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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Effects of Traffic Incidents on Adjacent Facilities and Alternative Re-Routing Strategies

Karaer, Alican 01 January 2018 (has links)
This study presents an analysis of detour operations as a concept of congestion management. Since a large portion of traffic delay emanates from traffic incidents, the goal of the study was to alleviate incident-induced impacts on freeways by diverting congested traffic on to adjacent roadway facilities. To balance the demand between freeway and arterial systems, optimization was required through Integrated Corridor Management (ICM). This thesis examines the justification and optimization of dynamic traffic routing strategies. Previous studies have justified detour operations based solely on traffic simulation results. This study quantifies the impacts from freeway incidents on a parallel arterial roadway using a data-driven signal processing technique, with operating speeds adopted as a performance measure. Results show that rerouting traffic to an adjacent arterial road, due to a freeway incident, can mitigate the mobility of the corridor with a probability of up to 88% depending on the type of incident and occurrence time. Results also indicate that diverting traffic during off-peak hours, especially for minor incidents, provides minimal mobility benefits. A secondary focus of this study explored the optimum dynamic traffic diversion, to an adjacent arterial roadway, from incident-induced freeway congestion to better utilize the freeway’s available corridor capacity. VISSIM, a microsimulation tool, was employed to simulate a freeway incident and measure the performance of detour operations. A 23 full factorial central composite design was used to establish a relationship between the performance of the detour operation and three control factors: incident duration, diversion rate, and demand level. The resulting regression equation predicts the corridor delay with over 83% accuracy. The findings of this study can potentially serve as a building block in the understanding and development of future ICM systems and incident management plans.
32

Obtenção de comprimidos contendo alto teor de produto seco por aspersão de Maytenus ilicifolia Mart. ex. Reissek - Celastraceae : desenvolvimento tecnológico de produtos intermediários e final / Obtainment of tablets containing high amount of a spray-dried product from Maytenus ilicifolia Mart. ex. Reissek. - Celastracea : technological development of intermediate and final products

