Mg Of Solids Research Articles

Human bile sorption by cancrinite-type zeolites

A nitrated cancrinite-type zeolite was synthesized from zeolite X, NaOH and NaNO 3 solutions under autogeneous pressure at 80 °C for 48 h. This zeolite was characterized by X-ray diffraction (XRD), FT-IR-spectroscopy, scanning electron microscopy (SEM) and BET surface area. XRD, SEM and FT-IR confirmed the presence of nitrated cancrinite-type zeolite without other collateral phases as sodalite. Then, this sodium zeolite was exchanged with potassium and calcium cations and finally, these modified zeolites were reacted with biliar solutions from human gallbladder. Several factors such as: mass of used cancrinite, nature of the exchanged cation and reaction time of the cancrinite–bile solution interactions were studied. The composition of bile solutions (bile acids, phospholipids and bilirubin) was analyzed before and after the cancrinite–bile solution reaction. Results showed that the components of the bile were notably reduced after the contact with solids. Ca-cancrinite, 120 min of reaction time and 500 mg of solids were the best conditions determined for the bile acid reduction in human bile. When the modified zeolites were compared with the commercial cholestyramine, it was found that zeolites were more active than the latter. These zeolites may be an alternative choice to diminish cholesterol levels in hypercholesterolemic patients.

Fluvial Dynamics of Thorium-230 in the Church Rock Event, Puerco River, New Mexico

Abstract The largest accidental surface release of radioactive materials in the United States occurred 16 July 1979, when a uranium tailings pond collapsed near Church Rock, New Mexico, releasing 378,500 m3 of liquids and 1000 mg of solids into the Puerco River. The resulting flood wave distributed radioactive thorium-230 through an 80-km reach of the river. A detailed analysis of 48 km of the entrenched channel shows that radionuclide concentrations in stream-bed sediments fluctuated irregularly with increasing distance from the source of contamination instead of declining exponentially as might be expected from hydraulic and geographic theory. Hydraulic calculations at 154 cross-sections in the 48-km reach show that concentrations of radionuclides in channel sediments were inversely related to unit stream power generated during the peak of the flood wave. Concentrations were also inversely related to the length of time that shear stress exceeded critical values during the passage of the flood wave. Regional geologic structure determined the arrangement of channel characteristics, hydraulic behavior of the flood, and the resulting transport and storage of contaminants in the channel. The Puerco River case suggests that in dam-burst events, the variable downstream distribution of hydraulic properties of the flood wave is the primary physical control on the geography of potentially hazardous concentrations of heavy metals.

Concentration of beryllium from biological samples.

Abstract Two new methods for concentrating beryllium from biological samples are reported. One method is the exchange of beryllium from dilute hydrochloric acid to di-2-ethylhexyl phosphoric acid (HDEHP). This exchange requires 30 minutes of mixing. In the other method, beryllium as an oxalate anion complex is exchanged to triisodctylamine (TIOA) in 10 seconds. Although neither method is specific for beryllium, microgram quantities of the element can be separated from gram quantities of solids. When 1 liter of urine that contained 7Be tracer was wet-ashed to 12 gm of inorganic salts and concentrated by the TIOA method, 95% of the tracer was recovered, and only 6 mg of solids accompanied the 7Be. In other tests of the TIOA method, 'Be in ten 250-ml urine samples was recovered at 98 ± 1% (relative standard deviation), and stable 9Be in microgram amounts was separated from urine and analyzed by atomic absorption spectrometry with similar recoveries.