The objective of this study was to investigate the removal of mercury chloride in flue gas emitted from municipal waste incinerator (MWI) by the adsorption of powdered activated carbon derived from the pyrolysis of waste tires (PAC-T). This study focused on the removal efficiency of mercury chloride and the adsorption capacity of PAC-T. The operation parameters investigated included temperature (30¢J and 150¢J) and powdered activated carbon injection rate (0.1, 0.2 and 0.3 g/hr). Experimental tests were conducted by the following three steps¡G the adsorption column test, the adsorption isotherm simulation, and the removal efficiency test in a pilot plant. The adsorption capacity of PAC-T for various inlet mercury chloride concentrations (55~215£gg/m3) at room temperature (30¢J) were 811~2,188£gg-HgCl2/g-PAC, while the absorption capacity of PAC-T at 150¢J were 214~700£gg-HgCl2/g-PAC which were lower than those at room temperature. It suggested that the adsorption capacity of PAC-T decreased as adsorption temperature increased. Furthermore, the adsorption of mercury chloride by PAC-T was an unfavorable adsorption isotherm. The adsorption column tests were performed to assess the rate of mercury chloride uptake by PAC-T at 30 and 150¢J. Results from the adsorption isotherm simulation indicated that mercury chloride at room temperature (30¢J) can be simulated by the Redlich and Peterson isotherm. However, the adsorption of mercury chloride at 150¢J can be simulated by the Langmuir isotherm. Experimental results from the pilot tests indicated that the removal efficiency of mercury chloride increased gradually with retention time and then leveled off as retention time was higher than thirty minutes. Moreover, the removal efficiency of mercury chloride increased dramatically as PAC-T injection rate increased from 0.1 to 0.3 g/hr. The highest removal efficiency of mercury chloride which can be achieved by waste-tire derived powdered activated carbon (PAC-T) and commercial powdered activated carbon (PAC-C) were 86.5% and 98.9%, respectively. In general, PAC-T was comparative to PAC-C for the removal of mercury chloride from flue gas on the basis of both physical and chemical properties and removal efficiency of mercury chloride.

This study investigated the adsorptive capacity and isotherm of HgCl2 onto spherical activated carbons (SAC) via thermogravimetric analysis (TGA). Activated carbon injection (ACI) is thought as the best available control technology (BACT) for mercury removal from flue gas. There are two major forms of vapor-phase mercury, Hgo and Hg2+, of which HgCl2 accounts for 60-95% of total mercury. Mercury emitted from the incineration of municipal solid wastes (MSW) could cause severely adverse effects on human health and ecosystem since it exists mainly in vapor phase due to high vapor pressure. Although the adsorptive capacity of HgCl2 onto activated carbon has been studied in previous adsorption column tests, only a few studies have thoroughly investigated the adsorption isotherms of HgCl2 onto SAC. Equilibrium and kinetic studies are important towards obtaining a better understanding of mercury adsorption. Many investigations have addressed the relationship between sorption kinetics and equilibrium for different adsorbent/adsorbate combinations. For the removal of vapor-phase mercury, several bench-pilot, and full-scale tests have be proceeded to examine the influence of carbon types, carbon structures, carbon surface characteristics, injection methods (dry or wet), amount of carbon injected, and flue gas temperature on mercury removal. In addition, the dynamics of spherical activated carbons (SAC) adsorbers for the uptake of gas-phase mercury was evaluated as a function of temperature, influent concentration of mercury, and empty-bed residence time. However, only a few studies investigated the adsorption isotherms of HgCl2 onto activated carbons. In this study, TGA was applied to obtain the adsorptive capacity of HgCl2 onto SAC with adsorption temperature (30~150oC) and influent HgCl2 concentration (50~1,000£gg/m3). Experimental results indicated that the adsorptive capacity of HgCl2 onto SAC was 0.67and 0.20 mg/gC at 30¡B70 and 150oC, respectively. This study investigated the adsorptive capacity of HgCl2 vapor onto SAC via TGA analysis. Experimental results indicated that the adsorptive capacity of SAC decreased with the increase of the adsorption temperature. Furthermore, the results suggested that that the adsorption of SAC on HgCl2 vapor was favorable equilibrium at 30 and 70¢J and unfavorable equilibrium at 150¢J. In comparison of the experimental data with isotherm equations, Freundlich isotherm fitted the experimental results better than Langmuir isotherm. The model simulations were found to fit very well to the high concentration experimental kinetic data for both adsorption and desorptionusing two adjust parameter, effective diffusivity, and the Freundlich isothermexponent.¡@The extracted model parameter, effective diffusivity and n, were then used to predict the experimental kinetic data for the same combination at other concentrations.