Soares, Luiz Alberto Lira January 2002 (has links)
As folhas de Maytenus ilicifolia são amplamente utilizadas na medicina tradicional brasileira no tratamento de distúrbios gástricos. Após a comprovação de sua eficácia e segurança, a referida droga vegetal tem sido objeto de diversos estudos com a finalidade de estabelecer parâmetros para o controle de qualidade. Neste sentido, foi avaliada a viabilidade do desenvolvimento de um método analítico fundamentado na precipitação de taninos empregando povidona como agente seqüestrante. Os dados revelaram que a remoção de taninos em solução é satisfatória quando empregada a povidona insolúvel. Foi observado que o polímero também é capaz de precipitar outros polifenóis além dos taninos presentes na solução extrativa de M. ilicifolia. Entretanto, as interações do polímero ocorrem preferencialmente com os derivados catéquicos. Adicionalmente foi desenvolvido e validado um método por CLAE para separação e quantificação de catequina e epicatequina em produtos derivados de M. ilicifolia. Não foram detectadas variações nas áreas dos picos ou nos tempos de retenção durante os ensaios de avaliação do método, sugerindo que as condições cromatográficas empregadas são satisfatórias. Para viabilizar a preparação de produto seco por aspersäo (PSA) em torre de secagem piloto munida de aspersor rotatório, foi necessária a concentração da solução extrativa. A operação foi realizada sob pressão reduzida até alcangar um teor de sólidos mínimo de 15 % (m/m). A operação de secagem da solução concentrada apresentou rendimento de 90 % e o PSA obtido apresentou partículas esféricas, com superfície rugosa e tamanho médio de 22,5 um. A caracterização tecnológica do material revelou que as suas propriedades tecnológicas, tais como, densidades, compressibilidade e fluxo, foram incrementadas quando comparados com o produto preparado em equipamento de bancada. Entretanto, estas modificações não foram suficientes para viabilizar sua compressão direta. Assim sendo, o material foi compactado em máquina de comprimir e em rolos para produção de grânulos. A análise do perfil compressional do PSA e dos granulados, empregando o modelo de Heckel, revelou que o aumento da força de compactação durante a operação de granulação foi o principal responsável pela diminuição no potencial de deformação plástica dos grânulos. Como conseqüência, a recompressão dos grânulos em máquina de comprimir originou compactos com dureza inferior àqueles preparados diretamente do complexo farmacêutico. Enquanto o PSA apresentou reduzida tendência ao rearranjo particular nos estágios iniciais da compressão, os grânulos sofreram intensa reacomodação decorrente da fragmentação e formação de novas pontes, assumindo comportamento plástico em pressões de compressão mais elevadas. Por fim, comprimidos contendo teor elevado de granulado de PSA foram preparados utilizando como adjuvantes a celulose microcristalina, o dióxido de silício coloidal e a croscarmelose sódica. A influência da concentração de dióxido de silício coloidal e croscarmelose sódica na formulação, sobre as respostas de dureza, friabilidade e tempo de desintegração dos comprimidos foram avaliadas através de um Desenho Composto Central. Os dados experimentais foram analisados estatisticamente, utilizando os modelos matemáticos para gerar superfícies de resposta. Os resultados indicaram que a concentração de dióxido de silício coloidal foi inversamente relacionada às respostas de dureza e friabilidade, enquanto que a concentração de croscarmelose sódica foi a principal responsável pela redução no tempo de desintegração. As condições ótimas foram selecionadas através da sobreposição dos gráficos, buscando uma formulação com menor tempo de desintegração, menor friabilidade e o máximo de dureza. A formulação eleita deve conter 1,2 % (m/m) de dióxido de silício coloidal e 5,0 % (m/m) de croscarmelose sódica. Nestas condições os comprimidos apresentaram dureza de 107,9 N, friabilidade de 0,56 % (m/m) e desintegração máxima em 6,8 min. / The leaves of Maytenus ilicifolia are widely used within the traditional Brazilian medicine due to its properties against gastric disorders. Once proved its efficacy and safety, this vegetable drug has been the object of several studies to establish the basis for quality control. Taking this into consideration, it was necessary to evaluate the feasibility of developing an analytical method based on the precipitation of tannins, by using polyvinylpyrrolidone for precipitation. The data have shown that the removal of the tannins in solution was successful when insoluble polyvinylpyrrolidone was used. Hereby it was observed that the polymer has also the ability to precipitate other polyphenols besides the tannins from the aqueous solution of M. ilicifolia. However, the interactions of the polymer happened mostly with the condensed tannins. Further it was developed and also validated an HPLC method to separate and quantify catechin and epicatechin present in aqueous extracts of M. ilicifolia. No significant variations of peak areas or retention times were observed when the evaluation of the method was executed, showing satisfactory chromatographic conditions. In order to make a spray dried extract (SDE) using a spray-drier fitted out with a rotary atomizer, it was necessary to concentrate the extractive solution. This operation had been performed under reduced pressure until a content of 15 % solids was achieved. The drying of the concentrated solution lead to a yield of 90 %, and the obtained SDE presented spherical particles, which have a rough surface and a mean particle size of 22,51.1.m. The technological characterization of the SDE showed that attributes such as densities (tap and bulk), compressibility and flow, have been improved when compared to the product prepared using a mini spray-drier supplied with a pneumatic nozzle. However, these modifications were not enough to enable its direct compression. Therefore, the material was compacted to produce granules after slugging or roller compaction, The compressional analysis of the SDE and each granule batch using the Heckel equation proved that the increase in the compaction force once processing the granulation was the main factor to reduce the material's ability to undergo plastic deformation. Consequently, the recompression of the granules in a tablet press led to compacts with a lower crushing strength compared to that prepared by direct compression of the pharmaceutical complex. Whereas the SDE has shown a reduced tendency to particle rearrangement at early stage of compression, the granules showed an intense fragmentation and rebound behavior, presenting a plastic behavior when higher compaction pressures were used. Finally, tablets containing a high dose of granulated spray dried extract of M. ilicifolia were prepared by using the following excipients: microcrystalline cellulose (filler/binder), colloidal silicon dioxide (glidant and moisture adsorber) and cross-linked carboxymethylcellulose (disintegrant). The influences of colloidal silicon dioxide (CSD) and cross-linked carboxymethylcellulose (CMC-Na) on the tablet hardness, disintegration time and friability were evaluated by a central composite design. The data were analyzed statistically and mathematical models were used to create response surfaces. The results have indicated that the concentration of CSD shows an inverse relation to the responses of hardness and friability, while the concentration of CMC-Na was the most important factor that caused a reduction of the time necessary for total disintegration. The optimal conditions for processing were chosen by the overlapping of graphics, taking into consideration that the formulation should present a minimum of disintegration time, lower friability and a maximum of hardness. Thus, it was found that the best formulation should have a content of 1.2% (w/w) of CSD and 5.0% (w/w) of CMC-Na. Regarding these conditions, the tablets have shown a hardness of 107.9 N, friability of 0.56% (w/w) and a disintegration time of 6.8 min.
33

