Sorption Of Aluminium Research Articles

Current State of the Gold Mining Waste from the Ores of the Ursk Deposit (Western Siberia, Russia)

The article presents the original results of the investigation of sulfide-bearing mine tailings dumps (Ursk, Western Siberia, Russia), the adjacent territory, and acid mine drainage flows. The novelty of this study is related to integration of geophysical and geochemical data. The geoelectrical structure of the dump and the drainage valley was determined using the electrical resistivity tomography (ERT) method. Magnetic anomalies above the surface of the site were identified using ground magnetic surveys. The orthophotomap and a digital elevation model were obtained on the basis of aerial photography from an unmanned aircraft. The model of thermal imaging allows us to identify a number of temperature anomalies in the upper part of the dump slope and filtration zone in the drainage valley, caused by exothermic reactions. The digital relief model was constructed comprising three zones: (1) oxidation, (2) leaching, and (3) mixing and dilution. The oxidation zone is marked by low electrical resistivity (1–10 Ω·m), low pH values of the drainage waters (pH 3.61), low values of the modulus of the magnetic induction vector, and heating by +5 °C compared to the solid dump material that is not actively exposed to water. The oxidative conditions and low pH values favor the dilution of the Fe2+ compounds in the drainage solutions, which also contain Cu (3000 μg/L), Pb (1200 μg/L), As (1300 μg/L), and Hg (34 μg/L). The zone of the primary geochemical barrier is formed within the first 400 m, where the major proportion of dissolved elements if deposited. The second iron–aluminum sorption geochemical barrier is formed at a distance of 1000 m at the mixing zone with the Ur River. The stable geochemistry of surface waters, formed due to the inflow of drainage waters into the Ur River and further into the reservoir, persists at a distance of up to 7.7 km from the dump.

Sorption of rare earth metals, iron and aluminum from phosphoric acid by sulfocationites

Sorption of rare earth metals, iron and aluminum from phosphoric acid by sulfocationites

THE SORPTION OF OFLOXACIN BY HYDRATED ALUMINA AND SILICON

The sorption of ofloxacin (OFL) – the antibiotic from class of fluoroquinolones has been studied on alumina (γ-Al2O3) different acid-base modifications – acidic Al2O3(acidic), neutral Al2O3 (Neutral) and the basic Al2O3 (core) and amorphous silica – silica gel (SG ) L 5/40 and aerosil A-300. Determination of ofloxacin in solutions has been carried out by spectrophotometry on spectrophotometer SF-46 at λ = 291 nm and acidity 7. To clarify the nature of the sorption surfaces of OFL hydrated on aluminum and silicon oxides were studied according to the degree of extraction (S%) from pH, contact time of the phases (min.) sample from the sorbent mass (g); sorption isotherms were built and antibiotic desorption was studied. The OFL significant recovery (~ 60%) is observed at the pH range of 4 ÷ 8, and reaches its maximum (80-85%) at pH 7. The maximum degree of extraction of the antibiotic on aerosil A-300 and L 5/40 silica realized at pH 6 and it was ~ 80%. Comparative analysis of the forms constructed isotherms (L – type) indicates a significant affinity investigated hydrated oxides to sorbate. The value of the static exchange capacity and concentration ratios can proof that. Differences in the quantitative characteristics of sorption of aluminum and silicon oxides are associated with nature and the acid-base properties of adsorption sites. In the study of the OFL concentrates desorption in static mode dilute NaOH and HNO3 solutions it was found that growth desorption degree occured with increasing concentration. Desorption was 2-3 times better in the case of aluminum oxide than silicon oxide when there were the same concentrations of acid and alkali. This is another confirmation of the participation in various sorption interactions forces of physical and chemical nature.

Comparative study on the biosorption of aluminum by free and immobilized cells of Bacillus safensis KTSMBNL 26 isolated from explosive contaminated soil

The study describes the sorption of aluminum by Bacillus safensis isolated from an explosive contaminate site. In a batch system, the optimum pH, temperature and contact time on biosorption of Al and cell growth were found to be 6.0, 35°C and 24h, respectively with initial metal concentration of 100mg/l Al. In immobilization studies, sodium alginate was used as supporting material for cell entrapment under optimized conditions. The variation in the protein banding pattern, functional groups and nature of Al treated and untreated bacterial cells were studied using SDS-PAGE, FTIR and XRD. While comparing the results of batch and immobilized sorption studies, the metal removal efficiency of free cells (92mg/l) was slightly higher than the immobilized cells (84mg/l). But the maintenance of high cell density, low processing cost, repeated and continuous uses are all recommends the immobilization technique for large scale water treatment.

