Porous, high surface area activated carbon (AC) can be used to remove certain irritating and toxic gases from contaminated air streams. Impregnating AC with carefully selected chemicals can improve ACs adsorption capacity for certain gases and provide adsorption capacity for gases that un-impregnated AC cannot fi lter. Impregnated activated carbons (IACs) and ACs can be used as the active component in respirators. Comparative studies of di fferent commercially available AC samples and of IAC samples, prepared from a wide variety of di fferent chemicals, were performed. The gas adsorption capacity of the samples was tested using sulfur dioxide (SO2), ammonia (NH3), hydrogen cyanide (HCN) and cyclohexane (C6H12) challenge gases and compared to results obtained from a commercially available broad spectrum respirator carbon. The samples were characterized using wide angle x-ray di raction (XRD), small angle x-ray scattering (SAXS), nitrogen adsorption isotherms, thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). Highlights of this work include the discovery of a IAC sample prepared from zinc nitrate (Zn(NO3)2) and nitric acid (HNO3) that, after heating at 180 C under argon, had overall dry gas adsorption capacity that was greater than the commercially available sample. The importance of pore size on the C6H12 adsorption capacity of AC was demonstrated using SAXS and nitrogen adsorption data. A relationship between decreased humid C6H12 capacity and pre-adsorbed water was shown using SAXS, TGA and gravimetric studies.

Tertiary treatment methods were tested on secondary effluent from an abattoir biological wastewater treatment plant with the purpose of renovating it for re-use in the abattoir. The colour and dissolved organic matter could be removed to such an extent that the water would comply with water of insignificant health risk (Department of Health). The treatment process sequence proven to be effective in upgrading this water so insignificant health risk standard were coagulation with a polymer blend, separation, ozonation, filtration and activated carbon filtration. The development of biologically activated carbon in practice was accepted as inevitable and desirable for optimum water quality, but not tested. A deciding factor in the selection of an appropriate treatment was that the final water would also have acceptable corrosion properties. / Dissertation (MSc)--University of Pretoria, 2010. / Chemical Engineering / unrestricted

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: In order to exploit lower grade and complex platinum group metal resources, cheaper and more efficient alternatives to the conventional mill-float-smelt-refine route are being sought. Leaching of platinum and palladium with cyanide has been proposed a number of times as a promising precious group metals (PGM) process option, and although platinum extractions are problematic, progress into the understanding of cyanide leaching of PGM containing ore and concentrate has been made. The platinum and palladium leaching will typically take place at elevated temperatures, which can range from 55°C on heaps to 180°C in autoclaves, with a better degree of leaching occurring with higher temperatures. Although this process for Pt and Pd extraction is a promising process option, research regarding the feasibility of the subsequent upgrading and recovery of the pregnant PGM leach solution, however, has been lacking. Since the carrier-phase extraction of gold using activated carbon offers significant advantages over other processes in terms of simplicity, the high pre-concentration factor, rapid phase separation, and relatively low capital and operating costs, activated carbon was deemed the most suitable sorbent for a Pt and Pd adsorption and stripping process. Very little is published on the adsorption of PGM cyanides onto activated carbon and when the effect of impurities such as base metals and thiocyanate together with a suitable elution method, are considered, no information could be found in the open literature. This study was launched and in general it was found that the activated carbon process does seem to be a viable process consideration for the upgrading of PGMs in a cyanide leach stream. Adsorption rates for dilute PGM solutions (0.15mg/L Pt, 0.38 mg/L Pd, 0.1 mg/L Au) in a stirred vessel indicated a high rate of adsorption within the first 60 minutes (giving more than 98% recovery of precious metals). A comparison of the Pt isotherm (25°C) to Au isotherms from literature indicated a similar loading capacity, while that of Pd was found to be significantly lower. In common with most diffusion controlled processes, an increase in the adsorption rate of platinum, palladium and gold cyanide with an increase in temperature was observed, while experiments with consecutive contacts of the PGM cyanide solution onto the activated carbon revealed that with an increase in temperature, the