Study to determine the content of some chlorbenzen compounds from unintentional emission sources in industrial zones in Thai nguyen province

1 MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY ------- *** ------- STUDY TO DETERMINE THE CONTENT OF SOME CHLORBENZEN COMPOUNDS FROM UNINTENTIONAL EMISSION SOURCES IN INDUSTRIAL ZONES IN THAI NGUYEN PROVINCE Major: Analyticalchemistry Code: 9.44.01.18 SUMMARY OF DOCTORAL THESIS Ha Noi, 2019 2 This thesis is completed at: Vietnam Academy of Science and Technology Scientific instructors: Assoc. Dr. TU BINH MINH Assoc. Dr. NGUYEN THI HUE Thesis reviewer 1: Prof. Dr. Thesis reviewer 2: Assoc. Dr. Thesis reviewer 3: Assoc. Dr. The thesis will be presented to the scientific council at the Vietnam Academy of Science and Technology at ..h, date .., month .., year 2019 3 INTRODUCTION 1. The urgency of the thesis Research on the pollution of persistent organic compounds (POPs) has been receiving the attention of many scientists all around the world. The assessment of pollution levels and emissions of dioxin- like chlorobenzene compounds such as hexaclobenzene (HCB), Pentaclobenzene (PeCB), tetrachlorene (TeCB), triclobenzene (TCB), diclobenzene (DCB) is the scientific basis for countries. Participating in signing the Stockholm Convention to implement the plans for management, disposal and environmental pollution treatment by POPs well. In Vietnam, the focus is mainly on studying U-POPs such as dioxin, furans and PCBs in soil, sediment, organisms and human. Disclosures related to unintentional emissions of chlorbenzen compounds into the environment from industrial manufacture and waste disposal in Vietnam are limited. From above problems, it is necessary to research into the overall sources of emissions and the level of environmental pollution caused by the sources of industrial waste of chlorbenzenes, optimizing the efficiency of the process analysis in accordance with conditions in Vietnam. This is a topical issue in current conditions when health and environment in Vietnam are at an alarming level. Therefore, I decided to choose the topic "Study to determine the content of some chlorbenzen compounds from unintentional emission sources in industrial zones in Thai Nguyen province", contributing to the protection and sustainable development of ecological environment in Thai Nguyen province. 2. Research objectives of the thesis - Study the process of simultaneous determination and evaluation of the method of analyzing 7 chlorobenzene, including 1,2- 4 dichlorobenzene (1,2-DCB); 1,3-dichlorobenzene (1,3-DCB); 1,2,4- trichlorobenzene (1,2,4-TCB); 1,2,3,4-tetrachlorbenzene (1,2,3,4- TeCB), 1,2,4,5-tetraclobenzene (1,2,4,5-TeCB); pentaclobenzene (PeCB) and hexaclobenzene (HCB) in trace and superficial content in flue gas samples and industrial waste (fly ash, bottom ash, input materials). - Adopting an optimal procedure to simultaneously identify chlorobenzene in industrial samples including waste gas, ash, materials of some industrial fields in industrial zones in Thai Nguyen province. - Preliminary assessment of the level and emission characteristics of chlorobenzene from the thermal process of a number of industrial fields including waste incinerators, metallurgy, brick production and cement production. 3. The main research contents of the thesis - Study the process of simultaneous determination and evaluation of the method of analyzing 7 chlorobenzene + Survey and select optimal conditions to analyse chlorbenzen compounds on gas chromatography equipment using electronic resonance detector (GC-ECD) and mass spectrometry (GC- MS) + Investigate optimization of processing samples including extraction, cleaning and enrichment. + Verification of analytical methods: determination of linear range, calibration curve, detection limit and quantitative limit, recovery coefficient and repeatability of the method. - Apply the optimal procedure to simultaneously identify chlorbenzenes in industrial samples. 