O processo galvanotécnico é responsável por gerar efluentes que contêm metais tóxicos e substâncias recalcitrantes. As restrições quanto à qualidade do lançamento de efluentes temse intensificado. Uma alternativa para essa problemática são os processos de separação por membranas, como a osmose inversa. O presente estudo teve por objetivo analisar duas estratégias para a melhoria do desempenho de uma central de tratamentos galvânicos, compostas por suas estapas atuais de tratamento como: Tratamento físco-químico, oxidação avançada, filtração simples e trocador iônico) e a possibilidade da inserção da osmose inversa no processo existente (estratégia 1) ou a substituição do trocador iônico pela membrana de osmose inversa (estratégia 2). Neste estudo foi utilizada uma membrana de poliamida com camada seletiva de polissulfona, poisdd foi observada a eficiência das estratégias propostas perante os parâmetros ambientais, em que foram observadas remoções superiores a 92% de níquel total, 90% de cobre total, 81% de zinco total, 93% de fósforo total, 87% de demanda química de oxigênio, 90% de nitrogênio amoniacal e 100% de sólidos suspensos totais para a estratégia 1. Neste trabalho, ainda foram analisados os modelos de bloqueio pela metodologia de Hermia e avaliadas as resistências da membrana, utilizando o efluente galvânico. Os resultados mostraram que a membrana apresentou 80% de resistência por concentração para a estratégia 1 e 40% de fouling para a estratégia 2. Em ambas estratégias, o modelo de Hermia apresentou maior índice para bloqueio irreversível e padrão. Para a estratégia 1, o processo ocorreu ao longo de 180 minutos, e foi observada uma redução do fluxo de permeado de 63%. Após a limpeza química, foi observada uma recuperação do fluxo superior a 93%, sendo que os 7% que não foi possível se recuperar correspondem ao fouling irreversível. Para a estratégia 2, o processo ocorreu ao longo de 90 minutos com uma redução de fluxo de 94%. Após a limpeza a química, foi observada uma recuperação de fluxo de 71%, também mostrando a presença de fouling irreversível. Com a utilização do software Rosa 9.1 DOW, foi detectada para uma demanda de 10m³/h, a necessidade de 3 módulos de osmose inversa com 24 membranas, com uma área de filtração de 891,84 m², com uma pressão de trabalho de 6 bar de pressão e uma potência de bomba de 3,48 kWh. O software mencionado detectou problemas de CaSO4, devido às características do efluente para aumentar a vida útil das membranas. Isso implicaria em um sistema de abrandamento antes de ser submetido à osmose inversa. A avaliação econômica simplificada em comparação ao modelo atual de tratamento e a inserção de uma nova tecnologia, implicaria na instalação de um movo equipamento que triplicaria os custos atuais da central de tratamento de efluentes. Tendo em vista que os padrões de lançamento estão com níveis no limite da legislação, o novo equipamento traria segurança no cumprimento da legislação sem ficar na eminência de autuações perante o órgão ambiental. Mesmo com a estratégia 2 atendendo os padrões de lançamento e possibilitando a substituição de um processo, a estratégia 1 mostou-se mais eficaz, por apresentar menores concentrações finais, consequentemente, resultando em maior tempo de operação e maior viada útil da membrana, com menores paradas para limpezas químicas e custos operacionais. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES. / The galvanotechnical industry is responsible for generating effluents containing heavy metals and recalcitrant substances. The restrictions on the quality of effluent discharge have intensified. An alternative to this problem are membrane separation processes, such as reverse osmosis. The present study had the objective of analyzing two strategies to improve the performance of a galvanic treatment center, composed of its current stages of treatment as: physico-chemical treatment, advanced oxidation, simple filtration and ion exchange. Then, it was studied the possibility of insertion of the reverse osmosis in the existing process (strategy 1) or the replacement of the ion exchanger by the reverse osmosis membrane (strategy 2). For this purpose, a polyamide membrane with a selective polysulfone layer was used, where the efficiency of the proposed strategies was observed for the environmental parameter. Using strategy 1, the results were observed above 92% of total nickel, 90% of total copper, 81% of zinc, 93% of total phosphorus, 87% of chemical oxygen demand (COD), 87% of ammonia nitrogen and 100% of total suspended s’olids. The Hermia methodology and the membrane resistance, using the galvanic effluent, were also analyzed by the blocking models. The results showed that the membrane presented 80% resistance per concentration for strategy 1 and 40% of fouling for strategy 2. In both strategies, the Hermia model presented a higher index for irreversible and standard block. For strategy 1, the process occurred over 180 minutes and a permeate flux reduction of 63% was observed. After the chemical cleaning, a recovery flow superior to 93% was observed, and 7% that could not be recovered correspond to irreversible fouling. For strategy 