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In this study, sorption distribution coefficients were determined for 71 pharmaceuticals, aiming to describe their sorption behavior to powder activated carbon (PAC). The data are expected to be applied when designing and upgrading wastewater treatment plants (WWTP) for improved removal of pharmaceuticals by applying sorption to PAC as an additional removal technique. Sorption isotherms were determined for the pharmaceuticals over a concentration interval covering a wide range from 0.08 to 10 µg/L using PAC at a concentration of 10 mg/L. The best fitted sorption isotherms were used to calculate the distribution coefficients (Kd) and these were applied to estimate that the PAC doses needed to achieve a target concentration of 10 ng/L in the effluent. A target concentration was used since neither discharge limit values nor environmental quality standards in general have been defined for these compounds. Using a %-removal approach does not guarantee achievement of concentrations low enough to protect the water ecosystems. Some of the pharmaceuticals will be reduced by the addition of small amounts of PAC. Examples are atenolol, carbamazepine, citalopram, codeine, fluoxetine and ibuprofen. For others, e.g., oxazepam, an alternative treatment has to be considered since the requested dose is too high to be realistic for a target concentration of 10 ng/L.

In response to concerns over the translocation of P from soils to P-sensitive water bodies, there is high demand for developing simple indicators for evaluating a soil’s risk of releasing P into solution. Many studies have shown that the degree of soil phosphorus saturation (DPS), calculated as the ratio of soil P concentration to soil P sorption capacity (PSC), is good predictor of a soil’s risk of releasing P in solution. In this study we compared four different DPS indices in how well they predicted dissolved P following extraction with either a 0.01 M CaCl2 (PCaCl2) solution or deionized water (PW). The first two indices were calculated from the ratio of extractable P to extractable Al and Fe using either acid ammonium oxalate (AlOX + FeOX) or ammonium lactate solutions (AlAL + FeAL). The second two DPS indices were calculated from the ratio of either Olsen-extractable P or AL-extractable P with sorption capacity estimated from the single point P sorption index (PSI). On a subset of 11 soils, we compared the different methods for estimating PSC with fitted Langmuir sorption maximum (Smax) using data from complete sorption isotherms. Both (AlOX + FeOX) and PSI were well correlated with Smax and hence regarded as good estimates for P sorption capacity. Conversely, (AlAL + FeAL) was not significantly correlated with Smax. P saturation calculated from PSI together with PAL or POls predicted PCaCl2 and PW best, whereas P saturation calculated from ammonium oxalate predicted PCaCl2 and PW the least. We did not find notable improvements in the regression models when we added a second explanatory variable (clay content, pH or total carbon) to the models. Our results show that multiple measures of P saturation provide similar predictions of a soiĺs potential for releasing dissolved P into soil solution. This provides flexibility in how P saturation indices are calculated to identify leaching prone hotspots.

A new fitting model for sorption by glassy polymers is suggested based on the Flory–Huggins (FH) equation with a composite formula for the FH interaction parameter, χ, which is applicable if sorption experimental data shows a single-maximum variation of the FH parameter. Namely, a power-like and a linear approximation is assumed for χ(φ1), as a function of solvent volume fraction φ1, before and after the point of its maximum. After determining the maximum point from a direct inspection of the sorption data, the three fitting parameters are evaluated by solving two independent least-square minimization problems. Several sorption studies of biopolymers taken from the literature show that the endset of the glass transition region is correlated with the position of the maximum of the FH interaction parameter. Based on this hypothesis and the Vrentas–Vrentas model for sorption of glassy polymers, a theoretical framework for the glass transition analysis is developed. In particular, the solvent-induced glass transition temperature variation can be estimated from the sorption isotherm as a function of the solvent content corresponding to temperatures above the temperature of sorption.

Práce se soustředí na vybrané rostlinné doplňky stravy z řas, mladých výhonků obilnin, listů keře čajovníku, listů stromů a bylin ve formě prášků, jejich pěstování, zpracování a nutriční využití. Popisuje jednotlivé bioaktivní látky, které se v rostlinných materiálech vyskytují, zabývá se problematikou antioxidantů, metodami používanými k hodnocení antioxidační kapacity různých druhů látek a měřením sorpčních vlastností pro vyobrazení sorpčních izoterm., This work focuses on selected plant-based supplements from micro algae, cereal grasses, tree leaves and herbs in a form of green powders. Describes their cultivation, processing, nutritional use and bioactive substances. Research and experimental part focuses on a topic of antioxidants, methods used to evaluate the antioxidant capacity and measurement of sorption properties to describe sorption isotherms., Fakulta chemicko-technologická, Studentka seznámila členy zkušební komise s obsahem své bakalářské práce, poté byla seznámena s posudkem vedoucího bakalářské práce. Studentka odpověděla na otázky členů zkušební komise., Dokončená práce s úspěšnou obhajobou

Lesser mealworm (Alphitobius diaperinus) is an insect species that can be reared on an industrial scale for human consumption. In this study, the hydration behavior of processed lesser mealworm food ingredients (whole powder, protein concentrate, textured protein) was analyzed in comparison to whey protein concentrate and tofu. Moisture adsorption isotherms were determined gravimetrically over 0.11–0.96 water activity range at 5 and 20 °C, and seven sorption models were applied to fit the experimental data. The Guggenheim-Anderson-de Boer model performed best on the isotherms of all studied samples. The determined adsorption isotherms were type III according to Brunauer classification. Mealworm protein concentrate presented the strongest hydration capacity at 20 °C, followed by whey protein concentrate and whole mealworm powder. Textured mealworm protein and tofu exhibited similar hydration behavior at 5 °C. Moreover, browning and agglomeration of mealworm protein concentrate powder were observed at water activities of 0.73 and higher, which can be explained by its composition and porous structure and were not typical for whey protein concentrate. The moisture adsorption results are important for the prediction of lesser mealworm ingredients shelf-life or prevention of undesirable quality changes during storage, but more research on microbial growth and sensory quality is needed.

С применением низкотемпературной адсорбции азота экспериментально определены удельная поверхность и распределение пор по размерам для активного угля из осиновой древесины. Показано, что удельная поверхность мезопор может достигать 290 м2/г. Полученные результаты выявили, что основное количество микропор в осиновом активном угле имеет размеры в пределах 1–1,2 нм, а основное количество мезопор – в пределах 3–5 нм. Изменение продолжительности процесса активации оказывает существенное влияние практически на все характеристики пористой структуры активного угля, получаемого на основе осиновой древесины. С повышением продолжительности активации увеличиваются средняя ширина и удельная поверхность мезопор, а также общий объем и удельная поверхность пор. Вместе с тем средняя ширина микропор несколько снижается. Материал обладает высокими сорбционными свойствами относительно извлечения ионов Fe3+, Zn2+, Cu2+, NO3–. Результаты независимой экспертизы полученного активного угля показали, что он может применяться для очистки природных вод и в технологии очистки вод оборотного цикла предприятий горно-металлургического комплекса., The specific surface area and pore size distribution for active carbon from aspen wood were experimentall determined using low-temperature nitrogen adsorption. It is shown that the specific surface area of mesopores can reach 290 m2/g. The obtained results showed that the main number of micropores in the aspen active carbon has dimensions in the range of 1–1,2 nm, and the main number of mesopores-in the range of 3–5 nm. The change in the duration of the activation process has a significant effect on almost all the characteristics of the porous structure of active carbon obtained on the basis of aspen wood. With increasing activation duration, the average width and specific surface area of mesopores, as well as the total volume and specific surface area of pores, increase. At the same time, the average width of micropores is slightly reduced. The material has high sorption properties with respect to the extraction of Fe3+, Zn2+, Cu2+, and NO3– ions. The results of an independent examination of the obtained active carbon showed that it could be used for natural water treatment and in the technology of water treatment of the recycling cycle of mining andmetallurgical enterprises.