5 + Analysis of the content of chlorbenzenes in gas samples and solid samples taken from factories in Thai Nguyen province and some northern provinces on GC-ECD equipment and confirm the presence of above chlorinated benzene compounds GC-MS. + Evaluation of homogeneous characteristics is the ratio of the content of each substance to the total content of chlorobenzene, in the types of industrial waste gases and solid waste samples. + Evaluation of emission factors is to find out annual emissions and the risk of chlorobenzene on humans from a number of industries in Thai Nguyen province. 4. New contributions of the thesis 1. Optimized conditions to simultaneously identify 7 clobezen targets, in industrial samples (waste gas samples and waste solid samples (Fly ash, bottom ash) in trace amounts and super stains using GC-ECD and GC-MS. 2. Successfully developed the process of analyzing chlorbenzen compounds in trace amounts and super stains. 3. The first step was to identify and determine the emission level through the emission factor and the annual emission of 7 chlorbenzenes from industrial solid waste samples in Thai Nguyen province. This is the first published study in Vietnam on unintentional emission levels of chlorbenzenes in some industries. Thereby contributing to the control of emissions to limit and completely eliminate hazardous POPs in the environment, meeting the requirements of the Stockholm Convention, towards sustainable development in Vietnam 6 CHAPTER 1: OVERVIEW OF RESEARCH PROBLEMS 1.1. OVERVIEW OF THE RESEARCH SUBJECT 1.1.1. Overview of Chlorobenzens Derivatives of chlorbenzenes C6H (6-x) Clx form a stable and colorless group with a pleasant odor. Chlorine can be substituted for six hydrogen atoms on benzene rings to be able to form twelve different chlorinate compounds including: Monoclobenzene (MCB); ortho-diclobenzene (1,2-DCB); meta-diclobenzene (1,3-DCB), para- diclobenzene (1,4-DCB); 1,2,3-triclobenzene, 1,2,4-triclobenzene; 1,3,5-triclobenzene; 1,2,3,4-tetraclobenzene; 1,3,4,5-tetraclobenzene; 1,2,4,5-tetraclobenzene; Pentaclobenzene; Hexaclobenzene. The physical and chemical properties of clobenzene (CBz) compounds when they are released into the environment, are likely to evaporate into the atmosphere. The atmospheric CBz will be decomposed primarily through reactions with hydroxyl radicals to produce nitroclobenzene, clophenol, and fatty dicarbonyl products, which continue to be removed by photochemistry or reaction with hydroxyl radicals. CBz compounds released into water will accumulate in suspended solids and sediments (especially rich organic sediments). All CBz are easily absorbed by humans and animals through the digestive and respiratory pathways.The absorption is affected by the position and number of chlorine in chlorobenzene congeners. After absorption, chlorbenzenes quickly distribute to organs, accumulate mainly in adipose tissue and can remain there for a long time, in small amounts in the liver and other organs 1.1.2. the formation of chlorbenzen compound from some industrial activities An incomplete destruction of burned materials in which CBz is available. CBz Formed by the metabolism of compounds is precursor or formed in low temperature areas from carbon particles and chlorine compounds - synthesized denovo. However, the CBz emission content during combustion depends very much on the 7 combusting conditions and the presence or absence of catalytic materials. CBz can also be formed due to the chlorination process of HCB (Figure 1.1) in the presence of catalysts such as Cu, CuO, High / a-Fe2O3 metal .....) to create copper lower chlorine CBs 1.2. DOMESTIC AND OVERSEAS STUDY SITUATION 1.2.1. Studies in the world In recent years, a number of studies have also focused on unintentional POPs emissions from the production of non-ferrous metals and ferrous metals, iron ore production of iron and steel, coke production and other secondary color metallurgy process. A research in China in the industry of zinc and lead metals production in 2007 showed that the average emission factor of PCDD / Fs in gas samples for lead and zinc manufacturing industry is 98.2 and 0.35, respectively. ng TEQ / (Nm3); in fly ash samples is 5.64 ng TEQ / g with zinc industry; 0.05 ng TEQ / g in lead manufacturing industry. Emission factors of gas samples for PCBs from zinc and lead production are respectively 2,786 and 0,002 ng TEQ / Nm3.The formation and reduction of emissions of clobenzene, polychlorinated dibenzo-p- dioxin and dibenzofurans polychlorinated (PCDD / Fs) have been studied in a typical dry cement kiln in China. Emissions of PCDD / F and CBz in emissions are 0.16 ng I-TEQ Nm-3 and 26 µg / Nm3 respectively. The concentration of 1,2-DCB ranges from 100 - 9424 ng / Nm3; 1.3 and 1.4 –DCBz are 223 - 6409 ng / Nm3 1,3,5 / 1,2,4 / 1,2,3- TCB in the range of 35 - 3542 ng / Nm3 (of which 1.2, 4 accounts for the largest amount); 1,2,3,5-TeCB & 1,2,4,5-TeCB range between 2 - 491 ng / Nm3, while isomer 1,2,3,4-TeCB is 6 - 562 ng / Nm3 ; Concentrations PeCB and HCB range from 1 to 335 ng / Nm3 and 1 to 128 ng / Nm3 respectively. 1.2.2. Domestic studies in Vietnam Studies on POPs compounds such as dioxin / furan, DDT, PCBs in Vietnam have been of interest since the end of the 20th century because of their toxicity and changes in awareness in 8 environmental protection of managers as well as scientists. However, in Vietnam, the focus is only on studying POPs in environmental objects of soil, sediment, organisms and people to overcome the consequences of chemical toxins / dioxin. No claims have been made regarding the assessment of the emissions of chlorbenzen compounds (DCB, TCB, TeCB, PeCB, HCB) unintentionally emissions in many industrial production and recycling industries. So the assessment and comparison of pollution levels and emission sources for this group of substances face many difficulties. CHAPTER 2: EXPERIMENT AND RESEARCH METHOD 2.1. SCOPE AND SUBJECTS OF RESEARCH The research object of the thesis is 7 chlorbenzen targets of 5 isomers, including dichlorobenzene (1,2; 1,3 - DCB); trichlorobenzene (1,2,4- TCB); tetraclobenzene (1,2,3,4; 1,2,4,5-TeCB); Pentaclobenzene (PeCB) and hexaclobezen (HCB). * Industrial factories and incinerators in Thai Nguyen province are listed in table 2.1 * Industrial production plants and incinerators in Northern provinces of Vietnam collected for comparison with samples collected from Thai Nguyen Table 2. 1. Information about actual samples orde r Sample factory name Date of samplin g Factor y sign Type of productio n Capacit y (ton / h) Emissio n rate (Nm3 / h) Averag e capacit y / year THÁI NGUYÊN 1 Viet Trung black metallurgy factory 03/2014 NMLK 1 iron and steel 6,0 31000 8040 2 Metallurgic al company 2 06/2014 NMLK 2 Zinc oxide 1,0 14700 7000 9 3 Duc Thinh Mechanical Company 12/2017 NMLK 3 Cast Iron 2,5 - 2496 4 Thai Nguyen Black Metallurgy Joint Stock Company - Nam Son Black Metallurgic al Plant 03/2017 NMLK 4 Cast Iron 5,8 - 8040 5 Mechanical Factory Z115 Ministry of Defense - Thai Nguyen 12/2017 NMLK 5 Steel rolling 0,04 - 8040 6 Thai Son tunnel brick factory 03/2014 NMVL 1 Brick 5,8 16500 6530 7 Khe Mo tunnel brick factory 03/2017 NMVL 2 brick 5,0 - 8040 8 Quan Trieu Cement Factory 06/2014 NMVL 3 Cement 40 - 7920 9 Phuc loi Trade and Service Cooperativ e 06/2014 LDCN Industrial waste 0.25 