amount of PGMs that were adsorbed, decreased with each loading. In the absence of free cyanide and base metals, it was found that after 4 consecutive contacts, 99% of the total amount of platinum and palladium adsorbed at 25°C, compared to 85% of the platinum and 83% of the palladium at 50°C. No difference could be seen between the adsorption of gold cyanide at 25 and 50°C after 4 contacts. It has also been established that the detrimental effect of free cyanide on the adsorption of PGMs will increase as the temperature increases. The detrimental effect of the presence of Cu and Ni was found to depend on the amount of these base metals adsorbed, which in turn will depend on the cyanide concentration and the solution temperature. Adsorption of Pt and Pd has been found to be significantly more affected by temperature, cyanide and base metals than the adsorption of gold and needs to be carefully taken into consideration with the design of a PGM adsorption circuit to ensure sufficient Pt and Pd recovery. It is therefore highly likely that an activated carbon recovery process for Pt and Pd cyanide will not be as robust as the gold CIS (carbon-in-solution) process, which is considered to be one of its main advantages. The feasibility of eluting platinum and palladium cyanide complexes from activated carbon was investigated. It was found that platinum and palladium elute from activated carbon almost to completion in 4 to 5 bed volumes (BV) at 80°C, while the elution of gold at this temperature is slow, with a significant amount of gold (≈ 55 %) still to be eluted after 16 bed volumes. An increase in Pt and Pd elution kinetics was demonstrated with an increase in temperature with 99% recovery achieved at 4 BVs with an elution temperature of 95°C. Cyanide pre-treatment has been found to have a large influence on PGM elution. The effect of the NaCN concentration shows an increase in the recovery of Pt, Pd and Au as the cyanide increases from 0 to 2 %, after which the recovery starts decreasing again as the NaCN concentration increases from 2 to 4%. The NaOH concentration was also found to affect the PGM recovery and at 0% NaCN, an increase in the recovery is seen, while at a higher cyanide concentration (2 and 3% NaCN) a decrease in the PGM recovery occurs when the NaOH concentration is increased from 0.22% to 1.65%. A general decrease in Pt, Pd and Au recovery was seen as the ionic strength of the elution water increased and is consistent with literature on Au elution. The effect of a hydrochloric acid pre-treatment, which forms part of the process to remove calcium build-up from the activated carbon, was investigated, and for all the cases the Pt and Pd recovery increased when an acid pre-treatment was performed, compared to no acid pre-treatment. In none of the cases did any of the Pt, Pd or Au elute with the acid or the following rinsing water. The acid pre-treatment performed at 70°C removed a significant 64% to 75% of the Ni present and an additional 9.1% to 10.5% in the following rinsing water step. In the presence of copper cyanide, the elution order has been found to be copper, palladium, platinum and gold, which is the opposite order of adsorption preference. The cyanide pre-treatment has also been found to have a major influence on the elution of Cu and can be explained by the difference in the absorbance strength between the different copper cyanide complexes. The presence of Cu did not have a negative effect on the elution of the PGMs at strong pre-treatment (2% NaCN and 0.55% NaOH) conditions, but at weak pre-treatment conditions (0% NaCN) the recovery of Pt and Pd was reduced by between 10 and 18% after 5 BVs when Cu was present. The presence of 100 mg/L KSCN salt added to the leach solution during the adsorption stage, reduces the elution recovery of the PGMs at 4 BVs from 90% for Pt and Pd, when not present, to approximately 70% when present. The addition of the additional K+ ions reduced the recovery by less that 4% at 4 BV, which indicates that the possible formation of a PGM bonding with thiocyanate ([Pt(SCN)4]2- and [Pd(SCN)4]2-), which adsorb onto carbon, but doesn’t adsorb with water, cannot be ruled out completely. A maximum amount of 0.15% for Pt, 0.28% Pd and 0.6% Au was found to report to the pre-treatment solution at 25°C. For higher pre-treatment temperatures, the amount of Pt and Pd reporting to the pre-treatment solution increased significantly to approximately 8% at 80°C, while the increase in gold was marginal to 0.8% at 80°C. For the higher loading on the activated carbon (7000 mg/kg Pt and Pd), which is expected to be a better representation of plant conditions, 0.07% Pt, 0.11% Pd and 0.12% Au reported to the pre-treatment solution. The PGMs reporting to the pre-treatment solution is attributed to the distribution of the PGMs on the carbon particle, and even though very small, a certain amount of these PGMs would readily desorb or wash off the