Soluble Aluminum Research Articles

Treatment of Industrial Electroplating Wastewater by Electrochemical Coagulation Using Carbon and Aluminum Electrodes

Electroplating wastewater is considered one of the most hazardous liquid wastes due to the presence of high contraction of toxic metals. Consequently, treatment of such wastewater is essential to protect the environment and waterways. Heavy metal ions are frequently of high toxicity and require treatment to the allowable standards for wastewater discharge. Electrochemical methods are more suitable for heavy metals removal due to their ability to reduce metal concentration to less than the permissible limits as well as allowing recovery of valuable metals. The aim of the present study is treatment of real electroplating wastewater. For this purpose, synthetic as well as real electroplating wastewaters were examined using soluble aluminium electrodes and insoluble carbon electrode along with ferric chloride and / or alum as coagulants. Factors affecting this treatment process were studied extensively, namely: current intensity, material of the electrode, pH and time. The obtained results proved that the best removal was achieved at 30 minutes and a potential difference 15 volt for aluminum electrode and 10 volts for carbon electrode. The later was combined with ferric chloride as coagulant. When the synthetic solution was examined by using aluminum electrode, the removal rate reached 97.2%, 97% and 96% for Zn, Cu, and Ni, respectively. By using carbon electrode in combination with ferric chloride, the respective removal rate reached 97.5%, 97.2% and 97.1%. By using the real electroplating wastewater and aluminum electrode, the removal rate reached 80%, 76.6% and 93.4% for Zn, Cu, and Ni respectively and by using carbon electrode and ferric chloride the achieved removal rate was 81.6%, 77.3% and 94.4% successively. It was concluded that the use of carbon electrode with FeCl3 is more suitable than aluminum electrode due to the dissolution of aluminum ions from electrode into the solution.

An ultrathin melted layer on magnesium alloy manufactured by low power laser

Low power Yb-fibre laser surface melting (LSM) was applied to modify the AZ31B magnesium alloy. The LSM treated samples presented poor formation qualities when the laser power was lower than 80 W. Samples without obvious macro-defects were obtained as the laser power higher than 88 W. The thickness of each melted layer was less than 125 μm. The grains of melted layer were refined and the solid solubility of aluminum increased. The average microhardness of the LSM treated samples was improved 37.7%. The corrosion resistance of LSM treated samples was raised by an order for magnitude and the wear resistance was improved 33% when the laser power was 104 W.

Corrosion Behavior of Die-Cast and Friction Stir-Processed AZ91 Magnesium Alloys in 5% NaCl

Corrosion resistance and microstructure by optical microscopy of commercially available die-cast, friction stir-processed (without aluminum powder) and friction stir-processed (with aluminum powder) AZ91 magnesium (Mg) alloys (three conditions) were investigated. For corrosion study, salt spray and immersion tests in 5% NaCl solution were carried out. Corrosion behavior was analyzed by scanning electron microscopy for investigation of pits available after 48 h in specimens of all three conditions. This SEM investigation proved that AZ91 Mg alloy that is friction stir-processed with aluminum powder has the lowest pit size compared to the friction stir-processed AZ91 Mg alloy and commercially available die-cast AZ91 Mg alloy. This is because of more solubility of aluminum in α-phase and high fraction of β-phase (Mg17Al12) which improves corrosion resistance of friction stir-processed AZ91 Mg alloy with aluminum powder.

Thermodynamic modelling of fluids from surficial to mantle conditions

Carbon is subducted to depths where metamorphism liberates water-bearing fluids. The C-bearing fluids facilitate partial melting of the upper mantle, generating magmas that may erupt as arc volcanics. Degassing of the magmas releases CO 2 and other volatile species to the atmosphere. Over geological time, this process contributes to the composition of the atmosphere and planetary habitability. Here I summarize the background needed to carry out theoretical geochemical modelling of fluids and fluid–rock interactions from surficial conditions into the upper mantle. A description of the general criteria for predicting equilibrium and non-equilibrium chemical reactions is followed by a summary of how the thermodynamic activities of species are related to measurable concentrations through standard states and activity coefficients. Specific examples at ambient conditions involving dilute water are detailed. The concept of aqueous speciation and how it can be calculated arises from this discussion. Next, I discuss how to calculate standard Gibbs free energies and aqueous activity coefficients at elevated temperatures and pressures. The revised Helgeson–Kirkham–Flowers equations of state are summarized and the revised predictive correlations for the estimation of equation of state coefficients in the Deep Earth Water (DEW) model are presented. Finally, the DEW model is applied to the solubility and speciation of aqueous aluminium.