2, the process occurred over 90 minutes with a 94% of flow reduction. After cleaning, a flow recovery of 71% was observed, also showing the presence of irreversible fouling. The Rosa 9.1 DOW software showed that for a demand of 10m³ / h it would take 3 reverse osmosis modules with 24 membranes, filtration area of 891,84 m², working pressure of 6 bar pressure and a pump power of 3.48 kWh. The mentioned software detected problems of CaSO4, due to the effluent characteristics to increase the useful life of the membranes. This would imply a slowing system before being subjected to reverse osmosis. The simplified economic evaluation compared to the current treatment model and the insertion of a new technology, would entail the installation of a moving equipment that would triple the current costs of the effluent treatment plant. Considering that the release standards are at the limit of the legislation, the new equipment would treat security in compliance the legislation without being in the eminence of notices before the environmental agency. Even with strategy 2 meeting the launching standards and allowing the substitution of a process, strategy 1 has been shown to be more effective, since it presents lower final concentrations, resulting operating bigger life of the membrane, with lower stops for chemical clean-ups and operating costs.

Orientador: Ming Chih Chiu / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-19T15:57:12Z (GMT). No. of bitstreams: 1 Sehn_GeorgiaAneRaquel_M.pdf: 2236870 bytes, checksum: 99206af2cdbd6bef903b1752c992b66e (MD5) Previous issue date: 2012 / Resumo: O óleo de farelo de arroz, além de ser utilizado como alimento, é conhecido pelo seu atributo nutricional, devido a sua fração insaponificável rica em antioxidantes como os tocoferóis, tocotrienóis e em especial o ?-orizanol, que dão ao óleo uma maior resistência à oxidação e à deterioração. Além disso, diversos estudos mostram a habilidade destes compostos em reduzir os níveis de colesterol no plasma sanguíneo e em suprimir o crescimento de células cancerígenas. O refino dos óleos tem como finalidade a remoção de compostos, como ácidos graxos livres, gliceróis parciais (mono e diacilgliceróis), fosfolipídios não hidratávies, pigmentos, produtos de oxidação, metais, resíduos de proteínas, ceras, hidrocarbonetos, partículas e contaminantes químicos, porém este refino apresenta diversos inconvenientes, como a perda de nutrientes e antioxidantes naturais pelas altas temperaturas e longa duração das etapas do processo. A tecnologia de membranas vem ganhando destaque nos processos industriais, principalmente na tecnologia de alimentos, simplificando-os, reduzindo o consumo de energia e poluentes, devido à possibilidade de não adição de agentes químicos utilizados pelos processos tradicionais. O objetivo da primeira etapa do trabalho foi o estudo do desempenho de membranas poliméricas compostas por polifluoreto de vinilideno (PVDF) e poliestersulfona (PES) na aplicação da degomagem em miscela do óleo bruto de farelo de arroz utilizando um módulo de filtração tangencial de bancada, além de uma análise comparativa das técnicas de filtração de óleo em miscela com hexano e álcool etílico em condições de temperatura, velocidade tangencial e pressão constantes. A membrana PVDF com massa molar de corte (MMC) de 50 KDa em miscela com hexano (30/70 m/m) demonstrou maior retenção de fosfolipídios (95,5%) associada a um fluxo elevado de permeado (48,1 L/m2.h), para um fator de concentração de 1,40. O objetivo da segunda parte do trabalho foi o estudo da retenção dos ácidos graxos livres e compostos minoritários frente à nanofiltração em membranas de PES com MMC de 200 e 400 Daltons e em relação ao solvente álcool etílico absoluto e álcool etílico 95%. Observou-se que a presença de impurezas, como a cera, reduziu a eficiência da interação solvente/soluto no processo de desacidificação, havendo necessidade de uma etapa de deceragem do óleo. Comprovou-se que a adição de água no álcool etílico reduziu a perda de óleo no permeado, e preservou compostos nutracêuticos devido o aumento da interação solvente/soluto na desacidificação. Em relação a compostos de cor, clorofila e carotenóides observou-se baixa retenção, ainda menor no teor de clorofila devido a baixa interação destes compostos com o solvente e tamanho de poros utilizados / Abstract: Rice bran oil, besides being used as food, is known for its nutritional attributes, owing to their unsaponifiable matter, rich in antioxidants tocopherols, tocotrienols and particularly ?