Ash from poultry feather gasification was investigated as an adsorbent for Cd removal from synthetic wastewater under a range of operational conditions: initial pH (2–8) and salinity (8–38 mS/cm) of wastewater, ash dosage (2.5–50 g/L), Cd concentration (25–800 mg/L) and contact time (5–720 min). The ash was highly alkaline and had low surface area and micropores averaging 1.12 nm in diameter. Chemical/mineralogical analysis revealed a high content of P2O5 (39.9 wt %) and CaO (35.5 wt %), and the presence of calcium phosphate, hydroxyapatite and calcium. It contained only trace amounts of heavy metals, BTEX, PAHs and PCBs, making it a safe mineral by-product. Cd adsorption was described best with Langmuir and pseudo-second order models. At pH 5, an ash dosage of 5 g/L, 40 min contact time and 100 mg Cd/L, 99% of Cd was removed from wastewater. The salinity did not affect Cd sorption. The maximum adsorption capacity of Cd was very high (126.6 mg/g). Surface precipitation was the main mechanism of Cd removal, possibly accompanied by ion exchange between Cd and Ca, coprecipitation of Cd with Ca-mineral components and Cd complexation with phosphate surface sites. Poultry ash effectively removes high concentrations of toxic Cd from wastewater., Validerad;2020;Nivå 2;2020-11-30 (alebob)

The relationship between Equilibrium Moisture Content (EMC) and Equilibrium Relative Humidity (ERH) was measured in three varieties of soybeans grown in Manitoba (Akras R2, Lono R2 and Podaga R2) with the objective of modelling mathematically the adsorption and desorption isotherms. The effect of three post-harvest conditions: (a) freshly harvested soybeans (b) soybeans subjected to three drying and wetting cycles, and (c) soybeans subjected to three freezing and thawing cycles was investigated on the sorption isotherms of the soybean varieties. The adsorption and desorption experiments were conducted at 5, 10, 15, 20, 25 and 30°C using a dynamic ERH apparatus. Significant differences were found in all pairs of adsorption-desorption characteristics indicating the presence of hysteresis in the soybean samples at all the temperatures tested. The hysteresis magnitude ranged between 0.23 to 4.5% moisture content (MC) measured on dry basis. The modified Halsey equation and the modified Oswin equation were similar in predicting the sorption isotherms of the experimental data, with the former being superior in predicting the desorption data at low RH. The parameters calculated for the modified Halsey equation are applicable for temperatures above 10°C in the range of 10 to 80% RH for desorption and 30 to 80% RH for adsorption. Freshly harvested samples of the three soybean varieties produced similar isotherms, without significant differences among them. However, soybeans varieties responded differently to the effect of pre-treatments (i.e. drying/wetting and freezing/thawing cycles). Significant differences at 10, 15, 20, 25 and 30°C were found in the adsorption isotherms of Akras and Lono soybeans subjected to drying and wetting cycles. Adsorption isotherms of Akras and Podaga soybeans subjected to freezing and thawing cycles were significantly different from the fresh samples of iii these varieties. The effect of drying and wetting cycles on the desorption isotherms was

[EN] Citrus aurantium flowers are high value aromatic and medicinal plants. The storage conditions and quality of dried Citrus aurantium flowers depends on their hygroscopic stability. The equilibrium moisture content was determined at temperatures (from 30 to 60 °C), and the sorption phenomenon is well described by Peleg model. The optimal water activity for the storage of the product was estimated at awop=0.373. Afterwards, the net isosteric heat was evaluated in the range of 88 kJ.mol−1 for small values of the moisture content (Xeq=0.14kg water/kg d.b), and it decreased along with the increase of Xeq. The experimental drying curves showed only a falling rate period. Finally, Midilli-Kucuk model was found to be the more suitable to describe the drying kinetic of Citrus aurantium flowers.

Volcanic soils cover 1% of the Earth’s surface but support 10% of the world’s population. They are among the most fertile soils in the world, due to their excellent physical properties and richness in available nutrients. The major limiting factor for plant growth in volcanic soils is phosphate fixation, which is mainly attributable to active species of aluminium and iron. The sorption and desorption of phosphate is studied on the surface horizons of two African agricultural soils, a silandic Andosol (Rwanda) and a vitric Andosol (São Tomé and Principe). Both soils are slightly acid. The silandic Andosol is rich in active aluminium forms, while the vitric Andosol has high amounts of crystalline iron and aluminium oxides. Sorption isotherms were determined by equilibrating at 293K soil samples with phosphate solutions of concentrations between 0 and 100 mg P L−1 in NaNO3; phosphate was determined by visible spectrophotometry in the equilibrium solution. To study desorption, the soil samples from the sorption experiment were equilibrated with 0.02 M NaNO3. The isotherms were adjusted to mathematical models. In almost all the concentration range, the adsorption of phosphate by the silandic Andosol was greater than 90% of the amount added, being lower in the vitric Andosol but always higher than 65%. The high sorption by the silandic Andosol is attributed to its richness in non-crystalline Fe and Al, while in the vitric Andosol crystalline iron species seem to play a relevant role in the adsorption. The sorption isotherms of both soils fitted to the Temkin model, the adjustment to the Langmuir or Freundlich models being unsatisfactory; throughout the range studied, the sorption increases with increasing phosphorus concentration, a maximum sorption is not predictable (as occurs when the sorption is adjusted to the Langmuir model). For an added P concentration of 100 mg L−1 (3.2 mmol L−1 ), the sorption is 47.7 µmol P g−1 in the silandic Andosol and 41.6 µmol P g−1 in the

[EN] Drying kinetics of Saccharina latissima (raw and blanched) at low temperatures (10.0, 25.0 and 38.0 °C) was studied. The effective moisture diffusivity coefficient varied due to temperature alterations in the range between 1.4 and 4.5 10-10 m2/s for raw and 0.91 and 2.56 10-10 m2/s for blanched seaweeds. Significant changes in structural properties and chemical composition resulted in a much longer drying time of blanched seaweeds, when compared with raw. Drying temperature of 38.0 °C resulted in more brown color, when compared with other samples. Sorption characteristics of dried raw seaweeds depended on salt content and showed high accumulation of moisture at relative humidity of air of 80.0 %. The blanched seaweeds showed linear accumulation of moisture within increasing of relative humidity of drying air from 20.0 to 80.0 %, but high level of hysteresis was determined between sorption and desorption isotherms. The shrinkage development within dewatering of blanched and raw samples was also studied.

The use of As-rich water for irrigation in agricultural soils may result in As accumulation in soil and crops, with the consequent risk of its entry into the food chain. The effectiveness of three different Fe-based materials (a commercial iron oxide (Bayoxide®), lamination slag (a by-product of the hot rolling of steel) and a commercial red mud derivative (ViroBind™)) used as soil amendments to minimise the impact of irrigation with As-rich water in an agricultural soil-plant system was evaluated in a pot experiment. Simultaneously, the influence of organic and inorganic fertilisation (olive oil mill waste compost versus NPK fertiliser) on the effectiveness of iron oxide in As adsorption processes was also assessed. The As adsorption capacity of the amendments was determined in a preliminary batch experiment using sorption isotherms. Then, a pot experiment was carried out in a growth chamber using an agricultural soil (arenosol) from Segovia province (central Spain), amended with the different materials, in which Lactuca sativa (lettuce) was grown for two months. The As adsorption capacity was higher in the commercial iron oxide and in the red mud derivative, which fitted the Freundlich model (no saturation), than in the lamination slag, which fitted the Langmuir model (limited adsorption). All the materials decreased the pore water As concentration compared to the control (by 29–80%), but only iron oxide reduced As availability in the soil, and none of the amendments decreased the As concentration in plant leaves. The combination of iron oxide and compost did not significantly improve plant growth, but increased nutrients (N, K, Ca, Na and Mg) concentrations and availability in the soil and their concentration in the plants, relative to the other treatments and the control. Therefore, this seems to be a viable option to prevent As leaching and improve the plant nutritional status.

The general objective of this work is to contribute to the characterization and the mathematical modeling of the convective drying of fermented Amazonian cocoa beans (Theobroma cacao var. Forasteiro). A combined approach is used, including the analysis of the bean physical characteristics, the determination of the bean sorption isotherms, the realization of drying experiments in a convective dryer (for different operating conditions) and the development of a mathematical model, based on the different transport (heat and mass) phenomena involved inside and outside the beans during their drying. The results show that the drying of an Amazonian cocoa bean can be divided in two phases. It is demonstrated that this is due to the combination of two elements. First, the initial volumetric concentration of water is higher in the shell than in the core of the bean. Second, at the beginning of the drying, the drying rate is controlled by both internal and external transport phenomena while, in the second part of the drying (for moisture content of the bean below 0.5 kg of water/kg of dry matter), it is totally controlled by the water diffusion inside the bean. The model is compared to the experimental results in order to characterize the effective diffusion coefficient of water inside a bean. It is shown that this diffusion coefficient approximately doubles when the temperature is increased from 30 to 60 °C. It is close to 1.5 × 10−10 m2/s at 60 °C. Finally, measuring the polyphenol content of the dry beans allows assessing that, regarding chocolate quality, the fermented Amazonian cocoa beans should be dried at 30–40 °C., SCOPUS: ar.j, info:eu-repo/semantics/published

