Sorption

A new chelating resin incorporating imidazolyl azo groups into a matrix of polystyrene divinylbenzene has been prepared. The exchange capacity of the resin for the ions mercury(II), silver(I) and lead(II) as a function of pH has been determined. The resin exhibits no affinity to alkali, or alkaline earth metals. It is highly selective for only mercury(II) and silver(I). In column operation it has been observed that mercury(II) in trace quantities is very effectively removed from river water spiked with mercury(II) at the usual pH of natural waters.

The sequential extraction test, known as a BCR procedure, was used to assess a leachability of heavy metals (Zn, Cd, Pb, Cu) from the metallo-organic sorbent-iron humate-loaded with these metals. The sequential test allowed to discriminate between various fractions of heavy metals, namely the acid-extractable fraction, the fraction bound to Fe oxides, and the fraction bound to organic matter. It was proven that the heavy metals are bound mainly to Fe oxides and organic matter, and thus they may be relatively hardly liberated into the environment. The BCR sequential extraction test exhibited a very good repeatability, when it was applied to the loaded sorbent-relative standard deviations were typically lower than 10%.

Diffusion of mass in a solid cylinder with concentration dependent diffusivity (or temperature-dependent thermal conductivity in case of heat diffusion) does not admit of an analytical solution except in special cases. The 'shrinking core model' has been used to develop an approximate analytical solution in certain circumstances. The model, generally useful to describe heterogeneous solid-fluid reactions, is applied to theoretically analyze the adsorption-diffusion phenomena of methylene blue dye in a glass fiber in the present work. Theoretical equations have been derived for the case of diffusivity as an exponential function of concentration. The diffusivity parameters are evaluated by global minimization of the error between the experimental and the theoretical concentration history. Other forms of diffusivity, namely constant diffusivity and diffusivity varying linearly with concentration are found to involve larger errors. A parametric sensitivity analysis of the error has been done. The shrinking core model could satisfactorily interpret the experimental dye concentration profile in the substrate.

Both visible near-infrared (VNIR) and mid-infrared (MIR) spectroscopy have been claimed to better predict pesticide sorption in soils than other methods. We compared the performances of VNIR and MIR spectroscopy for predicting both organic carbon content (f OC ) and the sorption affinity (K d ) of diuron in 112 surface soils from South Australia. Separate calibration models were developed between VNIR and MIR spectra, and f OC and K d using partial least-squares (PLS) regression. MIR clearly outperformed VNIR for predictions of both f OC and K d in soils. Correlation (R 2 ) and accuracy (RPD) indices were 0.4 and 1.3 for the VNIR-PLS model versus 0.8 and 2.3 for the MIR-PLS model, respectively, for K d prediction. PLS loadings for sorption prediction were compared in terms of the soil information they contained. While VNIR loading did not include any direct spectral information regarding soil minerals, MIR loading included peaks associated with sand, clays, and carbonates. Perhaps by better predicting f OC and integrating the effects of OC as well as minerals, the MIR-PLS model provided a better prediction for diuron K d values in our calibration set.

A large number of substrates potential for removal of phosphorus (P) in wastewater has been reviewed. The substrates consist of natural materials, industrial by-products and man-made products. Most substrates have been investigated in batch and column studies in the laboratory; others have also been tested in field trials. The results from these investigations vary, but a few substrates, e.g. wollastonite, slag material and, to some extent, light weight aggregate products, have demonstrated promising properties with regard to P-sorption capacity and hydraulics. The problems of normalisation of data are discussed, as well as the substrates potential benefits for on-site wastewater treatment.

A procedure for the determination of three chloroanisoles (2,4,6-trichloro, 2,3,4,6-tetrachloro and pentachloroanisol), as well as their precursor chlorophenols (2,4,6-trichloro, 2,3,4,6-tetrachloro and pentachlorophenol), involved in the presence of cork taint in red wine has been developed. Samples, up to 1 l, were concentrated using a 200 mg Oasis HLB solid-phase extraction (SPE) cartridge. Chlorophenols were quantitatively eluted from this sorbent with 3 ml of methanol. Chloroanisoles were mainly recovered in a second fraction of n-hexane (2 ml). Both fractions were combined and mixed with an aqueous solution of sodium bicarbonate and 50 l of acetic anhydride. Chlorophenols were acetylated in the aqueous-methanolic phase and extracted to n-hexane. Chloroanisoles remained unaffected in the n-hexane layer. Both groups of compounds were determined by gas chromatography-tandem mass spectrometry in the same chromatographic analysis. Using a temperature programmable vaporization injector detection limits from 0.2 to 2.4 ng l −1 , below their sensorial threshold level in red wine, were obtained for all compounds. Average recoveries higher than 80% and acceptable precision were achieved using red wine samples spiked with the analytes at different concentration levels.