Obtenção de comprimidos contendo alto teor de produto seco por aspersão de Maytenus ilicifolia Mart. ex. Reissek - Celastraceae : desenvolvimento tecnológico de produtos intermediários e final / Obtainment of tablets containing high amount of a spray-dried product from Maytenus ilicifolia Mart. ex. Reissek. - Celastracea : technological development of intermediate and final products

Soares, Luiz Alberto Lira January 2002 (has links)
As folhas de Maytenus ilicifolia são amplamente utilizadas na medicina tradicional brasileira no tratamento de distúrbios gástricos. Após a comprovação de sua eficácia e segurança, a referida droga vegetal tem sido objeto de diversos estudos com a finalidade de estabelecer parâmetros para o controle de qualidade. Neste sentido, foi avaliada a viabilidade do desenvolvimento de um método analítico fundamentado na precipitação de taninos empregando povidona como agente seqüestrante. Os dados revelaram que a remoção de taninos em solução é satisfatória quando empregada a povidona insolúvel. Foi observado que o polímero também é capaz de precipitar outros polifenóis além dos taninos presentes na solução extrativa de M. ilicifolia. Entretanto, as interações do polímero ocorrem preferencialmente com os derivados catéquicos. Adicionalmente foi desenvolvido e validado um método por CLAE para separação e quantificação de catequina e epicatequina em produtos derivados de M. ilicifolia. Não foram detectadas variações nas áreas dos picos ou nos tempos de retenção durante os ensaios de avaliação do método, sugerindo que as condições cromatográficas empregadas são satisfatórias. Para viabilizar a preparação de produto seco por aspersäo (PSA) em torre de secagem piloto munida de aspersor rotatório, foi necessária a concentração da solução extrativa. A operação foi realizada sob pressão reduzida até alcangar um teor de sólidos mínimo de 15 % (m/m). A operação de secagem da solução concentrada apresentou rendimento de 90 % e o PSA obtido apresentou partículas esféricas, com superfície rugosa e tamanho médio de 22,5 um. A caracterização tecnológica do material revelou que as suas propriedades tecnológicas, tais como, densidades, compressibilidade e fluxo, foram incrementadas quando comparados com o produto preparado em equipamento de bancada. Entretanto, estas modificações não foram suficientes para viabilizar sua compressão direta. Assim sendo, o material foi compactado em máquina de comprimir e em rolos para produção de grânulos. A análise do perfil compressional do PSA e dos granulados, empregando o modelo de Heckel, revelou que o aumento da força de compactação durante a operação de granulação foi o principal responsável pela diminuição no potencial de deformação plástica dos grânulos. Como conseqüência, a recompressão dos grânulos em máquina de comprimir originou compactos com dureza inferior àqueles preparados diretamente do complexo farmacêutico. Enquanto o PSA apresentou reduzida tendência ao rearranjo particular nos estágios iniciais da compressão, os grânulos sofreram intensa reacomodação decorrente da fragmentação e formação de novas pontes, assumindo comportamento plástico em pressões de compressão mais elevadas. Por fim, comprimidos contendo teor elevado de granulado de PSA foram preparados utilizando como adjuvantes a celulose microcristalina, o dióxido de silício coloidal e a croscarmelose sódica. A influência da concentração de dióxido de silício coloidal e croscarmelose sódica na formulação, sobre as respostas de dureza, friabilidade e tempo de desintegração dos comprimidos foram avaliadas através de um Desenho Composto Central. Os dados experimentais foram analisados estatisticamente, utilizando os modelos matemáticos para gerar superfícies de resposta. Os resultados indicaram que a concentração de dióxido de silício coloidal foi inversamente relacionada às respostas de dureza e friabilidade, enquanto que a concentração de croscarmelose sódica foi a principal responsável pela redução no tempo de desintegração. As condições ótimas foram selecionadas através da sobreposição dos gráficos, buscando uma formulação com menor tempo de desintegração, menor friabilidade e o máximo de dureza. A formulação eleita deve conter 1,2 % (m/m) de dióxido de silício coloidal e 5,0 % (m/m) de croscarmelose sódica. Nestas condições os comprimidos apresentaram dureza de 107,9 N, friabilidade de 0,56 % (m/m) e desintegração máxima em 6,8 min. / The leaves of Maytenus ilicifolia are widely used within the traditional Brazilian medicine due to its properties against gastric disorders. Once proved its efficacy and safety, this vegetable drug has been the object of several studies to establish the basis for quality control. Taking this into consideration, it was necessary to evaluate