The excellent matching between the sorption and desorption temperatures of hexahydrated SrBr2and those required for solar heat storage for building applications, the high heat of reaction (67.5 kJ/mol of water) coupled with the gain/loss of 5 mol of water per mole of salt make this salt an appealing sorbent for solar thermal energy storage applications coupled to space heating. Due to the morphological instability of this salt, it is necessary to incorporate it in a porous matrix as a composite sorbent. A new composite material for thermochemical energy storage applications was developed. It consists of a mesoporous silica gel impregnated by strontium bromide with salt content equal to 58 wt.%. The structure and the sorption properties of the composite were characterized by SEM-EDX, temperature dependent XRD, XRF, and N2sorption measurements. The salt is homogeneously distributed inside the pores of the silica gel. Water sorption isotherms were measured between 20 °C and 80 °C, which enabled us to understand the sorption mechanism. A mathematical model was developed and used to fit the experimental data in order to predict the sorption behavior of the composite at different conditions (influence of temperature and pressure conditions on the cycle loading lift and energy storage density). The interest of using such a composite for thermal energy storage application is then discussed (thermal energy produced by solar collector and used for space heating). A high cycle loading lift of 0.22 g/g is obtained corresponding to an energy storage capacity of 230 W h/kg and an energy storage density of 203 kW h/m3of packed bed composite (between 30 °C and 80 °C at 12.5 mbar) is reported, with an excellent stability over 14 sorption/desorption cycles. The sorption kinetics of this composite is enhanced compared to pure salt. Test on a laboratory scale open type reactor gives a maximum specific thermal power of 200 W/kg and a mean specific thermal power of 92 W/kg at 30 °C and 1, SCOPUS: ar.j, info:eu-repo/semantics/published

The isosteric heats of sorption of two varieties of quinoa (Chenopodium quinoa Willd.) grain were determined by the static gravimetric method at four temperatures (40, 50, 60 and 70 °C) and in relative humidity environments provided by six saturated salt solutions. Six mathematical equations were used to model the experimental data: GAB, Oswin, Henderson, Peleg, Smith and Halsey. The isosteric heat of sorption was determined using the parameters of the GAB model. All the equations were shown to be appropriate by the coefficients of determination (R2) and the mean absolute error (MA%E). The influence of temperature was observed because the adsorption of water by the grains was lower at higher temperatures. The equilibrium moisture contents for security of storage, for long periods of time at water activity lower than 0.65, were 12 - 13%. The effect of temperature on the parameters of the GAB model was analysed using the exponential Arrhenius equation. The isosteric heats of sorption were determined by applying the Clausius-Clapeyron equation as a function of humidity. The isosteric heat at 5% moisture for grains of the Blanca de Juli variety was 3663 kJ/kg and for the Pasankalla variety it was 3393 kJ/kg. The experimental data for isosteric heat as a function of humidity were satisfactorily modelled using three mathematical equations.

High total and bioavailable concentrations of As in soils represent a potential risk for groundwater contamination and entry in the food chain. The use of organic amendments in the remediation of As-contaminated soils has been found to produce distinct effects on the solubility of As in the soil. Therefore, knowledge about As adsorption-desorption processes that govern its solubility in soil is of relevance in order to predict the behaviour of this element during these processes. In this paper, the objective was to determine As adsorption and desorption in four different soils, with and without compost addition, and also in competition with phosphate, through the determination of sorption isotherms. Batch experiments were carried out using three soils affected differently by previous mining activity of the Sierra Minera of La Unión-Cartagena (SE Spain) and an agricultural soil from Segovia province (central Spain). Adsorption was higher in the mining soils (and highest in the acidic one) than in the agricultural soils, although the latter were not affected negatively by organic matter or phosphate competition for sorption sites. The results show that As adsorption in most soils, both with and without compost, fitted better a multimolecular layer model (Freundlich), whereas As adsorption in competition with P fitted a monolayer model (Langmuir). Moreover, the use of compost and phosphate reduced the adsorption of As in the mining soils, while in the agricultural soils compost increased their low adsorption capacity. Therefore, the use of compost can be a good option to favour As immobilisation in soils of low adsorption, but knowledge of the soil composition will be crucial to predict the effects of organic amendments on As solubility in soils and its associated environmental risk.

[ES] En este trabajo se estudiaron diferentes materias primas de interés para la preparación de un alimento complementario destinado a la población infantil del departamento del Chocó (Colombia), entre las que se encuentran dos variedades de plátano de cocción en tres estados de madurez (verde, pintón y maduro): popocho (Musa exótica L.) y primitivo (Musa acuminata AA), chontaduro (Bactris gasipaes), cacao (Theoborma cacao L.), pacó (Gustavia superba (Kunth.) O. Berg) y quinua (Chenopodium quinua). Se partió de las muestras secas y trituradas, analizándose el contenido en humedad, cenizas, proteínas, grasas y almidón. También se estudió la estabilidad de las muestras en función del nivel de humectación. Para ello, éstas fueron acondicionadas en cámaras con humedades relativas del 11% al 75% (20 °C). Una vez alcanzaron el equilibrio se obtuvieron las correspondientes isotermas de sorción, ajustándose a cuatro modelos descritos en bibliografía: BET, GAB, Henderson y Caurie. Se analizó la temperatura de transición vítrea (Tg) por calorimetría diferencial de barrido (DSC) y se analizaron los cambios en las propiedades mecánicas y ópticas de las muestras con diferente contenido en humedad. En general, el plátano de ambas especies en estado verde, posee un mayor contenido en macronutrientes y mayor valor energético. Para formular un alimento equilibrado, de acuerdo con las recomendaciones del aporte diario energético de la dieta, sería necesario completar el aporte de proteínas. Dadas las características de los complementos estudiados, se recomendaría el empleo del chontaduro, quinua y cacao por su composición equilibrada en macronutrientes. En cuanto al estudio de estabilidad, las isotermas de sorción se clasificaron de tipo II. El mejor ajuste de los datos de sorción se encontró con el modelo de Henderson, excepto para el pacó que obtuvo un mejor ajuste al modelo de Caurie. Ningún producto en polvo presentó problemas de apelmazamiento, únicamente en el plátano popocho p, [EN] In this work different raw materials of interest for the preparation of a supplementary food for the child population of the department of Chocó (Colombia) were studied. Two varieties of cooking bananas in three maturity stages (green, ripe and mature): popocho (Musa exótica L.) and primitivo (Musa acuminata AA), chontaduro (Bactris gasipaes), cacao (Theoborma cacao L.), pacó (Gustavia superba (Kunth.) O. Berg) and quinoa (Chenopodium quinoa) were used. The dried and powdered samples were analyzed in terms of the water content, ash, protein, fat and starch. Stability of the samples as a function of the moisture level was also studied. For this, they were put in chambers with relative humidities from 11% to 75% (20 °C). Once the equilibrium was reached, sorption isotherms were obtained, and data were adjusted to four models described in literature: BET, GAB, Henderson and Caurie. Glass transition temperature (Tg) was measured by differential scanning calorimetry (DSC) and changes in the mechanical and optical properties of the samples with different water content were analyzed. In general, both species of bananas in the green state, had a higher content of macronutrients and higher energy value. To formulate a balanced food, according to the recommendations of daily energy intake from the diet, it would be necessary to supplement the protein content. As for the nutritional characteristics of the supplements studied, the use of chontaduro, cocoa and quinoa could be recommend for balanced macronutrient composition. As for the stability study, sorption isotherms were classified of type II. In general, sorption data were best fitted to Henderson's model, except for pacó which better fitted to Caurie’s model. Powdered product did not show caking problems, only in ripe and mature popocho banana a rubbery nature was observed, with significant changes in the mechanical properties due to the moisture. So that its glass transition temperature was analyzed, concluding that, [CA] En este treball es van estudiar diferents matèries primeres d’interès per a la preparació d'un aliment complementari destinat a la població infantil del departament del Chocó (Colombia), entre les que es troben dues varietats de plàtan de cocció en tres estats de maduresa (verd, pintón i madur): popocho (Musa exòtica L.) i primitiu (Musa acuminata AA), chontaduro (Bactris gasipaes), cacau (Theoborma cacau L.), pacó (Gustavia supersuperba (Kunth.) O. Berg) i quinoa (Chenopodium quinoa). Es va partir de les mostres seques i triturades, analitzant-se el contingut en humitat, cendres, proteïnes, greixos i midó. També es va estudiar l'estabilitat de les mostres en funció del nivell d'humectació. Per a això, estes van ser preparades en cambres amb humitats relatives del 11% al 75% (20ºC). Una vegada van aconseguir l'equilibri es van obtindre les corresponents isotermes de sorció, ajustant-se a quatre models descrits en la bibliografia: BET, GAB, Henderson i Caurie. Es va analitzar la temperatura de transició vítria (Tg) i es van analitzar els canvis en les propietats mecàniques i òptiques de les mostres amb diferent contingut en humitat. En general, el plàtan d'ambdues espècies en estat verd, posseïx un major contingut en macronutrients i major valor energètic. Per a formular un aliment equilibrat, d'acord amb les recomanacions de l'aportació diària energètica de la dieta, seria necessari completar l'aportació de proteïnes. Donades les característiques dels complements estudiats, es recomanaria l'us del chontaduro, quinoa i cacau per la seua composició equilibrada en macronutrients. Quant a l'estudi d'estabilitat, les isotermes de sorció es van classificar de tipus II. El millor ajust de les dades de sorció es va trobar amb el model de Henderson, excepte per al pacó que va obtindre un millor ajust al model de Caurie. Cap producte en pols va presentar problemes d'atapeïment, únicament en el plàtan popocho pintón i madur es va observar un cert caràcter gomós, amb canvi