-oryzanol. This especial composition provides the oil greater resistance to oxidation and deterioration. Additionally, several studies demonstrate the importance of these compounds in reducing cholesterol levels in blood plasma and suppressing growth of cancer cells. The refining of oils aims at removing compounds such as free fatty acids, partial glycerides (mono and diglycerides), phospholipids, pigments, oxidation products, metals, proteins, waxes, hydrocarbons, water, particulates and chemical contaminants. However, this refining has several disadvantages such as loss of nutrients and natural antioxidants due to exposure to high temperatures and long process steps. The membrane technology has been emphasizing in industrial processes, especially in food technology, simplifying processes, reducing energy consumption and pollutants, due to non-use of chemical agents. This work focused firstly, the study of the efficiency of the polymeric membranes composed of PVDF and PES on crude rice bran oil degumming, using in a tangential filtration. There were compared two oil micelle system, rice bran oil micelle with hexane and rice bran oil miscella with ethyl alcohol at constant conditions of temperature, tangential velocity and pressure. The PVDF membrane with 50 kDa in hexane miscella (30/70 w/w) showed greater retention of phospholipids (95.5%) associated with a high flow rate (48.1 L/h.m2) for a concentration factor of 1.40. The purpose of the second part of this work was to study the behavior of free fatty acids and minor compounds against nanofiltration process, using PES membranes with molar weight cut-off (MWCO) 200 and 400 Daltons and two micelle phases, with absolute ethyl alcohol and with ethyl alcohol 95%. It was observed that the presence of impurities, such as wax, reduced the efficiency of the solvent / solute interaction in the deacidification process, requiring a dewaxing step. It was shown that the addition of water in ethyl alcohol reduced the loss of oil in the permeate fraction and the nutraceutical compounds were preserved due to increased solvent / solute interaction in deacidification. In relation to color compounds, the membrane separation technology did not show reduction in chlorophyll content in retentate fraction, possibly due to no interaction of the solvent / solute. For carotenoids, it was observed a small reduction in the content of these compounds in the retentate fraction, which probably occurred due to the interaction of these compounds with the solvents used / Mestrado / Tecnologia de Alimentos / Mestre em Tecnologia de Alimentos

DMagister Scientiae - MSc / The proton exchange membrane is one key component of direct methanol fuel cells, which has double functions of conducting protons, separating fuels and oxidant. At present, the performance and price of sulfonic acid proton exchange membrane used in direct methanol fuel cells are deeply concerned. In order to reduce membrane 's cost and improve performance of Nafion membrane, three different kinds of membranes have been studied in this thesis. These membranes are SPEEK membranes, SPEEK/ZP composite membranes and Nafion/ZP composite membranes. / South Africa

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Polysulfone hollow-fibre membranes were fabricated via the dry-wet solution spinning technique. The objective was to demonstrate the influence of the various fabrication parameters on the diameter and mechanical properties of the hollow-fibre membranes and to optimize the spinning process by controlling these parameters with a computer control system. The effects of the operation parameters were investigated using an experimental design based on a fractional factorial method (Taguchi’s design of experiments). The parameters that were considered are the spinneret size, dope solution temperature, bore fluid temperature, coagulation bath temperature, dope extrusion rate, bore flow rate and the take-up speed. A new pilot solution spinning plant was installed and upgraded, and a computer control system, based on LabView, was developed to control, monitor and log the experimental data. The diameter of the hollow-fibres were determined using a scanning electron microscope (SEM) while the mechanical properties were measured using a tensile tester. The effects of diameter size and wall thickness of the hollow-fibres on the performance of the membranes were studied. The results showed the significance of the fabrication parameters that dominate the diameter and strength of the hollow-fibres. / AFRIKAANSE OPSOMMING: Polisulfoon holvesel membrane is met ‘n droë-nat oplossingspin proses vervaardig. Die doel hiermee was om die invloed van verskeie vervaardigingsparameters op die deursnee en meganiese eienskappe van die holvesel membrane te demonstreer asook om die spin proses te optimeer deur gerekenariseerde beheer van die aanleg. ‘n Eksperimentele ontwerp, gebaseer op ‘n gedeeltelike faktoriaal metode (Taguchi se eksperimentele ontwerp) is gebruik om die invloed van die vervaardigingsparameters te ondersoek. Die parameters wat oorweeg is, is spindop grootte, materiaal temperatuur, boorvloeistof temperatuur, stolbad temperatuur, materiaal ekstrusie tempo and opwen spoed. ‘n Nuwe oplossingspin loodsaanleg was geïnstalleer en opgegradeer en ‘n rekenaar beheerstelsel, gebaseer op LabView, is ontwikkel om die aanleg te beheer, moniteer en eksperimentele data te stoor. Die deursnee van die holvesel is gemeet met ‘n skanderingelektron mikroskoop (SEM) terwyl die meganiese eienskappe bepaal is met ‘n trektoets apparaat. Die effek van die deursnee en wanddikte van die holvesels op die werkverrigting van die membrane is ook bestudeer. Die resultate toon watter vervaardigingsparameters is beduidend vir die deursnee en sterkte van die holvesels.