carbon. It has thus been established here that the stripping of adsorbed platinum cyanide complexes from activated carbon consists of a two step batch process, which involves the pre-treatment of the metal-loaded activated carbon with a relatively strong sodium cyanide and sodium hydroxide solution, prior to the elution step with de-ionized water at 80°C. Through the development of a mathematical model to describe this process, it was found that the rate of release of the platinum ions is governed by the amount of platinum and sodium on the activated carbon and the concentrations of these ions in the bulk of the liquid. This is mathematically described by a modified Freundlich isotherm equation and the mass transfer diffusion equation. The dependency of the platinum elution rate on the sodium concentration on the activated carbon, as suggested by gold related literature (Van Der Merwe and Van Deventer, 1990, Stange, 1990), is confirmed. Furthermore it has been found that the rate of platinum elution interchangeably depends on the equilibrium of the Pt ions at the carbon-liquid interface and the mass transfer of these Pt ions from the interface to the bulk liquid. As both of these rate-limiting factors were found to depend on the sodium concentration, the dominant platinum elution rate limiting factor shifts as the sodium concentrations change as the elution progresses. Four main time periods are used to simplify and to describe this process. The benefits of fundamentally understanding this process can ultimately lead to improved elution, better process control, shorter elution times, smaller elution columns or assist in the development of a continuous elution process. / AFRIKAANSE OPSOMMING: Nuwe prosesse om komplekse laer graad waardevolle metaal ertse te onwikkel in plaas van die konventionele maal-flotasie-smelt-raffineer proses word tans ondersoek. Loging van platinum en palladium met sianied is verskeie kere al voorgestel as n belowende proses opsie en alhoewel die ekstraksie van platinum nog 'n probleem is, is vordering al gemaak om die logings proses beter te verstaan. Die loging van platinum en palladium met sianied sal tipies plaasvind by hoër temperature wat kan wissel van 55°C in n hoop logins proses tot 180°C onder druk. Beter loging vind plaas soos wat die temperatuur styg. Alhoewel hierdie proses belowend is, is daar nog geen navorsing beskikbaar t.o.v die volgende stap in die proses wat die opgradering van die logings oplossing behels. Aangesien die gebruik van geaktiveerde koolstof in die goud industrie baie voordele inhou soos die eenvoudigheid van die proses, hoë opgraderings faktor, relatiewe vinnige adsorpsie en lae kapitaal en operationele kostes, mag hierdie tegnologie ook geskik wees vir Pt en Pd. Baie min is gepubliseer oor die adsorpsie van waardevolle metale (PGMs) met geaktiveerde koolstof en wanneer die effek van onsuiwerhede soos basis metale en thiosianied saam met n afstropings metode in ag geneem word, kon geen informasie in the literatuur gvind word nie. Hierdie studie is dus geloots en in die algemeen is daar bevind dat die geaktiveerde koolstof metode wel n geskikte oplossing bied vir die opgradering van PGMs in 'n sianied logings stroom. Adsorpsie snelheid vir verdunde PGM oplossings (0.15mg/L Pt, 0.38 mg/L Pd, 0.1 mg/L Au) in bekers wat geroer is, was vinnig vir die eerste 60 minutte (98% herwinning van die PGMs) en 'n vergelyking tussen die Pt adsorpsie isoterm en gepubliseerde Au isoterms wys op n relatiewe soorgelyke ladings kapasiteit. Die isotherm van Pd was egter laer. Soortgelyk aan meeste diffusie beheerde prosesse, het 'n verhoging van temperatuur gelei tot vinniger adsorpsie snelhede vir Pt, Pd en Au. Indien oplossings egter herhaaldelik met dieselfde koolstof in kontak gebring word, is bevind dat met 'n verhoging in temperatuur, die totale hoeveelheid PGMs wat absorbeer, met elke kontak verminder. In die afwesigheid van sianied en enige basis metale, het die totale hoeveelheid Pt en Pd wat geabsobeer is na 4 opeenvolgende kontake verminder van 99% by 25°C tot 85% adsorpsie van Pt en 83% Pd by 50°C. Daar was geen veskil tussen die adsorpsie van Au by 25°C en 50°C na 4 kontakte nie. Dit is ook vasgestel dat die negatiewe effek van vrye sianied in die oplossing, groter word soos wat die temperatuur verhoog. Die negatiewe effek van die teenwoordigheid van Cu en Ni, hang af van die hoeveelheid van hierdie metale wat absorbeer word wat weer bepaal word deur die sianied konsentrasie asook die temperatuur van die oplossing. Die mate waar in Pt en Pd ge-absorbeer word deur koolstof, word aansienlik meer beïnvloed deur temperatuur, sianied konsentrasie en die teenwoordigheid van basis metale as wat die adsorpsie van Au beïnvloed word. Met die ontwerp van n PGM adsorpsie proses, sal dit sterk in aanmerking geneem moet word, om seker te maak dat so min as moontlik Pt en Pd verlore gaan. Dit wys ook dat 'n geaktiveerde koolstof proses