Uptake and sorption of aluminium and fluoride by four green algal species

BackgroundWe examined the uptake and sorption of aluminium (Al) and fluoride (F) by green algae under conditions similar to those found in the effluents of the aluminium industry. We took into account the speciation of Al in the medium since Al can form stable complexes with F and these complexes may play a role in the uptake and sorption of Al. We compared the capacity of four species of green algae (i.e. Chlamydomonas reinhardtii, Pseudokirchneriella subcapitata, Chlorella vulgaris, and Scenedesmus obliquus) to accumulate and adsorb Al and F. The selected algae were exposed during 4 days, covering all growth phases of algae, to a synthetic medium containing Al and F at pH 7.0. During this period, dissolved Al as well as cellular growth were followed closely. At the end of the exposure period, the solutions were filtered in order to harvest the algal cells. The cells were then rinsed with enough ethylene diaminetetraacetic acid to remove loosely bound ions from the algal surface, determined from the filtrates. Finally, the filters were digested in order to quantify cellular uptake.ResultsLittle difference in Al removal was observed between species. Aluminium sorption (15%) and uptake (26%) were highest in P. subcapitata, followed by C. reinhardtii (7% and 17% respectively), S. obliquus (13% and 5%), and C. vulgaris (7% and 2%). However, none of these species showed significant uptake or sorption of F. We also studied the influence of pH on the uptake and sorption of Al and F by P. subcapitata. We measured a combined uptake and sorption of Al of 50% at pH 7.5, of 41% at pH 7.0, and of 4% at pH 5.5. Thus, accumulation was reduced with acidification of the medium as expected by the increased competition with protons and possibly by a reduced bioavailability of the Al-F complexes which dominated the solution at low pH.ConclusionOut of the four tested species, P. subcapitata showed the highest sorption of aluminium and fluoride under our test conditions. These results provide key information on the development of an environmental biotechnology which can be applied to industrial effluents.

Biosorption of manganese (II) and aluminium (III) ions from aqueous solution by immobilized Trichoderma asperellum BHU216

<p>Removal of Al<sup>3+</sup> and Mn<sup>2+</sup> from solution by Trichoderma asperellum BHU216 immobilized on Irvingia gabonensis matrix in a batch system was investigated. Effect of biosorption conditions contact time, pH, bead size and spore load were studied. Equilibrium isotherms and re-usability of biosorbent were also determined. The result showed that optimum sorption of Mn<sup>2+ </sup>and Al<sup>3+</sup> by immobilized sorbent was achieved at 7 mm bead size and 1.6 g l<sup>-1</sup> spore load. Optimum pH were 5 and 6 while equilibrium was attained at 120 and 180 mins for Mn<sup>2+</sup> and Al<sup>3+</sup> sorption respectively. Immobilized biosorbent was used in more than 5 batch cycles with over 50% removal achieved in 3 and 5 cycles for Al<sup>3+</sup> and Mn<sup>2+</sup> sorption. Brunauer-Emmett-Teller (BET) isotherm had the best-fit than both Langmuir and Freundlich isotherms for both metals (R<sup>2</sup> =0.98 and 0.92 for Mn<sup>2+</sup> and Al<sup>3+</sup> respectively). Manganese sorption proceeded at both surface and multi-layer levels with high sorption rates 18.88 mg/L and 19.72 mg l<sup>-1</sup>, while aluminium sorption was feasible in a multi-layer process with low uptake (0.87 mg g<sup>-1</sup>). This study showed that immobilized T. asperellum BHU216 can effectively act as biosorbent for Mn(II) and Al(III) sorption from solution.</p>

Study of sorption purification of lithium hydroxide solutions from aluminum by resin ANB-11g