Water quality from surface sources is fast deteriorating due to pollution from organic compounds. Among the organic compounds are chlorophenols, which are described as priority pollutants because of their detrimental effects. One way of removing them from water is by using membranes. However direct removal of chlorophenols using membranes is limited due to the inherent problem of membrane fouling. The thesis describes fabrication of thin film composite membranes modified with Ag-TiO2 and Ag-ZnO for enhancing filtration properties of the membranes for removal of 2-CP and 2,4-DCP and improving the antifouling properties of the modified membranes. Chlorophenols, 2- CP, 2,4-DCP and 2, 4, 6-TCP were determined from Vaal and Klip River using SPE- HLPC method. The SPE - HPLC method was validated by determining breakthrough volume, repeatability, reproducibility, linearity, MDL and LOQ. Nanoparticles (NPs), Ag, ZnO and TiO2 and nanocomposites (NCs), Ag-TiO2 and Ag-ZnO were synthesized using precipitation method and chemical reduction for Ag. The NPs and NCs were characterised using UV-Vis, FTIR, XRD, SEM and EDX. The synthesised NPs and NCS were evaluated for photocatalytic degradation of 2-CP and 2,4-DCP, antimicrobial activity against E.coli. and toxicity against Daphnia magna. Nanocomposites were then embedded into the PA thin film membrane surface using interfacial polymerisation and PES as a support material to produce the antifouling Ag-TiO2/PA-TFC and Ag-ZnO/PA-TFC membranes. The control PATFC membrane was prepared with no added NCs to the membrane. The membranes were characterised using ATR-FTIR, contact angle, SEM and AFM. The performance of the membranes was tested using permeation flux (using pure water and 2-CP / 2,4-DCP solutions as feed) against the neat PA-TFC membrane. Membranes were further tested for rejection of 2- CP and 2, 4 – DCP, antifouling properties and flux recoveries. The stability of the antifouling properties of the membrane was evaluated through silver release test. The performance of the membranes was tested using real water samples from Vaal and Klip Rivers. The SPE-HPLC method was repeatable, reproducible with % RSD less than 5%. Linearity range of (0.1-50 µg/ L) and recoveries of spiked water samples of more than 97% for 2-CP and 2,4-DCP but lower at 64 and 75% for 2.4.6-TCP were achieved. The Ag, TiO2 and ZnO NPs showed characteristic peaks of NPs with UV-Vis. The absorption peaks were all blue shifted due to quantum confinements. The crystalline structures were confirmed as face centred cubic, anatase and hexagonal wurzite for Ag, TiO2 and ZnO respectively. The morphology as observed from SEM showed spherically shaped nanoparticles with average sizes of 68.25 ± 4.7 and 50.92 ± 3.39 nm for Ag and TiO2 respectively. The ZnO NPs were rod -like shaped with average length = 603 nm ± 50.4 and a width = 82.92 ± 5. 40nm. Successful incorporation of silver into the TiO2 and ZnO structures was confirmed by elemental analysis, EDX. From SEM images, silver particles were distributed around TiO2 particles and ZnO rods. The presence of silver showed a remarkable improvement in photodegradation of 2-CP and 2,4-DCP from less than 40% to 86% with 2, 4- DCP. Silver modified TiO2 and ZnO showed antibacterial activity against E.coli. with minimum concentration of inhibition as low as 1.56 mg/L for both Ag-ZnO (5) and Ag-TiO2 (5). Silver was more toxic against Daphnia magna than Ag-ZnO (5) and AgTiO2 (5). The polyamide layer was confirmed by the presence of the amide I peak at 1650 cm1 and 1670 cm-1 in the Ag-TiO2/ PA-TFC and Ag-ZnO/ PA-TFC membranes. The appearance of NCs particles spread across the surface of the thin layer of the membranes as observed from surface SEM images confirming their incorporation into the PA layer. The presence of the NCs in the membranes improved water flux, water permeation, rejection of 2- CP, and 2,4-DCP, antifouling properties of the membranes and flux recoveries of more than 93 % was achieved. Silver release test revealed that Ag-ZnO/PA-TFC membrane performed better than AgTiO2/PA-TFC membrane because of the steady release of silver, which shows long lasting antifouling properties. When applied to real water samples from Vaal and Klip River, the prepared membranes showed better antifouling properties than the neat PA-TFC membrane