In this master thesis the sorption of heavy metals on activated carbon and zeolite was analyzed. The chosen heavy metals (Ag+, Cu2+, Zn2+) have been analyzed separately and as a mixture in order to check their sorption affinity toward granulated active carbon (GAC) and natural zeolite. These heavy metals are commonly found in some industrial wastewater and they need to be removed from effluent in order to protect environment. Heavy metals in solid phase are treated as solid waste materials that go on other ways of treatment. Granulated active carbon is widely used and efficient, but also expensive, and natural sorbents (such as zeolite) are low-cost and easily found in nature. The idea is to compare and try to change GAC with zeolite, if it proves to be efficient enough. The sorption capacity (efficiency of removal) and kinetics of sorption process (removal efficiency with time period) have been analyzed. Sorption efficiency has been analyzed through sorption kinetics and sorption isotherms. Sorption kinetics has been analyzed by using two models of kinetics: Pseudo-first order model (Lagergren model) and pseudo-second order model. Sorption isotherms have been analyzed by using three different isotherm models: Freundlich model, Langmuir model and Jovanovic model. For processing of results 'DataFit' (Oakdale engineering, USA) was used and data in the fifth chapter, 'Results and discussion', are obtained by using this software. Analysis of samples was carried out in a flame atomic absorption spectrometers in 'Anahem' laboratory and at the Institute of Nuclear Sciences 'Vinca'. Sample preparation, solutions and execution of experiments was carried out in the laboratory of Civil Engineering, University of Belgrade. By analyzing the results of sorption kinetics, it was found that both sorbent have the greatest affinity for silver and that the adsorption of silver occurs at a higher speed than the adsorption of copper and zinc. Competitive sorption showed that 50 % of sil, U okviru ovog rada analizirana je sorpcija teških metala na aktivnom uglju i zeolitu. Analizirana je sorpcija jona Ag+, Cu2+, Zn2+ pojedinačno i u smeši, kako bi se uporedile sorpcione karakteristike i afinitet u odnosu na granulisani aktivni ugalj (GAU) i prirodni zeolit. Odabrani teški metali se često mogu pronaći u industrijskim otpadnim vodama. U cilju zaštite životne sredine, ovi metali moraju biti uklonjeni iz efluenata. Teški metali u čvrstoj fazi se tretiraju kao čvrsti otpad koji se nakon adsorpcije može proslediti na dalji tretman prečišćavanja. Granulisani aktivni ugalj izabran je zbog široke upotrebe i velike efikasnosti. Za razliku od aktivnog uglja, koji je skup, prirodni sorbenti (u koje spada i zeolit) su jeftini i lako se mogu pronaći u prirodi. Cilj rada bio je upoređivanje aktivnog uglja i zeolita i analiza mogućnosti zamene aktivnog uglja zeolitom u slučaju da se zeolit pokaže dovoljno efikasnim. Ispitivan je sorpcioni kapacitet (efikasnost uklanjanja), kao i kinetika (efikasnost uklanjanja u određenom vremenskom periodu). Efikasnost sorpcije analizirana je kroz kinetiku sorpcije i izoterme. Kinetika sorpcije je analizirana pomoću modela pseudo-prvog reda (model Lagergren-a) i modela pseudo-drugog reda. Sorpcione izoterme su analizirane pomoću modela Freundlich-a, Langmuir-a i Jovanović-a. Za obradu rezultata korišćen je program 'DataFit' (Oakdale engineering, USA) i prikazani podaci u okviru rezultata i diskusije su dobijeni korišćenjem ovog softvera. Analiza uzoraka je rađena na plamenim spektrometrima za atomsku apsorpciju u 'Anahem' laboratoriji i Institutu za nuklearne nauke 'Vinča'. Priprema uzoraka, rastvora i izvođenje eksperimenata rađeno je u laboratoriji Građevinskog fakulteta Univerziteta u Beogradu. Analizom rezultata kinetike sorpcije, utvrđeno je da se oba sorbenta imaju najveći afinitet prema srebru i da se adsorpcija srebra odvija većom brzinom nego adsorpcija bakra i cinka. Kompetitivna sorpcija pokazuje da se 50 % jona srebra i

The moisture sorption isotherms of Algerian bay leaves (Laurus nobilis) were determined experimentally in this work. The equilibrium moisture contents of the leaves were measured at 40, 50, and 60 °C using static gravimetric method. Six mathematical models were tested to fit the experimental data of sorption isotherms and predict the hygroscopic behavior during storage or drying. Peleg model was found to be the best fitting model for describing the sorption curves. The net isosteric heat of sorption was computed fromthe equilibrium data at different temperatures by applying the integrated form of the Clausius-Clapeyron equation. The net isosteric heat of sorption is inversely proportional to the equilibrium moisture content and isfound to be an exponential function of moisture content.

In order to accelerate the thermal modification process, Scots pine sapwood samples were subjected to two types of treatments. One group of samples was impregnated with water and exposed to 220oC and the second group was initially treated with low concentration of acids (1 mol l-1 AlCl3 and a mixture of 0.5 mol l-1 H2SO4 and 1 mol l-1 AlCl3), and then heated at different temperatures (180 and 120oC) to achieve comparable mass loss (ML) levels. The water vapour sorption isotherms of the thermally and acid-treated wood samples were determined using a dynamic vapour sorption (DVS) apparatus. Increasing the temperature in both thermally and acid-treated samples resulted in ML attributable to hemicelluloses degradation. As a result thereof, dimensional stability and reduction in the hygroscopicity of wood were observed. Acid-treated samples heated at lower temperature exhibited similar water sorption behaviour as water-treated samples subjected to considerably higher temperature. The sorption data were analysed using the Hailwood-Horrobin (H-H) and excess surface work (ESW) models. The data indicated that the monolayer and polylayer sorption were reduced by the acid and thermal treatments, but acid treatment reduced the monolyer sorption stronger than the thermal. The effect of thermal and acid treatments on the flexibility of the cell wall matrix could not be fully distinguished.

Most deterioration processes in cement based materials are closely related to moisture sorption and moisture transport properties. Therefore, it is important to study these properties, both theoretically and practically. This work is an experimental investigation in this field. Nowadays, the cement industry produces cements with increasing amounts of supplementary cementitious materials (SCMs) to limit CO2 emissions from concrete production. Knowledge about the moisture properties of concrete made from these blended cements is limited. This project has therefore been an attempt to further develop our understanding of the moisture properties of cement based materials, such as sorption isotherms and sorption transport properties in the presence of SCMs. This has been done by studying sorption isotherms mainly using the sorption balance method, and moisture transport coefficients using both the cup method and a sorption dynamic method. The experimental investigations were made on three types of hydrated cement pastes and mortars (OPC, OPC + 70% slag and OPC + 10% silica fume) with three different w/b –ratios (w/b) for cement paste (0.6, 0.5, 0.4) and two different w/b for cement mortar (0.5, 0.4). Sorption isotherms were determined for cement pastes and mortars in both hygroscopic and the super-hygroscopic relative humidity ranges using the sorption balance method, and the pressure plate method. The conclusion from this part of the study was that the desorption isotherms at low RH (0-30%) for different binders and different w/b-ratios are similar. At higher RHs the samples with silica fume and slag have higher moisture content than OPC samples. This is explained by that they have a higher amount of gel pores and a lower amount of capillary pores than OPC samples. The sorption isotherm at high RHs is difficult to validate experimentally, due to the critical RH of pore solutions. Steady-state and transient measurements of transport coefficients were also made. The dynami

Moisture sorption isotherms of persimmon leaves were determined at 20, 30 and 40 °C using the standard gravimetric static method over a range of relative humidity from 0.06 to 0.9. The experimental sorption curves were fitted by seven equations: Henderson, Halsey, Smith, Oswin, BET, GAB and Caurie. The Halsey, Smith, GAB and BET models were found to be the most suitable for describing the sorption curves. The isosteric heat of sorption of water was determined from the equilibrium data at different temperatures. It decreased as moisture content increased and was found to be a polynomial function of moisture content.

