Presence Of Aluminum Ions Research Articles

Enhancing the Immobilization of Hexavalent Chromium by the Interlayer Anion Adsorption of the Brucite-Transformed LDH in the Presence of Aluminum Ions

Current studies of chromium adsorption kinetics at the solid–liquid interface often neglect the influence of coexisting ions in complex wastewaters. Thus, it is critical to explore the hexavalent chromium Cr(VI) adsorption kinetics of solid-phase brucite (Mg(OH)2) in liquid-phase wastewater containing coexisting aluminum ions (Al(III)). This paper reveals that the presence of Al(III) significantly enhanced the Cr(VI) adsorption efficiency onto Mg(OH)2, with a peak of up to 91% compared to 5% for the absence of Al(III). The main reason for this enhancement was the initial surface ternary complexation of Mg(OH)2 and the cationic (Al(III)) isomorphic substitution to form Mg(II)-Al(III) layered double hydroxides (LDH), which also indicates a solid-phase transition on the surface of Mg(OH)2, which led to electrostatic adsorption in the gallery and made Cr(VI) immobilized and not readily released. Further calculation and analysis of the adsorption energy confirmed the mechanism of Cr(VI) adsorption. It was also concluded that Cr(VI) migration in Mg(OH)2-containing minerals was affected by the phase transformation of solids in the presence of Al(III). Hence, this study not only reveals the adsorption mechanism during the treatment of composite pollutant wastewater but also provides the methodological reference for brucite synergistic adsorption to remove heavy metal ions and purify and treat complex polluted wastewater.

Inhibition of aluminum silicate scaling by phosphonate additives under geothermal stresses

The formation, precipitation, and deposition of so-called “aluminum silicate” in geothermal waters have been subjects of intense interest. Such scaling poses a severe threat to the smooth process of any water-supported industrial system that utilizes water that is high in both aluminum and silicate. The aim of our approach is the systematic study of the influence of phosphonate-based chemical additives on silica polycondensation chemistry in the presence of aluminum ions. The focus of this work is the prevention of “aluminum silicate” formation using a variety of well-known phosphonate additives. These are: 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), hydroxyethylidene-1,1-diphosphonic acid (HEDP), amino-tris(methylenephosphonic acid) (AMP), hexamethylenediamine-tetrakis(methylene-phosphonic acid) (HDTMP), diethylenetriamine-pentakis(methylene phosphonic acid) (DTPMP) and bishexamethylenetriamine-pentakis(methylenephosphonic acid) (BHMTPAMP). Inhibition experiments were carried out in solutions of silicate (150 ppm, expressed as SiO2) and aluminum (a variety of concentrations, as Al) at pH 7.0. The phosphonate additives used were found to act as stabilizing agents, most likely by complexing the Al3+ cations and, thus, preventing “aluminum silicate” formation. On the basis of a plethora of experimental data, a number of useful functional insights have been generated, which add to building a more complete and comprehensive picture of the mechanism of “aluminum silicate” formation and stabilization.

On-line carbon dots synthesis using flow injection analysis. Application to aluminium determination in water samples

An on-line synthesis of CDots is proposed for the first time, using the flow injection analysis (FIA) technique, which was coupled, in a single system, to the analytical determination of aluminium in water samples. The nanoparticles were obtained from the carbonization of glucose and iron(III) in an acidic medium, and their photoluminescence increased in the presence of aluminium ions. Under optimal experimental conditions, the proposed method has shown an acceptable linearity range –between 0.04 and 3.0 mg L−1 (R2 = 0.9999) – and a detection limit of 0.007 mg L−1. The analysis of drinking water and groundwater samples showed good accuracy (recoveries ranged between 91 – 113%) and RSD% < 13. The on-line system exhibited a high sample throughput (36 h−1), since no incubation time was required.

Understanding of the factors slowing down metakaolin reaction in limestone calcined clay cement (LC3) at late ages

Factors which could explain the slowing down of the metakaolin reaction in LC3 blends are investigated. Portlandite availability and the presence of aluminium ions in the pore solution are shown not to be limiting factors.Hydrates can only precipitate in solution filled pores. Internal relative humidity measurements indicate that at 28 days solution is present only in pores with radii below 13 nm. An enhancement of metakaolin reaction was obtained at late ages when the larger capillaries are filled with solution. The lower limit of the water filled pores was more difficult to analyse since there is a lack of precision in determining interfacial energies of hydrates and pore solution of the system. However, this study gives an indication of order of magnitude where the growth of hydrates could be slowed down.