Contaminants can exist in a wide range of states in aqueous environments, especially in surface waters. They can be freely dissolved or associated with dissolved or particulate organic matter depending on their chemical and physical characteristics. The freely dissolved fraction represents the most bioavailable fraction to an organism. These freely dissolved contaminants can cross biomembranes, potentially exerting toxic effects. Passive sampling devices (PSDs) have been developed to aid in sampling many of these contaminants by having the ability to distinguish between the freely dissolved and bound fraction of a contaminant. A new PSD, the Lipid-Free Tube (LFT) sampler was developed in response to some of the shortcomings of other current PSD that sample hydrophobic organic contaminants (HOCs). The device and laboratory methods were original modeled after a widely utilized PSD, the semipermeable membrane device (SPMD), and then improved upon. The effectiveness, efficiency, and sensitivity of not only the PSD itself, but also the laboratory methods were investigated. One requirement during LFT development was to ensure LFTs could be coupled with biological analyses without deleterious results. In an embryonic zebrafish developmental toxicity assay, embryos exposed to un-fortified LFT extracts did not show significant adverse biological response as compared to controls. Also, LFT technology lends itself to easy application in monitoring pesticides at remote sampling sites. LFTs were utilized during a series of training exchanges between Oregon State University and the Centre de Recherches en Ecotoxicologie pour le Sahel (CERES)/LOCUSTOX laboratory in Dakar, Senegal that sought to build "in country" analytical capacity. Application of LFTs as biological surrogates for predicting potential human health risk endpoints, such as those in a public health assessment was also investigated. LFT mass and accumulated contaminant masses were used directly, representing the amount of contaminants an organism would be exposed to through partitioning assuming steady state without metabolism. These exposure concentrations allow for calculating potential health risks in a human health risk model. LFT prove to be a robust tool not only for assessing bioavailable water concentrations of HOCs, but also potentially providing many insights into the toxicological significance of aquatic contaminants and mixtures. / Graduation date: 2010

Over the past decade, membrane based gas separations have gained traction in industry as an attractive alternative to traditional thermally based separations due to their potential to offer lower operational and capital expenditures, greater ease of operation and lower environmental impact. As membrane research evolves, new state-of-the-art membrane materials as well as processes utilizing membranes will likely be developed. Therefore, their incorporation into existing thermally based units as a debottlenecking step or as a stand-alone separation unit is expected to become increasingly more common. Specifically for natural gas, utilization of smaller, more remote natural gas wells will require the use of less equipment intensive and more flexible separation technologies, which precludes the use of traditional, more capital and equipment intensive thermally based units. The use of membranes is, however, not without challenges. Perhaps the most important hurdle to overcome in membrane development for natural gas purification is the ability to maintain high efficiency in the presence of harsh feed components such as CO₂ and H₂S, both of which can swell and plasticize polymer membranes. Additionally, as this project demonstrates, achievement of similarly high selectivity for both CO₂ and H₂S is challenged by the different governing factors that control their transport through polymeric membranes. However, as others have suggested and shown, as well as what is demonstrated in this project, when CO₂ is the primary contaminant of interest, maintaining high CO₂/CH₄ efficiency appears to be more important in relation to product loss in the downstream. This work focuses on a class of fluorinated, glassy polyamide-imides which show high plasticization resistance without the need for covalent crosslinking. Membranes formed from various polyamide-imide materials show high mixed gas selectivities with adequate productivities when subjected to feed conditions that more closely resemble those that may be encountered in a real natural gas well. The results of this project highlight the polyamide-imide family as a promising platform for future membrane material development for materials aimed at aggressive natural gas purifications due to their ability to maintain high selectivities under aggressive feed conditions without the need for extensive stabilization methods.

