Residual Aluminum Research Articles

Synthesis of phosphosulphate substance and properties of its structured mixture with quartz sand

Purpose. Creation of binder based on orthophosphoric acid and aluminum sulfate, study on its structure and physicochemical patterns of formation, determination of the properties of structured mixtures for the needs of foundry. Methodology. In the work, X-ray qualitative and quantitative analysis was performed on the Rigaku Ultima IV unit, and differential thermal analysis was performed on the STA 449 C Jupiter synchronous thermal analyzer. Orthophosphoric acid, technical thermal, of 85% concentration, 18-hydrous sulfate of aluminum Al2(SO4)3 18H2O and quartz sand of brand 3K5O3025 were used. The strength of core mixtures was determined on the US-700 unit on standard cylindrical samples with a diameter and height of 50mm. The roughness of the cast surfaces was determined on a profilometer model 107622 with computer processing of the obtained data and construction of profilograms. To determine the propensity of the core mixtures to form caking, a hexagon sample was used according to the method by M.Fedorov. Breakability was determined on standard cylindrical samples with a diameter and height of 50 mm according to the original method described in the text of the article. Findings. For the first time, the mechanism of formation of aluminum phosphates with binding properties during the interaction of aluminum hydrate crystal sulfate Al2(SO4)3 18H2O with orthophosphoric acid in the temperature range of 100200 has been investigated. The formation is proved of an intermediate phase during heating aluminum hydroxide Al(OH)3, which, in contrast to its sulfate, according to the results of thermodynamic analysis is able to interact with acid. Formation of aluminum in the system of ortho- and metaphosphates, which features binding properties and ensures high strength of samples based on quartz filler, has been established. The thermal transformations of the obtained binder, which consists of a combination of aluminum phosphates with its residual sulfate, are studied. Stages of gradual disintegration of crystal hydrates, formation of new aluminum phosphates and thermal decomposition of residual sulfate are recorded. The tendency to burn and knockout of the developed core mixtures was determined. Originality. For the first time, a description has been developed of the mechanism of formation of aluminum phosphates with binding properties during the interaction of its sulfate crystal hydrate Al2(SO4)3 18H2O with orthophosphoric acid in the temperature range of 100200. Practical value. A new inorganic binder from orthophosphoric acid and 18-aqueous aluminum sulfate has been obtained for foundry production. The scheme of its preparation involves preliminary mixing and heating of the specified reagents with the resulting formation of a dry powder material which consists of phosphates and residual aluminum sulfate, and therefore it is called phosphosulfate. The binding has a long shelf life and is introduced into the mixture in a ready-made form while the technology of its production is less energy-intensive and long-lasting compared to the preparation of traditional metal phosphate binding.

Improvement of permeation flux by evaluating the effects of coagulated-humic acids flocs and pH during coagulation-microfiltration hybrid process for water treatment: Performance, fouling modeling, specific energy consumption, and processes comparison

The objective of this study is to analyze the relation between flocs shape and the permeation flux stability in a pilot-scale Coagulation/Flocculation-Microfiltration hybrid process for humic acids removal from water under different coagulant dose and pH values. Besides, the treatment performance was examined. The results showed that at pH 7.1 and polychloride of aluminum coagulant of 10−1 mmol Al.L−1, coagulation/flocculation was effective in maintaining membrane permeability flux. Also, UV254, TOC, and turbidity removal efficiencies were almost ≥ 90%. In addition, this condition proved a potent effect on residual aluminum control and specific energy consumption, where they were, respectively, 0.0852 kWh.m−3 and 20 µg.L−1. Furthermore, humic acids fouling using four Hermia mechanisms (individual and combined) was modeled. Complete pores blocking and cake filtration appeared to be the major mechanisms of microfiltration membrane fouling. Finally, this hybrid process was compared with the most used technologies for the humic acids removal from water. It was concluded that the former process is more reliable, efficient, and cost-effective.