Feasibility of aluminum recovery and MgAl2O4 spinel synthesis from secondary aluminum dross

The feasibility of aluminum recovery from secondary aluminum dross by extraction with NaOH solution and the subsequent synthesis of MgAl2O4 spinel by sintering the extracted slag were studied. The extraction percentage of soluble aluminum from the dross reached 80% at a temperature of 353 K, liquid-to-solid ratio of 12 mL·g−1, stirring speed of 300 r·min−1, and an extraction time of 15 min; the hydrolysis percentage of AlN reached 40% with an extraction time of 30 min. The activation energies of the soluble aluminum and AlN extracted from the dross were 7.15 and 8.98 kJ·mol−1, respectively, indicating that their kinetics were controlled by outer diffusion without a product layer. The extracted slag was sintered in the temperature range 1373–1773 K; MgAl2O4 spinel with a compressive strength as high as 69.4 MPa was produced in the sample sintered at 1673 K for 3 h. This value exceeds the threshold (40 MPa) prescribed by the National Standard for the Magnesia and Magnesia−alumina Refractory Bricks of China (GB/T 2275–2007). These results establish the effectiveness of aluminum recovery from secondary aluminum dross and subsequent MgAl2O4 spinel synthesis.

A novel process for the selective precipitation of valuable metals from lepidolite

The treatment of lepidolite by a multistage leaching process was studied for the extraction of alkali metals as alkali alums and brines. The precipitation characteristics of the aluminum and fluorine in the solution were also investigated. The transformation of the mineralogical species in lepidolite into albite and silicon dioxide was tentatively identified by X-ray diffraction measurements. The crystallization was aimed at the separation of rubidium and cesium from an acidic solution containing potassium as the main contaminant. The alum mixture contained on average 7.5% potassium, 1.3% rubidium and 0.30% cesium. The main crystalline components were aluminum sulfate and AlF(SO4)·5H2O after concentration. The aluminum in the solution was removed by adding potassium sulfate with a K/Al mole ratio of 2 at various pHs to yield an overall aluminum precipitation of 62.1–66.6%. Under weakly acidic and neutral conditions, soluble aluminum may transform into insoluble aluminum, such as Al(OH)3. Additionally, soluble AlFx(3−x)+ species tended to precipitate directly with OH−, thereby achieving the formation of Al-OH-F complexes. The AlFx(3−x)+ species at high pH were partially dissociated into F− and AlOH2+, Al(OH)2+ and Al(OH)4−, and the buffering effect of F− inhibited the transformation of the precipitated Al(OH)3 into soluble aluminates due to the formation of Al-OH-F complexes. The residual aluminum and fluorine contents were on average 0.0065 g/L and 0.042 g/L, respectively, in the mother liquor after neutralization at pH 9. The loss of lithium increased from 1.1% to 5.4% as the pH increased from 5 to 9. These findings imply that aluminum and fluorine can play significant roles in the recovery of alkali metals from lepidolite, and the precipitation of aluminum from leaching solutions as alums can cause a loss of lithium.

Aluminium release by coated and uncoated fluid-warming devices.