20000 2640 10 Dong Hy General Hospital 03/2014 LDYT Medical waste 0.2 - 1536 11 Incinerator for domestic waste - Da- Phu Luong town 03/2017 LDSH 1 Domestic waste 0,45 - 2900 12 Household waste 03/2017 LDSH 2 Domestic waste 0,7 - 2900 10 incinerator - Song Cau town 13 Waste incinerator - Trai CauTan Cuong waste incinerator 03/2017 LDSH 3 Domestic waste 0,45 - 2900 14 waste incinerator - Tan Cuong town 03/2017 LDSH 4 Domestic waste 0,7 - 2900 2.2. RESEARCH METHODS 2.2.1. Objectives of the study 2.2.2. research content 2.2.3. Methods of document review 2.2.4. Survey method 2.2.5. Experimental method 2.2.5.1. Sampling, shipping and preservation methods 2.2.5.2. Sampling and actual sample information 2.2.5.3. Method of CBz analysis on GC-ECD equipment 2.2.5.4. Study the sample processing process and confirm the use value of the method 2.2.5.5. Analysis of real samples 2.2.5.6. Evaluation of emission levels and assessment of the risk of chlorbenzen compounds 11 2.3. PROCESS OF ANALYSIS Figure 2.1 Process of analyzing CBz in solid samples Figure 2.2. Process of analyzing CBz in gas sample 12 CHAPTER 3: RESULTS AND DISCUSSION 3.1. SURVEY THE OPTIMIZED CONDITIONS FOR ANALYSIS OF CBZ TIMES ON GAS ACCESSORIES 3.1.1. Investigate optimal conditions with CBz standard solution on GC-ECD equipment 3.1.1.1. Column temperature program According to the results, it was found that the increase of high temperature from 120oC – 150oC was not suitable, so the thesis selected the temperature of 70o C as the initial temperature then gradually increased the temperature to 120oC in 2 minutes, the separation of substances with more reasonable retention time. CBz results show that at a low heating rate of 5 ° C / min long analysis time (more than 30 minutes) causes time to analyze as well as other factors. High heating speed of 20° C / min causes peaks to be eluted quickly, thus resulting in peak duplication. At a heating speed of 10°C / min, it’s good for peak separation and reasonable analysis time (about 20 minutes). Therefore, choosing a heating speed of 10° C / min for further studies. After investigating the optimal conditions when analyzing CBz with GC-ECD, the parameters are listed in Table 3.1. Table 3.1. Excellent parameters when analyzing CBz on GC-ECD 2010 device Pump port temperature 220 ° C Air flow mode Pressure Column head pressure 100 kPa Volumetric suction sample 1 µl Pu p mode Divide the line Line split rate 1:10 Sample pumping program Pressure Fl w rate through column 1 ml / minute Separation column SPB-608 (30 m × 0.25 mm × 0.25 µm) Column oven temperature program 70 oC 70 oC to 120oC Heating speed 10° C / min; hold 2 minutes 13 120 oC to 280oC Heating speed 10° C / min; hold for 5 minutes Total analysis timephân tích 18minutes Detector Temperature 300 °C Gas carries Nitrogen 3.1.1.2. Sample pump conditions Results of analysis on GC-ECD showed that when using non- split mode, the peak has a special tail-pulling phenomenon at peak 1 and 2, which affects the process of determining the area of peak used for quantification. The thesis chooses split-line mode to analyze CBz on GC-ECD equipment. At low current conditions of 1: 5, peaks tend to move toward the solvent peak. 1: 20 high current split conditions for low signal PeCB, HCB signal, increase the influence of baseline during analysis. Therefore, the thesis uses the ratio of 1:10 for the peaks of the CBz signals and is used in the next survey conditions. The result of retention time of CBz is shown in Table 3.2 Table 3.2. Retention time of CBz standard solutions on GC- ECD equipment Number Name of substance Retention time (minute) 1 1.3 Diclobenzen 4.667 2 1.2 Diclobenzen 5.310 3 1.2.4 Triclobenzen 7.812 4 1.2.4.5 Tetraclobenzen 10.707 5 1.2.3.4 Tetraclobenzen 11.974 6 Pentaclobenzen 14.016 7 Hexaclobenzen 16.729 8 CB 209 17.545 9 Pentanitroclobenzen 17.885 3.1.2. Results of evaluation of stability of CBz analytical signal on GC-ECD device 3.1.2.1. Stability of analytical signals Calculated results of research CBz for repeated injections of standard solution at low concentration C1 and high concentration C2 have RSD values varying from 1.27% to 15.0% (<20%) which shows repeatability of good analytical signals, high stability. 