Kontaminacija pijaće vode arsenom predstavlja jedan od najvećih ekoloških problema današnjice. Svetska Zdravstvena Organizacija je 1993. godine donela preporuku da koncentracija arsena u vodi za piće ne bude veća od 10 μg/L. Kao jedna od najbolje raspoloživih tehnika za smanjenje koncentracije arsena iz voda izdvojila se sorpcija.U prvom delu ove doktorske disertacije ispitan je efekat hemijske modifikacije komercijalno dostupnih sorbenata (BIRM, MGS i MTM) na efikasnost sorpcije arsena.Hemijskom modifikacijom titanom i cirkonijumom povećan je kapacitet sorpcije BIRM-a, modifikacijom titanom povećan je sorpcioni kapacitet MTM-a, dok hemijska modifikacija MGS nije uticala na sorpcioni kapacitet. MTM modifikovan titanom je uspešno uklonio As(III) ili As(V) početne koncentracije 0.2 mg/L u pH opsegu od 5 do 8 na vrednost ispod preporučene od strane Svetske Zdravstvene Organizacije.U drugom delu rada mehano-hemijskom reakcijom sintetisani su sorbenti na bazi MnO2, Fe2O3 i smeše Fe2O3:MnO2 u masenom odnosu 3:1. Ispitivanjem zavisnosti kapaciteta sorpcije od vremena trajanja mehano-hemijske sinteze, utvrđeno je da za MnO2 i Fe2O3 sa povećanjem vremena mehano-hemijske sinteze dolazi do povećanja kapaciteta sorpcije arsena. Pri mehano-hemijskoj sintezi materijala sa smešom Fe2O3:MnO2 u masenom odnosu 3:1 najbolji sorpcioni kapacitet (2.89 i 3.84 mg/g za As(III) i As(V), respektivno) je dobijen za vreme sinteze od 30 minuta. Od materijala sintetisanih mehano-hemijskom sintezom, smeša Fe2O3:MnO2 u masenom odnosu 3:1 mlevena 30 minuta se pokazala kao najbolja za uklanjanje arsena iz voda. Kinetika sorpcije na ovom sorbentu je brza, dobro je opisana pseudo-drugim redom reakcije sa doprinosom površinske difuzije i intračestične difuzije redu sorpcije. Prisustvo hlorida i sulfata ne utiče na kapacitet sorpcije materijala dok fosfati smanjuju sorpciju arsena za manje od 20 % pri koncentraciji fosfata od 10 mmol/L. Arsen sorbovan za ovaj materijal je čvrsto vezan i njegova mobiliza, Contamination of drinking water with arsenic represents one of the biggest environmental problems today. World Health Organization in 1993. recommended that the amount of arsenic in drinking water should not be higher than 10 μg/L. Sorption is considered as one of the best available techniques for removal of arsenic from water.In the first part of doctoral thesis effect of chemical modification of commercially available sorbents (BIRM, MGS and MTM) was investigated.Chemical modification of BIRM with Ti and Zr increased sorption capacity, modification with Ti increase of sorption capacity of MTM while chemical modification of MGS didn`t affect it`s sorption capability. MTM modified with Ti successfully removed As(III) or As(V) initial concentration 0.2 mg/L, in pH range from 5 - 8 to value below recommended by World Health Organization.In the second part of work mechano-chemical reaction was used for synthesis of sorbents on the basis of MnO2, Fe2O3 and mixture of Fe2O3:MnO2 in weight ratio 3:1. Investigating dependence of sorption capacity from duration of mechano-chemical synthesis was found that, for MnO2 and Fe2O3, with increase of duration of mechano-chemical synthesis, sorption capacity for arsenic increases. For mechano-chemical synthesis of material on the basis of Fe2O3:MnO2 mixture in weight ratio 3:1, the best sorption capacity (2.89 and 3.84 mg/g for As(III) and As(V), respectively) was achieved with the synthesis time of 30 minutes. From materials that were mechano-chemically synthesized, Fe2O3:MnO2 mixture in weight ratio 3:1 milled for 30 minutes proved to be the best for arsenic removal from water. Kinetic of sorption on this sorbent was fast, with good correlation with pseudo-second rate model and contribution of intraparticle diffusion and surface diffusion to the rate of sorption. Presence of chloride and sulphate anions didn`t affect on sorption capacity of materials while presence 10 mmol/L of phosphates decreased arsenic sorption for less than 2

[ES] El consumo de hortalizas frescas es, sin duda, la mejor forma de beneficiarse de sus propiedades nutricionales, pero su alto contenido en agua hace que sean altamente perecederas y que tengan una vida útil relativamente corta. Es por ello por lo que se precisa de un procesado para obtener productos vegetales más estables. En este trabajo se analiza la calidad, tras la deshidratación mediante tres tratamientos diferentes (secado por aire caliente, secado por microondas y liofilización), de pimiento (Capsicumannuum L. `California Wonder¿) rojo y amarillo. Por otra parte, con el fin de establecer las condiciones de almacenamiento óptimas, se determinaron las isotermas de sorción, ajustándose los datos a los modelos de GAB y BET. Se realizaron determinaciones del contenido en humedad (xw), actividad del agua (aw) y color para las muestras frescas, y de sus propiedades mecánicas y de color para las muestras después del almacenamiento. Los resultados muestran tanto la influencia del tratamiento como de la variedad en todos los parámetros estudiados. El secado por aire caliente y la liofilización fueron más efectivos a la hora de deshidratar el pimiento que el secado por microondas. Además, se observó una estrecha relación entre las condiciones de almacenamiento y los cambios en el color y en la textura de los productos., [EN] The consumption of fresh vegetables is certainly the best way to maximize its nutritional properties, but their high water content makes them highly perishable and relatively shortens their lifetime. That is why it is necessary to make a treatment in order to obtain more stable vegetables. This document analyzes the quality after three different dehydration treatments (hot air drying, microwave drying and Freeze-drying) that are applied using red and yellow pepper (Capsicum annuum L. 'California Wonder'). Furthermore, in order to establish the optimum storage conditions we had to determine sorption isotherms and adjust the data to suit BET and GAB models. Determinations were made of moisture content (xw), water activity (aw) and color for fresh samples, and for samples after storage measurements of mechanical properties and color. The results shown the influence of treatment and the variety in all parameters studied. Hot air drying and freeze drying were more effective at dehydrating the peppers than microwave drying. In addition, there was a close relation between storage conditions and changes in color and texture of the products., [CA] El consum d'hortalitzes fresques és, sens dubte, la millor forma de beneficiar-se de les seues propietats nutricionals, pel seu elevat contingut en aigua fa que siguen altament peribles i que tinguen una vida útil relativament curta. És per aixo pel que es precisa d'un processat per a obtenir productes vegetals més estables. En aquest treball s'analitza la qualitat, desprès de la deshidratació mitjançant tres tractaments diferents (secat per aire calent, secat per microones i liofilització), de pimentó (Capsicumannuum L. "California Wonder") roig i groc. Per altra banda, amb la finalitat d'establir les condicions d'emmagatzemament optimes, es determinaren les isotermes de sorció, ajustant-se les dades als models de GAB i BET. Es realitzaren determinacions en el contingut d'humitat (Xw), activitat de l'aigua (aw) i color per a les mostres fresques, i de les seues propietats mecàniques i color per a les mostres desprès de l'emmagatzemament. Els resultats mostren tant l'influència del tractament com la varietat en tots els paràmetres estudiats. El secat per aire calent i la liofilització foren més efectius a l'hora de deshidratar el pimentó que el secat per microones. A més, es va observar una estreta relació entre les condicions d'emmagatzematge i els canvis en el color i la textura dels productes.

