Direct conversion of cellulose to 5-hydroxymethylfurfural (HMF) using an efficient and inexpensive boehmite catalyst.

High efficiency conversion of cellulose to 5-hydroxymethylfurfural (HMF) remains a challenge today. A simple solid acid catalyst Boehmite (γ-AlOOH) with high hydrothermal stability was prepared and used as sole catalyst for the direct conversion of cellulose into HMF in mixed reaction solvents of ionic liquid 1-buthyl-3-methylimidazolium chloride (BmimCl) and dimethyl sulfoxide (DMSO). This was aimed at developing an efficient and inexpensive catalyst for the production of HMF. The effects of factors such as water, solvent, catalyst load, temperature and reaction duration were investigated. An impressive HMF yield of 58.4% with 97.2% cellulose conversion was obtained at 160 °C after 2 h. More importantly, the catalyst γ-AlOOH was reused several times without loss of its catalytic properties. After five reaction runs, an HMF yield of 47.8% with 91.0% conversion was also obtained. In addition, the catalyst γ-AlOOH displayed excellent catalytic effects on the degradation of other carbohydrates. High yields of HMF from other carbohydrates such as glucose (61.2%), starch (62.7%) and inulin (70.5%) were achieved using γ-AlOOH as the catalyst. The proposed catalytic method shows a promising potential for HMF preparation, especially for industrial-scale HMF production from renewable bioresources.

Comparative assessment of humoral immune responses of aluminum hydroxide and oil-emulsion adjuvants in Influenza (H9N2) and Newcastle inactive vaccines to chickens.

Context Adjuvants are compounds used in the preparation of inactive vaccines to enhance the immune response. Aluminum hydroxide (alum) is one of the first compounds approved by the Food and Drug Administration, which is used as adjuvants in vaccine products for humans. Montanide ISA 70 is an oil-emulsion adjuvant and is used in poultry inactive vaccines. Objective In this study, the effects of alum adjuvant on the efficiency and induction of immune response in inactive vaccines of Influenza and Newcastle are compared with those of ISA 70. Materials and methods Six groups of 7-d-old specific-pathogen-free chickens were inoculated with 0.3 ml of the prepared vaccines via the subcutaneous route in the neck. Immune response in each group after 7, 14, 21, 31, 41, and 45 d was evaluated using the technique of hemagglutination inhibition. Results The results were compared using SPSS software. Results showed that vaccines containing adjuvant ISA 70 depicted a higher increase in the immune response and adjuvant of 20% alum is similar to adjuvant of ISA 70 in boosting the immune system. There was no statistically significant difference between 10% and 20% alum, but these adjuvants are visibly different from ISA 70. Conclusion In conclusion, alum can be used as an easily accessible, harmless, and effective adjuvant; however, to increase the immune period using the inactive vaccines for poultry, more research would be necessary.

A tannin-based agent for coagulation and flocculation of municipal wastewater: Chemical composition, performance assessment compared to Polyaluminum chloride, and application in a pilot plant.

Chemical composition and flocculation efficiency were investigated for a commercially produced tannin - based coagulant and flocculant (Tanfloc). The results of Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive Spectroscopy (EDX) confirmed what claimed about the chemical composition of Tanfloc. For moderate polluted municipal wastewater investigated in both jar test and pilot plant, Tanfloc showed high turbidity removal efficiency of approximately 90%, while removal efficiencies of BOD5 and COD were around 60%. According to floc size distribution, Tanfloc was able to show distinct performance compared to Polyaluminum chloride (PAC). While 90% of flocs produced by Tanfloc were smaller than 144 micron, they were smaller than 96 micron for PAC. Practically, zeta potential measurement showed the cationic nature of Tanfloc and suggested coincidence of charge neutralization and another flocculation mechanism (bridging or patch flocculation). Sludge Volumetric Index (SVI) measurements were in agreement with the numbers found in the literature, and they were less than 160 mL/g. Calcium cation as flocculation aid showed significant improvement of flocculation efficiency compared to other cations. Finally Tanfloc showed competing performance compared to PAC in terms of turbidity, BOD5 and COD removal, floc size and sludge characteristics.