the feasibility of developing an analytical method based on the precipitation of tannins, by using polyvinylpyrrolidone for precipitation. The data have shown that the removal of the tannins in solution was successful when insoluble polyvinylpyrrolidone was used. Hereby it was observed that the polymer has also the ability to precipitate other polyphenols besides the tannins from the aqueous solution of M. ilicifolia. However, the interactions of the polymer happened mostly with the condensed tannins. Further it was developed and also validated an HPLC method to separate and quantify catechin and epicatechin present in aqueous extracts of M. ilicifolia. No significant variations of peak areas or retention times were observed when the evaluation of the method was executed, showing satisfactory chromatographic conditions. In order to make a spray dried extract (SDE) using a spray-drier fitted out with a rotary atomizer, it was necessary to concentrate the extractive solution. This operation had been performed under reduced pressure until a content of 15 % solids was achieved. The drying of the concentrated solution lead to a yield of 90 %, and the obtained SDE presented spherical particles, which have a rough surface and a mean particle size of 22,51.1.m. The technological characterization of the SDE showed that attributes such as densities (tap and bulk), compressibility and flow, have been improved when compared to the product prepared using a mini spray-drier supplied with a pneumatic nozzle. However, these modifications were not enough to enable its direct compression. Therefore, the material was compacted to produce granules after slugging or roller compaction, The compressional analysis of the SDE and each granule batch using the Heckel equation proved that the increase in the compaction force once processing the granulation was the main factor to reduce the material's ability to undergo plastic deformation. Consequently, the recompression of the granules in a tablet press led to compacts with a lower crushing strength compared to that prepared by direct compression of the pharmaceutical complex. Whereas the SDE has shown a reduced tendency to particle rearrangement at early stage of compression, the granules showed an intense fragmentation and rebound behavior, presenting a plastic behavior when higher compaction pressures were used. Finally, tablets containing a high dose of granulated spray dried extract of M. ilicifolia were prepared by using the following excipients: microcrystalline cellulose (filler/binder), colloidal silicon dioxide (glidant and moisture adsorber) and cross-linked carboxymethylcellulose (disintegrant). The influences of colloidal silicon dioxide (CSD) and cross-linked carboxymethylcellulose (CMC-Na) on the tablet hardness, disintegration time and friability were evaluated by a central composite design. The data were analyzed statistically and mathematical models were used to create response surfaces. The results have indicated that the concentration of CSD shows an inverse relation to the responses of hardness and friability, while the concentration of CMC-Na was the most important factor that caused a reduction of the time necessary for total disintegration. The optimal conditions for processing were chosen by the overlapping of graphics, taking into consideration that the formulation should present a minimum of disintegration time, lower friability and a maximum of hardness. Thus, it was found that the best formulation should have a content of 1.2% (w/w) of CSD and 5.0% (w/w) of CMC-Na. Regarding these conditions, the tablets have shown a hardness of 107.9 N, friability of 0.56% (w/w) and a disintegration time of 6.8 min.
34

Teoretické vlastnosti a aplikace pokročilých modelů plánovaného experimentu / THEORETICAL PROPERTIES AND APPLICATIONS OF ADVANCED DESIGNS OF EXPERIMENT

Hrabec, Pavel January 2020 (has links)
The methodology of the design of experimnet has become an integral part of the optimisation of manufacturing processes in recent decades. Problems regarding designs of experiments are still up to date, especially because of a variety of approaches to collecting and evaluating data. Scientists in different research and development areas often do not take into account possible shortcommings or even essential assumptions of selected design and/or its evaluation methods. This disertation thesis summarizes theoretical bases of selected designs of experiments. Describes several applications of central composite design on responses regarding wire electrical discharge machining process. And compares different designs of experiment for response surfaces of five parameters with regards to algoritmic selection of statistically signifficant parameters.
35