The results of studying the main regularities of the sorption of aluminum on complexing resin ANB-11g from lithium hydroxide solutions are given. The sorbent contains functional groups of methylglucosylamine (N-methylglucamine) and is produced by amination of chloromethylated copolymer of styrene and divinylbenzene by methylglucosylamine. Tests of its chemical and thermal stability in solutions containing 48 g/dm3 LiOH showed that ANB-11g retains sorption properties after 30 days contact with it. Heating of the studied sorbent in this solution to 373 K doesn’t lead to a change in IR spectra-they are identical to the original. It was established on constructing the sorption isotherms of aluminum from solutions with 12–96 g/dm3 LiOH that an increase of the resin’s capacity for aluminum is observed with increasing content of the alkali in the original solution. The sorbent is regenerated by a diluted solution of the alkali with heating of the eluent to T = 323–363 K. As a result of pilot industrial testing of sorption purification of lithium hydroxide solutions to remove aluminum, the content of metal in them decreased by 1–2 orders of magnitude in them depending on the volume of solutions that passed through the resin. The degree of aluminum desorption was 99.5%.

Comparative hydrolysis and sorption of Al and La onto plant cell wall material and pectic materials

Pectin, which is an important component of plant cell walls, strongly binds Al and this may play a role in expression of Al toxicity. Sorption of aluminium (Al) and lanthanum (La) from aqueous solutions onto pectic acid, Ca-pectate and plant cell wall material was pH dependent. For Al at pH 3, sorption was less than the available sorption sites (i.e., the cation exchange capacity) on all three sorbents, whereas at pH 4, sorption of Al was in excess of available sorption capacity. By contrast, sorption of the trivalent Al analogue La corresponded to the available sorption capacity on all three sorbents at pH 5. This indicates, therefore, that Al hydrolyses at ≥ pH 4, and hydrolysis increases with Al concentration in solution. Further, it is proposed that the sorption of Al to pectin leads to deprotonation of the galacturonic acid (GalA) residues. Sorption of Al to pectin limits hydrolysis of Al, thereby shifting the pH of hydrolysis to a higher value. Hydrolysis of Al results in its sorption in excess of the stoichiometric equivalent (assuming the free Al3+ ion), leading to oversaturation of the pectin with Al. Staining of the metal-pectate complexes with the metachromatic dye eosin showed that with increasing Al saturation (but not La saturation), the complex developed a positive net charge, due to formation of some positively charged Al-complexes. The development of a positive charge on the Al-pectate complex may have major effects on cellular transmembrane potential and nutrient acquisition by plant roots. This is the first report of Al binding in excess of binding sites and development of a net positive charge on Al-pectate.

A Novel Bio-Eco Technology Combined System for Rural Domestic Wastewater Treatment in a Tourism Area: A Full-Scale Study

Characteristics of rural water consumption and sewage discharge in a tourism area were determined through an investigation of local villages in Lugu Lake (Yunnan Province). Based on the results of this evaluation, a novel bio-eco technology combined system was developed for high-quality wastewater treatment and recycling at low cost in the rural area. In this combined system, the bio-technique unit is an integrated oxidation ditch with vertical circle (IODVC), and the eco-technique unit consists of a wetland eco-filter, a subsurface infiltration and an eco-ditch. A full-scale wastewater treatment plant of this combined system was built in Lige Village, which is located at the Lugu Lake Tourism Area. The performance of the bio-eco combined system showed that its effluent quality reached up to grade III of the surface water standards (GB3838-2002), that is, the concentration of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), and total phosphorus (TP) in final effluent was less than 10, 1, and 0.1 mg/L, respectively, whereas the COD of 140–300 mg/L, NH4+-N of 40–70 mg/L, and TP of 3–5 mg/L in the influent, respectively. Furthermore, evaluation of the P adsorption of the local soil revealed that the P was removed by the ecological treatment unit of the bio-eco combined system via the fixation and sorption of iron and aluminium in the soil. The effluent of the full-scale wastewater treatment plant was used as the source water of a local landscape ecological wetland. Results demonstrated that this bio-eco combined system could be a feasible technology for wastewater treatment in this kind of rural areas.