Uranium in well drinking water of Kabul, Afghanistan and its effective, low-cost depuration using Mg-Fe based hydrotalcite-like compounds.

Toxic elements in drinking water have great effects on human health. However, there is very limited information about toxic elements in drinking water in Afghanistan. In this study, levels of 10 elements (chromium, nickel, copper, arsenic, cadmium, antimony, barium, mercury, lead and uranium) in 227 well drinking water samples in Kabul, Afghanistan were examined for the first time. Chromium (in 0.9% of the 227 samples), arsenic (7.0%) and uranium (19.4%) exceeded the values in WHO health-based guidelines for drinking-water quality. Maximum chromium, arsenic and uranium levels in the water samples were 1.3-, 10.4- and 17.2-fold higher than the values in the guidelines, respectively. We next focused on uranium, which is the most seriously polluted element among the 10 elements. Mean ± SD (138.0 ± 1.4) of the 238U/235U isotopic ratio in the water samples was in the range of previously reported ratios for natural source uranium. We then examined the effect of our originally developed magnesium (Mg)-iron (Fe)-based hydrotalcite-like compounds (MF-HT) on adsorption for uranium. All of the uranium-polluted well water samples from Kabul (mean ± SD = 190.4 ± 113.9 µg/L; n = 11) could be remediated up to 1.2 ± 1.7 µg/L by 1% weight of our MF-HT within 60 s at very low cost (<0.001 cents/day/family) in theory. Thus, we demonstrated not only elevated levels of some toxic elements including natural source uranium but also an effective depurative for uranium in well drinking water from Kabul. Since our depurative is effective for remediation of arsenic as shown in our previous studies, its practical use in Kabul may be encouraged.

Metal catalysts for steam reforming of tar derived from the gasification of lignocellulosic biomass.

Biomass gasification is one of the most important technologies for the conversion of biomass to electricity, fuels, and chemicals. The main obstacle preventing the commercial application of this technology is the presence of tar in the product gas. Catalytic reforming of tar appears a promising approach to remove tar and supported metal catalysts are among the most effective catalysts. Nevertheless, improvement of catalytic performances including activity, stability, resistance to coke deposition and aggregation of metal particles, as well as catalyst regenerability is greatly needed. This review focuses on the design and catalysis of supported metal catalysts for the removal of tar in the gasification of biomass. The recent development of metal catalysts including Rh, Ni, Co, and their alloys for steam reforming of biomass tar and tar model compounds is introduced. The role of metal species, support materials, promoters, and their interfaces is described.

A PARAFAC-based long-term assessment of DOM in a multi-coagulant drinking water treatment scheme.

A parallel factor (PARAFAC) analysis approach was used to study the character and composition of dissolved organic matter (DOM) in a multicoagulant (two aluminum-based coagulants) full scale drinking water treatment plant. A three year, long-term assessment was conducted based on deconstruction of the excitation-emission matrices (EEM) of over 1000 water samples collected before and after parallel coagulation treatment basins. Two humic moieties and a protein-like group were identified in the raw and treated waters. Apportionment of fluorophores was established using a novel approach based on the overall fluorescence intensity (OFI) of PARAFAC components. Uncorrected matrix correlation (UMC) revealed minimal changes of the fluorescence moieties after treatment (UMC > 0.98), and a comparable effect of both coagulants on the structure (UMC > 0.99) and distribution of these groups. Coagulation increased the proportion of the protein-like fluorophore and preferentially removed a humic-like group irrespective of the coagulant. Preference for this moiety was supported by a coagulant-affinity factor derived from the association between PARAFAC components after treatment. The suitability of a PARAFAC-based approach for coagulant evaluation/selection was demonstrated when compared to a dissolved organic carbon (DOC)-based criterion. This paper contributes to the understanding of the behavior of PARAFAC components in water treatment processes and presents several approaches for the future monitoring and control of coagulation at full scale treatment facilities.

New insight into artifactual phenomena during in vitro toxicity assessment of engineered nanoparticles: study of TNF-α adsorption on alumina oxide nanoparticle.