The use of fluid-warming systems is recommended for infusion rates >500ml.h-1 to avoid peri-operative hypothermia. Some fluid-warming devices use disposable aluminium-heated plates for heat transfer, but there is no protective coating to separate the fluid from the heated aluminium surface. It is unknown if this could promote release of aluminium into infusion fluids. We investigated a coated (Fluido compact) and an uncoated (enFlow) fluid-warming device using normal saline or balanced electrolyte solution as infusion fluids, pumped through the heated disposables at flow rates of 2, 4 and 8ml.min-1 for 60min each. Aluminium concentrations in the fluid samples were analysed using graphite furnace atomic absorption spectrometry. With saline the coated and uncoated devices yielded aluminium concentrations below the level of quantification (<128μg.l-1 ). Similarly, balanced electrolyte solution in the coated device yielded aluminium concentrations <128μg.l-1 . However, balanced electrolyte solution in the uncoated device yielded aluminium concentrations of up to 6794 (3465-8002 [1868-7421]) μg.l-1 . Repeating this last study at a flow rate of 2ml.min-1 resulted in quite high aluminium concentrations when the uncoated device was not heated (~1000μg.l-1 ) and higher concentrations after the device was heated. We conclude that using uncoated aluminium plates in fluid-warming systems can lead to a risk of administering potentially harmful concentrations of aluminium when balanced crystalloid solutions are used. The mechanism is unclear, but heat is in part involved. Coating for aluminium within medical devices in direct contact with infusion fluids should be recommended.

Column Bioleaching of Fluoride-Containing Secondary Copper Sulfide Ores: Experiments With Sulfobacillus thermosulfidooxidans.

Bioleaching is a mature technology, which is widely employed commercially in the leaching of primary sources of metals (ores, concentrates, and mine residues). The current work discussed the effects of aluminum sulfate additions to the growth medium, PLS recirculation and bleeding on the column bioleaching of secondary copper sulfide ores with a significant content of fluoride-containing minerals. Fluoride is toxic to bacteria at the pH of bioleaching but its toxicity may be overcome in the presence of soluble aluminum and ferric iron. Therefore, experiments were carried out in 10 × 100 cm height aerated columns, loaded with 10 kg of crushed and agglomerated copper ore and inoculated with Sulfobacillus thermosulfidooxidans. Initially, fluoride concentrations of up to 2.5 g/L in the pregnant leach solution were observed due to the fast dissolution of fluoride-bearing minerals. Aluminum was added to the leaching solution to reduce the Al/F ratio so that the concentration of HF (the main toxic species) was decreased, but while the total fluoride concentration was higher than that of aluminum, the bacterial population as low. Therefore, the current work emphasizes that it is possible to set up conditions to enable bioleaching even at high fluoride concentrations. Following this approach, copper extractions above 90% were achieved for a H2SO4 consumption ranging from 128.8 to 206.1 Kg/ton.

The effect of understory on cation binding reactions and aluminium behaviour in acidic soils under spruce forest stands (Southern Poland)

Acidic forest soils with two dominant understories, bilberry (Vaccinium myrtillus L.) or alpine lady fern (Athyrium distentifolium Tausch ex Opiz), have been investigated to evaluate the influence of the understory on sorption properties and aluminium behaviour. We investigated acidity, cation exchange properties, organic matter content (SOM) and quality as well as Al bonding to organic matter in humus horizons of soils taken from two different locations. SOM was the major contributor to total cation exchange capacity (CECt) and effective cation exchange capacity (CECe), and a strong relationship was found between SOM and both CECt and CECe, independently of the understory and location. SOM differed in quality, having more fulvic acids in soils under bilberry than in soils under alpine lady fern. For that reason, SOM in soils under bilberry complexed more Al in the exchangeable form in the soluble fulvic acid fraction such that they could be easily washed out, while in soils under alpine lady fern aluminium was mainly bound more stably. We also found that the chemical character of Al depended on the understory type. In soils under bilberry the relation between base saturation and pH could be successfully modelled by a modified Henderson–Hasselbalch equation when Al was considered as a base cation, which is typical for forest podzols. However, in soils under alpine lady fern, this model was efficient only when Al was treated as an acid cation. We concluded that alpine lady fern as the main understory species reduces solubility and potential toxicity of aluminium, thus significantly affecting soil biogeochemistry.