A critical study on the efficacy of kinetic sorption modeling to elucidate the effective removal pathways

Modeling of aluminum sorption on natural oxide was studied to show the efficacy of sorption modeling in disclosing the possible sequestration mechanism(s). In this study, sorption of Al(III) on natural oxide was studied, and the resulting sorption data were fitted to the derived unsteady- and steady-state models. The well-known Langmuir–Freundlich, Langmuir, Freundlich, and linear isotherm models were also extracted from kinetic expressions, and it was shown that they are established on the same basis and hence they do not help to significantly enhance or multiply the information extracted from any one of the models. The applied kinetic modeling was based on the presumptions that the sorption process is reversible and that both adsorption and desorption may follow any rate order. The derived models, without any simplification, had more successful fit to the sorption data than those of the long-familiar adsorption models, possibly because of the abundance of the model parameters. Both the reversible and pseudo-second-order kinetic models fitted well to the experimental data of kinetic studies with similar success on the basis of R 2. The fitting of the sorption equilibrium data to the general isotherm model, the model form without any simplification, suggested that the adsorption-rate order for the entire test range varied between 1.9530 and 1.3588, whereas the desorption-rate order varied between 0.6411 and 0.4861. Studies on both kinetic and isotherm model fitting, together with the observed changes in ionic strength, pH, and enthalpy at sorption, implied that ion-exchange might have been an effective process contributing to Al(III) removal, with physisorption probably contributing to the removal to a small extent, although the claims still remain indecisive. Both the pore-size distribution of the sorbent and intraparticle diffusion model together confirmed that interparticle (external film) diffusion was negligible, even as intraparticle diffusion was effectively occurring through macro- and mesopores. It was concluded that the main difference between the discussed isotherm models originates from the assumptions made and their success to fit the experimental data is largely dependent upon the number of model parameters, the order of which, in descending number of parameters, can be classified as general model, the Langmuir-Freundlich model, the Langmuir model, the Freundlich model and linear model.

Does the degree of pectin esterification influence aluminium sorption by the root apoplast?

This study investigates the influence of the degree of pectin esterification (DE) on the sorption of aluminium (Al) by plant roots. Ca-pectates, with varying degrees of esterification, are major constituents of the soil–root interface and of the root apoplast. Ca-pectate networks (Ca–PG and Ca–Al–PG) were formed at three DEs (0%, 26%, 65%) with custom-made cells and used as a model system for the root cell wall. Sorption of Al was conducted for 24 h at a range of oxalic acid concentrations (0–500 μM) at pH 4.50 to examine two different metal resistance mechanisms of plants. In fact, plants release organic acids either to desorb or to complex metals to prevent their sorption by plant roots.Thermal analysis showed that Al sorption did not seem to affect the stability of the pectate gels and the presence of hydrophobic groups (–CH3) at DE > 0% seemed to even increase the stability of the gels decreasing thermal decomposition. Results suggest two potential Al tolerance mechanisms: (a) high oxalic acid concentrations (500 μM) were able to desorb almost 100% and 72% at DE 65 and 0%, respectively; (b) high oxalic acid concentrations (500 μM) and thus molar ratios of 5:1 (oxalate/Al) reduced Al sorption by 98% and 86% at DE 65 and 0%, respectively. In conclusion, both mechanisms indicate that high degrees of esterification as 65% are much more efficient in excluding Al from the apoplast and might therefore contribute to Al resistance in plants.

Efficient preconcentration and determination of traces of aluminum ion using silica-bonded glycerol sorbent

A solid-phase extraction system was proposed for the determination of aluminum after preconcentration with glycerol-bonded silica gel. The method is rapid and efficient for the enrichment of aluminum ions at trace levels. Optimal sorption conditions were found for sorption and desorption of aluminum ions. The effects of diverse ions on the sorption and recovery of aluminum have been studied and it was shown that the selectivity of the sorption process was very good. A very satisfactory preconcentration factor of 500 was achieved by this method. The lowest concentration of aluminum ions for quantitative recovery was 2 ng ml −1. The capacity of sorbent was 400 μg per gram of sorbent. The method showed good reproducibility (R.S.D. = 2.2% for n = 7) and was applied to the determination of aluminum in mineral water, hair and green tea samples.