The potential of mesoporous silica-alumina (MSA) modified by acid leaching as alternative support for Pt catalysts was studied in hydrodesulfurization (HDS) of thiophene and benzothiophene. The supports were characterized by N 2 adsorption, XRD, 27 AL MAS NMR, electron microscopy (SEM, HRTEM) and by activities in cyclohexene isomerization and cumene cracking. The composition of the catalysts and Pt dispersion were determined by ICP and H 2 or CO sorption, respectively. Progressive leaching of the parent MSA from 50% Al 2 O 3 to 11% Al 2 O 3 content led to increase of the BET surface area and exposition of strong acidity. This positively affected the activities of the reduced Pt catalysts in thiophene HDS. Deposition of 1.5 wt.% Pt on MSA (11% Al 2 O 3) by using Pt(NH 3) 4 (OH) 2 as precursor gave the best catalyst, several times more active in thiophene HDS than the weight equivalents of sulfided CoMo/Al 2 O 3 or reduced Pt/HY zeolite. In benzothiophene reaction, its activity was slightly above that of CoMo/Al 2 O 3 and about twofold compared to Pt/HY.

The parameters of the 'G.A.B.' equation are discussed from mathematical and physical point of view. Clear limits of those parameters are determined. The point of inflexion of the 'G.A.B.' isotherm was also analysed with the conclusion that the 'G.A.B.' isotherm behaves too rigidly to be able to describe complicated sorption cases. The different possibilities of some other isotherms for such a purpose were displayed.

Linear alkylbenzenesulfonates (LAS) are anionic surfactants that are used in large quantities in industrial and consumer products. They enter the environment primarily through wastewater and sludge. In this study, the sorption of LAS to the surfaces of sediment particles was investigated as a function of LAS homologue, H + concentration in solution, Ca 2+ concentration in solution, sediment properties, and concentration of solids. Evidence for both hydrophobic and specific or electrostatic interactions was seen. Isotherms were generally nonlinear and were represented well by the Freundlich and the virial (electrostatic) equations. Comparisons of apparent distribution ratios, D (L/kg), for linear portions of the isotherms showed ∆ log D/∆ log n CH2 ≈ 0.4, ∆ log D/∆ log [H + ] ≈ 0.17, and ∆ log D/∆ log [Ca 2+ ] ≈ 0.23. The value of D for different sediments seemed to correlate most closely with the organic carbon content (f oc ) of the sediments. The value of the distribution ratio increased with the concentration of solids in the system; this effect could be explained partially by the concomitant increase in Ca 2+ concentration in solution.

The present study was conducted to evaluate the feasibility of nano-alumina for nitrate removal from aqueous solutions. The nature and morphology of sorbent was characterized by XRD, FTIR, BET and SEM analysis. Batch adsorption studies were performed as a function of contact time, initial nitrate concentration, temperature, pH and influence of other interfering anions. Nitrate sorption kinetics was well fitted by pseudo-second-order kinetic model. The maximum sorption capacity of nano-alumina for nitrate removal was found to be ca. 4.0 mg g −1 at 25 ± 2 • C. Maximum nitrate removal occurred at equilibrium pH ca. 4.4. The nitrate sorption has been well explained using Langmuir isotherm model. Results from this study demonstrated the potential utility of nano-alumina for nitrate removal from water.

Here we report a separation of a cationic dye, acridine orange (AO), by use of magnetic nanoparticles (␥-Fe 2 O 3 ). The particles were showed to capture 98% of the dye within the first 20 min of contact time. The maximum sorption capacity of the magnetic nanoparticles (MNPs) for AO was 59 mg/g. The sorption isotherms fit well with the Freundlich model. The sorption kinetics fits well the pseudo-second-order rate equation model. 60-90% dye recovery was achieved by rotary evaporating the dye bearing nanoparticles in acetone. The nanoparticles were recycled for additional dye removal.

