Adsorption

Aim  To evaluate marginal seal, water sorption, solubility and loss of mass after brushing of several temporary filling materials.Methodology  For marginal seal, Class I cavities, including endodontic access preparations, were made in human molar teeth and restored using one or other of several temporary filling materials (n = 10): zinc oxide/calcium sulphate-based cement (Cavit, 3M,ESPE, St. Paul, MN, USA), zinc oxide/eugenol cement (IRM, Dentsply Caulk, Milford, DE, USA), glass ionomer cement (Vidrion R, SSWhite, Rio de Janeiro, RJ, Brazil) or a dimethacrylate-based filling (Bioplic, Biodinâmica, Londrina, PR, Brazil). Dye penetration was assessed after thermocycling and immersion in 0.5% basic fuchsine solution. For water sorption, solubility and loss of mass analyses, disc-shaped specimens were made. Water sorption and solubility were evaluated by mass alteration after storage in distilled water for 7 days (n = 7). Loss of mass was calculated based on the difference of mass after abrasion with a toothbrush (n = 5), and surfaces were analysed by SEM. Data of water sorption, solubility and loss of mass were submitted to anova and Tukey’s test, and marginal sealing data to Kruskal–Wallis test (P < 0.05).Results  Statistically significant differences were observed for marginal sealing (P < 0.0001), water sorption (P < 0.01), solubility (P < 0.01) and loss of mass (P < 0.05). Bioplic had the best marginal seal. Cavit had the greatest water sorption and solubility. Vidrion R and Bioplic had the lowest solubility. Loss of mass after brushing was higher for Cavit, followed by Bioplic, IRM and Vidrion R. Cavit and Vidrion R were worn aggressively by brushing.Conclusions  The resin-based temporary filling Bioplic produced the best marginal seal, and was associated with the lowest water sorption, solubility and loss of mass.

The potential of Pleurotus ostreatus spent mushroom compost (PSMC) as a green biosorbent for nickel (II) biosorption was investigated in this study. A novel approach of using the half-saturation concentration of biosorbent to rapidly determine the uptake, kinetics and mechanism of biosorption was employed together with cost per unit uptake analysis to determine the potential of this biosorbent. Fifty per cent nickel (II) biosorption was obtained at a half-saturation constant of 0.7 g biosorbent concentration, initial pH in the range of 4–8, 10 min contact time, 50 mL 50 mg/L nickel (II) initial concentration. The experimental data were well fitted with the Langmuir isotherm model and the maximum nickel (II) biosorption was 3.04 mg/g. The results corresponded well to a second pseudo order kinetic model with the coefficient of determination value of 0.9999. Based on FTIR analysis, the general alkyl, hydroxyl or amino, aliphatic alcohol and carbonyl functional groups of biosorbent were...

Various adsorption techniques are available to remove serum autoantibodies and subsequently detect the underlying alloantibody in previously transfused patients with autoimmune haemolytic anaemia. We planned to establish a suitable adsorption technique in our transfusion service which can remove all autoantibodies and detect underlying alloantibodies rapidly, cheaply and effectively. We evaluated 71 direct antiglobulin test-reactive patients with warm AIHA over a period of 20 months. Twenty-three of these 71 patients who had a previous history of blood transfusion or pregnancy and were confirmed carriers of autoantibodies (indirect antiglobulin test-reactive) were considered for the adsorption study. Depending on the adequacy of samples, history of blood transfusion and severity of anaemia either autoadsorption or alloadsorption or both using polyethylene glycol (PEG) or low ionic strength saline (LISS)-papain were performed. Underlying alloantibodies were detected in 7 of the 23 pa...

Fluids in porous media are commonly studied with analytical or simulation methods, usually assuming that the host medium is rigid. By evaluating the substrate’s response (relaxation) to the presence of the fluid we assess the error inherent in that assumption. One application is a determination of the ground state of 3He in slit and cylindrical pores. With the relaxation, there results a much stronger cohesion than would be found for a rigid host. Similar increased binding effects of relaxation are found for classical fluids confined within slit pores or nanotube bundles.