Identifying key residual aluminum species responsible for aggravation of nanofiltration membrane fouling in drinking water treatment

Residual aluminum has been identified as one of the key foulants responsible for nanofiltration (NF) membrane fouling in drinking water treatment. However, the extent to which each species of residual aluminum contributes to membrane fouling and the underlying mechanisms are not yet clear. In this study, various pretreatments were applied to a lake water, which generated feed waters of different residual aluminum and species distribution. It was found that Ala (monomeric and oligomeric aluminum species) were mainly in the form of complexes (Ala-NOM) with natural organic matter (NOM), with proportions greater than 70%. The membrane fouling experiments showed that NF operation was sensitive to the presence of Ala, in which a small increase in the Ala concentration of the order of tens of μg/L could greatly aggravate membrane fouling. In contrast, Alb and Alc (intermediately and highly polymeric aluminum species) did not contribute substantially to the membrane fouling process. The membrane fouling potential of Ala increased with increasing coexisting NOM concentration. Results showed that Ala and NOM have a synergistic relationship during membrane fouling. More rigorously, Ala-NOM, rather than Ala itself, are therefore the key residual aluminum species that aggravate NF membrane fouling. The Ala produced by polyaluminum chloride (PACl) had a higher membrane fouling potential than that produced by AlCl3, which was due to the lower polymerization degree of Ala and the more stable complexes with NOM formed when PACl was used. Use of AlCl3 as a coagulant would therefore mitigate NF membrane fouling caused by residual aluminum.

Comparative evaluation of pilot-scale reactors based on pulsating floc blanket clarification and conventional clariflocculation technologies in simultaneous treatment of natural organic matter and turbidity

Abstract Simultaneous treatment of synthetic raw water containing natural organic matter (6 mg L−1) and clayey turbidity (0–20 NTU) was carried out with PACl on continuous upflow type pilot-scale models of pulsating floc blanket clarifier (PFBC) and conventional clariflocculator (CC) each designed for a capacity to treat about 8,000 liters per day, to understand mechanistic differences in their functioning. Fluidized bed of pre-flocculated particles prompted contact flocculation and enmeshment which lowered the residual turbidity for PFBC (0.07 ± 0.09 NTU) compared to CC (2.48 ± 1.71 NTU). Fine particles suspended in water clarified from PFBC and CC were hetero-disperse with Zavg as 2,341 nm and 5,693 nm respectively. On average, total residual aluminum was found to be 147 ± 33 ppb and 141 ± 51 ppb, while dissolved residual aluminum was found to be 31 ppb and 59 ppb for PFBC and CC respectively. Average total organic carbon reduction by PFBC and CC was 70.4% and 67.7% respectively. Size, structure and fractal dimensions of flocs were studied and average settling velocity of PFBC flocs was calculated to be 37% higher than CC flocs. Distinctness in characteristics of sludge formed in the two reactors has been highlighted by means of SEM micrographs and FT-IR spectra.

Optimizing coagulation–flocculation processes with aluminium coagulation using response surface methods

A data-based multivariate method such as response surface methods and desirability function is considered advantageous for analysing coagulation treatment optimization. Thus, this study investigated the optimization of coagulation–flocculation using response surface methodology. The parameters investigated were pH, alum dose and alkalinity. The optimum coagulation conditions for the individual responses: turbidity, colour, residual aluminium and phenanthrene were pH 7.0, alum dose 80.0 mg/L and alkalinity 80.0 mg/L; pH, 6.5, alum dose 70.0 mg/L and alkalinity 90.0 mg/L; pH, 7.0, alum dose 63.2 mg/L and alkalinity 80.0 mg/L and pH 6.2, alum dose 80.0 mg/L and alkalinity of 80.0 mg/L, respectively. The model equation derived from the optimization study was adequate for predicting the response values. The quadratic model was significant (p < 0.0001), and it had a high correlation (R2, 0.746–0.975) and an insignificant (LOF, p > 0.05) lack of fit.

CONTACT CLARIFIERS IN DRINKING WATER TREATMENT PROCESSES

The article deals with the issues of resource-saving technology in the preparation of drinking water on contact clarifiers. One of the methods of water purification from coarse and colloidal contaminants is the method of contact coagulation using aluminum sulfate coagulant. It is advisable to use contact clarifiers in single-stage treatment schemes for low-turbid colored and cloudy-colored waters, when the total content of suspended solids in the water entering the contact clarifiers, including the suspension formed as a result of introducing reagents into the water, does not exceed 150 mg/l. With a higher content of suspended matter in water, the water consumption for washing contact clarifiers increases sharply. To intensify the preparation of drinking water on contact clarifiers, a resource-saving technology is proposed using contact clarifiers using a modified aluminum sulfate coagulant solution, which makes it possible to: reduce the consumption of coagulants used in water purification, improve the quality of water clarification by weighing substances, and reduce the cost of water treatment. Theoretical prerequisites for improving the operation of contact clarifiers with a modified coagulant solution are considered. The use of a modified coagulant solution allows, without deteriorating the quality of water clarification, to reduce the calculated doses of the coagulant by an average of 25-30%, which confirms the feasibility of using a modified aluminum sulfate coagulant solution when clarifying water on contact lights. It has been established that the treatment of clarified water with a modified aluminum sulfate coagulant solution during contact coagulation makes it possible to reduce the residual aluminum content in clarified water by an average of 50-60%, the quality of water purification in terms of bacteriological and hydrobiological indicators is much higher than when treating water with a conventional coagulant solution.