[ES] En este trabajo se ha estudiado el efecto de la humedad (muestras almacenadas a 11,3; 32,8; 43,2; 57,6; 68,9 y 75,3% de humedad relativa) y del contenido en glicerol (0 y 30% p/p respecto al biopolímero) en el comportamiento térmico de aislado de proteína de guisante (PPI) y de quitosano (Q), caracterizado mediante calorimetría diferencial de barrido (DSC). Los termogramas obtenidos para el PPI mostraron la presencia de endotermos, relacionados con la desnaturalización/agregación de la proteína, eliminación de agua y fusión, y de exotermos, correspondientes a la descomposición del biopolímero. Los termogramas obtenidos para el Q presentaron dos endotermos y un exotermo, relacionados con la eliminación de agua libre, la desacetilación y la descomposición del quitosano, respectivamente. El PPI con glicerol (PPI-Gly) no mostró endotermo de fusión, observándose un salto en el termograma entorno 190ºC relacionado con la transición vítrea. Los resultados muestran que el PPI podría ser empleado en procesos de termoformado como la extrusión, dada la elevada temperatura de descomposición del PPI (>300 ºC) que permite el ablandamiento del biopolímero antes de su descomposición., [CA] En aquest treball s'ha estudiat l'efecte de la humitat (mostres emmagatzemades a 11,3; 32,8; 43,2; 57,6; 68,9 i 75,3% d'humitat relativa) i del contingut en glicerol (0 i 30% p/p respecte al biopolímer) en el comportament térmic d'aïllat de proteína de pèsol (PPI) i de quitosano (Q), caracteritzat mitjançant calorimetría diferencial d'escombratge (DSC). Els termogrames obtinguts pel al PPI van mostrar la presencia de endoterms, relacionants amb la desnaturalització/agregació de la proteína, eliminació d'aigua i fusió i de exoterms corresponents a la descomposició del biopolimer. Els termogramesobtinguts per al Q van presentar dues endoterms i un exoterm, relacionats amb 'eliminació d'aigua lliure, la acetificació i la descomposició del quitosa respectivament. La presencia de glicerol va modificar lleugerament el comportament tèrmic de la proteína del pèsol. Així en el PPI amb glicerol (PPI-Gly) no va mostrar endoterm de fusió, observant-se un salt en el termograma entorn 190ºC relacionat amb la transició vítrea. Els resultats mostren que el PPI podría ser emprat en procesos de termoformat com l`extrusió, donada l`elevada temperatura de descomposició del PPI (>300ºC) que permet l'estovament del biopolimer abans de la seva descomposició., [EN] This paper has studied the effect of humidity (samples stored at 11.3, 32.8, 43.2, 57.6, 68.9 and 75.3% relative humidity) and glycerol content (0 and 30% w / w respect to the biopolymer) on the thermal behavior of pea protein isolate (PPI) and chitosan (Q), characterized by differential scanning calorimetry (DSC). Thermograms obtained for the PPI showed the presence of endotherms related to the denaturation / aggregation of the protein, water removal and fusion, and exotherm, corresponding to the decomposition of the biopolymer. Thermograms obtained for the Q had two endotherms and an exotherm related to the elimination of free water, deacetylation and decomposition of chitosan, respectively. The PPI with glycerol (PPI-Gly) showed no melting endotherms, showing a jump in the thermogram about 190 ° C related to the glass transition. The results show that the PPI could be 2 used in thermoforming processes such as extrusion, because of the high decomposition temperature PPI (> 300 º C) allows the softening of the biopolymer prior to decomposition.

Regularities of the sorption of nickel from hydrate pulps using amino carboxylic cationites ANKB-35, S 930, and TP 207 are investigated. Kinetic curves and sorption isotherms for these cationites are constructed. It is revealed that it is reasonable to absorb nickel from pulps at pH = 4-5. The desorption of nickel from cationites is investigated. It is shown that cationite TP 207 possesses the maximal sorption capacity. © 2013 Allerton Press, Inc.

Convective drying is an effective post-harvest method to the extend shelf life of vegetables and to reduce the mass for transportation. The heat load during drying, however, affects the quality attributes negatively. Today, consumers in the industrialized world pay a raised attention on food quality, and especially to the nutritional value of food. This increased demand on quality has become a challenge for drying research, and to retain the nutritional value, mild drying conditions must be applied. However, at these conditions the energy efficiency to remove the water from the product by evaporation is low; often below 50%. Moreover, due to the growing global market for dried products, drying contributes more and more to the global energy consumption and CO2-emission. Hence, there is a need for high energy efficient drying methods with low CO2-emission. A straightforward solution to increase drying energy efficiency is high temperature drying, but these conditions are conflicting with the aim to retain nutritional components. To combine these two aims, i.e. energy efficient drying and retention of nutritional components, is a challenge for drying research. In this thesis work, the conflict between quality retention and energy efficiency is investigated for the drying of broccoli. The approach in this work is based on mechanistic driven drying modeling and optimization. The approach includes three crucial elements: 1) mechanistic driven model development, 2) model validation, and 3) mechanistic model assisted optimization. In the first parts of the thesis advanced mechanistic drying models are introduced. These are the Free Volume theory for moisture transport (Chapter 2), and the Flory-Huggins Free Volume theory to describe sorption isotherms (Chapter 3). The strength of these theories is that the mobility of water is based on the changes in physical state during drying (from rubbery to glassy state) and the mixing properties of water, biopolymers and solutes. Thes

Sorption of 75 active pharmaceutical ingredients (APIs) to three different types of sludge (primary sludge, secondary sludge with short and long sludge age respectively) were investigated. To obtain the sorption isotherms batch studies with the APIs mixture were performed in four nominal concentrations to water containing 1 g of sludge. The range of APIs concentrations was between ng L-1 to μg L-1 which are found in the wastewater effluents. Isotherms were obtained for approximately 45 of the APIs, providing distribution coefficients for linear (Kd), Freundlich (Kf) and Langmuir (KL) isotherms. Kd, Kf and KL ranging between 7.1×104-3.8×107, 1.1×10-2- 6.1×104 and 9.2×10-3- 1.1L kg-1, respectively. The obtained coefficients were applied to estimate the fraction of APIs in the water phase (see Abstract Graphic). For 37 of the 75 APIs the predicted presence in the liquid phase was estimated to > 80%. 24 APIs were estimated to be present in the liquid phase between 20 - 80 %, and 14 APIs were found to have < 20% presence in the liquid phase, i.e. high affinity towards sludge. Furthermore, the effect of pH at values 6, 7 and 8 was evaluated using one way ANOVA-test. A significant difference in Kds due to pH changes were found for 6 of the APIs (variation 10-20%). Graphical abstractHiglights ► Sorption isotherms were experimentally obtained for roughly 45 of active pharmaceutical ingredients (APIs). ► By sorption to sludge the removal of 31 APIs were estimated to be < 20%.in the WWTP. ► By sorption to sludge the removal of 15 APIs were estimated to be >80% in the WWTP. ► For 13of the API the sorption to sludge was stronger than 1.2 ×106 L kg-1. ► For 10 of the API the sorption to sludge was less than 100 L kg-1

[EN] Modeling constitutes a fundamental tool with which to analyze the influence of ultrasound on mass transfer phenomena during drying. In this work, the study of the effect of power ultrasound application on the drying kinetics of eggplant was addressed by using different models based on theoretical (diffusion) or empirical approaches. Drying kinetics of eggplant cylinders (height 20mm and diameter 24 mm) were carried at 40°C and 1 m/s applying different ultrasonic powers: 0, 6, 12, 19, 25, 31, and 37 kW/m 3. The experiments were carried out at least three times at each different ultrasonic power. Shrinkage and sorption isotherms were also addressed in order to attain an optimal description of eggplant drying. Applying ultrasound sped up the drying kinetics. The ultrasonic power was identified as having a significant (p<0.05) influence on both the effective moisture diffusivity and the mass transfer coefficient, which was well explained by linear relationships. The most complex model, which considered both external resistance and shrinkage to be significant phenomena, provided the best agreement with experimental data, giving percentages of explained variance of over 99.9% and mean relative errors of under 1.2% in every case. According to these results, ultrasound technology could have the potential to improve the convective drying of eggplant at an industrial scale. © 2011 Taylor & Francis Group, LLC.

[EN] Moisture content is a reference parameter for dried food because the growth of most microorganisms is inhibited below certain water activity levels. In addition, it has a determining influence on the evolution of important parameters, such as color and flavor, and on other properties and deterioration reactions, such as texture, oxidation processes and nutritional value. During the storage of some dried fruits, moisture is produced due to Maillard reactions and exchanged with the surrounding environment through the packaging. The evolution of dried foods during their shelf life depends on the storage conditions. The aim of this study is to analyze the evolution of the moisture content in dried apricots packaged in different types of containers, namely glass and thermosealed polypropylene trays. The samples were stored at constant temperatures: 5, 15, 25 and 35 °C and were analyzed periodically over a period of 12 months. The sorption isotherms of apricots used in this study were also determined. In order to model how the moisture evolved, an empirical kinetic model was tested. This model considers both water transfer from the fruit and also water production as a result of the Maillard processes. The explained variance was higher than 95% in the samples stored in trays, which were thermosealed with film. © Authors 2011.

