Adsorption characteristics of brilliant green dye on kaolin.

Experimental investigations were carried out to adsorb toxic brilliant green dye from aqueous medium using kaolin as an adsorbent. Characterization of kaolin is done by measuring: (i) particle size distribution using particle size analyzer, (ii) BET surface area using BET surface analyzer, and (iii) structural analysis using X-ray diffractometer. The effects of initial dye concentration, contact time, kaolin dose, stirring speed, pH and temperature were studied for the adsorption of brilliant green in batch mode. Adsorption experiments indicate that the extent of adsorption is strongly dependent on pH of solution. Free energy of adsorption (DeltaG0), enthalpy (DeltaH0) and entropy (DeltaS0) changes are calculated to know the nature of adsorption. The calculated values of DeltaG0 at 299K and 323K indicate that the adsorption process is spontaneous. The estimated values of DeltaH0 and DeltaS0 both show the negative sign, which indicate that the adsorption process is exothermic and the dye molecules are organized on the kaolin surface in less randomly fashion than in solution. The adsorption kinetic has been described by first-order, pseudo-second-order and intra-particle-diffusion models. It was observed that the rate of dye adsorption follows pseudo-second-order model for the dye concentration range studied in the present case. Standard adsorption isotherms were used to fit the experimental equilibrium data. It was found that the adsorption of brilliant green on kaolin follows the Langmuir adsorption isotherm.

Iron and hemoglobin status of the offspring of guinea pigs whose mother received large doses of vitamin C during pregnancy and lactation.

1. Lower level of serum and liver iron were noted in the offspring of experimental group quinea pigs who received 1, 2 and 3 mg ascorbic acid per 100 g body weight per day. 2. Similar results were obtained in the hemoglobin content of same animals. 3. Normal values were observed for hemoglobin and the content of iron in serum and liver in the same group of offsprings when they were fed 4 mg ascorbic acid per 100 g body weight per day.

Effects of high intake of vitamin C by the guinea pigs in pregnancy and lactation on the tissue levels of the vitamin in their offspring.

1. Though the growth-rate of the guinea pigs of both the groups - control and experimental were almost same, the gain in body weight in the offspring of experimental group animals were observed to be less when they were fed 1, 2 and 3 mg ascorbic acid per 100 g body weight per day. 2. Ascorbic acid content in the tissues of the offspring maintained on 1, 2 and 3 mg ascorbic acid belonging to the experimental group were low. 3. The rate of growth and the tissue content of ascorbic acid were found to be normal in the same group of animals when they were supplemented with 4 mg ascorbic acid per 100 g body weight daily.

Effect of ascorbic acid on histamine metabolism in scorbutic guinea-pigs.

1. In guinea-pigs fed an ascorbic-acid-free diet, as the ascorbic acid levels decreased the histamine levels in blood and urine rose steadily to maxima in about 10-12 days. The elevated histamine levels persisted in the blood and urine of scorbutic guinea-pigs and the histamine levels in lung, gastric mucosa and spleen also increased. The increased histamine content of the urine, blood and other tissues in the ascorbic-acid-depleted condition could be brought back to normal levels by administration of a single dose of ascorbic acid 5 mg/100 g body wt. guinea-pig. 3. The drop in the elevated histamine level was not due to an indirect effect of ascorbic acid on histamine forming capacity, histaminase activity or histamine release.

Growth and ascorbic acid metabolism in rats and guinea pigs fed cereal diets.

The nutritional values of the whole grain principal cereals, namely, wheat, rice, corn, and a millet bajra, were investigated by growth studies and studies on ascorbic acid metabolism in rats and guinea pigs. Growth was markedly retarded by feeding the rats unfortified whole grain cereals. Among the whole grain cereals, rice provided the lowest nutritional value, and the cooking of rice affected the nutritional value further. In weanling rats, ascorbic acid synthesis at the subcellular level was inhibited, and tissue storage of ascorbic acid was decreased in rats fed whole grain cereals. In guinea pigs fed whole grain cereals, the utilization of ascorbic acid was increased. Ascorbic acid supplementation at various levels indicated that the requirement for ascorbic acid increased five times in guinea pigs fed whole grain cereals. The increased intake of the vitamin was not needed when the whole grain cereals were enriched with 15% casein.

Nutrient interrelationship of ascorbic acid and iron in rats and guinea pigs fed cereal diets.

Iron at a daily dose of 5 mg per animal was toxic to rats and guinea pigs fed unfortified whole wheat flour and whole rice flour diets. In rats, a species capable of synthesizing ascorbic acid, iron supplementation resulted only in decreased growth. In guinea pigs, iron administration resulted not only in decreased growth but also in high mortality. The apparent toxicity of iron was not observed when wheat flour was fortified with 15% casein. In guinea pigs, administration of ascorbic acid (k mg per 100 g body weight per day) along with iron not only counteracted the toxic effect of iron, but also led to a greater utilization of iron as revealed by increased hemoglobin and serum iron levels accompanied by decreased spleen iron content. Iron administration, however, resulted in decreased ascorbic acid synthesis (in rats only) and increased ascorbic acid utilization as revealed by lowered urinary, blood, and other tissue levels of the vitamin.