This study investigated the production of powdered activated carbon derived from carbon black of pyrolyzed waste tires, and their adsorptive capacity on vapor-phase mercury chloride (HgCl2) using both adsorption column and thermogravimetric adsorption systems. The adsorption isotherms and kinetic models were further simulated in the study. In addition, an innovative compositive impregnation process was developed to increase the sulfur content of powdered activated carbon derived from waste tires. The activation of carbon black to form powdered activated carbon was performed in a tubular oven. The operating parameters including activation temperatures, activation time, and water feed rates were investigated in this study. Experimental results indicated that the yield of carbon-black derived powdered activated carbon (CBPAC) decreased with the increase of activation temperature, activation time, and water feed rate, while the BET surface area and pore volume decreased. In the comparison of activation time and water feed rate in the activation process, activation time had an important impact on the production of specific surface area than water feed rate. The optimal operating parameters included activation temperature of 900¢J, activation time of 180min, water feed rate of 0.5 mLH2O/gC-sec, and water injection behind activation process of 17.5 min. From the analysis of carbon surface, the carbon contents of powdered carbon black (PCB), CBPAC, commercial powdered activated carbon (CPAC) were 89.5%, 87.6%, and 88%, respectively. The C (1s) peak region of PCB consisted of 49.8% C-C, 38.9% C-O, 10.5% C=O or O-C-O. Similar analysis results showed that the total area of the C (1s) peak region of CBPAC consisted of 57.5% C-C, 26.8% C-O, 8.1% C=O or O-C-O, and 7.6% O-C=O. Similar to CPAC, the C (1s) peak region consisted of 42.6% C-C, 41.8% C-O, and 15.6% O-C=O. Furthermore, the sulfur contents of PCB and CBPAC were both 0.5%. The S (2p) peak region of PCB consisted of 58.9% ZnS (zinc sulfide) and 41.1% S=C=S. For CBPAC, the S (2p) peak region solely contained S=C=S. The comparison of two sulfur impregnation processes revealed that the innovative compositive impregnation process could simultaneously increased the sulfur content and the BET surface area of powdered activated carbon (PAC), however, the direct impregnation process increased the sulfur content while the BET surface area of PAC decreased linearly. Without the disadvantages of time and energy consumption associated with direct impregnation, the compositive impregnation is an efficient and energy-saving process for producing sulfurized PAC with a high BET surface area and high sulfur content. Experimental results obtained from the adsorption column tests indicated that the influence of the adsorption depth on the adsorptive capacity of CBPAC did not vary much, while the adsorptive capacity of CBPAC increased with HgCl2 concentration. Furthermore, the adsorptive capacity of CBPAC on vapor-phase HgCl2 was less than that of CPAC at the adsorption temperatures of 25~150¢J and high humidity of 12.3 wt %. The difference of adsorptive capacity for CBPAC and CPAC correlated closely with BET surface area and sulfur content. Results form the thermogravimetric adsorption analysis indicated that the adsorptive capacity of CBPAC and initial adsorption rate on vapor-phase HgCl2 increased with HgCl2 concentration and decreased with adsorption temperature. In the kinetic modeling, the deviation of experimental and simulated values simulated by the pseudo-first-order model was lower than those of pseudo-second-order models. Furthermore, the r (correlation coefficient) of pseudo-first-order and pseudo-second-order models were 0.9745~0.9977 and 0.9217~0.9780, respectively. It suggested that the pseudo-first-order model could simulate the adsorption of HgCl2 onto CBPAC better than pseudo-second-order model.

In the present study, both in vitro and in vivo experiments were performed to investigate modes of action of selected EDCs including mercury chloride (HgCl2), bisphenol A (BPA), vinclozolin (VZ) and Di-(2-ethylhexyl)-phthalate (DEHP) on male reproductive physiology in fish. Results obtained from in vitro studies showed that EDCs decrease sperm motility via disruption in energetics and damage to spermatozoa; however the effective doses are higher than reported in the environmentally relevant concentrations. In contrast, in vivo studies showed adverse effects of BPA, VZ, and DEHP on sperm quality at environmentally relevant concentrations. Decrease in sperm quality is associated with disruption in testicular steroidogenesis, particularly inhibition of androgens. Only BPA induced vitellogenin production, associated with increase in transcripts of estrogen receptor, androgen receptor and cytochrome P450 mRNA at the high dose approaching environmental level. Inhibition of androgen production is due to disruption in transfer of cholesterol into the steroidogenesis pathway, because transcript of steroidogenic acute regulatory protein mRNA was decreased. In addition, BPA acts through sex steroid-mediated mechanism while DEHP mode of action is sex-steroid independent mechanism.

