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M Arpah1),E. Diyah2),E.Nurlela2)
Jurnal Teknologi dan Industri Pangan , 2004,
Abstract: BET equation (IUPAC standard) and GAB equation (European Project Group on physical properties of food recommendation standard) for monolayer capacity value evaluations were used for testing the moisture adsorption experimental data of powdered white and black papper, cloves, nutmeg and cinnamon. The BET equation fits only up to aw = 0.44, while the GAB isotherm fits and covers a much wider range (0.06 Keywords BRT --- GAB --- monolayer
Pretreatment of black liquor from refined cotton production by acidification and adsorption using activated carbon fiber

Zhao Xu,Zhao Quanlin,Meng Qingqiang,Ye Zhengfang,

环境工程学报 , 2013,
Abstract: Acidification and activated carbon fiber (ACF) adsorption were investigated for removal of organic pollutants from black liquor generated from refined cotton production. Acidification is to remove lignin, while ACF adsorption is to remove the remaining organic matters from black liquor. UV-vis spectroscopy, FTIR were used to evaluate the chemical changes of black liquor. The acute toxicity of black liquor before and after adsorption was evaluated by bacterial bioluminescence assays. The results indicated that the main organic components of black liquor are guaiacyl (G-) and hydroxyphenyl (H-) lignin. When pH=2.0 for acid precipitation, ACF dosage was 90 g/L, 85% of COD could be removed after 5 h of adsorption at 40°C. The adsorption process can be described by Redlich-Peterson isotherm model. The kinetic data followed the pseudo-second-order equation and the adsorption process was endothermic. After acidification and ACF adsorption, up to 95% of the acute toxicity of black liquor was removed, which may be favorable for further biological treatment.
Chemical Industry and Chemical Engineering Quarterly , 2011,
Abstract: TIn this work, removal of malachite green (MG) from aqueous solution using a low cost adsorbent, tamarind seed, was investigated. The adsorbent was characterized using SEM, BET surface area analyzer, and FT-IR. Decolourization of malachite green was studied as a function of different adsorption parameters such as temperature, adsorbent dose, contact time, adsorbent size and agitation speed. These parameters were optimized using response surface methodology (RSM). The significance of different adsorption parameters along with their combined effect on the adsorption process has been established through a full 50 factorial design. Langmuir, Freundlich, Redlich Petersen, Dubnin Redushkevich and Tempkin adsorption isotherm equations were used in the equilibrium modeling. Experimental data follows the Langmuir adsorption isotherm. The adsorption process follows a pseudo first order and intra-particle diffusion is found to be the rate-controlling step.
PEMODELAN ISOTERMIS SORPSI AIR PADA MODEL PANGAN [Modelling of Moisture Sorption Isotherm in Food Model]  [cached]
Dede R Adawiyah*,Soewarno T. Soekarto
Jurnal Teknologi dan Industri Pangan , 2010,
Abstract: Moisture sorption isotherm of food powder products is pertinent in processing and stability of food. Food model consisted of tapioca starch, casein, palm oil and sucrose. The moisture sorption isotherm curves of the food model, tapioca starch and casein were sigmoid indicating the typical shape of amorphous product, while the water sorption isotherm of sucrose was a broken-line curve showing typical shape of crystalline material. The Guggenheim – Anderson-de Boer (GAB) model was the best model to predict sigmoid sorption isotherm curve (tapioca starch, casein and food model) at the whole range of experimental aw (0.07 – 0.97) while the Braunauer Emnet Teller (BET) model only fitted for aw up to 0.6. The Water binding capacity of tapioca at monolayer (Mm) was higher than casein and food model but the coefficient of adsorption energy (C) was lower than that of casein. Addition of oil at the food model decreased the water binding capacity at monolayer. The Grover model was more suitable than Ross model to predict the water sorption isotherm curve of food model from its composition.
Which are Better Conditioned Meshes Adaptive, Uniform, Locally Refined or Localised  [PDF]
Sanjay Kumar Khattri,Gunnar Fladmark
Mathematics , 2006, DOI: 10.1007/11758525_14
Abstract: Adaptive, locally refined and locally adjusted meshes are preferred over uniform meshes for capturing singular or localised solutions. Roughly speaking, for a given degree of freedom a solution associated with adaptive, locally refined and locally adjusted meshes is more accurate than the solution given by uniform meshes. In this work, we answer the question which meshes are better conditioned. We found, for approximately same degree of freedom (same size of matrix), it is easier to solve a system of equations associated with an adaptive mesh.