Understanding the effect of residual aluminum salt coagulant on activated sludge in sequencing batch reactor: Performance response, activity restoration and microbial community evolution

To investigate the effect of residual coagulant after coagulation pretreatment on activated sludge system of wastewater treatment plants (WWTPs), comparative evaluation of lab-scale sequencing batch reactors under different poly-aluminum chloride (PAC) concentrations (20 and 55 mg/L), presenting the performance differences of reactors. Results showed that the PAC concentration of 20 mg/L slightly enhanced the average removal efficiencies of chemical oxygen demand (COD) and total nitrogen (TN), up to 93.43% and 72.52%. Whereas, an inhibition effect was exerted at the PAC concentration of 55 mg/L, the average removal efficiencies decreased to 88.56% and 57.80% respectively. Similarly, the residual aluminum salts showed a concentration effect of low promotion and high inhibition on sludge activity index. The content of specific oxygen utilization rate (SOUR) and dehydrogenase (DHA) sharply decreased by 30.17% and 53.56% under the high PAC concentration of 55 mg/L. Activity recovery phase showed that the suppression of aluminum salt coagulant on biological system was reversible. High-throughput sequencing presented that the relative abundance of microbes showed obvious variations at different PAC concentrations, and certain bacteria in Chloroflexi and Bacteroidota exhibited better adaptability to the high PAC concentration environment. Nevertheless, the antagonism action between denitrifying genera and other genera as well as the downregulation of functional enzymes regarding nitrogen metabolism gave rise to the deterioration of denitrification under the high PAC concentration of 55 mg/L. This study revealed the influence mechanism of residual aluminum salt coagulant on activated sludge system, providing strategies for efficient decontamination and long-term stable operation of biological system in wastewater treatment plant under the condition of adding PAC.

Adsorption of fluoride by using sodium alginate coated poly-aluminium chloride (PAC) sludge: preparation, characterisation and mechanism

ABSTRACT Poly-aluminium chloride (PAC) sludge is a waste product created during drinking water treatment, usually generated in large quantities and typically landfilled. More attention must be directed to environmental-friendly management and economically sustainable of Al-based sludge. In this work, a low-cost and environmental-friendly adsorbent prepared by sodium alginate coated PAC sludge (SPS) was investigated for fluoride removal. Basic preparing parameters including heating temperature (200–800°C), sodium alginate concentration (0.5–5 wt%), particle size (1–2 mm, 2–3 mm, 3–4 mm) and operating parameters including dosage (1–14 g/L), solution pH (4–11), temperature (10–35°C), co-existing anions (NO3 −, Cl−, SO4 2-, PO4 3-) were examined to evaluate the optimum defluoridation capacity. The prepared SPS adsorbents reached a high removal efficiency of 95.6% with initial fluoride concentration of 10 mg/L, dose of 8 g/L, contact time of 24 h, pH value of 7 and temperature of 10°C. The kinetic study indicated that fluoride adsorption followed the pseudo-second-order kinetics well (R2 = 0.9942), and adsorption isotherms can be well described by Freundlich model (R2 = 0.9952). Thermodynamic studies showed the fluoride adsorption was spontaneous and exothermic. The elements and functional groups of SPS adsorbents were analysed by using EDS and FTIR, respectively. The adsorption mechanism involved physisorption, ligand-exchange and electrostatic attraction. According to N2 adsorption–desorption isotherm, the SPS was mesoporous material which facilitated the adsorption of fluoride ions. Also, aluminium presented in form of Al-OH in SPS adsorbents had significant contribution in fluoride adsorption. The concentration of the residual aluminium ions was 4.48 × 10−3 mg/L which is lower than the China Drinking Water Standard. The encouraging results of this preliminary study indicated that SPS is an environmental-friendly and cost-effective treatment option for groundwater with fluoride pollution.

