engleski

Application of ICP-OES : Determination of Heavy Metals in Extracts of Textiles Applying Utrasonic and Microwave Techniques

Many recent investigations have proved that metals present on textile materials can cause problems during fiber processing, dyeing or bleaching and that metals have a bad effect on the product quality. Their negative influence on human health is also very well known: damages of organs, disorders in respiratory tract and lung diseases, dysfunction of the heart, blood and blood producing organs, disorders in the nervous system, skin diseases, abnormalities in fertility and pregnancy. Accumulation of heavy metals in body tissues and binding to enzymes may disrupt the functioning of cells, which may also lead to development of tumors or cancers. Since metals present on textiles have influence on human health, and with regard to the fact that the same elements cause problems in textile manufacturing, this research will focus on their determination and removal from textiles by microwaves and by ultrasonic extraction. This research covered the development and validation of the method inductively coupled plasma – optical emission spectrometry (ICP-OES) for 29 different elements (Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Co, Cu, Fe, K, Hg, Mg, Mn, Mo, Na, Ni, Pb, Sc, Si, Se, Sn, Sm, Sr, Tl, V, and Zn) determination on textile materials applying different certified reference materials. ICP-OES was chosen due to its advantages: simultaneous determination of many elements of interest in the same sample and very low detection limits. Optimization of the textiles digestion procedure was done by comparing dry mineralization, open vessel and microwave digestion. Adsorption and desorption of 29 elements was monitored on standard cotton and wool materials. Ultrasonic and microwave extractions of metals after adsorption on cotton and wool were optimized and the results were compared to the classical extraction procedure. Experiment design and optimization of all extraction procedures were done in Design Expert 6 State Ease software. The optimum of ultrasonic extraction was achieved with 1M HCl – 1M HNO3 – H2O= 3.32/2.83/93.85 (v/v, cotton), and for microwave extraction with 22.44/0.00/77.56 (cotton) and 33/0/67 (wool), respectively. Classical extraction achieved optimum in 20.68/0/79.32 or 0.00/22.82/77.18 (cotton) and 33/33/34 or 29.75/3.77/66.48 (wool). Sophisticated extraction procedures proved to be more efficient, faster and ecologically and economically favorable. The extracted quantities of heavy metals from textile clothing materials were determined in artificial sweat and results were compared to the limits prescribed by the international standards. The goal of this part of the dissertation was development of an analytical method for determination of toxic and carcinogenic metals being extracted from different textile materials during usage. For this reason, the elements important for the human health were investigated: after extraction in the artificial acidic sweat solution from textiles made of cotton, flax, wool, silk, viscose, and polyester materials, eight heavy metals were determined by ICP-OES. Results in the sweat extracts (minimum-maximum in μ g / mL) were: Al 0.11-1.58, Cd 0.02-0.05, Cr 0.01-0.32, Cu 0.05-1.95, Fe 0.04-0.20, Mn 0.01-2.17, Ni 0.05-0.10, and Zn 0.67-4.67. According to the results, the majority of detected elements were below the concentration limits given by the European standards. Total amount of present heavy metals was determined after microwave digestion of materials at the maximum temperature of 200 0C (350 W) in 7 M nitric acid. This method was compared with the traditional open vessel digestion and dry mineralization, but was proven to be the most efficient digestion procedure. The resulting solutions were analyzed by ICP-OES. The impact of heavy metals on textile processing in the Croatian textile industry, in which different problems caused by metals arise during the bleaching step, was also investigated. Textiles were sampled during different steps in textile processing from Croatian textile industry, in which approximately 1 % of the material was being ruined during the bleaching process. Results of fabrics taken before the bleaching process showed 10-100 times higher copper concentration than normal. Copper was found to be the dominant metal (8.1 -108.4 μ g / mL), followed by iron (16.9 – 37.9 μ g / mL). Since those metals induce radical decomposition of hydrogen peroxide that damages the cellulose fibers, it was the most probable reason for the damaging of the processed cotton materials. The results of the above described investigations should contribute to the improvements and development of new textile production applications for the removal of heavy metals present in textile raw materials and on the produced clothing, resulting in better processing efficiency and final product quality. The proposed treatment should be implemented in the final stages of textile processing: after applying microwave and ultrasonic extraction heavy metals would be completely removed. This would result in a better textile product quality and in a reduction of production expenses, because the degradation of cellulose fibers during hydrogen peroxide bleaching could be prevented. This will also result in textile products fulfilling the international quality standard requirements, as well as achieving higher prices on the market.

heavy metals; ultrasonic extraction; microwave extraction and digestion; ICP-OES; textiles; optimization ;

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