Inorganic Aluminum Research Articles

무기항균제 및 난연제를 함유한 PVC 복합소재의 항균 및 난연 특성

본 연구는 세균에 대한 항균효과와 난연 특성을 갖는 신소재의 개발이 목표이다. 제올라이트의 기공에 은과 아연을 포함한 무기항균제(inorganic bacteriocide, IB)와 친환경 무기계 난연제인 aluminum trihydroxide(ATH)를 함유한 PVC 복합소재인 PVC/IB/ATH를 제조하였다. 두 종류의 세균으로 탁도 분석법, 진탕 배양법, drop-test, 이중 염색법을 사용하여 PVC/IB/ATH 복합소재의 항균효과 실험결과 99%의 항균효과를 확인하였다. 또한 한계산소농도 지수와 열중량 분석으로 PVC/IB/ATH 복합소재의 난연 특성을 확인한 바, ATH와 무기항균제의 알루미늄 성분에 의존적으로 증가하였다. 또한 PVC/IB/ATH 복합소재의 열적 특성은 소폭 증가하였다. 결론적으로, PVC/IB/ATH의 응용은 의료 산업, 항균 시스템 그리고 난연 물질과 같은 다양한 분야에 이용될 것으로 기대한다.

Investigation of the effect of lanthanum oxide on the thermal stability of alumina aerogel

Monolithic alumina aerogels were prepared with inorganic aluminum salts as raw material by epoxide-assisted sol–gel method. The structure and morphology of the monolithic alumina aerogels doped with different lanthanum oxide concentration were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption–desorption method and field emission scanning electron microscope. The results indicate that the pure alumina aerogel is translucent and sky blue in color. Alumina aerogels gradually changes into opaque blocks of ivory with increasing the amount of lanthanum oxide. The addition of lanthanum oxide can increase the specific surface area of alumina aerogels and improve their thermal stability at high calcination temperature. After calcination at 1000 °C for 2 h, alumina aerogel doped with 10 wt% lanthanum oxide is still amorphous phase and its specific surface area can reach 282 m2/g, which is much higher than pure alumina aerogel.

Sensitivity of Na+/K+-ATPase isoforms to acid and aluminum explains differential effects on Atlantic salmon osmoregulation in fresh water and seawater

Atlantic salmon (Salmo salar) smolts are sensitive to acid rain and associated increases in dissolved inorganic aluminum (Al) resulting in decreased seawater tolerance at this critical life stage. Salmon have two major isoforms of the catalytic alpha subunit of Na+/K+-ATPase (NKA), with NKAα1a being the major freshwater (FW) isoform and NKAα1b the major seawater (SW) isoform. Here we evaluate physiological markers of SW preparedness and NKAα1a and NKAα1b isoforms after short-term exposure to acidified water and acidified water with added Al (acid–Al). Atlantic salmon smolts were exposed to low ion FW (Control), low ion acidic water (pH 5.2; acid), and low ion acidic water (pH 5.2) with moderate levels of added inorganic Al (35 μg·L−1; acid–Al) for 4 days. Acid exposure resulted in loss of salinity tolerance (higher plasma chloride (Cl) after SW exposure) and significantly decreased the levels of gill NKAα1b but not NKAα1a protein abundance. Acid–Al exposure resulted in loss of plasma Cl in FW and higher plasma Cl in SW and decreased NKAα1a and NKAα1b abundance. The loss of salinity tolerance in smolts can be explained by the differential sensitivity of NKA isoforms to acid.