Investigation on the sorption of aluminium in drinking water by low-cost adsorbents

Aluminium is one of the trace inorganic metals present in drinking water. High aluminium concentrations (3.6 to 6 mg/l) may precipitate as aluminium hydroxide affecting aquatic life. Aluminium is also a suspected agent of neurological disorders such as Alzheimer’s disease and senile dementia. The present investigation aims at the sorption of aluminium from drinking water using a low-cost adsorbent. Rice husk char and activated rice husk char were prepared and characterised for various physicochemical properties. The performance of rice husk char (RHC) was compared with other low-cost adsorbents for their aluminium removal capacity. The effect of pH, initial concentration, contact time and temperature was studied for adsorption of aluminium from water under batch conditions. The maximum adsorption capacity was observed with rice husk char at an optimal pH of 4.2. The adsorption of aluminium follows the Freundlich adsorption isotherm. The rate of aluminium adsorption was successfully described by a first-order kinetic model. The thermodynamic study revealed that aluminium adsorption is an exothermic process and the adsorption decreases with an increase in temperature.

Leaching Properties of Estuarine Harbor Sediment before and after Electrodialytic Remediation

Electrodialytic remediation (EDR) can be used to extract heavy metals from a variety of different media. In this work, contaminated harbor sediments from two locations in the United States and one in Norway were subjected to EDR, and were compared with batch extractions conducted with the sediment. pH-dependent leaching tests were used to evaluate changes in leaching properties of treated and control sediments. Significant fractions of total concentrations were removed during treatment (35–95% with an average of 75% for all sediments and elements investigated). The release of elements in pH-dependent leaching tests, however, demonstrated equal or greater leaching from treated sediments in the neutral pH range. Dissolved organic carbon appears to be a significant contributor to post-treatment increases in leaching, and dissolution of significant iron and aluminum sorption sites is hypothesized to also play a role. This research highlights the importance of understanding contaminant speciation and availability, as total metals concentrations, in this particular case, do not relate to estimates of the environmental availability of metals (total concentrations were typically two to three orders of magnitude greater than concentrations released during pH-dependent leaching).

Sensitivity analysis with a phosphorus diagenesis model (SPIEL)

Sensitivity analysis is an important part of the modelling procedure. In this paper, sensitivity analysis of a phosphorus diagenesis model (SPIEL) was used for determining the most important parameters and forcing functions, as well as the potential influence of technical in-lake measures on phosphorus (P) release from the sediment. The model “Sedimentary Phosphorus In Eutrophic Lakes” (SPIEL) includes sub-modules for calculating the aerobic layer thickness, the iron–sulphur cycle and the free aluminium sorption capacity. The results of a detailed sensitivity analysis for different module combinations were compared. By means of graphical representation of the cause and effect chains, the synergistic and compensatory effects of different processes on P release in Lake Sempach were discussed. The importance of the iron–sulphur cycle and of the aerobic layer thickness for the P release in this lake is demonstrated.

Characterisation of Ca– and Al–pectate gels by thermal analysis and FT-IR spectroscopy

Thermal analysis (TG–DTA) and FT-IR spectroscopy have been performed on calcium–pectate membranes to investigate their structure and the consequent variation caused by aluminium sorption. Calcium–polygalacturonate (Ca–PG) membranes, model systems of the soil–root interface, were exposed to aluminium solutions at different concentrations (25–800 μM). Three different pHs (3.50, 4.00 and 4.50) were chosen to study the influence of different aluminium species, such as [Al(H 2O) 6] 3+, [Al(OH)(H 2O) 5] 2+ and [Al(OH) 2(H 2O) 4] +, on the structure of the Ca–PG membrane. The DTA profiles and FT-IR spectra showed how aluminium sorption induces structural modifications leading to a reorganisation of the chain aggregates and a weakening of the structure. Higher pH, that is, 4.00 and 4.50, and thus hydrolytic aluminium species and related higher calcium content maintain a more regular structure than at pH 3.50. At pH 3.50, both the effect of [Al(H 2O) 6] 3+ and a major calcium release had a greater impact and thus induced a greater weakening of the structure.