Study of matrix modifications by nano-clay on the mechanical properties of AA3003 honeycomb sandwich panels

Face/core debonding is one of the crucial problems of composite sandwich panels which consist of AA3003 aluminium honeycomb and glass fiber reinforced polymer face sheets. The panel was prepared by a hand-lay process at different nano-clay weight addition of 0%, 2%, 4%, and 6% with the objective of improving face/core adhesion. Interface bonding between face sheets and honeycomb core composite sandwiches and their mechanical behavior were investigated under in-plane compression and bending load. The flexural property of sandwich panels due to the influence of variation in strain rate is further determined. The morphologies of fractured samples were investigated by scanning electron microscope (SEM). The results revealed a significant improvement in mechanical characteristics when nano-clay was loaded to the composites at a concentration from 2 to 4 wt%, and the in-plane compression and flexural failure load values increased by 45% and 81%, respectively, when compared to a pristine sample. It was observed that increasing strain rate led to the increase in failure load of the sandwich panel. SEM images of fractured surfaces showed residual aluminium honeycomb was present in the face sheet, which indicates better adhesion between aluminium honeycomb core and face sheets.

Exfoliation of Al-Residual Multilayer MXene Using Tetramethylammonium Bases for Conductive Film Applications.

This study describes the concise exfoliation of multilayer Ti3C2T x MXene containing residual aluminum atoms. Treatment with tetramethylammonium base in a co-solvent of tetrahydrofuran and H2O produced single-layer Ti3C2T x , which was confirmed via atomic force microscopy observations, with an electrical conductivity 100+ times that of Ti3C2T x prepared under previously reported conditions. The scanning electron microscopy and X-ray diffraction measurements showed that the exfoliated single-layer Ti3C2T x MXenes were reconstructed to assembled large-domain layered films, enabling excellent macroscale electric conductivity. X-ray photoelectron spectroscopy confirmed the complete removal of residual Al atoms and the replacement of surface fluorine atoms with hydroxy groups. Using the exfoliated dispersion, a flexible transparent conductive film was formed and demonstrated in an electrical application.

Combustion characteristics of cross-linked fluorinated polymer supported aluminum/oxidizer microsphere in HTPB propellant

Combustion behaviors of propellant depend heavily on the architecture of the pocket bounded by coarse AP particles. In order to achieve a better control of the meso-scale architecture of the pocket, overcoming random mixing of the fine particles inside propellant, two kinds of cross-linked fluorinated polymer supported Aluminum/Oxidizer microspheres containing fine Al and oxidizer particles are fabricated by emulsion solvent evaporation and in-situ polymerization method (ESV-ISP), which are used to replace the fine Al and oxidizer particles of the Al/AP/HMX/HTPB propellant. The morphologies of the Al/Oxidizer microspheres and the corresponding propellants are studied, it shows that the fine Al and oxidizer particles are well dispersed and arranged in the microspheres. Besides, the average sizes of the microspheres are ranging from 113.9 ± 4.3 μm to 183.0 ± 5.9 μm, and equivalent to that of the Al-rich clusters located inside the pocket. The energy property and combustion performance of the propellants indicated that the combustion heat of the propellants containing Al/Oxidizer microsphere is increased by about 200 J/g, while the fraction of residual active aluminum is decreased by 77.8%, additionally, the D50 and D(4,3) of the combustion residue are both reduced significantly. Large Al aggregate nearby the burning surface is observed clearly in the blank propellant, while it could not be observed in the propellants containing Al/Oxidizer microsphere. Furthermore, compared to the pressure exponent (n), 0.34, of the B-Propellant, the n of the Al/AP-Propellant and the Al/HMX-Propellant significantly drop to 0.24 and 0.25, respectively, and the burning rate (r) could be adjusted and controlled by the Al/Oxidizer microsphere consisting of different fine oxidizer particles. It demonstrates that using the structurally ordered Al/Oxidizer microsphere could successfully achieve a better control of the meso-scale architecture of the pocket in typical Al/AP/HMX/HTPB propellant.

Positive effects of organic fluoride on reduction of slag accumulation in static testing of solid rocket motors of different diameters

The serious slag accumulation produced by the combustion agglomeration of aluminum (Al) in solid composite propellants always reduces the specific impulse of the solid rocket motors and affects their reliability. The actual effects of the organic fluoride OF on reducing slag accumulation under solid rocket motor conditions are systematically investigated by adding the OF into HTPB propellants and performing a series of tests. The XRD patterns and SEM observation show that the slag is mainly composed of the unreacted Al and alumina (Al2O3), and most of the slag has a lamellar structure. OF noticeably reduces slag accumulation and increases the combustion efficiency of aluminum in the Φ315 and Φ480 motors. When adding 2 wt% OF into HTPB propellants, the mass and residual aluminum content of the slag in the Φ315 motors decrease by about 26.5% and 34.9% respectively, and the mass and residual aluminum content of the slag in the Φ480 motors decrease by about 42.7% and 57.2% respectively. Furthermore, the characteristic slag size decreases from greater than 30 cm to smaller than 3 cm in the Φ480 motors. The throat ablation has also been weakened after adding OF in the formulations.

