Research On The Method For Rapid Detection Of Heavy Metals In Textiles

As we all know,lead and cadmium are toxic heavy metals.The chemicals containing lead and cadmium are often used as stabilizing agent during the textile coating process,which cause lead and cadmium pollution in textile coating.Lead and cadmium can be absorbed by human body through skin contacting and other means,then enrich in bone,liver,kidney,heart and brain.When the heavy metal concentration in the body exceeds a certain value,they can make huge damage to human nerve system,blood,bone,digestive system and reproductive system,and bring high risks for human health.There are many methods which are commonly used for the detection of heavy metals,such as inductively coupled plasma atomic emission spectrometry,atomic fluorescence spectrometry,atomic absorption spectrophotometry and so on.These methods are more expensive and more complicated,they cannot meet the needs of rapid detection.First of all,the effects of digestion temperature,digestion time and other conditions on wet digestion and microwave digestion were studied,so the pretrement conditions of textiles were determined.Then,cadion and malachite green were used as chromogenic agent of cadmium ion and lead ion respectively.Cadmium and lead can be complexed with above chromogenic agent,thus the color of solutions changed,then the chromogenic conditions of cadmium and lead were optimized,at last the study established a cheap,simple,and efficient approach that can detect total lead and cadmium in textiles.Firstly single factor experiment and orthogonal experiment were used to optimize the pretreatment conditions of textiles,and then the conditions for the determination of lead and cadmium ions were optimized.Finally,a method for the determination of total lead and cadmium in textile coatings was established.The best wet digestion conditions are: digested at 160 ? for 50 min,5 m L nitric acid and 1 m L hydrogen peroxide solution.The recoveries of lead and cadmium are about 85.07 %~98 % and 84.88 %~98.7 % respectively.The best microwave digestion conditions are: digested at 140 ? for 8 min,4.5 m L nitric acid and 0.4 m L hydrogen peroxide solution.The recoveries of lead and cadmium are about 89.63 %~99.34 % and 87.55 %~99.18 % respectively.The optimal conditions for the determination of cadmium ions are: 30 ?L 0.1% cadion solution,0.1 m L 10% Triton X-100 solution at p H 11.With the increase of cadmium concentration,the color of solution turn from purple to red.The lowest total cadmium content which can be distinguished with naked eyes clearly is 3 mg/kg,and the color of solution can remain stable for 1 h.The optimal conditions for the determination of lead ions are: 0.5 m L 0.05% malachite green solution,1.25 m L 1.2 mol/L potassium iodide solution and 0.25 m L 0.06 mol/L ascorbic acid solution at p H 3.With the increase of lead concentration,the color of solution change from blue to light green.The lowest total lead content which can be distinguished by naked eyes clearly is 60 mg/kg,and the color of solution is stable for 1 h.Compared with the existing standard GB/T 30157-2013,the established method of this study is cheaper,simpler,and time consuming,it can quickly detect the total lead and total cadmium content in textiles coatings.Therefore,the method is more suitable for the needs of actual testing.