vir Pt en Pd, nie so onvatbaar vir proses veranderings sal wees soos wat die Au proses is nie, wat as een van die groot voordele van die Au proses beskou word. Die afstropery van die Pt en Pd sianied komplekse is ondersoek en gevind dat by 80°C, amper al die Pt en Pd binne 4 to 5 bed volumes (BV) van die geaktiveerde koolstof gestroop kan word. Die afstropery van Au by hierdie temperatuur is stadig en sowat 55% van die Au bly nog oor op die koolstof na 16 BVs. Die snelheid waarteen die Pt en Pd afgestroop word verhoog indien die temperatuur verhoog word en by 95°C is 99% van die Pt en Pd herwin na 4 BVs. Voorafbehandeling van die gelaaide koolstof met sianied, het 'n groot uitwerking op die PGM afstroping. Soos wat die NaCN konsentrasie verhoog word vanaf 0 tot by 2%, verhoog die PGM herwinning maar daal ook weer indien die NaCN konsentrasie verder verhoog word vanaf 2% tot by 4%. Die NaOH konsentrasie het ook n invloed gehad. By 0% NaCN, het die PGM herwinning verhoog soos wat die NaOH konsentrasie verhoog is maar by hoër sianied konsentrasies van 2 en 3%, is n daling in die herwinning waargeneem soos wat die NaOH verhoog is vanaf 0.22% tot by 1.65%. N algemene daling in die Pt, Pd and Au herwinning is waargeneem soos wat die ioniese sterkte van die stropings water toegeneem het. Dit stem ooreen met gepubliseerde navorsing oor die afstroping van Au. Om kalsium van die geaktiveerde koolstof te verwyder, word die koolstof vooraf met soutsuur gewas. Hierdie stap is vir Pt en Pd ondersoek en daar is bevind dat vir al die gevalle, die herwinning hoër was wanneer die gelaaide koolstof met soutsuur behandel is teenoor geen behandeling nie. In geen van die gevalle, is Pt, Pd of Au saam met die soutsuur of die daaropvolgende was water afgestroop nie. Voorafbehandeling met soutsuur teen 70°C lei wel daartoe dat tussen 64 en 75% Ni afgestroop word saam met die soutsuur en n verdere 9.1 to 10.5% saam met die daaropvolgende was water. In die teenwoordigheid van koper sianied, word Cu eerste afgestroop met Pd, Pt en dan Au wat daarop volg. Dit is presies die teenoorgestelde orde waarin die metale geabsorbeer word. Die voorafbehandeling met sianied, het ook 'n beduidende effek op die stroping van Cu. Dit kan verduidelik kan word aan die hand van die verskillende koper sianied komplekse wat vorm wat elkeen 'n verskillende affiniteit het vir adsorpsie. Wanneer 2% NaCN en 0.6% NaOH in die vooraf behandeling stap gebruik word, het die teenwoordigheid van koper geen negatiewe invloed op die afstroping van die PGMs gehad nie maar die herwinning is wel met 10% en 18% verlaag by 5 BVs wanneer geen sianied in die voorafbehandeling stap gebruik is nie. Wanneer 100 mg/L KSCN sout by die adsorpsie stap gevoeg word, daal die herwinning van die PGMs in die stropings stap van 90% tot 70% by 4 BVs. Die addisionel K+ katione verminder die herwinning met slegs 4% by 4 BVs wat beteken dat die vorming van adisionele komplekse soos [Pt(SCN)4]2- en [Pd(SCN)4]2-, wat nie op die normale metode afgestroop kan word, 'n moontlikheid mag wees. N maksimum van 0.15% vir Pt, 0.28% Pd en 0.6% Au word in die vooraf behandelings stap af gestroop. Indien die temperatuur van hierdie stap verhoog word na 80°C, verhoog die hoeveelheid Pt en Pd wat na hierdie stroom raporteer na 'n beduidende 8% tewyl Au basies onveranderd bly by 0.8%. Vir geaktiveerde koolstof wat hoër gelaai is (7000 mg/Kg Pt en Pd) en dus 'n beter verteenwoordiging van aanleg kondisies is, het 0.07% Pt, 0.11% Pd en 0.12% Au raporteer na die vooraf behandelings stap. Dit word toegeskryf aan die verspreiding van die PGMs op die koolstof wat hoofsaaklik op die oppervlakte voorkom en alhoewel die hoeveelheid klein is, word 'n sekere hoeveelheid slegs afgewas. Dit is dus vasgestel hier, dat die afstroping van Pt 'n twee stap proses is. Die eerste stap is die voorabehandeling van die koolstof met 'n sianied oplossing en daarna volg die afstroping van die Pt met suiwer water teen ongeveer 80°C. Met die ontwikkeling van n wiskundige model, is bevind dat die snelheid waarteen die Pt afgestroop word, beïnvloed word deur die hoeveelheid Pt en Na wat op die koolstof oppervlakte is, asook die konsentrasies van die metale in die vloeistof. Dit word wiskundig beskryf deur n gemodifiseerde Freundlich isotherm vergelyking asook deur die massa diffusie vergelyking. Die Pt afstropings snelheid wat afhanklik is van die Na konsentrasie kan vergelyk word met die afstroping snelheid van Au wat ook afhanklik is van die Na konsentrasie (Van Der Merwe and Van Deventer, 1990, Stange, 1990). Verder is bevind dat die snelheid van Pt stroping afhanklik is van beide die ewewig van Pt ione by die koolstof-vloeistof grens asook die massa beweging van Pt ione van die koolstof-vloeistof grens na die vloeistof. Beide hierdie snelheids bepalende faktore word bepaal deur die Na konsentrasie en skuif soos wat die Na konsentrasie verander soos wat die afstroping plaasvind. Vier hoof tyd periodes word gebruik om hierdie verskynsel te verduidelik. Deur die proses fundamenteel te verstaan, kan uiteindelik lei tot 'n beter proses, beter beheer, korter afstropings tye, kleiner toerusting of die ontwikkeling van 'n kontinue proses.