Biomolecules can be adsorbed on nanoparticles (NPs) and degraded during in vitro toxicity assays. These artifactual phenomena could lead to misinterpretation of biological activity, such as false-negative results. To avoid possible underestimation of cytokine release after contact between NP and cells, we propose a methodology to account for these artifactual phenomena and lead to accurate measurements. We focused on the pro-inflammatory cytokine tumor necrosis factor TNF-α. We studied well-characterized boehmite engineered NP [aluminum oxide hydroxide, AlO(OH)]. The rate of TNF-α degradation and its adsorption (on boehmite and on the walls of wells) were determined in cell-free conditions by adding a known TNF-α concentration (1500 pg/ml) under various experimental conditions. After a 24-h incubation, we quantified that 7 wt.% of the initial TNF-α was degraded over time, 6 wt.% adsorbed on the walls of 96-well plates, and 13 wt.% adsorbed on the boehmite surface. Finally, boehmite NP were incubated with murine macrophages (RAW 264.7 cell line). The release of TNF-α was assessed for boehmite NP and the experimental data were corrected considering the artifactual phenomena, which accounted for about 20-30% of the total.

Decontamination of outdoor school swimming pools in Fukushima after the nuclear accident in March 2011.

Because of radioactive fallout resulting from the Fukushima Daiichi Nuclear Power Plant (NPP) accident, water discharge from many outdoor swimming pools in Fukushima was suspended out of concern that radiocesium in the pool water would flow into farmlands. The Japan Atomic Energy Agency has reviewed the existing flocculation method for decontaminating pool water and established a practical decontamination method by demonstrating the process at eight pools in Fukushima. In this method, zeolite powder and a flocculant are used for capturing radiocesium present in pool water. The supernatant is discharged if the radiocesium concentration is less than the targeted level. The radioactive residue is collected and stored in a temporary storage space. Radioactivity concentration in water is measured with a NaI(Tl) or Ge detector installed near the pool. The demonstration results showed that the pool water in which the radiocesium concentration was more than a few hundred Bq L was readily purified by the method, and the radiocesium concentration was reduced to less than 100 Bq L. The ambient dose rates around the temporary storage space were slightly elevated; however, the total increase was up to 30% of the background dose rates when the residue was shielded with sandbags.

Low-cost and effective phenol and basic dyes trapper derived from the porous silica coated with hydrotalcite gel.

Novel low-cost and effective adsorbents of phenol and basic dyes were made by coating amorphous silica with hydrotalcite (HT) gel followed by soaking in alkaline solution, and the surface basic-acidic properties of resulting composites were evaluated by CO(2)-TPD, Hammett indicator method and NH(3)-TPD, respectively. Both BET surface area and microporous surface area of the composites were increased after they were soaked with alkaline solution; meanwhile the center of pore size distribution was changed from 9 to 3-4 nm. These composites efficiently captured phenol in gaseous and liquid phases, superior to mesoporous silica such as MCM-48 or SBA-15 and zeolite NaY, and the equilibrium data of gaseous adsorption could be well fitted to Freundlich model. These modified silicas also exhibited high adsorption capacity forward basic dyes such as crystal violet (CV) and leuco-crystal violet (LCV), reaching the adsorption equilibrium within 1 h and offering a new material for environment protection.

Thermodynamic assessment of Hg(II)-gibbsite interactions.

