the adsorption.Langmuir Freundlich model can well describe the adsorption behavior of fluorobenzoic acid,chlorobenzoic acid and bromobenzoic acid on activated carbon,and their limit adsorption capacities are 58.38,111.98,and 139.90 mg/g.Activated carbon particles can achieve good adsorption and separation of organic halogens by using the oscillation adsorption method.The organic halogens samples adsorbed on the activated carbon were converted into hydrogen halide gas at 950 ? for 9 minutes under the condition of 160 m L/min oxygen flow rate.After absorption by 30 mmol/L sodium hydroxide solution,the concentration of halogen ion was determined by ion chromatography.The recovery rate of the three halogens can reach more than 80%,which meets the basic needs of determination.Methodological investigations showed that the average recoveries of organic fluorine,organic chlorine,and organic bromine were 85.4?102.5%,96.2?102.4%,82.4?91.7%,and the relative standard deviation(RSD)were 1.3?5.9%,4.2?5.2%,1.8?2.8%.The total halogen test results of 10 common textile dyeing and finishing auxiliaries showed that no fluorine was detected in the tested samples,some samples contained trace bromine,and chlorine was detected in all the auxiliaries.Among them,ATMP and imidazoline auxiliaries have attracted our attention due to their high total chlorine content.The organic halogen test results of the above samples show that none of the tested samples contained organic fluorine or organic bromine components;the three kinds of auxiliaries including ATMP contained organic chlorine components,while no organic chlorine is detected in imidazoline auxiliaries.The experimental results are consistent with the relevant information of textile dyeing and finishing auxiliaries,such as the composition and production process,which were found in the early stage.The test results of actual samples show that this method has good applicability and can be effectively applied to the detection of organic halogens in textile dyeing and finishing auxiliaries.