In various industries, specialized filters with activated carbon are used for adsorbing mercury from air-flows. MRT has eight such Activated CarbonFilters (ACFs) in one of their devices. The main purpose of research is tostudy the flow in the ACF filter and suggest a mathematical model for the complete system through which an improved design can be found.Simulation of a single ACF illustrates how the current system’s air flow does not cover the whole filter leaving part of the carbon bed unused forthe adsorption. This is validated by experimental data. A theoretical studybased on a mathematical model is made and the improved air flow pattern of a re-designed ACF is presented. An additional improvement is that byswitching inlet and outlet the usable time of the filters is prolonged.

De part leur surface poreuse développée, les carbones activés montrent une grande efficacité pour l’adsorption de composés organiques en solution et la dépollution de l’eau. Cependant, l’adsorption est souvent irréversible et se pose le problème de la régénération de l’adsorbant. Dans ce travail, nous avons examiné les potentialités de piégeage réversible d’un herbicide, la bentazone, sur des tissus de carbone activé en utilisant un procédé électrochimique. Nous avons montré que la polarisation cathodique permet véritablement de régénérer la porosité du tissu de carbone avec une cinétique de désorption rapide et supérieure à la cinétique d’adsorption. Le processus d’adsorption fait intervenir essentiellement des interactions dispersives, en partie atténuées par les répulsions électrostatiques avec les groupes de surface dissociés. La bentazone s’adsorbe à plat par interactions et envahit les ultramicropores. La désorption sous polarisation négative implique des forces électrostatiques répulsives entre la surface de carbone polarisée et la bentazone chargée négativement, significativement renforcées par la présence du champ électrostatique, d’autant plus à des valeurs de pH élevées. L’électrodécomposition de l’eau joue un rôle crucial en provoquant une augmentation locale de pH dans la porosité, favorisant la dissociation de la bentazone, et donc en accentuant les répulsions électrostatiques. Les taux de désorption sont élevés et atteignent jusqu’à 95% au second cycle de désorption, sans altérer les propriétés physico-chimiques initiales de l’adsorbant carboné. Lors du premier cycle de désorption, on constate qu’une partie de la bentazone reste piégée irréversiblement (30 à 50%), soit parce qu’elle est bloquée dans l’ultramicroporosité ou bien parce qu’elle est adsorbée au niveau de feuillets qui ne sont pas connectés électriquement aureste du réseau carboné, et restent donc inefficaces lors de la polarisation de l’électrode. / With their highly developed porous surface, activated carbons show a great efficiency for adsorption of organic compounds in solutions and for water decontamination. Indeed, adsorption has often an irreversible character and the problem concerning the regeneration of the adsorbent appears. In this study, we have examinated the reversible trapping of a herbicide, bentazone, on activated carbon cloths using an electrochemical technique. We have shown that cathodic polarization allows the regeneration of the porosity of activated carbon cloth with a quick kinetic of desorption, higher than the kinetic of chemical adsorption. The adsorption process implies dispersive interactions, partially attenuated by electrostatic repulsions with the dissociated acidic surface groups. The bentazone is adsorbed in a flat position with its aromatic ring parallelel to the carbon surface, through interactions, and is able to enter in the ultramicropores. The desorption under negative polarization involves electrostatic repulsions between the carbon surface which is negatively polarized and the dissociated bentazone molecule. These repulsions are increased significantly with the existence of the electrostatic field, and the effect is more pronounced at high pH values. The electrochemical decomposition of water plays a crucial role by increasing the local pH in the pores, and favoring the dissociation of bentazone, and therefore the electrostatic repulsions. The desorption level reaches high values, until 95% during the second cycle of desorption, without altering the physico-chemical properties of the activated carbon cloth. During the first step of desorption, we notice that a part of the bentazone is trapped irreversibly (30 à 50%). This is caused by either the blockage of the adsorbate in the ultramicropores or the absorption of bentazone on graphene sheets which are not connected to the carbon network and are therefore insensible to polarization.