The classic Langmuir and Freundlich sorption models and a dual-mode approach have been tested to study the sorption of aromatic molecules onto β-cyclodextrin polymers as well as onto analogous sucrose polymers, obtained using the same crosslinking agents (epichlorohydrin, succinyl chloride, toluene diisocyanate, and hexamethylene diisocyanate). The host–guest interaction of the sorbate within the cyclodextrin cavities corresponds to the hole-filling mechanism

BACKGROUND: The performance and mechanism of the biosorptive removal of Ni 2+ and Zn 2+ from aqueous solution using grapefruit peel (GFP) as a new biosorbent was investigated by using different experimental approaches, such as potentiometric titration, Fourier transform infrared (FTIR) and energy-dispersive X-ray spectroscopy (EDX) analysis, chemical blocking of functional groups and concomitant release of cations (Ca 2+ , Mg 2+ , Na + , K + ) from GFP with metal (Ni 2+ , Zn 2+ ) uptake. RESULTS: GFP removed Ni 2+ and Zn 2+ rapidly, with 84.73% and 92.46% of the equilibrium sorption being reached in 30 min for Ni 2+ and Zn 2+ , respectively. The equilibrium process was described well by the Langmuir isotherm model, with maximum sorption capacity of 1.33 and 1.51 meq g −1 for Ni 2+ and Zn 2+ , respectively. Release of cations (Ca 2+ , Mg 2+ , Na + , K + ) and protons H + from GFP during uptake of Ni 2+ and Zn 2+ and EDX analysis of GFP before and after metal sorption revealed that the main mechanism of sorption was ion exchange. FTIR spectroscopy showed that carboxyl and hydroxyl groups were involved in the sorption of Ni 2+ and Zn 2+ . Blocking of these groups revealed that carboxylic group was responsible for 78.57% and 73.31% of Ni 2+ and Zn 2+ removal, respectively whereas 22.63% and 28.54% was due to the hydroxyl group. The GFP could be regenerated using 0.1 mol L −1 HCl, with more than 98% metal recovery and reused for five cycles without any significant loss in its initial sorption capacity.

Batch experiments were conducted to study the sorption of uranium on selected clay minerals (KGa-1b and KGa-2 reference kaolinite, SWy-2 and STx-1b reference montmorillonite, and IBECO natural bentonite) as a function of pH (4-9) and 0.001, 0.01, and 0.025 M NaCl in equilibrium with the CO 2 partial pressure of the atmosphere. Uranium concentrations were kept below 100 lg L -1 to avoid precipitation of amorphous Uraniumhydroxides. Solely PTFE containers and materials were used, because experiments showed significant sorption at higher pH on glass ware. All batch experiments were performed over a period of 24 h, since kinetic experiments proved that the common 10 or 15 min are in many cases by far not sufficient to reach equilibrium. Kaolinite showed much greater uranium sorption than the other clay minerals due to the more aluminol sites available. Sorption on the poorly crystallized KGa-2 was higher than on the wellcrystallized KGa-1b. Uranium sorption on STx-1b and IBECO exhibited parabolic behavior with a sorption maximum around pH 6.5. Sorption of uranium on montmorillonites showed a distinct dependency on sodium concentrations because of the effective competition between uranyl and sodium ions, whereas less significant differences in sorption were found for kaolinite. The presence of anatase as impurity in kaolinite enhanced the binding of uranyl-carbonate complexes with surface sites. The kinetic of uranium sorption behavior was primarily dependent on the clay minerals and pH. A multisite surface complexation model without assuming exchange is based on the binding of the most dominant uranium species to aluminol and silanol edge sites of montmorillonite, respectively to aluminol and titanol surface sites of kaolinite. For eight surface species, the log_k was determined from the experimental data using the parameter estimation code PEST together with PHREEQC.