Sustainable alkaline activation of fly ash, aluminium anodising sludge and glass powder blends with a recycled alkaline cleaning solution

Introduction of new residues and wastes in the development of alkaline activated materials is a major concern regarding the spreading and dissemination of this technique. Such increase in the spectrum of available raw materials will decrease the need for long-distance transportation of the more traditional precursors that have been tirelessly used in the past two decades (e.g. fly ash, blast furnace slag). Additionally, the use of commercial activators severely hinders its environmental and financial performance, promoting the need to develop waste-based activators. In this paper, wastes from the aluminium anodising and extrusion processes and from the production of optical lenses were combined with low-calcium fly ash, to produce binders exclusively made from wastes and residues. The performance was assessed through uniaxial compression strength tests, which were accompanied by the monitorisation of several physical properties, including temperature, pH and weight; and by a thorough microscopic analysis, including scanning electron microscopy, coupled with energy dispersive spectroscopy, and x-ray diffraction, for mineralogy characterisation. Results show that the addition of glass powder and aluminium anodising sludge to class-F fly ash optimised the final precursor, which was then successfully activated with a disposed solution, originally used to clean the aluminium extrusion steel dies. The inclusion of soluble silicon and aluminium in the precursor raised the compression strength after short-term curing, compared with pastes prepared only with fly ash.

Development of Accident-Tolerant FeCrAl Steels Containing Al2O3 Particles by Means of Internal Al Oxidation

FeCrAl ferritic steels containing dispersed Al2O3 particles instead of Y2O3 or Ce2O3 particles were developed for accident-tolerant fuel cladding in light-water reactors. Forcible addition of only oxygen through mechanical alloying can create Al2O3 particles by precipitation during annealing above 973 K. The oxygen content was controlled to use oxidation of internal aluminum to form Al2O3 particles and increase the number density of Al2O3 particles with an average diameter of around 40 nm. The size and number density of Al2O3 particles are significantly affected by lattice misfit, and thus interfacial energy between Al2O3 particles and the matrix, and by aluminum solubility into the ferrite matrix. The estimated Al2O3 particle strengthening stress is consistent with measured tensile stress at 973 K. Both stresses are slightly improved with increasing oxygen content, but are half the level of that in steel strengthened by Ce2O3 and CeAlO3 particles.

Mitigation of ASR expansion in concrete using ultra-fine coal bottom ash

The focus of this study is to both quantitatively and qualitatively assess the effectiveness of pulverized ultra-fine bottom ash as a cement replacement to mitigate the detrimental effects of alkali-silica reaction (ASR). Raw landfilled coal bottom ash was pulverized using a vibratory ball-mill at two different fineness levels. The pulverized bottom ash was used as a cement replacement in a mortar mix at various replacement rates (9, 23, 33 and 41%). The expansion of the pulverized bottom ash blended mortars were found to be 10% higher than the fly ash control specimens after normalization of the chemical composition. FTIR spectroscopy also revealed more polymerization in the pulverized bottom ash mixes than the FA mixes; but much lower than the control Portland cement mix. Overall, it is observed that the pulverized bottom ash can serve as an ASR mitigating cementitious material but is slightly less effective than class F fly ash most likely due to lower reactivity, and less solubility of alumina and silica.

PERBAIKAN PRODUKSI TANAMAN JAGUNG PADA ULTISOL MENGGUNAKAN ABU TERBANG BATUBARA DAN KOMPOS TANDAN KOSONG KELAPA SAWIT

The potential of Ultisols, especially in East Kalimantan for the development of food crop agriculture is faced with constraints on phosphorus availability due to low soil pH and high solubility of aluminum (Al). The purpose of this study was to elucidate the effect of a combination application of coal fly ash (CFA) and oil palm empty fruit bunches (OPEFB) on the availability of phosphorus in an Ultisol from East Kalimantan and its impact on the production of maize. The combination of CFA and OPEFB consisted of seven treatments with three replications. The research was carried out in two steps. The first experiment (incubation in the laboratory), was carried out under non-leaching condition for 42 days. Parameters observed included soil pH, available soil P, total soil P, and soil exchangeable Al. The second experiment (growth experiments in a glasshouse), was were carried out by growing maize plants with the same treatment as for experiment 1. The plant height and leaf area were observed every week. At the harvest time (age 12 weeks), dry weight of shoots and roots, maize weight with cobs, and maize weight without cobs were observed. The results of soil incubation showed the decrease in the soil exchangeable Al- level, the increase in soil total-P, and soil available-P. The combination application of CFA and OPEFB did not have a significant impact on soil pH, and soil organic-C. The results of the glasshouse experiment showed that CFA and OPEFB were not significantly different in the parameters of plant height, leaf area of 12 weeks, weight of shoots and roots, maize weight with cobs, and maize weight without cobs.