Economic utilisation of biogas arising from sewage sludge is hampered by the need to remove siloxanes, which damage gas engines upon combustion. This thesis applies on-line Fourier transform infrared spectroscopy to measure siloxanes in biogas upstream and downstream of the activated carbon vessels designed to adsorb siloxanes. On-line analysis provides accurate measurement of siloxane concentrations with a detection limit below the siloxane limits set by engine manufacturers, high data intensity and timely identification of breakthrough. Cost savings of up to £0.007 kWh- 1 may be realised compared to existing grab sampling. Using on-line analysis, the performance of full-scale and bench-scale carbon vessels were measured. Full-scale carbon contactors are typically operated at Reynold’s numbers close to the boundary between the laminar and transitional regimes (Re = 40 - 55). This thesis demonstrates, at full- and bench-scale, that increasing the Reynold’s number to site the adsorption process in the transitional regime increases media capacity, by 36% in dry gas and by 400% at 80% humidity. It is postulated that the change in gas velocity profile which occurs as Reynold’s number increases reduces the resistance to siloxane transport caused by gas and water films around the carbon particles, and therefore increases the rate of the overall adsorption process. In the laminar regime (Re = 31) increasing humidity from zero to 80% led to the classical stepwise reduction in adsorption capacity observed by other researchers, caused by the increasing thickness of the water film, but in the transitional regime (Re = 73) increasing humidity had no effect as no significant water film develops. It is therefore recommended that siloxane adsorption vessels should be designed to operate at Reynold’s numbers above 55. By choosing a high aspect ratio (tall and thin) both Reynold’s number and contact time can be optimised.

O objetivo desta pesquisa foi o de estudar o desempenho de pós-filtros adsorvedores de carvão ativado granular de origem mineral e de origem vegetal, com relação a, principalmente, remoção de 2-metilisoborneol e trans-1,10-dimetiltrans- 9-decalol. Os ensaios experimentais foram conduzidos na estação de tratamento de água Alto da Boa Vista, empregando-se quatro filtros piloto em acrílico com diâmetro interno de 14,2 cm e 1,5 m de profundidade de meio filtrante cada, sendo dois deles preenchidos com o carvão ativado granular Filtrasorb 300 da CALGON (filtros 1 e 3) e os outros dois, com o carvão ativado granular 119 12x25 da CARBOMAFRA (filtros 2 e 4). Os filtros operaram em paralelo, 24 h por dia, 7 dias por semana, sendo o 3 e 4 abastecidos com água filtrada da estação; e o 1 e 2, com água filtrada ozonizada. A taxa média de aplicação nos filtros durante os ensaios foi de 143 m3m2.d, o que gerou um tempo de contato no leito vazio médio de 15 min. O tempo médio total de detenção nas colunas de ozonização ficou em 21 min e a dosagem média total de ozônio aplicada na água filtrada da estação em 1,11 mgL. Os valores de 2-metilisoborneol na água filtrada da estação de tratamento foram superiores aos da água ozonizada, indicando que a ozonização contribuiu para a redução (média de 53,4 %) deste composto. O filtro que apresentou os menores valores de 2-metilisoborneol foi o do carvão betuminoso, alimentado com água ozonizada (filtro 1), com uma remoção média de 50,6 %. Além disso, foi o único filtro que apresentou valores médios de 2-metilisoborneol abaixo da concentração limiar de odor ( 9,0 