Biocatalytic Production, Preparation and Characterization of Large-ring Cyclodextrins

Mokhtar, Mohd Noriznan 26 January 2009 (has links)
Cyclodextrins (CD) are cyclic oligosaccharides composed of six to more than sixty glucose units. Large-ring cyclodextrins (LR-CD) are novel CD comprised of more than eight glucose units with cavity structures and sizes different from that of commercially available CD<sub>6</sub> – CD<sub>8</sub>. LR-CD may offer unique molecular recognition properties and can be produced biocatalytically from starch using cyclodextrin glucanotransferase (CGTase, E.C. 2.4.1.19) in a short reaction time. LR-CD were isolated from glucose, CD<sub>6</sub> – CD<sub>8</sub> and other compounds by complexation of CD<sub>6</sub> – CD<sub>8</sub> as well as precipitation techniques. The yield of LR-CD (degree of polymerization from 9 to 21) was optimized using central composite design. Addition of polar organic solvents to the synthesis resulted in higher yields of LR-CD. LR-CD composed of 9 to 21 glucose units were successfully separated using reversed-phase of ODS-AQ chromatography and normal-phase of polyamine II chromatography. Maintaining optimized reaction conditions aided in a high yield of CD<sub>9</sub>; it could be separated with reasonable yield using a single step of polyamine II chromatography. A co-grinding method helped to obtain higher solubilization levels of glibenclamide, vitamin A acetate and vitamin D<sub>3</sub> in CD<sub>13</sub>, CD<sub>10</sub> and CD<sub>11</sub>, respectively when compared to other CD. Vitamin K<sub>1</sub> was solubilized in distilled water with CD<sub>6</sub> – CD<sub>13</sub> using a co-precipitation method. When compared with other CD, CD<sub>9</sub> was seen to be the best solubilizer. The analysis of complexes using ESI MS showed spironolactone and glibenclamide complexed with CD<sub>9</sub> and CD<sub>13</sub>, respectively.
36

[pt] ESTUDO NUMÉRICO DOS MOTORES À IGNIÇÃO POR COMPRESSÃO ASSISTIDA POR CENTELHA (SACI) / [en] NUMERICAL STUDY OF SPARK-ASSISTED COMPRESSION IGNITION ENGINES (SACI)

