Pigeon Pea Husk for Removal of Emerging Contaminants Trimethoprim and Atenolol from Water

The pace of industrialization and rapid population growth in countries such as India entail an increased input of industrial and sanitary organic micropollutants, the so-called emerging contaminants (EC), into the environment. The emission of EC, such as pharmaceuticals, reaching Indian water bodies causes a detrimental effect on aquatic life and ultimately on human health. However, the financial burden of expanding sophisticated water treatment capacities renders complementary, cost-efficient alternatives, such as adsorption, attractive. Here we show the merits of washed and milled pigeon pea husk (PPH) as low-cost adsorbent for the removal of the EC trimethoprim (TMP) and atenolol (ATN) that are among the most detected pharmaceuticals in Indian waters. We found a linear increase in adsorption capacity of PPH for TMP and ATN at concentrations ranging from 10 to 200 μg/L and from 50 to 400 μg/L, respectively, reflecting the concentrations occurring in Indian water bodies. Investigation of adsorption kinetics using the external mass transfer model (EMTM) revealed that film diffusion resistance governed the adsorption process of TMP or ATN onto PPH. Moreover, analysis of the adsorption performance of PPH across an extensive range of pH and temperature illustrated that the highest adsorption loadings achieved concurred with actual conditions of Indian waters. We anticipate our work as starting point towards the development of a feasible adsorbent system aiming at low-cost water treatment.

Heterogeneous degradation of precipitated hexamine from wastewater by catalytic function of silicotungstic acid in the presence of H2O2 and H2O2/Fe2+

The industrial wastewater produced by hexamine plants is considered as a major environmental polluting factor due to resistance to biodegradation. So the treatment of such wastewater is required. In this work, the removal of hexamine from wastewater and its degradation have been studied. Hexamine was precipitated through formation of an insoluble and stable compound with silicotungstic acid. The oxidative heterogeneous degradation of precipitated hexamine was carried out with hydrogen peroxide (H(2)O(2)) aqueous solution and H(2)O(2)/Fe(2+) under the catalysis of silicotungstic acid. The operating conditions including amount of precipitate, hydrogen peroxide and ferrous ion dosage, temperature, time and pH were optimized by evaluating the removal of total organic carbon from system. A total organic carbon conversion higher than 70% was achieved in the presence of H(2)O(2)/Fe(2+). The experimental results showed that hexamine can be effectively degraded with H(2)O(2) and H(2)O(2)/Fe(2+) under the catalysis of silicotungstic acid. It was interesting that the solution of dissolved precipitate with H(2)O(2) can re-react with hexamine after the removal of excess hydrogen peroxide. This observation indicates the catalysis role of silicotungstic acid in the degradation of hexamine. A kinetic analysis based on total organic carbon reduction was carried out. The two steps mechanism was proposed for the degradation of hexamine.

[Pharmacodynamic study of Relinqing granules on bacterial pyelonephritis model in rats]

OBJECTIVE

To observe the effects of Relinqing granules (powder of Polygonum capitatum extract) on the bacterial pyelonephritis model in rats.

METHOD

The rat bacterial pyelonephritis model was induced by injecting the escherichia coli ATCC-25922 into kidney parenchyma. The rats were divided ramdamly into Relinqing groups(52.32, 26.16 g x kg(-1)), norflorin group (0.03 g x kg(-1)), model group and normal control group, and were given experimental drugs by gastrogavage. The contents of leucocytes (WBC), occult bloo (BLD), glucose (GLU), protein (PRO), ketones, bilirubin and urobilinagen in urine were determined.

RESULT

As compared with the model group, Relinqing granules 6.0 g x kg(-1) (crude drug 52.32 g x kg(-1)) could decrease significantly the contents of WBC and BLD in urine and, however, had no markedly effects on the other biochemical parameters of urine.

CONCLUSION

Relinqqing granule has significant effects of decreasing urine WBC and BLD on the bacterial pyolonephritis in rats.

Removal of direct red 12B and methylene blue from water by adsorption onto Fe (III)/Cr (III) hydroxide, an industrial solid waste

Removal of direct red 12B and methylene blue by adsorption onto Fe (III)/Cr (III) hydroxide was studied using various parameters such as agitation time, dye concentration, adsorbent dose and pH. Equilibrium adsorption data followed both Langmuir and Freundlich isotherms. Adsorption followed second-order rate kinetics. The Langmuir adsorption capacity (Qo) was found to be 5.0 and 22.8 mg dye per g of the adsorbent for direct red 12B and methylene blue, respectively. Acidic pH was favorable for the adsorption of direct red 12B and basic pH for methylene blue. Desorption studies showed that chemisorption seems to be the major mode of adsorption.

Adsorption onto fluidized powdered activated carbon flocs-pACF

This work presents a new adsorption technique where the adsorbent (powdered activated carbon-PAC) is in the form of suspended flocs formed with water-soluble polymer flocculants. Thus, the adsorption of a typical dye, methylene blue (MB), was studied onto polyacrylamide flocs of PAC (PACF) in a fluidized bed reactor. The technique is based on the fact that the adsorption capacity of PAC does not decrease after flocculation because the adsorbed polymer occupies only a few surface sites, in the form of trains, loops, and tails. Moreover, the adsorption was found to proceed through a rapid mass transfer of MB to the adsorbing PAC flocs, in the same extent as onto PAC. Because of the rapid settling characteristics of the aggregates formed, the two phase separations, loaded PAC and solution, become easier. Thus, the technique offers the advantages of conducting simultaneously both adsorption and solid/liquid separation all in one single stage. Results obtained showed that high MB removal values can be attained in a fluidized bed reactor (>90%) and that PACF presents a much higher adsorption capacity (breakthrough points) than granulated activated carbon (GAC) in the same adsorbing bed. It is believed that this technique highly broadens the potential of the use of powdered activated carbon or other similar ultrafine adsorbents.

Solubilities of phenazopyridine, propranolol, and methimazole in supercritical carbon dioxide

The equilibrium solubilities of three drugs (phenazopyridine, propranolol and methimazole) were determined at temperatures ranging from 308 to 348 K and pressures from 122 to 355 bar in supercritical CO2 by a simple and reliable static method. The crossover region was observed for phenazopyridine, propranolol and methimazole at 180 bar. The solubilities were correlated using a semi empirical model. Correlation of the results shows good self-consistency of the data obtained.