ngL). O filtro que apresentou os maiores valores de 2-metilisoborneol foi o 4 (carvão vegetal alimentado com água filtrada da estação). / The main purpose of this research was to study the performance of granular activated carbon post filter adsorbers made of bituminous coal and vegetal coal (coconut), regarding, mainly, removal of 2-methylisoborneol and trans-1,10-dimethyltrans- 9-decalol. The experimental researches were conducted in the water treatment plant Alto da Boa Vista, using four pilot filters, made in acrylic, with an internal diameter of 14.2 cm and a filter media depth of 1.5 m, each. Two of them (named 1 and 3) were filled with the carbon Filtrasorb 300 (CALGON) and the other two (named 2 and 4), with the carbon 119 12x25 (CARBOMAFRA). The filters operated in parallel, 24 h per day, 7 days per week. The filters 3 and 4 were fed with filtered water from the plant and the filters 1 and 2, with filtered plus ozonated water. The average hydraulic loading rate in the filters was 143 m3m2.d and the empty bed contact time, 15 min. The average detention time in the ozone contact columns was 21 min and the average ozone dosage, 1.11 mgL. The 2-methylisoborneol values in the filtered water of the plant were higher than in the ozonated water, which indicates that the ozonation reduced (average of 53.4 %) this substance. The filter that showed the lower values of 2-methylisoborneol was the bituminous one, fed with ozonated water (filter 1), with an average removal of 50.6 %. Moreover, was the only one that presented average values of 2-methylisoborneol lower than the odor threshold concentration ( 9,0 ngL). The filter that presented the higher values of 2- methylisoborneol was the vegetal one, fed with filtered water (filter 4).

"The goals of this study were (1) to evaluate the impacts of pesticides used for mosquito control on drinking water and (2) to investigate the removal of permethrin from water using activated carbon. A review of current literature on pesticide usage, toxicity, occurrence in the environment, and treatment techniques to remove pesticides from drinking water was conducted. The focus of the literature review was on pesticides used for mosquito control. Permethrin is a synthetic pyrethroid insecticide used extensively in the United States (US) for mosquito control and in agriculture, with approximately 2 million pounds applied each year. Permethrin was selected for investigation based on its widespread use in the US, its inclusion on the Contaminant Candidate List 3 (CCL3), its health hazards, and the lack of previous research on the removal of permethrin from drinking water. The removal of permethrin from water using powdered activated carbon (PAC) was investigated. Equilibrium adsorption experiments to assess removal of cis-, trans-, and total permethrin were conducted using two types of PAC (WPH 650 and WPH 1000). Initial total permethrin concentrations ranged from 2.0 to 4.6 ug/L. PAC doses ranged from 0.0 to 10 mg/L. Results showed that PAC addition is an effective method for removing permethrin from water. Total permethrin concentrations were reduced by 38% with 0.05 mg/L of PAC WPH 650, and reduced to below the detection limit with 3 mg/L of PAC WPH 650. Total permethrin concentrations were reduced by 35% with 0.05 mg/L of PAC WPH 1000 and by 83% with 5 mg/L of PAC WPH 1000. Results for cis- and trans- permethrin were similar. The Freundlich isotherm model provided appropriate fits to the data with an R-squared value of 0.91 for both WPH 650 and WPH 1000."