Molecular Mechanisms Underlying Sugarcane Response to Aluminum Stress by RNA-Seq.

Some metals are beneficial to plants and contribute to critical physiological processes. Some metals, however, are not. The presence of aluminum ions (Al3+) can be very toxic, especially in acidic soils. Considerable parts of the world’s arable land are acidic in nature; mechanistically elucidating a plant’s response to aluminum stress is critical to mitigating this stress and improving the quality of plants. To identify the genes involved in sugarcane response to aluminum stress, we generated 372 million paired-end RNA sequencing reads from the roots of CTC-2 and RB855453, which are two contrasting cultivars. Data normalization resulted in 162,161 contigs (contiguous sequences) and 97,335 genes from a de novo transcriptome assembly (trinity genes). A total of 4858 and 1307 differently expressed genes (DEGs) for treatment versus control were identified for the CTC-2 and RB855453 cultivars, respectively. The DEGs were annotated into 34 functional categories. The majority of the genes were upregulated in the CTC-2 (tolerant cultivar) and downregulated in RB855453 (sensitive cultivar). Here, we present the first root transcriptome of sugarcane under aluminum stress. The results and conclusions of this study are a crucial launch pad for future genetic and genomic studies of sugarcane. The transcriptome analysis shows that sugarcane tolerance to aluminum may be explained by an efficient detoxification mechanism combined with lateral root formation and activation of redox enzymes. We also present a hypothetical model for aluminum tolerance in the CTC-2 cultivar.

Photoluminescence of Europium-Containing Materials Based on Fluorinated Yttria and Alumina

Luminescent materials have been prepared via thermal decomposition of a mixture of yttrium and europium trifluoroacetates and aluminum nitrate isolated from ethyl acetate, a low-polarity solvent. The influence of the composition of precursors and synthesis temperature on the composition, structure, and luminescence of the materials has been studied by vibrational and electronic spectroscopies, X-ray diffraction, and scanning electron microscopy. The results demonstrate that the major phases in the synthesized materials are (Y1 – хEux)F3, (Y1 – хEux)OF, and the (Y1 – хEux)2O3 ⋅ Al2O3 mixed oxide in various proportions. The percentage of fluorine atoms in the composition of europium-containing activator centers and the presence of aluminum ions influence the relative intensity of luminescence excitation and luminescence bands, the multiplicity of the 5D0 → 7F1,2,4 electron transitions (increasing it to the maximum value), the splitting energy of the strongest components of the 5D0 → 7F2 electron transition, and the efficiency of conversion of phonon energy in the oxide host to luminescence. The present results make it possible to synthesize materials with predictable spectral characteristics.

A phosphorescence “turn-on” probe for the detection and imaging of Al3+ based on aggregation-induced emission

Aggregation-induced emission luminogens (AIEgens) have been widely used to design fluorescent probes for chemosensing and bioimaging. However, it is still challenging to design long-lived AIE-active probes due to the lack of aggregation-induced phosphorescence (AIP) luminogens. In this work, we design and synthesize a long-lived molecular probe with aggregation-induced phosphorescence property for aluminum ion-specific detection by introducing multiple carboxylic acid groups in a unique twisted molecular skeleton, and develop a first phosphorescent detection method for aluminum ion based on aggregation-induced emission mechanism. The introduction of six carboxylic acid groups into the probe not only significantly enhances the water-solubility but also provides specific recognition unit for aluminum ions via complexation. The probe shows a very sharp emission enhancement in the presence of aluminum ions via aluminum ion-triggered aggregation-induced emission. The cytotoxicity test of the probe shows its biocompatible nature, and further imaging results in live human cells and roots of live Arabidopsis thaliana demonstrates that the designed AIP-active probe is capable of monitoring aluminum ions in complex biological systems. This work proposes a general design strategy for AIP-active probes, and provides valuable use of these AIP-active probes in bioimaging.