As discrete particles and/or as surface coatings on other minerals in natural systems, aluminum hydroxides are efficient sinks for Hg(II). The Hg(II) adsorption on gibbsite was determined as a function of temperature (T), pH, and the type of background electrolytes, i.e., NaNO(3), NaClO(4), and NaCl. When the equilibration time t(E) approximately 2 h, the Hg(II) retention on gibbsite was found to be a reversible process, which was ascribed to adsorption. The Hg(II) adsorption capacity, i.e., Gamma(Hg(II)), varied with the type of electrolyte used in accordance with the following order: Gamma(NO(3))(Hg(II)) > or = Gamma(ClO(4))(Hg(II)) > or = Gamma(Cl)(Hg(II)). In all cases, the estimated thermodynamic parameters showed that the Hg(II) adsorption on gibbsite was endothermic and spontaneous. The Hg(II) adsorption data were quantified with the Langmuir or Hill, and Dublin-Radushkevick (DR), isotherms at all temperatures and acidity levels examined. Always, the Hg(II) adsorption data were in compliance with the DR model. However, the Hg(II) adsorption in NaNO(3) or NaClO(4) was interpreted in terms of the Langmuir model. When NaCl was used as electrolyte, the Hg(II) adsorption was modeled well with the Hill equation. The mean free energy values calculated from DR plots concluded that Hg(II)-gibbsite interactions are a result of chemical bonding.

Retention of trace metals by solidified/stabilized wastes: assessment of long-term metal release.

Toxic elements found in wastes may have a negative impact on the environment, especially through the contamination of groundwater and plants. To reduce their mobility and availability, French regulations mandate the solidification and stabilization of toxic wastes. Many methods to stabilize and solidify wastes exist, among them the Ecofix process which employs low cost materials and consists of mixing wastes with lime, aluminum hydroxide, and silica. To evaluate the long-term behavior of solidified/stabilized (S/S) samples, their alteration under saturated conditions was studied in a water extractor, a Soxhlet-like device, used to follow the weathering of rocks. Kinetic measurements have shown that the release of Fe, Pb, Cd, Cr, and Cu was very slow, indicating a strong retention of these elements by the S/S materials prepared by the Ecofix process. To elucidate the mechanisms of retention of the trace metals, the mineral phases that existed in the S/S samples throughout and at the end of the extraction runs were studied by X-ray diffraction and by infrared and nuclear magnetic resonance spectroscopies. Scanning electron microscopic (SEM) examinations and electron microprobe analyses of the S/S samples were also performed at different stages of weathering. These observations revealed that assorted calcium silicate hydrates (C-S-H) were the predominant phases in the S/S preparations and that gradual alterations occurred in the structure of the investigated materials. The overall Ca/Si ratio of the C-S-H phases decreased as the enhanced alteration progressed. Although trace metals in oxide, hydroxide, and carbonate forms were found in the S/S materials, the bulk of the trace metals was incorporated in the matrix of the C-S-H phases.

A study of the alumina-silica gel adsorbent for the removal of silicic acid from geothermal water: increase in adsorption capacity of the adsorbent due to formation of amorphous aluminosilicate by adsorption of silicic acid.

Two kinds of adsorbents (Si adsorbent and Al adsorbent) for the removal of silicic acid from geothermal water to retard the formation of silica scales were prepared using silicic acid contained in geothermal water. The Si adsorbent was prepared by evaporating geothermal water, and the Al adsorbent was prepared by evaporating geothermal water after the addition of aluminum chloride. The specific surface area of the Si adsorbent was small and it's adsorption capacity of silicic acid was low. Although the specific surface area of the Al adsorbent was also small, it was significantly increased by the adsorption of silicic acid and it's adsorption capacity was high. Based on the change in the local structure of aluminum ion by the adsorption of silicic acid, the Al adsorbent was considered to be silica particles covered with crystalline aluminum hydroxide. Moreover, it was concluded that the increase in the specific surface area of the Al adsorbent and the decrease in the zeta potential were due to the formation of an amorphous aluminosilicate with a large surface area and a negative charge (one 4-coordinated Al) by the reaction between aluminum ions and silicic acids.

Gel de hidróxido de aluminio: análisis comparativo de métodos de separación sólido-líquido que se utilizan en su producción / Aluminum hydroxide: a comparative analysis of the solid-liquid separation methods used in its production

Se analizó de forma comparativa diferentes variantes de separación sólido-líquido para la obtención del gel de hidróxido de aluminio como sedimentación, filtración al vacío (por lotes y continua), filtración a presión y centrifugación. Se presentan las ventajas y desventajas de cada variante incluyendo un análisis técnico-económico de éstas. Se concluye que el uso de un filtro rotatorio al vacío satisface los requerimientos establecidos