No description available.

Mixed matrix hollow fiber membranes maintain the ease of processing polymers while enhancing the separation performance of the pure polymer due to inclusion of molecular sieve filler particles. This work shows the development process of high loading mixed matrix hollow fiber membranes for butane isomer separation, from material selection and engineering of polymer-sieve interfacial adhesion to mixed matrix hollow fiber spinning. The matching of gas transport properties in polymer and zeolite is critical for forming successful mixed matrix membranes. The nC4 permeability in glassy commercial polymers such as Ultem® and Matrimid® is too low (< 0.1 Barrer) for commercial application. A group of fluorinated (6FDA) polyimides, with high nC4 permeability and nC4/iC4 selectivity, are selected as the polymer matrix. No glassy polymers can possibly match the high permeable MFI to make mixed matrix membranes with selectivity enhancement for C4s separation. Zeolite 5A, which has a nC4 permeability (~3 Barrer) and nC4/iC4 selectivity (essentially ∞), matches well with the 6FDA polymers. A 24% nC4/iC4 selectivity enhancement was achieved in mixed matrix membranes containing 6FDA-DAM and 25 wt% treated 5A particles. A more promising mixed matrix membrane contains 6FDA-DAM-DABA matrix and 5A, because of a better match of gas transport properties in polymer and zeolite. Dual layer hollow fibers, with cellulose acetate core layer and sheath layers of 6FDA polyimides, were successfully fabricated. Successive engineering of the 6FDA sheath layer and the dense skin is needed for the challenging C4s separation, which is extremely sensitive to the integrity of the dense skin layer. The delamination-free, macrovoid-free dual layer hollow fiber membranes provide the solution for the expensive 6FDA polyimides spinning. Mixed matrix hollow fiber membranes are spun base on the platform of 6FDA/Cellulose acetate dual layer hollow fibers. Preliminary results suggest that high loading mixed matrix hollow fiber membranes for C4s is feasible. Following research is needed on the fiber spinning with well treated zeolite 5A nanoparticles. The key aspect of this research is elucidating the three-step (sol-gel-precipitation) mechanism of sol-gel-Grignard treatment, based on which further controlling of Mg(OH)2 whisker morphologies is possible. A Mg(OH)2 nucleation process promoted by acid species is proposed to explain the heterogeneous Mg(OH)2 growing process. Different acid species were tried: 1) HCl solution, 2) AlClx species generated by dealumination process and 3) AlCl3 supported on zeolite surfaces. Acids introduced through HCl solution and dealumination are effective on commercial 5A particles to generate Mg(OH)2 whiskers in the sol-gel-Grignard treatment. Supported AlCl3 is effective on both commercial and synthesized 5A particles (150 nm-1 µm) during the sol-gel-Grignard treatment, in terms of promoting heterogeneous Mg(OH)2 whiskers formation. But the byproduct of Al(OH)3 layer separates the Mg(OH)2 whiskers from zeolite surface, and leads to undesirable morphologies for polymer-zeolite interfacial adhesion. The elucidation of sol-gel-Grignard mechanism and importance of zeolite surface acidity on Mg(OH)2 formation, builds a solid foundation for future development towards ''universal'' method of growing Mg(OH)2 whiskers on zeolite surfaces.

The inherent thermal resistance of ceramic membranes allows for treatment of industrial waters at elevated temperatures. Traditionally, the high temperature of wastewater has been an issue compromising the integrity of polymeric membrane systems or requiring the temperature to be lowered for further treatments. In ceramic membrane systems, a decrease in viscosity with increasing temperature, however, can be utilized, which increases the permeate flux. In this study, the fouling of ceramic ultrafiltration by feed solutions containing colloidal silica was evaluated at temperatures between 25 – 90 °C seen in various industries. Ceramic membranes were able to perform well at elevated temperatures up to 90 ºC with sustained mechanical and chemical integrity. Results showed net benefit of filtration at elevated temperatures on permeate flux in spite of increasing total fouling resistance with temperature. When the temperature increased from 25 to 90 °C, there was a 90% increase in steady-state permeate flux. The dominant resistance was physically removable fouling, and the increase in fouling with feed temperature was supported by force balance analyses. This study provides a foundation from which further studies can be developed including pilot-scale testing, use of real wastewater, and the effects of operating conditions.