The aim of our study was to determine the efficacy of three different adsorbents, inorganic (modified zeolite), organic (esterified glucomannans) and mixed (inorganic and organic components, with the addition of enzymes), in protecting broilers from the toxic effects of ochratoxin A in feed. Broilers were fed diets containing 2 mg/kg of ochratoxin A (OTA) and supplemented with adsorbents at the recommended concentration of 2 g/kg for 21 days. The presence of OTA led to a notable reduction in body weight, lower weight gain, increased feed conversion and induced histopathological changes in the liver and kidneys. The presence of inorganic, organic and mixed adsorbents in contaminated feed only partially reduced the negative effects of OTA on the broiler performances. Broilers that were fed with adsorbent-supplemented feed reached higher body weight (17.96%, 19.09% and 13.59%), compared to the group that received only OTA. The presence of adsorbents partially alleviated the reduction i...

Dry powder formulations are often composed of fine drug particles and coarser carrier particles, typically alpha-lactose monohydrate. However, the performance of a powder formulation may be highly dependent on the lactose quality and source. This study investigated the characteristics of lactose that influence the drug-to-carrier interaction and the performance of lactose-based dry powder inhaler formulations. The selected lactoses differed in the preparation processes and the content of fine lactose particles. Efficiency testing was done using fluticasone propionate and terbutaline sulphate as model drugs. Inverse gas chromatography was used to determine the surface heterogeneity distribution of different energy sites of the lactose and to understand the mechanism by which the fine carrier particles can improve the performance of dry powder inhalers. To assess the adhesion of respirable-sized drug to carrier particles, a simple method was developed based on aspiration and consideri...

Rice husk a very low cost material has been utilized as adsorbent for the removal of lead from industrial effluents. Adsorption studies have been carried out at 28°C and the effect of initial lead concentrations (100-1000) mg/l, adsorbent dosage (0.05-1) g, pH (2-10) and contact time (10-180) min on lead uptake to establish a mathematical model description percentage removal of Pb (II). The influence of four parameters on the percentage removal of Pb(II) was examined using a response surface methodological approach. Box-Wilson design of experiments was adopted to find a useful relationship between these parameters and the removal efficiency. The experiment data collected by this method successfully fitted to a second order polynomial mathematical model. The optimum operating conditions of initial Pb (II) concentrations, adsorbent dose, pH and contact time were 325 mg/l, 0.7625 g, 4 and 137 min, respectively with high value of correlation coefficients (R= 0.9877). At these conditions, the maximum percentage removal of Pb(II) was 95.55% and lead uptake was 102.97 mg/g.The experimental data were analyzed using Langmuir and Freundlich isotherm models were applied in the adsorption studies. Langmuir model is found very well represent the equilibrium data with correlation factor is close to unity than the Freundlich model.

The inclusion of activated charcoal within hemodialysis membranes offers potentially improved plasma clearance of creatinine and middle molecules. However, the carbon becomes saturated with continued use and beyond 1 h removal of solutes is by dialysis alone. Two independently conducted crossover studies, to assess the efficacy of sorbent membrane dialysis (SMD) in the treatment of uremia, found predialysis urea levels increased by approximately 15%, creatinine by 10-15%, and inorganic phosphate levels by 10-18% on SMD compared to conventional hemodialysis. One study also observed &quot;middle molecule&#39; (peak &quot;b&#39;) levels elevated. No differences were observable in the clinical status of patients. The results suggest that the charcoal content of the SMD device is too small to effect any advantages over conventional dialysis.

Using first-principles calculations, we report structural and electronic properties of CO, NO and NO molecular adsorption on beta-In2Se3 in comparison to a previous study on alpha-phase. Analysis and comparison of adsorption energies and extent of charge transfer indicates beta-In2Se3 to be selective in detecting gas molecules. We found NO molecules acting as charge donor whereas CO and NO molecules as charge acceptors, respectively, experiencing physisorption in all cases. Owing to enhanced adsorption, faster desorption and improved selectivity of the gas molecules discussed in detail, we conclude beta-InSe to be a superior gas sensing material ideal for chemoresistive-type gas sensing applications.