14 3.1.2.2. Qualitative limit (LOD) and quantitative limit (LOQ) of the device The analytic results obtained the LOD value of the gas chromatograph for the study CBz ranging from 0.94 to 1.46 ppb and LOQ value from 3.14 to 4.87 ppb. This is a concentration with good detectional sensitivity and a relatively stable peak signal. 3.1.3. Determine the linear range of the calibration curve of CBz on GC-ECD device The calibration curves of substances has regression coeffiction R2 greater than 0,99 3.1.4. Analysis of CBz on GC / MS equipment 3.1.4.1. Optimal condition for CBz analysis on GC / MS equipment Table 3.3. Optimal parameters when analyzing CBz on GC-MS devices Table 3.4. Parameter of mass spectrometry and retention time of CBz on GC-MS device (a)-Chromatography scan CBz on GC-MS device (b) Chromatography standard CBz solution 10 ng / g ( 1: 1,3-DCB; 2: 1,2- DCB; 3: 1,2,4 - TCB; 4: 1,2,4,5 - TeCB;5: 1,2,3,4 – TeCB; 6: PeCB; 7: HCB;8: PeCNB) Figure 3. 1. Chromatogram of CBz on GC / MS device 15 Based on the analytical conditions on GC-MS, analyze and inject some analytical samples with complex background as waste ash onto GC-ECD and GC-MS to confirm the presence of Chlorbenzenes in these samples 3.1.4.2. Detection limit (IDL) and quantitative limit (IQL) of CBz on GC / MS equipment LOD values of GC / MS chromatography equipment for CBz range from 1.25 to 3.75 ppb and LOQ values from 4.16 to 12.5 ppb. 3.2. STUDYING CONDITIONS OF EXCLUSION AND EXECUTION OF CBz 3.2.1. Investigate the optimal conditions for sample cleaning on GC-ECD equipment 3.2.1.1. Liquid - solid extraction method The results of the survey show that the recovery of CBz which when extracting with different solvents varies widely from 66.7 to 96.1%. It can be seen that the recovery of all CBz is uniformly high when extracted with DM1.1 (from 81.8 to 96.1%) and DM 2.3 (80.3 - 93.0%). For compounds 1,2 and 1,3-DCB the recovery in DM 1.2 is quite high compared to other survey solvents (83 -85%) and the lowest in DM 2.1 solvent (65.2 - 67.6%). Thus, to be able to simultaneously identify 7 CBz, the thesis selected solvent extracting sample DM1.1 for high recovery evenly with all CBz, with relatively small standard deviation (<10%) 3.2.1.2. Soxhlet extraction method Results of CBz recovery by Soxhlet extraction method with solvents give the best recovery, uniformity and stability for 7 CBz (83.8 to 99.2%) when using solvent mixture DM 1.1 and DM 2.1 solvent (82.2- 108%). Results of recovery from two extraction methods showed that liquid-solid extraction method for ash and dust samples gave lower recovery than Soxhlet extraction method but still met the requirements 16 for analyzing trace amounts Volatile organic in the complicated sample matrix (recovery over 80%). 3.2.2. Survey optimal conditions during sample cleaning 3.2.2.1. Method of cleaning up the extract on the column using activated carbon silica gel mixture 10% Table 3.10. Survey elution solvent on silicagel extraction column + activated carbon 10% Name Diclometan : hecxan (1 :3) Aceton : hecxan (1 :1) Aceton : hecxan (1 :2) CH 1 (mL) CH 2 (mL) CH 3 (mL) 40 60 120 40 60 120 40 60 120 1,3 – DCB 76,5 81,3 79,8 78,6 79,1 64,9 73,3 81,2 67,7 1,2- DCB 78,3 82,4 70,9 75,7 79,6 63,1 72,6 79,1 61,2 1,2,4– TCB 80,2 80,5 72,5 79,8 79,5 64,4 78,3 81,7 73,7 1,2,4,5– TeCB 78,3 86,8 79,