CAIO FILIPPO RAMALHO LEITE 28 December 2021 (has links)
[pt] Nos últimos anos, a indústria automotiva se reinventou para atender às demandas do mercado, que tem se mostrado competitivo em um contexto com legislações ambientais severas. Uma alternativa para reduzir as emissões de gases de efeito estufa prejudiciais ao longo da vida do veículo são os carros elétricos. No entanto, a produção e o descarte de baterias elétricas ainda é um problema a ser resolvido. Por isso, as empresas também buscam alternativas para aumentar a eficiência do motor de combustão interna e desenvolver tecnologias verdes, como a Ignição por Compressão de Carga Homogênea ou a Ignição por Compressão Assistida por Centelha (SACI). Uma rotina MATLAB foi criada para prever o desempenho da combustão SACI de gás natural usando um modelo termodinâmico de duas zonas. Este trabalho realiza análise de sensibilidade para cinco parâmetros de desempenho: eficiência térmica (Nth), pressão efetiva média indicada (IMEP), emissões de NOx, temperatura média no cilindro (Tavg) e tempo de autoignição (AIT), com várias variáveis como a velocidade do motor (RPM), a razão de equivalência combustível-ar (0s), o tempo da centelha (0s), a razão de compressão (rc) e a pressão de admissão (Pint), usando planejamento de experimentos para avaliar o impacto dos fatores. O Planejamento de Composto Central indica que o RPM e o 0 foram os fatores mais importantes no SACI, uma vez que influenciam todos os parâmetros de desempenho. A Pint foi significativa em três parâmetros de desempenho (Nth, IMEP e Tavg), assim como o 0s (NOx, Tavg e AIT). A rc foi relevante em apenas um deles (AIT). Além disso, uma Análise Univariada foi feita para comparar as técnicas de ignição por centelha (SI) e SACI. Os resultados indicam que os motores SACI tendem a ser cerca de 9% mais eficientes e as emissões de NOx caem mais de 90%. / [en] In the last few years, the automotive industry has reinvented itself to meet the demands of the international market, which has been increasingly competitive in a context with environmental laws each year more severe. One alternative to lower harmful greenhouse gases emissions over the life of the vehicle is electric cars. However, the production and disposal of electric batteries is still a major problem to be solved. Therefore, companies are also searching for other potentialities to increase the internal combustion engine s efficiency and develop green technology, such as Homogeneous Charge Compression Ignition (HCCI) or Spark-Assisted Compression Ignition (SACI). A MATLAB routine was created to predict the performance of SACI multimode combustion of natural gas using a two-zone thermodynamic model. This work performs sensitivity analysis for five performance parameters: thermal efficiency (Nth), indicated mean effective pressure (IMEP), NOx emissions, mean in-cylinder temperature (Tavg), and auto-ignition timing (AIT), with several variables such as engine speed (RPM), fuel-air equivalence ratio (0s), spark timing (0s), compression ratio (rc), and intake pressure (Pint), using the design of experiments tools to assess the factors impact. The Central Composite Design indicates that RPM and 0 were the most important SACI factors since they influence all engine performance parameters. The Pint was significant in three performance parameters (Nth, IMEP and Tavg), as was 0s (NOx, Tavg and AIT). The rc, however, was relevant in only one of them (AIT). Furthermore, a Univariate Analysis (UA) was done to compare Spark-Ignition (SI) and SACI engines. The results show that SACI engines tend to be around 9% more efficient, NOx emissions drop notably, more than 90%, IMEP presents an increase of 76%, and Tavg decreases 200-300 K.
37

Novel nanostructured ternary metal oxide composite for sequestration of trace metals from simulated aqueous solutions.

Kupeta, Albert Jerry Kafushe 06 1900 (has links)
D. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology / A novel low-cost ternary Mn-Fe-Cu (MFC) metal oxide nanocomposite adsorbent was fabricated using facile co-precipitation method and successfully applied for the sequestration of Cr(VI) and As(III) from simulated aqueous efflent. The central composite design (CCD) of the response surface methodology (RSM) optimization technique determined the optimal working parameters for the preparation of the ternary MFC metal oxide nanocomposite. The spectroscopic microstructural analysis of the ternary MFC metal oxide nanocomposite was performed using fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) spectroscopy. The spectroscopic analyses revealed a rough surface with hydroxyl groups and the presence of mixed metal oxides in different valence states. The BET surface area, pore volume and pore size of the nanostructured MFC ternary metal oxide composite were found to be 77.2427 m2/g, 0.2409 cm3/g and 14.7560 nm, respectively. The pH drift method determined that the pHpzc of the adsorbent was 6.75. The batch technique was employed to investigate the adsorption dynamics (effects of ionic strength, co-existing anions, adsorbent regeneration and reuse) and optimum parameters (solution pH, adsorbent dosage concentration, desorption) of Cr(VI) and As(III) adsorption onto the MFC nanocomposite. The fitting of non-linear kinetic (pseudo-first-order, pseudo-second-order and Elovich), diffusion (intraparticle and Boyd) and isotherm (Langmuir, Freundlich and Dubinin-Radushkevich) models to the Cr(VI) and As(III) experimental adsorption data gave an insight into the adsorption mechanisms. The Langmuir adsorption capacities, qm (mg/g), were 168.71 at solution pH 3 and 35.07 at solution pH 9 for Cr(VI) and As(III) adsorption, respectively. The adsorption of Cr(VI) onto the ternary MFC metal oxide nanocomposite was physical and formed outer-sphere surface complexes through electrostatic interactions, while the removal of As(III) was specific due to inner-sphere surface complexation and ligand/ion exchange reactions. The results from XPS and FTIR analysis after the adsorption of Cr(VI) and As(III) showed that the surface hydroxyl groups on the MFC nanocomposite interacted with the Cr(VI) and As(III) species during the formation of the surface complexes. To facilitate ease of adsorbent removal from the treated simulated aqueous effluent, the ternary MFC metal oxide system was co-precipitated onto biochar support.

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