Hydrogen storage 2D NMR DFT calculations a b s t r a c t Liquid organic hydrides, e.g. 9-ethylcarbazole, are potentially interesting hydrogen storage materials because of their reversible hydrogen sorption properties. In the present work, hydrogenation reaction of 9-ethylcarbazole in the molten form was investigated over a wide variety of noble metal and nickel supported catalysts. The catalytic activity of 8.2 Â 10 À6 mol-ethylcarbazole/g of metal/s and selectivity of 98% towards a fully hydrogen loaded product were recorded over 5 wt% ruthenium on alumina which was prepared by mild chemical reduction of ruthenium salt. Using this catalyst the theoretical capacity of hydrogen uptake (5.7 wt%) was obtained and the rate of the reaction and activation energy were estimated. Due to its potential high hydrogen storage capacity, this system could be a promising on-board storage candidate for mobile applications. The structures of reaction products and intermediates were identified using 2D NMR techniques. These structures were also predicted to be thermodynamically stable using density functional theory (DFT), matching well with the experimental observations. (S.C. Tsang).

Sulfonamides (SAs) are one of the oldest groups of veterinary chemotherapeutic agents. As these compounds are not completely metabolized in animals, a high proportion of the native form is excreted in feces and urine. They are therefore released either directly to the environment in aquacultures and by grazing animals, or indirectly during the application of manure or slurry. Once released into the environment, SAs become distributed among various environmental compartments and may be transported to surface or ground waters. The physicochemical properties of SAs, dosage and nature of the matrix are the factors mainly responsible for their distribution in the natural environment. Although these rather polar compounds have been in use for over half a century, knowledge of their fate and behavior in soil ecosystems is still limited. Therefore, in this work we have determined the sorption potential of sulfadimethoxine and sulfaguanidine on various natural soils. The influence on sorption of external factors, such as ionic strength and pH, were also determined. The sorption coefficients (K d ) obtained for the sulfonamides investigated were quite low (from 0.20 to 381.17 mL g À1 for sulfadimethoxine and from 0.39 to 35.09 mL g À1 for sulfaguanidine), which indicated that these substances are highly mobile and have the potential to run off into surface waters and/or infiltrate ground water. Moreover, the sorption of these pharmaceuticals was found to be influenced by OC, soil solution pH and ionic strength, with higher K d values for soils of higher OC and lower K d values with increasing pH and ionic strength.

h i g h l i g h t s < The desiccant wheel as core component of a highly efficient HVAC pilot installation based on renewable energies. < Modeling and experimental validation of a desiccant wheel. < Using a validated physical model to build a simplified model. < Modeling and validation used from the same source.

Hybrid plasma catalyst technology has great potential for indoor air purification. However, humidity is a critical parameter in plasma catalytic processes. In this work, several catalysts were tested downstream of a DC corona discharge and the effect of humidity was investigated on both ozone and toluene removal. Next, sorption measurements onto the catalysts were performed for toluene, trichloroethylene and acetone, using an equilibrium partitioning in closed system procedure to explain the obtained results in a quantitative manner.

In forest soils contaminated by radiocesium ( 134 Cs and 137 Cs), deposition from the Fukushima nuclear accident, clay minerals might play important roles in long-term cesium (Cs) dynamics through sorption. To determine whether radiocesium can be retained within the organic layer and the upper mineral soil layers in the Fukushima region, we investigated the vertical distribution of 134 Cs and 137 Cs and the clay mineral composition in five soil profiles of varying radiocesium deposition levels and vegetation types. X-ray diffraction analyses and oxalate extraction suggested that hydroxy-interlayered vermiculites and shortrange-ordered aluminum (Al) and iron (Fe) compounds (i.e, allophane and ferrihydrite) were major clay mineral species of the upper soil layers. The vertical soil distribution of 134 Cs and 137 Cs suggested that most of them were retained in the organic layer and upper mineral soil layer under different levels of deposition. Within 1.5 years after the accident, both 134 Cs and 137 Cs were leached from the organic layer, and most of these (59-73%) were accumulated in the upper soil layer (0-5 cm). The proportion of 137 Cs (or 134 Cs) leaching from the organic layer was greater at sites receiving greater amounts of precipitation. The substantial accumulation of 137 Cs in the upper soil layer, irrespective of the 137 Cs deposition level or clay mineral composition, suggests that sorption capacities of clays and organic matter are sufficiently high to retain 137 Cs in the surface soil during at least the initial stage of contamination.