Development of a High-Strength Soluble Aluminum Alloy and Its Application in Oil Pressure Cracking

A method for hydraulic fracturing of a formation that includes injection of a fracturing fluid with sealing balls to reduce filtration of the fracturing fluid is known. The balls are selected so that fissures into which fracturing fluid is diverted are reliably sealed temporarily. The problem of sluicing and returning the balls arises when the well is put into operation. Steel balls or high-molecular-mass polymeric materials are currently most widely used. Sluicing high-density steel balls is difficult. Polymer balls are easily deformed so they are also difficult to return. The present work proposes the use of aluminum-alloy balls and studies the electrochemical dissolution mechanism of the material in the formation. The developed aluminum-alloy balls had rather good solubility and high mechanical properties. Use of sealing balls made of this material provided effective transfer of the working pressure during hydrofracturing and avoided the problem of returning the balls. Also, high-strength alloys that can be dissolved could find applications in various fields.

Exchanges of nitrogen and phosphorus across the sediment-water interface influenced by the external suspended particulate matter and the residual matter after dredging

Dredging is frequently implemented for the reduction of internal nitrogen (N) and phosphorus (P) loadings and the control of eutrophication. Residuals during dredging activities and external pollution loadings after dredging both commonly contribute to influence the effectiveness of dredging and have been widely discussed. In the current study, the exchanges of N and P across the sediment-water interface (SWI) to these two factors were compared in a six-month field incubation experiment. The results showed that the continuous deposition of external suspended particulate matter (SPM) led ammonium nitrogen (NH4+N) and soluble reactive phosphorus (SRP) fluxes across the newly formed SWI to increase by factors of 4.16 and 12.71, respectively, while residual material caused the same fluxes to increase by factors of 2.06 and 5.06. Both the deposition of external SPM and the residual matter led to higher increase of the fluxes of P across the SWI than those of the fluxes of N across the SWI after dredging. The SPM easily adsorbed P in the water due to extensive adsorption of water soluble organic matter (consisting primarily of easily-decomposed humic-like substances), iron, and aluminum. However, the decomposition of organic matter in the SPM after the deposition on the dredged sediment accelerated the dissolution of redox-sensitive P and organic P across the SWI after dredging. Both the increase in the fluxes of N and P across the SWI would further increase the concentrations of N and P in the overlying water and thereby aggravate the eutrophication status in lakes. More frequent dredging operations might be necessary to reduce the fluxes of N and P from the sediment due to the continuous influence of the external SPM and the residual matter.

Influence of calcium nitrate on morphology and corrosion characteristics of ammonium phosphate treated Aluminum coating deposited by arc thermal spraying process

In present study Al coating was deposited by arc thermal spraying process thereafter treated with different concentration of Ammonium phosphate mono basic (NH4H2PO4) and 0.1 M calcium nitrate [Ca(NO3)2] to fill the porosity. Impedance values of treated coating was increased at longer duration of exposure in artificial ocean water due to transformation of Brushite and Ammonium Aluminum hydrogen phosphate hydrate into metastable and sparingly soluble gypsum and Aluminum phosphate. 0.1 M Ca(NO3)2 has positive influenced with 1 M NH4H2PO4 on formation of compact and crystalline morphology as well as corrosion resistance of Al coating.

The influence of liquid type with grain size on the soil properties in hybrid corn growth