A Scanning Electron Microscopy Study of a Calcium‐Polygalacturonate Network in the Presence of Aluminum: A Model to Investigate Soil‐Root Interface Processes

The objective of this study was to investigate the effects of aluminum (Al3+) on a calcium‐polygalacturonate (Ca‐PG) network used as a soil‐root interface model. Calcium‐PG networks were exposed to Al3+ solutions at different concentrations (100, 200, 400, and 800 µM) at pH 3.50. In the present study, the scanning electron microscopy technique was used to evaluate morphological variations induced by Al3+sorption. Results showed how aluminum (Al) sorption induces conformational changes of the Ca‐PG complex. The Ca‐PG complex shows a regular structure with a honeycomb‐like pattern. Interlacing fibrils form a porous system, which can easily allow sorption and/or passage of nutrients as well as toxic elements. As Al becomes the predominant reticulating ion, the pores decrease in size and lose their regular shape. The scanning electron micrographs have in fact shown that Al sorption damages the Ca‐PG complex, leading to its collapse; the Ca‐Al‐PG networks exhibit an irregular uneven structure.

Aluminium speciation in natural water by sorption on a complexing resin

Very stable aluminium complexes may be present in natural waters, which can be detected only using appropriate methods. One of them is the resin titration based on the sorption of aluminium on a strongly sorbing resin, Chelex 100. It was here used to detect strong aluminium complexes, and to characterize them by determining their concentration, and the corresponding stability constant. High and low salinity waters were sampled in different sites in the North of Italy. In all the samples aluminium complexes with high stability constant, up to 10 17.4 M −1 in the less acidic solution, were detected. The stability constant depends mainly on the solution acidity, increasing with increasing pH up to 7. The concentration of the ligands responsible for the strong complexation is similar to that of aluminium (from 0.5 to 1.5 μM), or somewhat lower in the case of estuarine and sea waters. A small fraction of aluminium (from 0% to 2%) in freshwaters, higher in estuarine and sea waters (14% and 10%, respectively), is present in weakly bound forms which could also be the hydrolysis products. The conditional constants of the strong complexes were determined for the different samples examined. They were found to be slightly lower in the case of the high salinity waters, in which a value of 10 16.1 M −1 at pH 7.5 was obtained. This is probably due to the higher ionic strength in marine water, which strongly influences the complexation of trivalent metal ions, as seen for example also in the hydrolysis. It could be deduced that similar substances, but at different concentration, would be responsible for the aluminium complexation in the sea and freshwaters here examined. They could be natural organics like fulvic substances, or better some particular complexing sites in this substances with very high affinity for aluminium.

Complexation of labile aluminium species by chelating resins Iontosorb – a new method for Al environmental risk assessment

The utilization of chelating ion-exchange by the method based on binding strength and kinetic discrimination for aluminium fractionation was studied. Two chelating cellulose resins, Iontosorb Oxin (IO) and Iontosorb Salicyl (IS), were used for the determination of quickly reacting labile aluminium species. The possibilities of aluminium fractionation on these chelating resins were investigated by a solid phase extraction technique. The study of the pH (2.5–6.0) influence on the Al complexation by both resins indicates that at low pH the IS has lower sorption capacity but better adsorptive kinetic properties than IO. The optimal resin complexation time for reactive Al species was experimentally found after aluminium sorption study at pH 4.0 in synthetic solutions containing some inorganic and organic ligands, which simulate the composition of analysed acid soil and water samples. The negative influence of sulphate and iron on the Al complexation by IS resin was found and investigated. The flame atomic absorption spectrometry was used for the aluminium quantification.

Fluorimetric determination of aluminium in water by sequential injection through column extraction.

A fluorimetric procedure for the determination of aluminium with matrix removal in drinking water is proposed. The system is based both on the solid phase extraction of aluminium on a new chelating resin (XAD-4 modified by grafting salicylic acid) and the fluorimetric detection of a complex formed between 8-hydroxyquinoline-5-sulfonic acid (HQS) and Al(III), after elution of the resin by hydrochloric acid. The sorption and elution of aluminium were studied in both competitive and noncompetitive conditions, varying pH, flow-rates, volume and concentration of reagents, as well as time contact. The optimised procedure allows determination of Al3+ at the sub-ppb level (LOD: 0.2 microg L(-1) for 1 ml of sample) within a working range of 0.2-500 microg L(-1). The analytical procedure was successfully employed for the determination of aluminium in drinking water during and after flocculation/coagulation treatment processes.