Biodegradable Gelatin as Template for the Preparation of Mesoporous Alumina

In this study, we propose a time‐ and energy‐saving method using biodegradable gelatin as a green template and a low‐toxicity inorganic aluminum salt (Al(NO3)3·9H2O) as a low‐cost aluminum source for the preparation of mesoporous alumina (γ‐Al2O3). The effects of pH (pH 8.0–10.0), gelatin to aluminum source ratio (0–1.9), and the hydrothermal treatment time (0–72 h) are thoroughly explored. The gelatin can assemble with the aluminum species γ‐AlOOH via hydrogen bonding to prevent the self‐condensation of the γ‐AlOOH during the hydrothermal treatment. Distinctly, the mesoporous γ‐Al2O3 was obtained from the calcination of the resulting gelatin–γ‐AlOOH composites. Without gelatin, high‐crystallinity γ‐AlOOH formed after the hydrothermal treatment, which transformed into the nonporous γ‐Al2O3 with a small surface area (20 m2/g). Finally, it was found that with a gelatin/aluminum ratio of 0.81, reaction pH value of 8.0, and hydrothermal treatment time of 24 h, high‐surface‐area mesoporous γ‐Al2O3 (262 m2/g) with pore diameter of 6.3 nm could be synthesized.

Depth‐sensing indentation and nano‐dynamic mechanical properties of aluminum nitride nanoparticles reinforced high density poly‐ethylene nanocomposites

Inorganic aluminum nitride (AlN) nanoparticles offer numerous innovative applications in the field of electronic packaging due to its outstanding features; viz., high mechanical strength, stable crystal structure, excellent thermal conductivity, low coefficient of thermal expansion, low‐cost, and non‐toxicity. In this research, attempts have been made to investigate the effect of reinforcement of nano‐AlN particles in high density poly‐ethylene (HDPE) thermoplastic polymer on their nano‐mechanical properties using depth‐sensing indentation (DSI) technique. Polymer‐matrix nanocomposites composed of pure HDPE and 1–20 vol% nano‐AlN/HDPE composites are prepared via melt mixing followed by compression molding. Surface‐morphology and crystallinity of HDPE/nano‐AlN composites are characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). Nano‐scale hardness, modulus of elasticity, storage modulus, and loss tangent (tanδ) of HDPE/nano‐AlN composites have been evaluated using static and dynamic‐DSI. Both static and dynamic‐DSI results indicate that with increasing concentration of AlN nanoparticles in pristine HDPE, the nano‐mechanical properties display significant improvement. Results are discussed in relation to the surface‐morphology, crystallinity and interfacial adhesion between pure HDPE and nano‐AlN particles. A comparison between nano‐mechanical data extracted from static‐DSI and dynamic‐DSI techniques analysis is also attempted. POLYM. COMPOS., 40:240–254, 2019. © 2017 Society of Plastics Engineers

Tensile Strength of Al Particles/Sisal Fibres Hybrid Composite with Epoxy Matrix

The hybrid composite polymer system was prepared by a vacuum infusion. The reinforcement phase of the composite consists of natural fibers and inorganic aluminum particles. Hard inorganic particles are used in composite systems to optimize certain mechanical characteristics such as hardness, wear resistance or even strength. Hybrid system with an epoxy matrix and a variable concentration of reinforcing phases of aluminum min. purity of 99% (average particle size 31 μm) and sisal fibers was used in the experiment. Sisal fibers were used without a preferred orientation - it was a disordered long-fiber composite system and fibers were treated with 6% aqueous NaOH. The experiment focuses mainly on the hardness and strength characteristics of the composite. Electron microscopy was used to describe the particle morphology and size, and to evaluate matrix filler distribution and interphase interactions.

Assessment of aluminum bioavailability in alum sludge for agricultural utilization

Inorganic aluminum ions, [Al(H2O)6]3+, [Al(OH)(H2O)5]2+, and [Al(OH)2(H2O)4]+, are toxic to a number of crops. The aim of this study was to estimate the danger of soil contamination of bioavailable aluminum and heavy metals forms because of alum sludge which was a by-product of water, and wastewater treatment technology using aluminum coagulant is introduced into the soil. Aluminum and selected heavy metal fractionation was carried out in the post-coagulation sludge collected at a water treatment plant (where aluminum was used as a coagulant), fermented sewage sludge at a municipal wastewater treatment plant (which did not apply aluminum coagulant), and soil from water treatment plant as well as the mixtures of sludge and soil. It has been found that post-coagulation sludge used as natural fertilizer is a secondary source of bioavailable aluminum, especially when aluminum coagulants are used during water and wastewater treatment. The evaluation of applicability of the sludge to very weak acidic and acidic agricultural soils was carried out. The authors shall debate the question whether, in this case, the Regulation of EU and Polish Government on sewage sludge should also take the bioavailable aluminum into account and add to the list of the elements whose allowable contents are limited.