The Effect of Aluminum Ions on the Acidification and Aging of Paper

Paper documents provide important records of human civilization and so understanding the causes of paper document aging is very important to delay the process and prolong the lifespan of paper. This study used an anionic rosin as a sizing agent and aluminum sulphate as a fixing agent, to produce paper with different amounts of aluminum sulphate. The effect of different contents of aluminum ions on the acidification and aging of the paper was studied by accelerated aging experiments. The results showed that the presence of aluminum ions in paper could accelerate the acidification and aging process, and the higher the content of aluminum ions, the worse the durability of paper. In the process of accelerated aging, with increasing aluminum ion content, the rate of decline in the strength and whiteness of paper increased whilst the pH value decreased. Accelerated aging under the same conditions for 15 days caused the pH value, whiteness, tensile index and tear index of paper without aluminum ions to decrease by 14.77%, 3.15%, 7.99% and 11.70% respectively. In comparison, paper which had aluminum sulphate added to 30 kg per ton of paper, showed the decreases of pH, whiteness, tensile index and tear index by 22.62%, 4.35%, 24.66% and 31.07% respectively.

Control Valence and Luminescence Properties of Cerium Ions in Al2O3-SiO2 Glasses Prepared by Sol–Gel Method

In this study, the synthesis and luminescence properties (LP) of Al2O3-SiO2 glasses doped with different concentrations of Ce3+, namely, 0.05 mol.%, 0.1 mol.%, and 0.3 mol.% Ce3+, were investigated. The LP of the obtained samples were characterized by ultraviolet–visible absorption (UV–VIS) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and photoluminescence (PL) spectroscopy. The results showed that the valence states of the cerium ions can be controlled by heating the synthesized glasses in hydrogen atmosphere leading to change their LP. The existence of the absorption band at about 295 nm and of a broad band spectrum with a maximum at 250 nm can be attributed to Ce3+ ion and the charge transfer band of Ce4+ ion, respectively. A broad emission at 366 nm observed under excitation of UV light at 310 nm originated from the well-known 4f–5d transition of Ce3+ ion. The role of Al3+ ions is also considered when glass samples were treated under the hydrogen atmosphere. It is revealed that the presence of aluminum ions enabled controlling the valence states of cerium via the formation of OH bonds that can reduce Ce4+ to Ce3+ ions in glass sample treated in reduced atmosphere. The increasing of PL peaks appeared during the treatment under hydrogen atmosphere at high temperature.

Photo-stability of a flavonoid dye in presence of aluminium ions

The main colouring compounds of the dye plant weld (Reseda luteola L.) are the flavones luteolin (lut), lut-7-O-glucoside and lut-7,3ʹ-O-diglucoside. Alum (an aluminium salt)-premordanted wool dyed with weld leads to yellow colours that are of low resistance to light. The photo-stability of lut in aerated methanol–water 8:2 (v/v) solution upon irradiation with light above 300 nm was studied at different lut–Al3+ ratios. Experiments using extracts of weld to dye wool premordanted with increasing quantities of aluminium salts were also carried out. The photo-stability of lut in the polar protic solvent and the photo-resistance (light-fastness) of the colour of weld-dyed wool decrease with increasing concentrations of aluminium ions. Thus, the lower the [Al3+] used for mordanting the wool, the more light-fast its colour. Lowering the [Al3+] appears to have no negative influence on the wash-fastness of the colour. As the gain in light-fastness by the use of low [Al3+] to premordant the wool is not extensive, however, this does not seem to be a way to meet today's requirement of light-fastness of the colours of dyed textiles by itself. Nevertheless, it may be part of a bigger strategy to address the need for increased light-fastness of the colour of wool dyed with weld. Implementation of this approach by dyers is expected to clarify whether it results in benefits for textile dyeing practice.

Fabrication of chitosan/silver nanocomposite films and their fluorescence sensing of aluminum ions

A simple and efficient method for the fabrication of highly fluorescent chitosan/silver (CS/Ag) films is reported in this paper. The synthesis method uses NaBH4 as a reductant and involves less time and extremely mild experimental conditions. The structure, surface and fluorescence properties of the nano-sized CS/Ag films were investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy. Aluminium ion sensing was determined by and fluorescence intensity measurement. Fluorescence measurement by emission spectroscopy indicated that the emission wavelength of CS/Ag was 368 nm. Experimental results indicated that the fluorescence emission of the nanocomposite films was sensitive to the presence of aluminium ions, and a micro-amount of aluminium ions significantly increases the emissions. Under the optimum conditions, the fluorescence intensity of the films was linearly proportional to aluminium ion concentrations between 0 and 1·8 × 10−4 mol L−1. The films may be developed into sensors for aluminium ions.