Made available in DSpace on 2016-06-02T19:22:04Z (GMT). No. of bitstreams: 1 2543.pdf: 1092936 bytes, checksum: 2fe1545577f51cbb0e2fb861e1efb516 (MD5) Previous issue date: 2009-07-16 / Financiadora de Estudos e Projetos / The bone tissue is influenced by internal and external factors and heavy metals, as mercury, are examples of external or environmental factors. The mercury chloride (HgCl2) when absorbed by human body, deposits in the bone and fat tissue and dislocates bones and muscles minerals to circulation, being able to provoke illnesses. In this study, Wistar rats were divided in 4 groups: 3m, 6m, 9m and 12 months (12m) days of life. The animals were treated with HgCl2 or saline through gavage. The treatment began at 30 days of age, 5 times per week, during 60 days. The daily dose was of 0,3mg/Kg of body weight (BW) of HgCl2 and 0,1ml of saline/100g BW. After this period, the group 3m was sacrificed immediately afterwards by decapitation whereas the other groups had remained without treatment until they completed the desired age. The right femurs and vertebrae (L5) were removed for biometrics, physical and biomechanics analysis. The treatment with mercury chloride induced higher values of physical and biometric parameters in the 6m group and lower values in the 12m group and no odifications in the 3 and 9 m groups, when compared with saline treatment. Moreover, the treatment with CM promoted rats vaginal opening with 51 days of life in treated group whereas in the controls this opening occurred in 44,4 days of life.We concluded that the treatment with HgCl2, in the dose of 0,3mg/Kg BW retarded the age at the speed change of the growth of the animals, especially in 6m and 12m groups. Moreover, the HgCl2 promoted bone fragility in animals from 12m group, as can be observed by the analysis of the biometrics, physicals and biomechanics properties, in both femur and vertebrae. The treatment with CM still delayed the sexual maturity of rats. / O tecido ósseo sofre influências de fatores intrínsecos e extrínsecos. Entre os fatores externos ou ambientais, encontram-se os metais pesados, como por exemplo, o mercúrio. O composto cloreto de mercúrio (CM - HgCl2) quando absorvido pelo ser humano, se deposita no tecido ósseo e gorduroso deslocando minerais nobres dos ossos e músculos para a circulação, podendo provocar doenças. Neste estudo, ratas Wistar foram divididas em 4 grupos: 3m, 6m, 9m e 12 meses (12m) de vida. Os animais tratados com mercúrio receberam HgCl2 e os controles, salina por gavagem gástrica. O tratamento iniciou-se aos 30 dias de vida do animal, 5 vezes por semana, durante 60 dias. A dose diária foi de 0,3mg/kg de peso corporal de HgCl2 e de 0,1ml de salina /100g de peso corporal. Após esse período, o grupo 3m foi sacrificado logo em seguida por decapitação enquanto que os demais grupos permaneceram sem tratamento até que completassem a idade desejada. Os animais tiveram seus fêmures direitos e vértebras (L5) retirados para análise dos parâmetros biométricos, físicos e biomecânicos. O tratamento com CM promoveu aumentos dos valores dos parâmetros físicos e biométricos no grupo 6m e redução no grupo 12m, e inalteração nos grupos 3 e 9 meses. Além disso, o tratamento com CM promoveu abertura vaginal das ratas tratadas com CM aos 51 dias de vida enquanto que nos controles essa abertura ocorreu nos 44,4 dias de vida. Concluímos que o tratamento com HgCl2, na dose de 0,3mg/Kg PC retardou a idade em que ocorre a mudança de velocidade do crescimento dos animais, especialmente nos grupos 6m e 12m. Além disso, a contaminação com mercúrio promoveu fragilidade óssea nos animais do grupo 12m, comprovada pela análise das propriedades biométricas, físicas e biomecânicas, tanto dos fêmures como das vértebras, além de atrasar a maturidade sexual das ratas.

The object of this study is to design demembranation method on four freshwater species and its application on study of the influence of HgCl2 on the axoneme and motity sperm motility parameters. Demembranation was designed and examined for all investigated species common carp (Cyprinus carpio), sterlet (Acipenser ruthenus), perch (Perca fluviatilis) and african catfish (Clarias gariepinus). One-step and two-step method was designed and tested for common carp. One-step method was designed for sterlet and perch. Two-step method of demembranation was designed for african catfish. Demembranation was designed and examined for all species under examination. Sperm motility was evidently increased above normal physiological value. Other sperm motility parameters (velocity, percent of motile cells) slightly decreased. HgCl2 in concentration 0,01 mM to the demembranation medium didn't show effect on flagellar microtubule aparat and then to the motility parameters, except sterlet; demembranated sterlet sperm was inhibited at all used concentration of HgCl2. Concentration 0,1 mM had inhibition effect on carp and africant catfish spermatozoa. Concentration 1 mM HgCl2 inhibited sperm of all tested species.