Study On Measuring Methods Of Surfactants And Aromatic Compounds Adsorbed On Textiles During Laundry

In the washing process of fabrics,surfactants or aromatic compounds in detergents can adsorb on fabrics through hydrophobic and hydrogen bonds.Residual compounds in clothing may irritate the skin and cause harm to human health.However,due to the low adsorption capacity of compounds on fabrics,the sensitivity of conventional detection methods is not high enough,which makes quantitative analysis more difficult.This paper mainly studies the adsorption behavior of surfactants and aromatic compounds on textiles during washing process,aiming at exploring and establishing the quantitative detection technology of trace compounds adsorbed on textiles,grasping the influence of different organic compounds and fabric type on the adsorption amount,and providing a method for the follow-up study of the biosafety of residual compounds.In this study,cottons and polyester-cotton blend fabrics(T/C)were used as substrates.The fatty alcohol polyoxyethylene ether sulfate(AES)and octylphenol polyoxyethylene ether(OPEO)were used as model surfactants,and phenyl ethyl acetate,p-anisaldehyde,eugenol and α-violet ketone were used as the model aromatic compounds.The quantitative determination of the above compounds by total organic carbon analysis(TOC),high performance liquid chromatography(HPLC)and gas chromatography-mass spectrometry(GC-MS)was investigated.The advantages and disadvantages of each method were compared,and the adsorption behavior of two kinds of organic fabrics on different fabrics was further studied.The contents of this paper are as follows:(1)Fabrics were washed in AES(anionic surfactant)and OPEO(non-ionic surfactant)solutions respectively(simulated household washing process).The changes of wettability of fabrics before and after washing were measured by capillary effect and contact angle analysis.The changes of chemical composition on the surface of fabrics were semi-quantitatively measured by X-ray photoelectron spectroscopy(XPS).After that,residual liquid analysis method and extraction method were used,respectively,to quantitatively detect the adsorption amount of surfactant on fabric by analyzing the washing residue using TOC or the extract using HPLC.Theadsorption kinetics of surfactants on cotton fabric was further studied.The adsorption amount of AES was about 6.67 mg/g and that of OPEO was about 4.19 mg/g on cotton fabrics obtained by TOC method.Through the measurement of HPLC,the adsorption of AES on cotton fabrics was about 6.44 mg/g and that of OPEO was about 3.95 mg/g.The adsorptive capacity of surfactants measured by the two methods is almost the same.The TOC method is more convenient to operate,but it needs to simulate the washing process and can not be used to detect the surfactant content in existing textile samples directly.The HPLC method has higher accuracy,but it needs solvent extraction steps and takes longer time.(2)Four aromatic compounds with different structures were selected to determine their adsorption capacity on cotton and T/C textiles by GC-MS technology.Firstly,the conditions of GC-MS were optimized by changing the inlet temperature and carrier gas velocity.Then the adsorption capacity of four aromatic compounds on different textiles was determined.The adsorption kinetics and thermodynamic behavior of eugenol on cotton and polyester-cotton materials were investigated,and the thermodynamic adsorption equation and kinetic rate equation were fitted to deepen the understanding of the adsorption behavior of aromatic compounds on fabrics.It was shown that phenyl ethyl acetate,p-anisaldehyde,eugenol andα-violet ketone can adsorb on both cottons and T/C fabrics.Their adsorption capacity is phenols > esters > aldehydes > ketones.For eugenol,its adsorption capacity on cotton fabric is higher than that on T/C fabric.The adsorption isotherms of eugenol on cotton materials conform to Freundlich adsorption model,and the adsorption kinetics conforms to quasi-second-order kinetics.