The present study deals with the competitive adsorption of cadmium (Cd(II)) and nickel (Ni(II)) ions from aqueous solution onto rice husk ash (RHA). Non-competitive Redlich-Peterson (R-P) and Freundlich models represent the single metal ion equilibrium sorption data. The adsorption capacities for the binary mixtures-RHA system are in the order Ni(II) > Cd(II). The combined equilibrium sorption of Cd(II) and Ni(II) ions onto RHA is found to be antagonistic in nature and the extended Freundlich model was found to best represent the binary equilibrium isotherm data. .in (V.C. Srivastava).

The equilibrium, kinetics, and thermodynamics of the biosorption of Pb(II), Cd(II) and Zn(II) onto groundnut (Arachis hypogaea) shell were investigated under various physicochemical parameters. Optimisation studies were carried out using batch biosorption studies. The extent of the metal ion biosorption increased with increase in solution pH, initial metal ion concentration, dosage of biosorbent and contact time but decreased with the temperature of the system. The biosorption of each of the metal ions was found to be pH-dependent. Kinetic study showed that the metal ions biosorption process followed the pseudo-second-order kinetic model. The sorption of each metal ion was analysed with Freundlich and Langmuir isotherm models, in each case, the equilibrium data were better represented by Freundlich isotherm model. Thermodynamically, parameters such as standard Gibbs free energy (ΔG˚), standard enthalpy (ΔH˚), standard entropy (ΔS˚) and the activation energy (A) were calculated. The ...

Reduction of water activity aw can extend the shelf life and improve the quality of foods. After the optimal water activity has been selected, based on Karel’s aw-spoilage graphs, a simple decision scheme in this document helps to choose the best equation (“Law”) to calculate or adjust the water activity: for an aqueous one component  solution: Raoult’s and Norrish’ laws; spreadsheet “aw-Raoult-Norrish.xls”; or in case of an aqueous multi-component solution: Norrish’ and Ross’ laws; spreadsheet “Norrish-Ross.xls: aw calculations of a multi-component solution”. Both Excel spreadsheets, present in this document, simplify the tedious exponential aw calculations.
The water activity of a mixture of 2 to 5 solids can be predicted either by constructing the solids mixture sorption isotherm, or by using the Salwin equation. When applying the 3rd spreadsheet in this document, “Calculation Water Activity aw Solids Mixture.xls”, the  2 to 5 separate solids isotherms are converted into one new solids mixture sorption isotherm. Because the total water content of the solids mixture is known, the water activity of the solids mixture can be found from that new mixture isotherm. The calculations by the “aw Solid Mixture” spreadsheet are compared with aw findings from Salwin’s equation. Both aw values are in good agreement.
Several worked examples, for each of the 3 spreadsheets present, illustrate step-by-step the aw calculation of solutions and of solid mixtures.
Annex 1 lists the lowest water activity for growth and/or toxin production of many micro-
organisms in foods. Annex 2 shows the minimal aw for activity of the main food spoiling enzymes.

The past decade has seen considerable progress in the development of models simulating pesticide transport in structured soils subject to preferential flow (PF). Most PF pesticide transport models are based on the two-region concept and usually assume one (vertical) dimensional flow and transport. Stochastic parameter sets are sometimes used to account for the effects of spatial variability at the field scale. In the past decade, PF pesticide models were also coupled with Geographical Information Systems (GIS) and groundwater flow models for application at the catchment and larger regional scales. A review of PF pesticide model applications reveals that the principal difficulty of their application is still the appropriate parameterization of PF and pesticide processes. Experimental solution strategies involve improving measurement techniques and experimental designs. Model strategies aim at enhancing process descriptions, studying parameter sensitivity, uncertainty, inverse parameter identification, model calibration, and effects of spatial variability, as well as generating model emulators and databases. Model comparison studies demonstrated that, after calibration, PF pesticide models clearly outperform chromatographic models for structured soils. Considering nonlinear and kinetic sorption reactions further enhanced the pesticide transport description. However, inverse techniques combined with typically available experimental data are often limited in their ability to simultaneously identify parameters for describing PF, sorption, degradation and other processes. On the other hand, the predictive capacity of uncalibrated PF pesticide models currently allows at best an approximate (order-of-magnitude) estimation of concentrations. Moreover, models should target the entire soil-plant-atmosphere system, including often neglected above-ground processes such as pesticide volatilization, interception, sorption to plant residues, root uptake, and losses by runoff. The conclusions compile progress, problems, and future research choices for modelling pesticide displacement in structured soils.