Asynchronous Synergistic Damage Effect of Atomic Oxygen and Space Micro Debris on Kapton Film

In the low earth orbit environment, many environmental factors lead to the degradation of material properties. The synergistic effect of long-term atomic oxygen (AO) irradiation and instantaneous impact of micro debris (MD) on long-term and transient space environmental factors has attracted more and more attention. In this paper, the performance evolution of Kapton films under the conditions of MD, AO single factor load spectrum and MD + AO, AO + MD asynchronous synergistic load spectrum were studied by laser driven flyer and microwave atomic oxygen technology. The macro morphology, optical properties and quality changes of Kapton films before and after each load spectrum were compared, and the mechanism of micro morphology and structure changes was explored. The results show that compared with MD + AO loading spectrum, the surface holes of Kapton films are larger under AO + MD load spectrum condition, the residual aluminum particles formed by reverse sputtering of Al particles during impact are less, the average transmittance of the film decreases slightly, and the weight loss of Kapton film is slightly more under the same atomic oxygen exposure time. Under the condition of MD + AO load spectrum, plastic tearing cracks, craters and holes are formed on the surface of Kapton film; the edge of the hole formed under the condition of AO + MD load spectrum is straight, without obvious depression and tear characteristics. Under the condition of MD + AO load spectrum, due to the adhesion of Al after the impact of micro debris, the subsequent atomic oxygen erosion of the film is reduced, so the C-C bond is not seriously damaged, and a considerable part of the residual aluminum flyer is oxidized to alumina by atomic oxygen; The AO + MD loading spectrum test makes the film first eroded by atomic oxygen, resulting in the reduction in C–O bond and C–C bond. The fracture of C–N bond is caused by the hypervelocity impact of micro debris. Hypervelocity impact leads to the thermal decomposition of the material, destroys the C–N bond in the imide ring and generates an N–H bond. This study will provide a method reference and a reference for the multi-factor ground collaborative simulation of space environment of spacecraft materials.

Development of an integrating coagulation and reverse osmosis system to treat highly turbid water using synthesized coagulants.

In the present study a coagulation process was used as a pretreatment for a reverse osmosis (RO) membrane with turbid raw water collected from Bisalpur dam, Rajasthan, India. To optimize the coagulation performance, three kinds of coagulant, namely, alum (commercially available), synthesized inorganic polymeric coagulant-medium basicity (IPC-M), and inorganic polymeric coagulant-ultrahigh basicity (IPC-UH) were examined for turbidity removal with varying operating parameters. It was observed that in the optimum pH range of 6-7, the IPC-UH was the best performing coagulant with a 0.99 mg/L equivalent Al2O3 dose, revealing 2 NTU residual turbidity and residual aluminium of 0.001 mg/L. Moreover, the Langelier saturation index and Ryznar stability index values were evaluated at optimum conditions for all the three coagulants providing negligible scaling potential. Furthermore, the coagulant-treated water (100 L) was fed to the RO membrane, and the performance was noted in terms of flux, pressure, and total dissolved solids. It was observed that IPC-UH had the lowest reduction in permeate flux of 0.78 L/min/m2 compared with the commercially available coagulant alum (0.90 L/min/m2). Also, an increased feed pressure was observed for all the coagulant-treated waters with the lowest value of 2.3 kg/cm2 for IPC-UH, which was 2.5 kg/cm2 for alum (commercially available coagulant). Therefore, integration of coagulation before the RO system resulted in effective pretreatment of turbid water with very minute scaling.