Die Konservierung pflanzengenetischer Ressourcen durch Saatgutlagerung in Genbanken beschränkt sich weitestgehend auf Arten, deren Samen zum orthodoxen Lagerungstyp zählen. Die Lagerfähigkeit der Samen dieses Typs, dem die meisten landwirtschaftlichen und gärtnerischen Kulturarten angehören, wird durch zwei entscheidende Faktoren beeinflusst, durch den Samenfeuchtigkeitsgehalt und die Lagerungstemperatur. Die ?ultra-dry? Saatgutlagerung verfolgt die Strategie, das Saatgut so weit zu trocknen, dass eine nachfolgende Langzeitlagerung auch bei Raumtemperatur erfolgreich möglich ist. Die sonst in Genbanken übliche Tiefgefrierung des Saatgutes wäre damit nicht erforderlich, was für Genbanken in Entwicklungsländern mit unsicherer Energieversorgung sehr attraktiv ist. Für die Realisierung dieser Strategie sind jedoch die folgenden Fragen bislang nicht ausreichend beantwortet: ? Wird Saatgut durch die Trocknung auf Samenfeuchtigkeitsgehalte nahe 0 % geschädigt? ? Gibt es für die ?ultra-dry? Saatgutlagerung einen optimalen Samenfeuchtigkeitsgehalt oder eine optimale relative Luftfeuchtigkeit, bzw. eine jeweilige Ober- und Untergrenze oberhalb von 0 %? ? Wenn es eine solche Ober- und Untergrenze gibt, können diese dann als für alle Arten identisch angenommen werden? ? Wie gut ist die Lagerfähigkeit des Saatguts unter ?ultra-dry? Bedingungen und gilt die Lebensfähigkeitsgleichung von Ellis und Roberts (1980) auch im Bereich der ?ultra-dry? Lagerung? In umfangreichen und langen Experimenten wurde durch die Trocknung über Silikagel in Exsikkatoren (r.H. nahe 0 %) oder im Feintrocknungsraum (r.H. ca. 10 %) der Genbank des IPK Saatgut der zwei Zwiebelsorten Giugenese und Sturo (Allium cepa L.), der vier Rapslinien HR2203, HR2632, HR2660 und HR2693 (Brassica napus L.) und der drei Weizensorten Naturastor, Tommi und Triso (Triticum aestivum L.) auf Samenfeuchtigkeitsgehalte zwischen 7 % und 0 % in jeweils bis zu 39 Stufen eingestellt. Anschließend wurden die Saatgutproben in luftdic, The conservation of plant genetic resources through seed storage in gene banks is primarily restricted to relatively short lived plants with orthodox seeds, to which most agricultural and horticultural species belong. Their storage properties are influenced by two key factors, seed moisture content and storage temperature. Ultra-dry seed storage follows the theory that drying seeds to sufficiently low moisture contents could achieve successful long-term seed storage even at room temperature. The artificial freezing storage of seeds, which is usually used in modern gene banks, would not be required. This is very attractive for the gene banks in developing countries where energy supply is limited. The following questions are still remained to be answered for the realization of ultra-dry seed storage. ? Will the seeds be damaged by drying close to 0 % moisture content? ? Is there for ultra-dry seed storage optimal moisture content (OMC) or optimal relative humidity (ORH) as well as a respective upper and lower limit above 0%? ? If such upper and lower limits exist, are they identical among species? ? How good is the storability of the seeds under ultra-dry conditions? Does the improved seed viability equation of Ellis and Roberts (1980) also apply to the ultra-dry region? Seed samples of the four breed lines HR2203, HR2632,HR2660 and HR2693 of rape seeds (Brassica napus L.), the three cultivars Naturastor, Tomi and Triso of wheat (Triticum aestivum L.) and the two cultivars Giugenese and Sturo of onion (Allium cepa L.) were used. The moisture contents (MC) of onions, rape seed and wheat were adjusted separately to 39 different levels from near 0 % to 7 % in sealed desiccators with silica gel (r.H. close to 0 %) or in the fine-drying chamber (r.H. about 10 %) of the gene bank at IPK-Gatersleben. The dried seed samples were sealed individually in aluminum foil to keep the MC. The equilibrium relative humidity was determined after 14 days by using a metal thread sensor. S

The water content-water activity-glass transition temperature relationships of commercial spray-dried borojó powder, with and without maltodextrin, have been studied as related to changes in color and mechanical properties. The GAB and Gordon and Taylor models were well fitted to the sorption and glass transition data, respectively. The Boltzman equation adequately described the evolution of the mechanical parameter characterized in the samples with the difference between the experimental temperature and the glass transition temperature (T g) of the sample. The color of the samples showed a sigmoid change with water activity. The changes in the mechanical properties of borojó powder related to collapse development started when the sample moved to the rubbery state and began to be significant at about 10 °C above T g. The increase in the molecular mobility from this point on also favors browning reactions. Maltodextrin presence slows the caking kinetics but induces color changes to spray-dried borojó powder

Two akaganeite materials were tested for the removal of antimonate, trimethyl antimonate, arsenate, arsenite and dimethyl arsenate from water: a commercial product (GEH) and a synthesized akaganeite. The two materials show similar qmax values, but differ in their KL values. This could be a result of their different crystal sizes indicated by sharper XRD reflecions of the synthesized akaganeite compared with GEH. Batch experiments were carried out using all species to investigate the influence of the pH on their sorption onto the commercial material. The best results for the removal of antimonate and arsenate were achieved under acidic conditions, while the sorption of arsenite has an optimum at pH 7. The maximum loadings vary from 450 mg g-1 (antimonate at pH 2.2.) to 2 mg g-1 (trimethyl antimonate at pH 7). Competition reactions (up to a 10-fold excess of the competitor ion) were studied with antimonate, arsenate and phosphate. The sorption capacity of arsenate decreases up to 12.5 % by adding phosphate (ratio 1:10), but the addition of antimonate did not influence the sorption of arsenate. Conversely, the sorption of antimonate decreases due to the addition of 10-fold concentration of arsenate (31 %) or phosphate (27 %).

Práce se zabývá stanovením závislosti obsahu relativní rovnovážné vlhkosti na aktivitě vody pro vzorky taninu a pšeničného škrobu při teplotách 5, 15, 25 a 35°C statickou gravimetrickou metodou. Experimentální data byla popsána pomocí různých matematických modelů, jejichž parametry byly získány metodou nelineární nebo lineární regrese. S pomocí Clausius-Clapeyronovy rovnice byla získána závislost čistého izosterického tepla adsorpce na obsahu rovnovážné vlhkosti vzorků., The thesis deals with the determination of relative equilibrium moisture contents of tannin and wheat starch at different water activity levels in various temperatures (5, 15, 25, 35°C). The static gravimetric method was used in this study. Various mathematical equations have been applied to the experimental data and the parameters were obtained by non-linear and linear regression techniques. Net isosteric heat of adsorption was determined using Clausius-Clapeyron equation., Katedra analytické chemie, Studentka přednesla obhajobu své diplomové práce a zodpověděla dotazy zkušební komise., Dokončená práce s úspěšnou obhajobou

The sorption of inorganic arsenic species (arsenite and arsenate) from aqueous solutions onto steel-mill waste and waste filter sand, under neutral conditions, was investigated in this study. Additionally, the steel-mill waste material was modified in order to minimize its deteriorating impact on the initial water quality and to meet the drinking water standards. The influence of contact time and initial arsenic concentration was investigated using batch system techniques. To evaluate the application for real groundwater treatment, the capacities of the obtained waste materials were further compared to those exhibited by commercial sorbents, which were examined under the same experimental conditions. Kinetic studies revealed that waste slag materials are the most efficient in arsenic removal, reaching equilibrium arsenic sorption capacities in the range 47.6-55.2 mu g/g, while waste filter sand exhibited capacities of 25.4-29.8 mu g/g (for an initial arsenic concentration C-o=0.5 mg/L). The higher iron content in the slag materials was considered to be responsible for the better removal efficiencies, and the specific arsenic removal efficiency was estimated to be 220 mu gAs/gFe. The specific arsenic removal efficiency of the second active substance found in waste filter sand, manganese, was estimated to be 115 mu gAs/gMn. Equilibrium studies revealed the occurrence of both chemisorption and physical sorption processes. All the waste materials exhibited higher performances for As (V). The highest maximum sorption capacity was obtained by waste iron slag: 4040 mu g/g for As (V). The waste materials reached the arsenic removal capacities of the examined commercial materials, suggesting the feasibility of their application in real groundwater treatment.

