Adsorption of fluoride, chloride, bromide, and bromate ions on a novel ion exchanger.

A novel ion exchanger based on double hydrous oxide (Fe2O3Al2O3xH2O) was obtained by the original sol-gel method from easily available and cheap raw materials and employed for adsorption of F-, Cl-, Br-, and BrO-3 from simultaneous solutions. Adsorbent was characterized by potentiometric titration, zeta-potential, and poremetrical characteristics. A technologically attractive pH effect of F-, Br-, and BrO-3 sorption on the investigated double hydroxide of Fe and Al, which is capable of working in the pH range 3 to 8.5, was observed. Kinetic data on fluoride and bromide sorption fit well the pseudo-second-order model. Isotherms of fluoride, bromide, chlorine, and bromate ion sorption on Fe2O3Al2O3xH2O were obtained at pH 4. The isotherm of F- sorption fit well the Langmuir model; sorption affinity (K=0.52 L/mg) and sorption capacity (90 mg F/g) were high. In the competitive adsorption of bromide and bromate, bromide dominated at equilibrium concentrations of the ions >40 mg/L. The mechanism of fluoride adsorption to the surface of the model cluster of the sorbent synthesized and the geometry of the cluster itself were modeled with the HyperChem7 program using the PM3 method.

Characterisation of novel modified active carbons and marine algal biomass for the selective adsorption of lead.

This paper discusses the sorption performance of novel materials for the removal of lead(II) and copper(II) from near-neutral aqueous solutions. Active carbons with surface heteroatoms of oxygen and phosphorus have been prepared. The surface functional groups display weakly acidic ion exchange characteristics. The optimum solution pH for maximum metal sorption is related to the pK values of the surface functional groups. In oxygenated active carbons, pK values are not distinct but can be obtained by describing proton binding to the heterogeneous adsorbent surface as a continuous proton affinity distribution. Information derived from zeta-potential measurements combined with knowledge of the pK distribution function and concentration of surface functional groups has been used to explain the selectivity of oxidised active carbons towards lead(lI) in the presence of copper(II) from multi-metal bearing solutions. Marine algal-based biosorbents have been challenged with lead(II) and copper(II)-bearing wastewater. The weakly acidic carboxyl groups of structural polysaccharides present within the algal matrix display high sorption capacity for both metals. The negative surface charge of algal particles results in electrostatic interactions as well as coordination between metal species and the adsorbent surface. Proton affinity for the algal surface lowers the negative surface potential at pH values around 2. The surface functional groups in algae unlike those in oxidised active carbons may be represented by discrete acid-dissociation constant values. The influence of conformational differences in uronic-acid segments upon metal ion selectivity is discussed.

Haemoperfusion in the treatment of chronic renal failure in patients on haemodialysis.

The paper is concerned with materials characterizing physicochemical properties of haemosorbents of varying grades. Adsorption of different uraemic toxins was studied. The possibility of microembolization of internal organs and tissues with haemosorbent particles was explored in the course of prolonged treatment with the use of haemosorption. Different approaches to connecting the sorption column to the dialyzer were examined to disclose an optimal variant. The authors report the results of applying haemosorption in patients who had received haemodialysis therapy to prevent complications. The blood response to the prolonged haemosorption treatment was analyzed. It is recommended that long-term (6-7 hours) sessions of haemosorption might be performed using carbons having high sorption capacity.

[Alcohol dehydrogenase reaction on activated charcoal]. / Alkogol'degidrogenaznaia reaktsiia na aktivnykh ugliakh.

The alcohol dehydrogenase reaction on active charcoals has been studied. It is shown that the reaction rate on active charcoals decreases in comparison with usual conditions but the reaction being carried out for a longer period of time, the equilibrium shifts towards the NADH formation, which makes the NADH yield several times higher. A conclusion is made on the possibility of charcoals to influence the enzymic reactions in a living organism.

[Correction of metabolic changes in preserved donor blood using hemosorbents]. / Korrektsiia metabolicheskikh sdvigov v konservirovannoi donosrskoi krovi gemosorbentami.

The investigation of the effect of perfusion through the activated charcoal upon the biochemical and morphological parameters of the donor blood stored with the glucose-cytrate conservant during 14-21 days has shown normalization of the acid-base status, increased oxygen-transport function and energy balance of erythrocytes. So, blood continuously stored and purified with the help of sorbents is quite suitable for massive transfusions.

Immunosorbents based on uncoated synthetic charcoals: preparation, properties, applications.

By means of water-soluble carbodiimide coupling technique various bioligands were covalently attached to the surface of uncoated synthetic active carbons and a number of sorbents with certain biological functions were thus designed. Carbonaceous sorbents with immobilized ligands demonstrate increased affinity towards specific sorbates compared to that of starting matrix. As soon as SCN and SCS synthetic carbons are used uncoated they can be highly loaded with protein molecules - up to 80 mg serum albumin, 6-10 mg IgG rabbit etc. per gram of sorbent. Carbonaceous immunosorbents retain biocompatibility and substantial non-specific adsorptive capacity of initial hemosorbents. A conclusion is drawn that uncoated synthetic charcoals can serve a basis for design of selective hemosorbents intended for solving complicated problems of immunocorrection.

[Ultrasonic scanning and duodenoscopy in the diagnosis and treatment of obstructive jaundice]. / Ul'trazvukovoe skanirovanie i duodenoskopiia v diagnostike i lechenii obturatsionnoi zheltukhi.

In 186 patients with obstructive jaundice admitted to the clinic for diagnosis of its cause, the ultrasound scanning with duodenoscopy was employed. This permitted to establish the cause of jaundice in 84.9% of the patients and to choose proper therapeutic tactics at the shortest time after hospitalization. In 80% of the patients, an obstacle for bile outflow was liquidated by means of endoscopy. When it was not possible to established the cause of jaundice by the findings of ultrasound scanning and duodenoscopy, percutaneous transhepatic cholangiography was performed, which has proved to be successful in 5.9% of cases. Use of the given methods for diagnosis permitted to define the optimal therapeutic tactics in patients with obstructive jaundice, to reduce the lethality.

[The possibility of using carbon enterosorbents for normalizing cholesterol metabolism]. / O vozmozhnosti ispol'zovaniia uglerodnykh énterosorbentov dlia normalizatsii kholesterinovogo obmena.

The kinetics of bile acids (BA) and cholesterol adsorption from biological fluids (bile) and reference solutions on carbon SCN were compared with conventional medical carbon with the view of elucidating the role of adsorption in improving cholesterol metabolism. It was found that the adsorptive capacity of carbon adsorbents is determined, primarily, by their porous structure as well by the chemical properties of the adsorbing surface. The enterosorbents were tested both in experimental animals and in clinical trials and are now successfully employed for preventing and treating atherosclerosis as well as for normalizing lipid metabolism. A procedure for surgical treatment combined with adsorptive detoxication (enterosorption) for patients with obstructive jaundice has been developed.

[Enterosorption in the treatment of patients with chronic urticaria]. / Enterosorbtsiia v lechenii bol'nykh khronicheskoi krapivnitsei.

A synthetic carbon sorbent (SKNP-2) was included in the treatment of 197 patients with relapsing urticaria. Courses lasted 7, 14, 20 days. The clinical effect was favourable and its efficacy increased with prolongation of the therapy course time using the enterosorbent. Immunological parameters did not change in the course of treatment.