Made available in DSpace on 2016-12-23T14:04:34Z (GMT). No. of bitstreams: 1 Lorena Frasson.pdf: 1448726 bytes, checksum: 03fe202b674cae2a7d55326aec28abec (MD5) Previous issue date: 2012-06-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho teve como objetivo avaliar as características físico-químicas do carvão ativado (CA) gerado a partir da casca de coco e do pinus e tentar associá-las à capacidade de adsorção do herbicida 2,4-D pelos carvões ativados estudados por meio de ensaios de isotermas de adsorção em água destilada e deionizada (ADD) e em água filtrada (AF) a partir dos modelos de Freundlich e de Langmuir, assim como verificar se a redução da granulometria do carvão interfere na capacidade de adsorção do 2,4-D. O motivo pelo qual inicialmente se utilizou ADD foi avaliar a eficiência do CA em adsorver o herbicida sem que houvesse qualquer outro interferente que pudesse competir com o 2,4-D e para comparar os resultados obtidos em ADD com os obtidos na AF. O pH da solução de 2,4-D (6,86) foi ajustado para valores/condições reais de operação da ETA Carapina - ES, que forneceu a AF utilizada nesse trabalho. A pesquisa utilizou carvões ativados vegetais fornecidos por dois fabricantes brasileiros. Uma das empresas forneceu o CAG e o CAP derivados da casca de coco. O CAG foi utilizado na sua granulometria original (08x30 mesh), onde foi denominado de CA-1, e na granulometria menor que 325 mesh, denominado de CA-2. Já o CAP, fornecido por esta mesma empresa, foi denominado de CA-3. O outro fabricante forneceu o CAP derivado do pinus e este carvão foi denominado de CA-4. Dentre os carvões estudados, o CA-3 apresentou maior capacidade adsortiva máxima (qA,máx). As análises fisíco-químicas não contribuíram para a escolha do carvão mais eficiente e, estatisticamente, não houve diferença entre os ensaios realizados em ADD e AF / This research aims to evaluate the activated carbon (AC) physical-chemicals characteristics generated from coconut´s peel and pinus and associate them to 2,4-D herbicide adsorption capacity of studied activated carbons by adsorption isotherms assay in destilated and deionized water (DDW) and filtered water (FW) from Freundlich and Langmuir models, as well as verifying the carbon granulometry reduction interference on the 2,4-D adsorption capacity. Firstly, the DDW was used to evaluate the AC herbicide adsorption efficiency without any interferent which might compete with 2,4-D and to compare the results obtained from DDW with FW results. 2,4-D pH solution (6,86) was fitted to real operational values/conditions of Carapina Water Treatment Plant (WTP) ES, which provide the FW used in this study. The research used vegetable AC provided by two Brazilian producers. One company provided GAC and PAC derivated from coconut peel. The GAC used with the normal granulometry (08x30 mesh) was named CA-1, and with a granulometry lower than 325 mesh was named CA-2. CAP was named CA-3. The another company provided PAC derivated from pinus, which was named CA-4. CA-3 showed higher maximum adsorption capacity (qAmax). The physical-chemicals analysis did not contributed to the most efficient coal selection and, statistically, there were not differences between DDW and FW assays

Tendo em vista a existência de muitas comunidades no Estado de São Paulo (e em outros estados do Brasil), que utilizam água muitas vezes com qualidade imprópria ao consumo humano, o presente trabalho visa o desenvolvimento de uma instalação de filtração utilizando Carvão Ativado Impregnado com Prata (CAIP) com o intuito de eliminar alguma contaminação na água tratada devido à problemas tais como anomalias operacionais na ETA, tecnologia de tratamento inadequada, contaminação da rede de distribuição, reservação, dentre outros. Para a investigação experimental foram preparados três tipos de água de estudo, com baixos valores de turbidez e cor aparente. A água tipo I era isenta de contaminação, as águas tipo II e III apresentaram coliformes totais e fecais, sendo que a água tipo III utilizada na simulação da instalação como filtro domiciliar. Os ensaios realizados apresentaram taxa de filtração entre 200 e 250 m3/m2*d. Os resultados indicam que o CAIP apresentou propriedades adsorventes e é um poderoso agente desinfetante, reduzindo significativamente o NMP de coliformes totais e fecais de águas contaminadas. Porém, a desinfecção não foi completa e ocorreu excessivo desprendimento da prata do CAIP, inviabilizando o uso deste CAIP nesta instalação desenvolvida. / Minding the existence of many communities within the state of São Paulo (and other Brazilian states) which often use water unfit for human consumption, this work aims at the development of a filtering installation that uses Activated Carbon supporting Silver (AC(Ag)) in an attempt to eliminate any contamination in treated water. Such water contamination problems include, operational anomalies in the WTP, inadequate treatment technologies, contamination in the distribution net, and other filter specific problems. For the experimental investigation three types of test water were prepared, with low turbidity and apparent color values. Water type I was contarnination-free, water type II and III had total and fecal coliforms, and water type III was used in the simulation of domestic filtering installation. Tests showed a filtering rate between 200 and 250 m3/m2*d. Results point that AC(Ag) has adsorbent capabilities, in addition to being a powerful disinfection agent, and reduced significantly the number of total and fecal coliforms of contaminated waters. However, disinfection was not thoroughly, and silver was excessively dragged away, from the Activated Carbon, thus rendering the use of AC(Ag) unadvisable in the developed installation.