Liming activity is an effort to raise the soil pH so that the reaction is not acidic. Most of the plants are less tolerant of acidic soil (pH <7). Because acidic soil causes solubility of Aluminum (Al), Manganese (Mn), and Iron (Fe). For example, when Al’s solubility is high, Al does not only poison the plant but causes the essential element phosphorus (P) in the soil to be fixed (bound) by the Al so that it cannot be absorbed by the plant. This study aims to determine the effect of lime types with grain size on soil properties and growth and production of hybrid corn. This study uses nonfaktorial randomized block design (RBD) which consists of two treatment factors, namely the type of agricultural lime which is divided into 2 treatment levels, namely D1: Dolomite and D2: Calcite, each type is divided into 3 sizes namely: D1-1 is passes 60 mesh filter, D1-2 is passes 80 mesh filter, D2-1 is passes 60 mesh filter, D2-2 is passes 80 mesh filter. Thus, 4 treatments will be repeated 3 times, so that there will be 12 experimental units. Each experimental unit consists of 3 polybags, so that 36 polybags will be obtained. And in each experimental unit there were 2 sample plants. The results showed that lime treatment significantly affected plant height, wet weight of straw, ear length, ear diameter and ear weight per plant, but had no significant effect on the number of leaves, leaf area index, and flowering age.

Effect of Sulfur and Acid Soluble Aluminum Content on Precipitate and Microstructure of Grain-Oriented Silicon Steel

Effect of Sulfur and Acid Soluble Aluminum Content on Precipitate and Microstructure of Grain-Oriented Silicon Steel

Uptake and molecular impact of aluminum-containing nanomaterials on human intestinal caco-2 cells

Aluminum (Al) is one of the most common elements in the earth crust and increasingly used in food, consumer products and packaging. Its hazard potential for humans is still not completely understood. Besides the metallic form, Al also exists as mineral, including the insoluble oxide, and in soluble ionic forms. Representatives of these three species, namely a metallic and an oxidic species of Al-containing nanoparticles and soluble aluminum chloride, were applied to human intestinal cell lines as models for the intestinal barrier. We characterized physicochemical particle parameters, protein corona composition, ion release and cellular uptake. Different in vitro assays were performed to determine potential effects and molecular modes of action related to the individual chemical species. For a deeper insight into signaling processes, microarray transcriptome analyses followed by bioinformatic data analysis were employed. The particulate Al species showed different solubility in biological media. Metallic Al nanoparticles released more ions than Al2O3 nanoparticles, while AlCl3 showed a mixture of dissolved and agglomerated particulate entities in biological media. The protein corona composition differed between both nanoparticle species. Cellular uptake, investigated in transwell experiments, occurred predominantly in particulate form, whereas ionic Al was not taken up by intestinal cell lines. Transcellular transport was not observed. None of the Al species showed cytotoxic effects up to 200 µg Al/mL. The transcriptome analysis indicated mainly effects on oxidative stress pathways, xenobiotic metabolism and metal homeostasis. We have shown for the first time that intestinal cellular uptake of Al occurs preferably in the particle form, while toxicological effects appear to be ion-related.

Aluminium toxicokinetics after intramuscular, subcutaneous, and intravenous injection of Al citrate solution in rats.

Knowledge of dose linearity, plasma clearance, rate and extent of subcutaneous (SC) and intramuscular (IM) absorption of soluble aluminium (Al) citrate is considered a prerequisite for evaluation of toxicokinetic data obtained from SC or IM administration of Al adjuvants in medicinal products. Therefore, total Al plasma kinetics was investigated after SC, IM, and IV administration of single Al doses (36 and 360µg/kg IM or SC; 30 and 300µg/kg IV) given as citrate solution in rats. Control groups receiving vehicle (saline) were run in parallel to monitor background plasma Al levels over time resulting from dietary intake. Evaluation of Al plasma profiles was done by both non-compartmental analysis of baseline-corrected data and simultaneous model fitting to the raw data using a population kinetics approach. High anddose-independent total plasma clearance (6.6mL/min/kg) was observed after IV administration corresponding to 60-82% of normal rat GFR. This supports the previous assumptions that parenterally administered Al citrate is more rapidly cleared from plasma than other Al species (e.g., chloride or lactate). Furthermore, plasma exposure of Al (Cmax and AUC0-inf) increased dose-proportionally at all administration routes. Fast and complete absorption of Al was observed at each dose level after both SC and IM administration (bioavailability estimates: 88 and 110%). Estimates for the first-order absorption rate constant ka correspond to absorption half-lives of 36min (SC) and ≤ 13min (IM). There was no increase in tissue Al content (whole bone and brain) after 36µg/kg IM compared to control rats.