Molecularly imprinted polymers (MIPs) are tailor-made polymers with high selectivity for a given analyte, or group of structurally related compounds. The influence of the process parameters (the moles of functional monomer and cross-linker, the selection of functional monomer and solvent) on the preparation of oseltamivir (OS)-imprinted polymers was investigated. A mathematical method for uniform design to optimize these selected parameters and to increase the MIP selectivity for template molecules was applied. The optimal conditions to synthesize MIP were 0.69 mmol 30% acrylamide (AA) + 70% 4-Vinylpyridine (4-VP) and 5.0 mmol ethylene glycol dimethacrylate (EGDMA) copolymerized in 5 ml toluene in the presence of 0.1 mmol OS. MIP showed high affinity and selectivity for separation of the template molecule from other compounds. In the present study, we have established an effective LC-MS/MS method to identify and quantify OS with good sensitivity, accuracy and precision. Figure A Complexation; B polymerization and template removal; C MIP has high affinity to template molecule; D MIP has some affinity to template molecule analog; E MIP has no affinity to other chemicals with different type from template molecule. a Template molecule; b template molecule analog; c other chemicals

Flat extruded wheat and rye bread was equilibrated to variable water activities using saturated salt solutions. At those water activities the bread was subjected to compression and three-point breaking tests. Compression test showed that water antiplasticizes both investigated breads. In the range of water activities from 0 to 0.53 for wheat bread, and from 0 to 0.59 for rye bread, the compression force reached 600 N at true strain 0.8. Compression proceeded in two steps; hence the mechanical resistance of the surface layers is larger than that of the center of the slice. Above the critical water activities water plasticizes the breads, and decrease of compression force with increasing water activity is recorded.

h i g h l i g h t s " Pyrolysis temperature influenced crop residue-derived biochar (BC) properties. " High pyrolysis temperature led to increased surface area and aromaticity of BC. " TCE adsorption capacity was related to aromaticity and polarity of BC.

The total specific surface area (TSSA) and smectitic layer charge (Q s ) calculated from the structural formulae and unit-cell dimensions of 12 pure smectite samples were used as a reference in the design and evaluation of TSSA and Q s measurement techniques based on cation exchange capacity (CEC), H 2 O retention at 47% RH, and ethylene glycol monoethyl ether (EGME) retention. A thermogravimetric analysis-mass spectrometry (TGA-MS) technique was used to study the release of H 2 O from smectite on heating, and to introduce a correction for H 2 O remaining in the smectite after heating to 110ºC, because the sample weight at this temperature has been used routinely as a reference in CEC and EGME sorption measurements. A temperature of 200ºC was found to be the optimum reference for such measurements.

Reduction of water activity aW can improve the shelf life and the quality of foods. After
selecting the optimal water activity, a simple decision scheme helps to choose the best
equation (“Law”) to calculate or adjust the water activity: of an aqueous one component
solution (Raoult’s and Norrish’ laws), or of an aqueous multi-component solution (Norrish’ and Ross’ laws). For aqueous solutions of sugars, salts, electrolytes, and salt or fat replacers, three spreadsheets simplify the tedious exponential aW calculations: 
"aW-Raoult-Norrish.xlsx", and "aW-Pitzer equations.xlsx", for one component aqueous
solutions; spreadsheet "Norrish, Ross, Samapundo, Pitzer, and Baeza.xlxs" for
multi-component aqueous solutions. Sometimes, for a particular component, 2 or 3 aW equations are available; if possible, the equation’s  accuracy will then be reported.
The water activity of a mixture of 2 to 5 SOLIDS can be predicted either by constructing the solids mixture sorption isotherm, or by using the Salwin equation. When applying the
spreadsheet "Calculation Water Activity aW Solids Mixture.xlsx", the separate solids
isotherms are converted into one new solids mixture sorption isotherm. Because the total water content of the solids mixture is known, the water activity of the solids mixture can be found from that new mixture isotherm. Calculations with the "Solid Mixture" spreadsheet are validated by comparing its predicted solids mixture aW with the water activity, calculated by the Salwin equation. The two calculated solid mixture aW values are in good agreement.
Annex 1 lists the lowest water activity for growth and/or toxin production of many micro-
organisms in foods. Annex 2 shows the lowest aW for activity of the main food spoiling enzymes. Annex 3 gives many sources of Norrish k values; Annex 4 reports measured water activities for verification.
Several worked examples for each of the spreadsheets illustrate step-by-step the
aW calculation of aqueous solutions and of solid mixtures.