QC 20110211

The principal objective for this licentiate thesis is to develop a methodology and evaluation model in order to make the future relative humidity in a screeded concrete slab predictable. Residual moisture in screeded concrete slabs may redistribute to the top screed surface under semi-permeable flooring, thus elevating the relative humidity, RH, and possibly exceed the critical humidity level. Passing the critical humidity level may result in material damages on the flooring and adhesive. In order to avoid such damages there is a need of a methodology to estimate the maximum humidity obtained underneath flooring. Several screeded concrete slabs with PVC flooring, were prepared to reproduce and monitor moisture distribution and the occurring redistribution. The moisture distribution before flooring and after a certain time of redistribution is presented. In addition, sorption isotherms including scanning curves were determined in a sorption balance for materials used in the floor constructions, viz, w/c 0.65 concrete, w/c 0.4 concrete, w/c 0.55 cement mortar, and Floor 4310 Fibre Flow, a self leveling flooring compound. Repeated absorption and desorption scanning curves starting from the desorption isotherm were also investigated. Performed measurements enabled the development of both a qualitative and quantitative model designed to resemble the actual moisture redistribution and quantify the humidity achieved under flooring respectively. The hysteresis phenomenon of the sorption isotherm is considered in the model. The model is well suited for estimations of the future RH underneath flooring in a screeded concrete slab and may also be used on homogenous slabs.

In situ stabilization of toxic elements in contaminated soils by the addition of amendments is being considered as an effective technique for remediation.

Moisture buffering in the indoor environment is the ability, through absorption and desorption, of surface materials to attenuate the moisture variations of the indoor air. Moisture buffering plays an important role in understanding the risks for biological growth in surface materials in the indoor environment, e.g., mold growth on walls and house dust mites in beds, and thereby also have an impact on the health of the inhabitants. Apart from the health aspects, moisture buffering is also important to take into account in hygrothermal calculations as well as for design of indoor climate systems. The interaction between surface materials and the humidity of the indoor air is the scope of this Ph.D.-project reported in this thesis. The main objective is to enhance the understanding of the moisture buffering of surface materials in the indoor environment. The focus has been on moisture buffering in textile materials and upholstered furniture, common to Scandinavia. The moisture buffering has been investigated through experimental work, field measurements and modeling. The experimental work covers development of laboratory methods and determination of basic material properties to full scale climatic chamber measurements. A definition scheme regarding the moisture buffering in the indoor environment, at three spatial levels ?material, component and room level, is proposed. Within the project, a method, to determine sorption isotherms has been developed. The moisture sorption properties for textile materials, common in the indoor environment, have been determined. The moisture conditions in a chair seat and in two bed systems have been investigated through climatic chamber measurements and field measurements, respectively. Both types of upholstery have also been studied through mathematical models. The impact of furniture and furnishing, on moisture buffering performance, was studied in a full scale climatic chamber study. The main conclusion from the project is that mois

Natural steroid estrogens such as 17beta-estradiol in low nanogram per liter concentrations can adversely affect the reproductive health of aquatic organisms. The overall goal of this research was to quantify the sorption of 17beta-estradiol to three soils considered to be agriculturally productive from different physiographic regions in Virginia to aid in modeling the concentration of estrogens available for transport in runoff from agricultural fields. Batch equilibrium experiments were conducted with various concentrations of 17beta-estradiol (E2) in a background solution of 5 mM calcium chloride and 100 mg/L sodium azide added to four separate soil samples representative of productive agricultural soils from three different physiographic regions of Virginia. Groseclose loam, Myatt sandy loam and Cecil loam were supplied by the Crop and Soil Environmental Sciences Department at Virginia Tech. All soils were collected from the plow layer (0 to 15 cm) except for an additional Cecil soil sample from the Bt horizon. The concentration of E2 in the liquid phase was measured by gas chromatography/mass spectrometry (GC/MS) and was used to find the time to reach equilibrium and to develop sorption isotherms for each soil. The time required to reach equilibrium for all soils was less than 24 hours. A linear isotherm provided the best fit to model the sorption of E2 to Cecil and Myatt soils (R2 = 0.94 and 0.96, respectively). For Groseclose soil, the general form of the Freundlich isotherm fit best (R2 = 0.98), although the linear isotherm also provided a good fit (R2 = 0.93). The sorption of E2 to agricultural soil appears to be related to the organic carbon content of each soil (Pearson coefficient, 0.82). Attempts to analyze and create isotherms for conjugated E2 by deconjugating with metholysis were unsuccessful.

The bioavailability and ultimate fate of heavy metals in the environment are controlled by chemical sorption. To assess competitive sorption of Pb and Cd, batch equilibrium experiments (generating sorption isotherms) and kinetics sorption studies were performed using single and binary metal solutions in surface samples of four soils from central Spain. For comparisons between soils, as well as, single and binary metal solutions, soil chemical processes were characterized using the Langmuir equation, ionic strength, and an empirical power function for kinetic sorption. In addition, soil pH and clay mineralogy were used to explain observed sorption processes. Sorption isotherms were well described by the Langmuir equation and the sorption kinetics were well described by an empirical power function within the reaction times in this study. Soils with higher pH and clay content (characterized by having smectite) had the greatest sorption capacity as estimated by the maximum sorption parameter (Q) of the Langmuir equation. All soils exhibited greater sorption capacity for Pb than Cd and the presence of both metals reduced the tendency for either to be sorbed although Cd sorption was affected to a greater extent than that of Pb. The Langmuir binding strength parameter (k) was always greater for Pb than for Cd. However, these k values tended to increase as a result of the simultaneous presence of both metals that may indicate competition for sorption sites promoting the retention of both metals on more specific sorption sites. The kinetic experiments showed that Pb sorption is initially faster than Cd sorption from both single and binary solutions although the simultaneous presence of both metals affected the sorption of Cd at short times while only a minor effect was observed on Pb. The estimated exponents of the kinetic function were in all cases smaller for Pb than for Cd, likely due to diffusion processes into micropores or interlayer space of the clay minerals which oc

[abstract missing]

A model was developed on the basis of the literature for binding of water on solid starch by means of a combined sorption mechanism. Equations based on the theory of localized sorption on homogeneous surfaces (Langmuir and Brunauer, Emmett & Teller) were derived. An equation with three parameters from the theories of Guggenheim, Anderson and de Boer described experimental isotherms adequately up to a water activity of 0.9 and one based on polymersolvent interaction (Flory and Huggins) above that value. The experimental isotherms of water vapour on native starch were affected by temperature, gelatinization, partial hydrolysis and separation in components (amylose and amylopectin).

In the present catalogue sorption isotherms for more than 100 materials are plotted. A page of the catalogue shows both data values and a figure with data points and approximated curves. The data base has been built up using an IBM PC.

QS 2014

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Results of the development and evaluation of a sorption capacity of several polymer biosorbents combined with an inorganic matrix are provided. The potential use of whey to model sorption processes in an internal environment of the body is shown. Most effective combinations promoting selective elimination of an excess of accumulated metals from the body are proposed.

The effect of carboxy groups and the stable conformation of tert-butylcalix[4]arenes containing four carboxymethoxy substituents at the lower rim on their receptor properties toward organic substances and water was studied for the systems with guest vapor and solid host. For this purpose, the compositions of clathrates formed in these systems, their thermal stability, and parameters of the host-guest affinity were determined by the quartz microbalance method, thermogravimetry, thermogravimetry combined with differential scanning calorimetry and mass spectrometry, and static headspace gas chromatography. The introduction of four carboxymethoxy groups into tert-butylthiacalix[4]arene enhances its receptor capacity and affinity to water and aliphatic alcohols and decreases the thermal stability of the most part of the studied clathrates with hydrophobic guests except benzene. The studied tert-butylthiacalix[4]arene derivatives can be promising receptors for use in mass-sensitive sensors of the quartz microbalance type to methanol and ethanol vapors. © 2009 Springer Science+Business Media, Inc.

The influence of the calixarene macrocycle size on the thermodynamic parameters of inclusion formation in organic guest vapor - solid host systems was studied in the series of tert-butylcalix[4]arene (1), tert-butylcalix[6] arene (2), and tert-butylcalix[8]arene (3). For this purpose, sorption isotherms of a guest vapor by a solid host were determined using the static method of headspace GC analysis for the systems involving calixarenes 2 and 3 in addition to the earlier obtained data for calixarene 1. Besides, the stoichiometry and decomposition temperatures of saturated clathrates formed in these systems were determined using thermogravimetry. The compositions of some of these clathrates differ substantially from those of clathrates crystallized from a host solution in a liquid guest. For the most guests studied with the thermodynamic activity below 0.6, their uptake by calixarenes 1 - 3 changes in the series 2 < 1 < 3. As a whole, the trend for each particular parameter of clathrates of hosts 1 - 3 (stoichiometry, guest activity at 50% saturation of the host) with increasing the size of the calixarene macrocycle is specific for each guest studied. The results obtained are useful for the estimation of receptor properties of calixarenes in quartz microbalance sensors.