Analysis And Application Of Toxic Substances In The Production Of Fat Plastic Products

Recycling and reuse of waste printed circuit board to form the plastic resin.The plastic resin can be applied to various occasions which will improve the utilization ratio of waste printed circuit board.However,the secondary pollution caused by the toxic and harmful substances produced in the production and recycling of plastic resin is urgent.This paper introduced the production process of a kind of imitation stone slab,which is made of waste circuit board.According to the characteristics of the sample matrix,the method for the analysis of four kinds of toxic materials in the production process of imitation brick is established,such as dioxins?PCDD/Fs?,heavy metals lead?Pb?,polybrominated biphenyls?PBBs?and polybrominated diphenyl ethers?PBDEs?.Finally,these methods will be used to monitor these four kinds of toxic materials in the process of imitation brick.This experiment scheme use the Soxhlet Extraction?SE?with Toluene to detecting the 2,3,7,8-PCDD/Fs of solid sample.The extracts will be cleaned with multi-layer silica gel column and activated-charcoal column to obtained the dioxins samples.And the sample is separated by HRGC on 60 m capillary chromatographic columns and determined by HRMS on multiple ion detection?MID?mode.The identification of PCDD/Fs is based on the retention times of ¹³C-labelled standard and the abundance ratios of the two exacted mass-to-charge ratios.The quantitative analysis is performed using the ratios of the integrated areas of the ¹³C-labelled standards.The samples of waste printed circuit board and the plastic resin are analyzed by isotope dilution-high resolution gas chromatography-high resolution mass spectrometry?ID-HRGC-HRMS?.The results show that,the recovery rate of15 kinds of ¹³C-2,3,7,8-PCDD/Fs is 62.24% 86.29%,which meet the national standard requirements?17%¹81%?.In order to detect the PBBs and PBDEs of solid sample,an experimental scheme will be put forward by using Soxhlet Extraction?SE?with Toluene.The extracts are cleaned with silica gel column and be concentrated by evaporative concentration.The samples of waste printed circuit board and the plastic resin are analyzed by Gaschromatography-tandem Mass spectrometry?GC-MS/MS?.The results show that,the instrument detection limit is in the range of 3.26 ?g/m L⁹.25 ?g/mL.The recovery rate of PBBs and PBDEs are in the range of 71.44% 94.39 % and67.32%⁷5.71%.The relative standard deviations are in the range of 1.09%³.05%.Furthermore,the samples can be used the pretreatment of waste printed circuit boards and resin products by ashing and acid digestion,and used Quantitative analysis of lead content by ICP-AES and external standard method.The results show that,the linear correlation coefficients?R2?are greater than 0.999.The monitoring results of four kinds of toxic substances in the samples of imitation brick show that,the total TEQ of dioxins in imitation brick is 5.0860 ng TEQ/kg,the contents of PBBs and PPBDEs are 6.8869 ?g/g and 2.5570 ?g/g,and heavy metal contents of Pb is 0.0622 mg/g.The actual result data of these four kinds of toxic materials are much lower than the limit value of the Identification standards for hazardous wastes-Identification for toxic substance content?GB5085.6-2007?.The production process of imitation stone brick will not produced these four kinds of toxic substances.These toxic substances are produced from the raw material of the imitation brick.Waste water contains a small amount of toxic substances.