The water absorption characteristics during soaking of Terminalia superba ( Ofram), Terminalia ivorensis (Emere) as currently threatened timber species and Quassia undulata ( Hotrohotro) and Recinodendron heudelotii.(Wama) as lesser used timber species were studied to determine and compare their absorption and diffusion coefficients as potential substitutes for utilization. Water soaking was carried out for nineteen days and the data were fitted into the Fick's model to determine both the water absorption and diffusion coefficients. The study showed that, the mean values of the water absorption coefficient at initial stages of moisture sorption for Hortrohotro, Ofram, Emere and Wama were 3.51x 10 -3 , 4.31x10 -3 , 1.67x10 -3 and 8.27x10 -4 (kg/m 2 /s) respectively. The corresponding mean values of this parameter for the entire soaking process were also determined for the timber species viz; Ofram (2.91x 10 -3 ), Hortrohotro (2.58x 10 -3 ), Emere (1.14x 10 -3 ) and Wama (6.11x 10 -4 ) kg/m 2 s respectively. The measured diffusion coefficient for Wama, Emere, Ofram and Hotrohotro timber species were 9.637x10, -4 6.694x10 -3 4.185x10 -2 and 2.899x10 -2 kg/m 2 /s respectively. Emere and Wama had lower absorption and diffusion characteristics than Hortrohotro and Ofram. Based on this study, Wama could be substituted for Emere and Hortrohotro with Ofram.

Aerogel based insulation systems for ambient pressure environments were developed for liquid hydrogen (LH2) tank applications. Solutions to thermal insulation problems were demonstrated for the Space Shuttle External Tank (ET) through extensive testing at the Cryogenics Test Laboratory. Demonstration testing was performed using a 1/10th scale ET LH2 intertank unit and liquid helium as the coolant to provide the 20 K cold boundary temperature. Cryopumping tests in the range of 20K were performed using both constant mass and constant pressure methods. Long-duration tests (up to 10 hours) showed that the nitrogen mass taken up inside the intertank is reduced by a factor of nearly three for the aerogel insulated case as compared to the un-insulated (bare metal flight configuration) case. Test results including thermal stabilization, heat transfer effectiveness, and cryopumping confirm that the aerogel system eliminates free liquid nitrogen within the intertank. Physisorption (or adsorption) of liquid nitrogen within the fine pore structure of aerogel materials was also investigated. Results of a mass uptake method show that the sorption ratio (liquid nitrogen to aerogel beads) is about 62 percent by volume. A novel liquid nitrogen production method of testing the liquid nitrogen physical adsorption capacity of aerogel beads was also performed to more closely approximate the actual launch vehicle cooldown and thermal stabilization effects within the aerogel material. The extraordinary insulating effectiveness of the aerogel material shows that cryopumping is not an open-cell mass transport issue but is strictly driven by thermal communication between warm and cold surfaces. The new aerogel insulation technology is useful to solve heat transfer problem areas and to augment existing thermal protection systems on launch vehicles. Examples are given and potential benefits for producing launch systems that are more reliable, robust, reusable, and efficient are outlined.

The  problem  of environmental  pollution  is  more expressed and more present by the development of the industry and  the  growth  of  the  human  population.  Pollution  of  natural and wastewater is most often due to the release of heavy metals into  watercourses.  The  greatest  challenge  for  researchers  is choosing  the  right  biomass  from  a  large  number  of  low-cost biomaterials,  and  availability  and  price  are  very  important selection  factors.  Microbial  biomass,  forestry  waste  and agroindustrial complexes are most frequently examined, as well as  various  macromolecules  of  natural  origin.  In  this  paper, barley straw that arises as agricultural waste product in barley production  in  Bosnia  and  Herzegovina,  was  used  as  a biosorbent. In  the  experimental  part,  physical  and  chemical characterization  of    barley  straw  was  performed,  after  which the  efficiency  of  removing  Cd(II)  and  Ni(II)  from  aqueous solutions,  using  barley  straw,  and  the  influence  of  process parameters  (pH  value  of  aqueous  solution,  biosorbent  size, interaction  of  metal  ions)  on the  biosorption  capacity  were tested.It can be concluded that barley straw has good adsoption characteristics  for  the  use  as  a  low-cost  natural  sorbent  for  the removal of heavy metals from water.