Atmospheric deposition process for enhanced hybrid organic–inorganic multilayer barrier thin films for surface protection

In this study, organic polymer poly-vinyl acetate (PVA) and inorganic aluminum oxide (Al2O3) have been used together to fabricate a hybrid barrier thin film for the protection of PET substrate. The organic thin films of PVA were developed through roll to roll electrohydrodynamic atomization (R2R-EHDA) whereas the inorganic thin films of Al2O3 were grown by roll to roll spatial atmospheric atomic layer deposition (R2R-SAALD) for mass production. The use of these two technologies together to develop a multilayer hybrid organic-inorganic barrier thin films under atmospheric conditions is reported for the first time. These multilayer hybrid barrier thin films are fabricated on flexible PET substrate. Each layer of Al2O3 and PVA in barrier thin film exhibited excellent morphological, chemical and optical properties. Extremely uniform and atomically thin films of Al2O3 with average arithmetic roughness (Ra) of 1.64nm and 1.94nm respectively concealed the non-uniformity and irregularities in PVA thin films with Ra of 2.9nm and 3.6nm respectively. The optical transmittance of each layer was∼80-90% while the water vapor transmission rate (WVTR) of hybrid barrier was in the range of∼2.3×10−2gm−2day−1 with a total film thickness of∼200nm. Development of such hybrid barrier thin films with mass production and low cost will allow various flexible electronic devices to operate in atmospheric conditions without degradation of their properties.

Synthesis of an alumina enriched Al2O3-SiO2 aerogel: Reinforcement and ambient pressure drying

An alumina enriched Al2O3-SiO2 aerogel was successfully synthesized using an inexpensive inorganic aluminum salt Al(H2O)9(NO3)3 as the precursor and tetraethoxysilane (TEOS) as the framework reinforcing agent via a sol-gel process followed by ambient pressure drying. In order to show the enhanced effect of TEOS on aerogel, its structure and properties were detected by FESEM, TEM and BET. Furthermore, FTIR and Raman spectra were collected to explain the enhancement mechanism of TEOS to Al2O3-SiO2 aerogel at the molecular level. The FTIR spectra showed that some AlOSi and AlOSiOSiOAl bonds gradually formed during the reinforcement process. These long AlOSiOSiOAl chains supported and strengthened the alcogel skeleton and effectively avoided potential shrinkage and cracking during the ambient pressure drying process. In addition, Raman spectra supported this conclusion by verifying that AlOSi and SiOSi bonds were present. Moreover, the Raman spectra indicated that with the increase of the Si/Al mole ratio from 0 to 3.0, the primary gel skeleton of AlOAl bonds was gradually transformed to SiOSi bonds. When the Si/Al mole ratio was greater 3.0, SiOSi bonds became the primary bonds in the final aerogel.

High-Performance ZnPc Thin Film-Based Photosensitive Organic Field-Effect Transistors: Influence of Multilayer Dielectric Systems and Thin Film Growth Structure.