Aluminium hydroxide impregnated sawdust adsorbent: An eco-friendly and low-cost strategy for defluoridation of water

Environment-friendly and cost-effective adsorbent is necessary for removal of excess fluoride from water to control the spread of fluorosis among people in fluoride-rich area. Plant-based cellulosic materials are the preferred choice for this purpose. In this work, aluminium hydroxide impregnated sawdust (AHSD) adsorbent has been prepared, characterized and applied for defluoridation of water through batch and fixed-bed adsorption. Fluoride adsorption capacity of AHSD in batch adsorption experiment is 4.45 mg/g for the initial fluoride concentration between 5-50 mg/L. At low fluoride concentration, the Freundlich isotherm model fit reasonably well, while at higher fluoride concentration (> 40 mg/L) the Langmuir model show better fitting with the experimental data. The adsorption kinetics follow pseudo second-order kinetic model. In fixedbed column adsorption, 4 g of the adsorbent is capable of bringing down the fluoride concentration from 5 mg/L to < 1.5 mg/L (WHO limit) for 690 mL of contaminated water. Residual aluminium in the treated water was within permissible limit of WHO. The reasonably good adsorption capacity and effectivity in both batch and fixed-bed column adsorption suggests that AHSD is an environment-friendly, cost-effective and promising adsorbent for defluoridation of water.

Coagulation Residual Aluminum Suppresses the Performance of Activated Carbon Filter

Coagulation Residual Aluminum Suppresses the Performance of Activated Carbon Filter

Identifying Key Residual Aluminum Species Responsible for Aggravation of Nanofiltration Membrane Fouling

Identifying Key Residual Aluminum Species Responsible for Aggravation of Nanofiltration Membrane Fouling

Modeling Jar Test Results Using Gene Expression to Determine the Optimal Alum Dose in Drinking Water Treatment Plants

Coagulation is the most important process in drinking water treatment. Alum coagulant increases the aluminum residuals, which have been linked in many studies to Alzheimer's disease. Therefore, it is very important to use it with the very optimal dose. In this paper, four sets of experiments were done to determine the relationship between raw water characteristics: turbidity, pH, alkalinity, temperature, and optimum doses of alum [ .14 O] to form a mathematical equation that could replace the need for jar test experiments. The experiments were performed under different conditions and under different seasonal circumstances. The optimal dose in every set was determined, and used to build a gene expression model (GEP). The models were constructed using data of the jar test experiments: turbidity, pH, alkalinity, and temperature, to predict the coagulant dose. The best GEP model gave very good results with a correlation coefficient (0.91) and a root mean square error of 1.8. Multi linear regression was used to be compared with the GEP results; it could not give good results due to the complex nonlinear relation of the process. Another round of experiments was done with high initial turbidity like the values that comes to the plant during floods and heavy rain. To give an equation for these extreme values, with studying the use of starch as a coagulant aid, the best GEP gave good results with a correlation coefficient of 0.92 and RMSE 5.1

Benefits of Residual Aluminum Oxide for Sand Blasting Titanium Dental Implants: Osseointegration and Bactericidal Effects.

Objectives. The purpose of this work was to determine the influence of residual alumina after sand blasting treatment in titanium dental implants. This paper studied the effect of alumina on physico-chemical surface properties, such as: surface wettability, surface energy. Osseointegration and bacteria adhesion were determined in order to determine the effect of the abrasive particles. Materials and Methods. Three surfaces were studied: (1) as-received, (2) rough surface with residual alumina from sand blasting on the surface and (3) with the same roughness but without residual alumina. Roughness was determined by white light interferometer microscopy. Surface wettability was evaluated with a contact angle video-based system and the surface free energy by means of Owens and Wendt equation. Scanning electron microscopy equipped with microanalysis was used to study the morphology and determine the chemical composition of the surfaces. Bacteria (Lactobacillus salivarius and Streptococcus sanguinis) were cultured in each surface. In total, 110 dental implants were placed into the bone of eight minipigs in order to compare the osseointegration. The percentage of bone-to-implant contact was determined after 4 and 6 weeks of implantation with histometric analysis. Results. The surfaces with residual alumina presented a lower surface free energy than clean surfaces. The in vivo studies demonstrated that the residual alumina accelerated bone tissue growth at different implantation times, in relation to clean dental implants. In addition, residual alumina showed a bactericidal effect by decreasing the quantity of bacteria adhering to the titanium. Conclusions. It is possible to verify the benefits that the alumina (percentages around 8% in weight) produces on the surface of titanium dental implants. Clinical relevance. Clinicians should be aware of the benefits of sand-blasted alumina due to the physico-chemical surface changes demonstrated in in vivo tests.

Nanofiltration Membrane Fouling and Control Caused by Residual Aluminum in Feed Water

Nanofiltration Membrane Fouling and Control Caused by Residual Aluminum in Feed Water