Water activity and glass transition temperature concepts were used to investigate the connection between the two distinct criteria of food stability. The data on sorption isotherms and glass transition temperatures were obtained from the literature. Two most commonly used models i.e. GAB and Gordon-Taylor equations were used to model water activity/moisture content and glass transition temperatures/solids content relationships. The modelsÕ (GAB and Gordon-Taylor) parameters were used to estimate water activity and glass transition temperature at given moisture/solids content. Results indicate that there is a considerable discrepancy in the temperaturerelated stability criteria predicted by the concepts of water activity (a w ) and the glass phenomenon (T g ). A greater understanding of water sorption properties and T g is required to establish a sound processing and storage stability criteria.

Nitrate, due to its high water solubility, is possibly the most widespread groundwater contaminant in the world, imposing a serious threat to human health and contributing to eutrophication. Among several treatment technologies applied for nitrate removal, adsorption has been explored widely and offers satisfactory results especially with mineral-based and/or surface modified adsorbents. In this review, an extensive list of various sorbents from the literature has been compiled and their adsorption capacities for nitrate removal as available in the literature are presented along with highlighting and discussing the key advancement on the preparation of novel adsorbents tested for nitrate removal. (A. Bhatnagar). ication . The presence of elevated concentrations of NO 3 − in potable water has become a serious concern worldwide over the recent decades . The increase in NO 3 − levels can be linked to several kinds of human activities especially the intensive use of fertilizers in agriculture, which have led to the higher NO 3 − contamination of ground and surface water sources [13]. Nitrate does not readily bind to the soil causing it to be highly susceptible to leaching. Point and non-point sources of NO 3 − contamination 1385-8947/$ -see front matter

The total number of permanent staff working at the VINATOM as December 31, 2010 was 737 including the clerical service staff. The VINATOM was funded from the Government with the amount to 73.812 billion VN Dong for FY 2010. The international support for the VINATOM activities is committed over 437,378 USD to the operating projects including equipment, staff training and expert services. Main results of fundamental and applied research implemented in the year were presented in 77 scientific articles, reports and contributions published in many journals, proceedings of conferences, etc. These results were obtained on the basic of the IAEA technical cooperation projects (11 VIE projects), the regional projects (42 RAS projects), the research contracts with the IAEA (15 RCs). During the time of year 2010, in the VINATOM there were 2 graduated in Ph.D. courses; about 100 people have been trained abroad in the fields of nuclear science and technology.

An efficient adsorption process is developed for the decontamination of trivalent chromium from tannery effluents. A low cost activated carbon (ATFAC) was prepared from coconut shell fibers (an agricultural waste), characterized and utilized for Cr(III) removal from water/wastewater. A commercially available activated carbon fabric cloth (ACF) was also studied for comparative evaluation. All the equilibrium and kinetic studies were conducted at different temperatures, particle size, pHs, and adsorbent doses in batch mode. The Langmuir and Freundlich isotherm models were applied. The Langmuir model best fit the equilibrium isotherm data. The maximum adsorption capacities of ATFAC and ACF at 25 • C are 12.2 and 39.56 mg/g, respectively. Cr(III) adsorption increased with an increase in temperature (10 • C: ATFAC-10.97 mg/g, ACF-36.05 mg/g; 40 • C: ATFAC-16.10 mg/g, ACF-40.29 mg/g). The kinetic studies were conducted to delineate the effect of temperature, initial adsorbate concentration, particle size of the adsorbent, and solid to liquid ratio. The adsorption of Cr(III) follows the pseudo-second-order rate kinetics. From kinetic studies various rate and thermodynamic parameters such as effective diffusion coefficient, activation energy and entropy of activation were evaluated. The sorption capacity of activated carbon (ATFAC) and activated carbon fabric cloth is comparable to many other adsorbents/carbons/biosorbents utilized for the removal of trivalent chromium from water/wastewater.