The key impact and significance of a multilayer polymer-based dielectric system on the remarkable photoresponse properties of zinc phthalocyanine (ZnPc)-based photosensitive organic field-effect transistors (PS-OFETs) have been systematically analyzed at various incident optical powers. A combination of inorganic aluminum oxide (Al2O3) and organic nonpolar poly(methyl methacrylate) (PMMA) is used as the bilayer dielectric configuration, whereas in the trilayer dielectric system, a bilayer polymer dielectric, consisting of PMMA, as the low-k dielectric polymer, on top of poly(vinyl alcohol) (PVA), the high-k polar dielectric, has been fabricated along with Al2O3 as the third layer. Before fabricating the OFETs, a systematic optimization of the nature of growth of the ZnPc molecules, deposited on PMMA-coated glass substrates at different substrate temperatures (Ts) was performed and examined by atomic-force microscopy, field-emission scanning electron microscopy, X-ray diffraction, and Raman analysis. At 90 °C, the fabricated PS-OFETs with the Al2O3/PVA/PMMA trilayer dielectric configuration showed the best p-channel behavior, with an enhanced and remarkable photoresponsivity of R ∼ 9689.39 A W–1 compared to that of the Al2O3/PMMA bilayer dielectric system (R ∼ 2679.40 A W–1) due to the polarization of the dipoles inside the polar PVA dielectric, which increases the charge transport through the channel. The charge carrier mobility of the device also improved by one order (μh ∼ 1.3 × 10–2 cm2 V–1 s–1) compared to that of the bilayer dielectric configuration (μh ∼ 3.5 × 10–3 cm2 V–1 s–1). The observed specific detectivity (D*) and NEP values of the bilayer dielectric system were 6.01 × 1013 Jones and 2.655 × 10–17 W Hz–1/2, whereas for the trilayer dielectric system, the observed D* and NEP values were 5.13 × 1014 Jones and 1.043 × 10–17 W Hz–1/2, respectively. Additionally, the operating voltage of each of the fabricated devices was also very low (−10 V) due to the influence of the inorganic high-k Al2O3 dielectric layer. The electrical stability of all of the fabricated devices was also investigated by bias stress analysis under both light and dark conditions in vacuum. To the best of our knowledge, the photoresponsivity (R) reported here with an Al2O3/PVA/PMMA trilayer dielectric configuration is the highest reported value for thin film-based PS-OFETs, at a remarkably low operating voltage of −10 V, on low-cost glass substrates without indium tin oxide or/and Si/SiO2.

Gelation Performance and Feasibility Study of an Environmental Friendly Improved Inorganic Aluminum Gel for Conformance Control Under Harsh Reservoir Conditions

Despite its successful application in controlling excessive water production in many mature oilfields, polymer gel is facing some application limitations under harsh reservoir conditions. To settle these problems, an environmental friendly improved inorganic aluminum gel that composed of polyaluminum chloride (PAC) as main agent, urea as activator, and sodium sulfate as syneresis inhibitor was developed. The effects of mass ratios of PAC and urea, component concentrations and temperature on gelation performance were studied. The gel compatibility with various formation brines, long-term thermal stability, and permeability reduction ability were evaluated to account for the feasibility of gel application. Results showed that as the mass ratio of PAC and urea increased, the gelation time increased and the degree of syneresis decreased. The gelation time and the degree of syneresis decreased with the increase of sodium sulfate concentration, which indicated that sodium sulfate could play a role in accelerating gelation and inhibiting gel syneresis. The gelation time decreased with increasing temperature. The gel could tolerate sodium chloride concentration up to 150 g·L−1 and calcium chloride concentration up to 25 g·L−1. After aging for 120 days at 130 °C, no syneresis was observed in gel samples, which indicated that the gel had good, long-term thermal stability. The gel had good permeability reduction ability and was effective in plugging high permeability zone. Thus, these results indicated that the improved inorganic gel could be a potential candidate for conformance control under harsh reservoir conditions.

Morphological Controlled Growth of Nanosized Boehmite with Enhanced Aspect Ratios in an Organic Additive-Free Cationic–Anionic Double Hydrolysis Method

Well-crystallized boehmite nanoparticles showing different sizes and morphologies were fabricated in an organic additive-free cationic–anionic double hydrolysis method using inorganic aluminum chloride salt and sodium aluminate as dual aluminum sources. By adjusting the molar ratios of Al3+/AlO2– in the synthesis recipe, the boehmite particles’ shapes could be controllably tuned from two-dimensional flakes to one-dimensional (1D) rods, needles, and even fibers with enhanced particles’ aspect ratios. Through X-ray diffraction and high resolution transmission electron microscopy measurements, details of the microstructural features for boehmite particles were gained, and thus the growth habits are discussed, where in strong alkaline synthesis medium with a low Al3+/AlO2– molar ratio, dispersed nanoflakes grew with (010) and (101) faces as basal and lateral surfaces, while 1D nanoparticles, i.e. nanorods, nanoneedles, and nanofibers preferentially grew along the [100] direction with (100) and (101) faces une...