Photoluminescence Determination of Aluminum Using Glutathione-Capped Gold Nanoclusters

ABSTRACTAluminum is a common metal that is used extensively in daily life. However, over-exposure to aluminum may result in nervous system-related diseases. Thus, it is important to develop a rapid sensing method that can be used to screen samples. In this study, glutathione-capped gold nanoclusters with bright photoluminescence were demonstrated to be effective sensing probes for aluminum ions. The photoluminescence of glutathione-capped gold nanoclusters was enhanced in the presence of aluminum ions. The results show that glutathione-capped gold nanoclusters selectively determined aluminum ions in samples prepared in aqueous ammonium acetate buffer (pH 5.5). The acetate maintains the pH and serves as a chelating agent to interact with non-analyte metal ions. Therefore, other metal ions have little effect on the photoluminescence of the glutathione-capped gold nanoclusters. The photoluminescence of the glutathione-capped gold nanoclusters was switched on in samples containing aluminum ions. The selective sensing was based on chelation between the aluminum ions and ligands on the surface of the glutathione-capped gold nanoclusters. The limit of detection was estimated to be as low as approximately 100 nM. The method was used to determine the concentration of aluminum ions in lake water and soil extracts.

Highly sensitive and selective fluorescent “turn-on” probe for determination of aluminum ion in aqueous solution

ABSTRACTA novel fluorescent sensor, 1-((2-hydroxynaphthalen-1-yl)methylene) semicarbazide, was synthesized and characterized by infrared spectra, elemental analysis, electrospray ionization mass spectra. The fluorescent sensing behaviors of the sensor toward different metals ions, anions, and amino acids were determined by UV–vis and fluorescence spectroscopy. The fluorescent sensor exhibited obvious changes in its electronic and fluorescent spectral behavior in the visible region of the spectrum in the presence of aluminum ion with the lower detection limit was 8.9 × 10−9 M.

The application of Zn–Al-hydrotalcite as a novel anodic material for Ni–Zn secondary cells

ZnAl–CO3 layered double hydroxides (LDHs) are prepared by the constant pH co-precipitation method in this study and proposed as a novel anodic material for Nickel–Zinc secondary cells. The as-prepared samples are well-crystallized and have the plate-like morphology. It is shown that the reversibility of the electrode reaction of the ZnAl-hydrotalcites is much better than that of ZnO electrode in alkaline system probably due to the lamellar structure of ZnAl-hydrotalcites and the presence of aluminum ions. In spite of a little lower specific capacity, Zn–Al-hydrotalcite electrode has more stable cycling performance, higher charge efficiency and utilization ratio in comparison with ZnO electrode. The effect of Zn/Al molar ratio on the electrochemical performance is investigated and ZnAl-hydrotalcites with Zn/Al molar ratio of 4:1 exhibit the best performance. It delivers an initial discharge capacity of 400 mAh g−1 and the capacity retention ratio of 92.7% over 50 cycles. This proves that ZnAl-hydrotalcites electrode is more stable than ZnO electrode in alkaline electrolyte, thus resulting in much better cycling stability.

Performance of laboratory-scale constructed wetlands coupled with micro-electric field for heavy metal-contaminating wastewater treatment

This study reports the performance of laboratory-scale constructed wetlands coupled with micro-electric field (CWMEF) planted cannas ( Canna generalis) for heavy metal-contaminating wastewater treatment. The CWMEF had a better performance for heavy metal (HM) removal from wastewater than did the ordinary constructed wetlands (CWs). Owing to the stimulation of the suitable voltage and electrical exposure time, cannas may grew better and in fact assimilated more metallic ions in CWMEF than in CWs. The environmental conditions in CWMEF, such as the higher pH by electrolysis of water, the presence of aluminum ions by anodizing of aluminum, caused chemical precipitation, physical adsorption and flocculation of metallic ions.

Contributions to Studies Concerning the Behaviour of Al (III) Ion in Some Biological Systems

The aim of this study is to bring personal contributions referring to the influence of aluminum ion (Al3+) on some biological systems. For this research the biological system was represented by an experimental design on domestic rabbits, working with three groups (one control group � C and two experimental groups � E1 and E2). The procedure was realized by aluminum solutions administration, with and without association of citrate to E1 and E2 groups, compared to control group. We followed the variation of some lipids in blood serum (total lipids, triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol), the iron and total capacity for binding iron from blood serum, but also the modification of the concentration of trace and macroelements from liver of experimental animals. In our study are also presented chemical interactions specific for oxidative stress, process owed to the presence of aluminum ion (Al3+), which cause variations in lipidic metabolism.