Multilayer Adsorption of Interacting Polyatomics on Heterogeneous Surfaces  [PDF]
Fabricio Orlando Sánchez-Varretti,Guillermo Daniel García,Antonio José Ramirez-Pastor
Physics , 2011,
Abstract: In the present work we introduce a generalized lattice-gas model to study the multilayer adsorption of interacting polyatomics on heterogeneous surfaces. Using an approximation in the spirit of the well-known Brunauer--Emmet--Teller (BET) model, a new theoretical isotherm is obtained in one- and two-dimensional lattices and compared with Monte Carlo simulation. In addition, we use the BET approach to analyze these isotherms and to estimate the monolayer volume. In all cases, we found that the use of the BET equation leads to an underestimate of the true monolayer capacity. However, significant compensation effects were observed for heterogeneous surfaces and attractive lateral interactions.
Wet Sand flows better than dry sand  [PDF]
Jorge E. Fiscina,Christian Wagner
Physics , 2007,
Abstract: We investigated the yield stress and the apparent viscosity of sand with and without small amounts of liquid. By pushing the sand through a tube with an enforced Poiseuille like profile we minimize the effect of avalanches and shear localization. We find that the system starts to flow when a critical shear of the order of one particle diameter is exceeded. In contrast to common believe, we observe that the resistance against the flow of wet sand is much smaller than that of dry sand. For the dissipative flow we propose a non-equilibrium state equation for granular fluids.
Thermodynamic and Isotherm Analysis on the Removal of Malachite Green Dye Using Thespesia Populnea Bark  [PDF]
R. Prabakaran,S. Arivoli
Journal of Chemistry , 2012, DOI: 10.1155/2012/629089
Abstract: Activated carbon was synthesized from Thespesia Populnea Bark, a low cost material, by sulphuric acid activation; it was tested for its ability to eliminate malachite green in aqueous solution. The parameters studied included contact time, initial dye concentration, carbon dose, pH and temperature. The adsorption followed first order rate equation. In addition, it was found that the adsorption process was described by Freundlich and Langmuir isotherm models. Those models were applied to the equilibrium data. The absorption capacities (Qm) obtained from the Langmuir isotherm plots were 349.20, 365.43, 476.44, and 389.96 mg/g at 30°, 40°, 50°, and 60°C, respectively, at an initial pH 6.0. The temperature variation study showed that the malachite green dye absorption was endothermic and spontaneous with increased randomness at the solid solution interface. The thermodynamic parameters like ?H°, ?S°, and ?G° were calculated from the slope and intercept of the linear plots.
Multilayer Adsorption of Polyatomic Species on Homogeneous and Heterogeneous Surfaces  [PDF]
F. O. Sanchez-Varretti,G. D. Garcia,A. J. Ramirez-Pastor,F. Roma
Physics , 2008,
Abstract: In this work we study the multilayer adsorption of polyatomic species on homogeneous and heterogeneous bivariate surfaces. A new approximate analytic isotherm is obtained and validated by comparing with Monte Carlo simulation. Then, we use the well-known Brunauer-Emmet-Teller's (BET) approach to analyze these isotherms and to estimate the monolayer volume, $v_\mathrm{m}$. The results show that the value of the $v_\mathrm{m}$ obtained in this way depends strongly on adsorbate size and surface topography. In all cases, we find that the use of the BET equation leads to an underestimate of the true monolayer capacity.
Modeling of Experimental Adsorption Isotherm Data  [PDF]
Xunjun Chen
Information , 2015, DOI: 10.3390/info6010014
Abstract: Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained by batch tests in lab. The linearized and non-linearized isotherm models were compared and discussed. In order to determine the best fit isotherm model, the correlation coefficient (r 2) and standard errors (S.E.) for each parameter were used to evaluate the data. The modeling results showed that non-linear Langmuir model could fit the data better than others, with relatively higher r 2 values and smaller S.E. The linear Langmuir model had the highest value of r 2, however, the maximum adsorption capacities estimated from linear Langmuir model were deviated from the experimental data.
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