Preparation of large pore volume γ-alumina and its performance as catalyst support in phenol hydroxylation

Alumina was synthesized from Al(NO3)3, AlCl3 and Al3(SO4)2 with NaOH, and from NaAlO2 with HNO3 by addition of acidic solution to alkaline solution with a syringe pump. The as-produced Al2O3 precursors were supercritically dried and calcined at 500 °C to obtain mesoporous γ-alumina material. Results showed that all the inorganic aluminum salts could be used to synthesize high pore volume γ-alumina by controlling the precursor addition rate at room temperature and supercritical CO2 drying. However, the γ-alumina with the largest pore volume (5.4 cm3/g), BET surface area (423.7 m2/g) and pore size (37.8 nm) was obtained using Al(NO3)3 and NaOH. This γ-alumina was further used as a support for Fe-based catalyst with hydrogen peroxide to produce hydroquinone and catechol in the phenol hydroxylation reaction in 30 min at 80 °C. The conversion of phenol was 53.4% whereas the selectivity to dihydroxybenzenes-DHBs (hydroquinone-HQ and catechol-CAT) was as high as 96.2%, revealing that the larger pore volume takes effect in the γ-alumina as support for the Fe-based catalyst in the hydroxylation reaction, and that the γ-alumina may be a good candidate as the support for other important catalysts such as those used in the petroleum refining industry.

Application of lime (CaCO3) to promote forest recovery from severe acidification increases potential for earthworm invasion

The application of lime (calcium carbonate) may be a cost-effective strategy to promote forest ecosystem recovery from acid impairment, under contemporary low levels of acidic deposition. However, liming acidified soils may create more suitable habitat for invasive earthworms that cause significant damage to forest floor communities and may disrupt ecosystem processes. We investigated the potential effects of liming in acidified soils where earthworms are rare in conjunction with a whole-ecosystem liming experiment in the chronically acidified forests of the western Adirondacks (USA). Using a microcosm experiment that replicated the whole-ecosystem treatment, we evaluated effects of soil liming on Lumbricus terrestris survivorship and biomass growth. We found that a moderate lime application (raising pH from 3.1 to 3.7) dramatically increased survival and biomass of L. terrestris, likely via increases in soil pH and associated reductions in inorganic aluminum, a known toxin. Very few L. terrestris individuals survived in unlimed soils, whereas earthworms in limed soils survived, grew, and rapidly consumed leaf litter. We supplemented this experiment with field surveys of extant earthworm communities along a gradient of soil pH in Adirondack hardwood forests, ranging from severely acidified (pH<3) to well-buffered (pH>5). In the field, no earthworms were observed where soil pH<3.6. Abundance and species richness of earthworms was greatest in areas where soil pH>4.4 and human dispersal vectors, including proximity to roads and public fishing access, were most prevalent. Overall our results suggest that moderate lime additions can be sufficient to increase earthworm invasion risk where dispersal vectors are present.

Fixed dose aluminum sulfate treatment to eradicate the salmon parasite Gyrodactylus salaris: effects on benthic macroinvertebrates