Synchronous fluorescence and UV–vis spectroscopic studies of interactions between the tetracycline antibiotic, aluminium ions and DNA with the aid of the Methylene Blue dye probe

Synchronous fluorescence spectroscopy (SFS) was applied for the investigation of interactions of the antibiotic, tetracycline (TC), with DNA in the presence of aluminium ions (Al 3+). The study was facilitated by the use of the Methylene Blue (MB) dye probe, and the interpretation of the spectral data with the aid of the chemometrics method, parallel factor analysis (PARAFAC). Three-way synchronous fluorescence analysis extracted the important optimum constant wavelength differences, Δ λ, and showed that for the TC–Al 3+–DNA, TC–Al 3+ and MB dye systems, the associated Δ λ values were different (Δ λ = 80, 75 and 30 nm, respectively). Subsequent PARAFAC analysis demonstrated the extraction of the equilibrium concentration profiles for the TC–Al 3+, TC–Al 3+–DNA and MB probe systems. This information is unobtainable by conventional means of data interpretation. The results indicated that the MB dye interacted with the TC–Al 3+–DNA surface complex, presumably via a reaction intermediate, TC–Al 3+–DNA–MB, leading to the displacement of the TC–Al 3+ by the incoming MB dye probe.

The influence of fluorides on mouse sperm capacitation

Increasing infertility, due to pathological changes on sperm, has become a serious issue. Eco-toxicological effect of rising concentration of fluorides can be enhanced in the presence of aluminium ions by forming fluorometallic complexes, analogues of phosphate groups that interfere with the activity of G-proteins and P-type ATPases, which are part of several signalling pathways during sperm maturation. In order for sperm to gain fertilizing ability, they must undergo in the female reproductive tract, capacitation that includes tyrosine phosphorylation and consequent actin polymerization. The present paper reports the findings of 3-month oral toxicity in mice of fluorides at the concentrations 0, 1, 10, and 100 ppm and their synergic action with aluminium at dose of 10 ppm. There were no mortalities, clinical signs of discomfort or body weight loss during the experiment. The analysis revealed, for the concentrations of 10 and 100 ppm, abnormalities of spermatogenesis and ability of epididymal spermatozoa to capacitate in vitro, as the result of decreased sperm head tyrosine phosphorylation and actin polymerization. The enhancing overload caused by fluorides represents a potential factor, having an impact on function of sperm, hence contributing to a growing infertility in the human population.

Absorption Spectra of Caffeic Acid, Caffeate and Their 1:1 Complex with Al(III): Density Functional Theory and Time-Dependent Density Functional Theory Investigations

The UV-visible absorption spectra of caffeic acid, caffeate and of the predominant complex obtained in the presence of aluminum ion (1:1 stoichiometry) have been simulated by using the time-dependent density functional theory (TD-DFT) technique, taking into account solvent effects. Whereas the use of the B3LYP hybrid XC functional with the 6-31+G(d,p) basis set allows us to reproduce fairly well the essential features of the experimental spectra of caffeic acid and caffeate, it is necessary to introduce an effective core potential to properly describe the aluminum ion and its environment and to obtain a good agreement between theoretical and experimental spectra of the 1:1 complex. The ligand presents two potential complexing sites in competition. The results of our calculations show that the aluminum ion coordinates preferentially at the level of the catecholate group, and the [Al(H(2)O)(4)(CA)], [Al(H(2)O)(3)(OH)(CA)](-) and [Al(H(2)O)(4)(HCA)](+) complexed forms could coexist in aqueous solution at pH = 5.

Optimized bath for electroless deposition of palladium on amorphous alumina membranes

A new bath for the electroless deposition of palladium on anodic alumina (AA) membranes is proposed. It was found that the optimal conditions for the uniform deposition of palladium, with minimal damage to the AA membranes, were under conditions of pH 8.4 and plating times shorter than 30 min. The deposited Pd layer was detected by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The morphology of the AA membrane before and after plating was examined by scanning electron microscopy (SEM). EDX analysis revealed that palladium was deposited only on the surfaces of the membrane and Sn ions, coming from the sensitizing bath, were incorporated into the palladium layer. EDTA incorporated into the palladium layer was also detected by Fourier transform infrared spectroscopy (FTIR). The total amount of palladium deposited was evaluated both by atomic absorption spectroscopy (AAS) and by a new complexometric procedure specifically developed to estimate the quantity of palladium in the presence of aluminium ions.