Gyrodactylus salaris is an ectoparasite invasive to Norway that is highly virulent to pre-smolt stages of Atlantic salmon (Salmo salar). To eliminate the parasite without killing the salmon host, aqueous aluminum sulfate and sulfuric acid (AlS treatment) have been applied to infested rivers for short durations. When the River Lærdalselva and its tributaries were treated in the summer of 2012, we studied communities of macroinvertebrates in a small stream that received AlS for 18 days. We monitored pH, inorganic aluminum (Ali) and collected quantitative samples of macroinvertebrates. Concentrations of inorganic aluminum (Ali) were generally in the range of 20–50 µg/L, but episodes up to 95 µg/L were recorded. Six of the fourteen recorded macroinvertebrate taxa were, to some degree, negatively affected by the treatment. The acid sensitive ephemeropterans Baetis subalpinus and Baetis rhodani were almost eliminated from the treated site (p < 0.001 for both compared to the untreated site). Halfway into the treatment, abundances of Baetis were approximately 15 individuals per m2 at the treated site. Densities of Baetis at the untreated site were above 250 individuals per m2 throughout the treatment. The plecopteran Isoperla grammatica, the trichopteran Rhyacophila nubila, and the dipterans Chironomidae and Simuliidae also responded to the treatment, but the effects were not as prominent as for Baetis. For R. nubila and I. grammatica, the decline in population sizes could be a behavioral response related to lower prey densities (Baetis, Simuliidae, and Chironomidae). The reduction of Baetis led to a prominent reduction in the number of grazers and scrapers and gatherers/collectors (p = 0.004 for both groups). No such responses were found for the other feeding groups. Significant reductions in populations of Baetis can affect ecosystem functioning and, thereby, have implications for pre-smolt survival following AlS treatments.

Chitosan as a Drinking Water Treatment Coagulant

Inorganic aluminum or iron salts have been used for many decades to coagulate colloidal particles in surface water prior to flocculation, sedimentation and/or filtration. Although effective, inorganic coagulants have several disadvantages including large chemical dosages required for treating eutrophic waters, large volumes of chemical sludge produced, and toxic effects of metallic coagulants on the aquatic environment. Chitosan is a natural cellulose-like copolymer of glucosamine and N-acetyl-glucosamine. Because of their biodegradability chitosan-based materials have been suggested as a more eco-friendly coagulant for water and wastewater treatment. Chitosan was an effective coagulant in several prior laboratory studies. Practical application of chitosan as a drinking water treatment coagulant is evaluated here through a series of jar tests. The effectiveness of chitosan is compared to aluminum sulphate and ferric chloride with regard to treatment of algal-ladened waters. The optimum chemical dose for coagulation, optimum pH, and effectiveness for algae removal was determined for each coagulant. Practical aspects of applying chitosan at full-scale and the impact of feeding this chemical on overall treated water quality are addressed.

Template-free synthesis of mesoporous γ-alumina with tunable structural properties

Mesoporous γ-Al2O3 (MA) with agglomerated nanoparticles was successfully synthesized by using aluminum sulfate as inorganic Al resource, and hexamethylene tetramine (HMTA) as precipitant without using any surfactants, via a hydrothermal method. All the experimental processes experienced the hydrolysis, precipitation and calcination steps. The structural and morphological properties of uncalcined and calcined samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry differential thermal gravity (TG-DTG) and N2 adsorption–desorption. The bulk density of the sample is 0.682cm3g−1, and the specific surface area is 273.302m2g−1. The pore diameters (7.1nm and 9.7nm) indicate that a typical bimodal mesoporous structure was formed within MA. In order to tune the structural properties of MA, various kinds of inorganic aluminum sources and precipitating agents were employed to carry out contrast experiments, which leaded to regular variations in the specific surface area (200.898–273.302m2g−1), pore volume (0.121–1.327cm3g−1) and pore size (3.7–35.9nm). At the same time, the experimental results also demonstrated that the various kinds of Al resources and precipitants had no effects on the crystal structure of MA. However, the morphologies of samples, such as nanoparticles, short fibers, flower-like and block-shaped, can be controlled effectively. The present study provides a simple and effective approach for preparing MA, and the structural properties of MA can be controlled precisely by carefully choosing aluminum sources and precipitants. The approach of this work not only allows us to investigate the growth mechanism of the final product, but also reduces cost and the environmental pollution effectively than other template methods.

高水热稳定有序介孔Al-SBA-15材料的优化合成及表征

借助无机铝盐自水解所产生的弱酸性环境,通过改变水热处理温度及无机铝盐的引入种类和引入量来调控合成体系中Al-OH及材料孔壁中Si-OH的相对含量,在不引入矿物质强酸的条件下,一步合成了具有高Al引入量且孔壁硅、铝物种达到原子水平均匀分散的Al-SBA-15介孔材料.表征结果表明,当以硝酸铝为铝源,水热处理温度和投料硅铝比分别为140℃和10时,所得样品具有高度有序的二维六方介孔结构及较高的水热稳定性,在经800℃高温水蒸气处理2 h后,其介孔比表面积和孔体积仅分别降低了18.82%和16.67%.此外,骨架Al的引入使所得样品同时具有B酸和L酸中心,且具有相对较强的酸性,在异丙苯催化裂化反应中表现出明显活性.

A facile route to aqueous phase synthesis of mesoporous alumina with controllable structural properties

Mesoporous aluminas (MAs) with tunable structural properties, including BET surface area, pore volume and pore size, were successfully synthesized based on a sol–gel process via hydrolysis of aluminium isopropoxide associated with a structure-directing agent (SDA) as template in an acidic aqueous system. The effect of template type, template addition amount and inorganic aluminium precursor doping on the structural properties of the resulting MAs were systematically investigated. Four templates, including two non-ionic triblock copolymers P123 and F127, an amine based cationic quaternary surfactant cetyltrimethylammonium bromide (CTAB) and an anionic surfactant sodium dodecyl sulfate (SDS) were examined at varying amount. Three inorganic aluminium precursors, viz aluminium sulfate, aluminium nitrate and aluminium chloride, were used as the substitution aluminium sources to aluminium isopropoxide. The MAs synthesized were characterized using thermogravimetry – differential thermal analysis (TG–DTA) for decomposition and mass loss characteristics upon calcination, X-ray diffraction (XRD) for bulk crystallinity, transmission electron microscopy (TEM) for nano-scale morphology and N2 physisorption techniques for porous structural properties. For a given SDA, increasing the amount of surfactant addition markedly improved the porosity of the MA synthesized. In terms of the ability to influence the structural properties of the resulting MAs such as BET surface area, pore volume and pore size, the SDAs tested followed a descending order of F127 > P123 > CTAB > SDS. MAs with the greatest pore volumes and pore sizes with narrow PSDs were obtained when the doping ratios of Al(NO3)3, AlCl3 and Al2(SO4)3 were 15%, 30% and 2%, respectively. Depending on the type and addition amount of SDA and the aluminium precursor composition, the BET surface area, pore volume and pore size of MAs could be adjusted in the ranges of 178 m2 g−1 ∼ 358 m2 g−1, 0.4 cm3 g−1 ∼ 1.9 cm3 g−1 and 5.5 nm–30.1 nm, respectively.

NEW TYPE OF ECOLOGICALLY CLEAN SMALL-SCALE POWER PLANTS BASED ON FAST COMBUSTION OF WATER-ALUMINUM SUSPENSION AND BIOGAS COMBUSTION IN MATRIX BURNERS

The paper describes the new type of highly effective ecologically clean small-scale power plants that use renewable energy resources of both organic and inorganic origin, notably biogas and aluminum. The oxidation of aluminum in water suspensions proceeds in combustion wave in high temperature reactor at pressures up to 100 atm and temperatures 2500-3000 o C. The process let separate generation of hydrogen and high temperature steam. The first stage involves the combustion of water-aluminum suspension of stoichiometric composition with the production of hydrogen and rigid frame of very hot aluminum oxide. At the second stage after hydrogen removing the additional portion of water is introduced into reactor. At the interaction with hot aluminum oxide this water converts to high temperature steam. After aluminum oxide removing the process can be repeated. Such process enables us to escape the penetration of highly dispersed corundum particles in power plant. As a combustor for low calorific biogas a volumetric matrix burner is used. The possibility of stable combustion of low calorific biogas in such combine power plant is provided both by the peculiarities of matrix combustors and addition of hydrogen generated at the combustion of water-aluminum suspension. Thus, such combination enables us to use two different types of renewable energy sources in combined device. At that, aluminum oxidation produces hydrogen that provides sustained combustion of low calorific biogas in matrix burner for ecologically clean distributed power generation from renewable sources.