NISCAIR Online Periodicals Repository Collection: JSIR Vol.63(08) [August 2004]

Study on axial mixing in open and packed columns with and without pulsation

Thu, 29 Jul 2004 22:58:59 GMT

Title: Study on axial mixing in open and packed columns with and without pulsation

Authors: Feroz, S; Rao, Z Pramod; Kumar, P V Ravi; Prasad, V S R K

Abstract: Axial mixing in open and packed columns with and without the application of pulsation is studied. It is found that the dispersion coefficient increases with increase in flow rate, amplitude of pulsation in both open and packed columns, and with frequency it increases to some extent and then decreases. In packed columns the dispersion coefficient is found to increase with increasing particle diameter. The dispersion coefficient is found to be much higher with pulsation than without pulsation in both open and packed columns. The data in the present study without pulsation follow pure convection model for open column and are found to be in good agreement with Bischoff correlation for packed column. Correlations are developed for the axial dispersion coefficient in open and packed columns based on modified N_pe – N_Re numbers, considering the effects of all the parameters studied in the present work.

Page(s): 672-676

Treatment of pulp and paper mill effluent

Thu, 29 Jul 2004 22:58:59 GMT

Title: Treatment of pulp and paper mill effluent

Authors: Garg, Anurag; Narayana, V V V S S; Chaudhary, Parmesh; Chand, Shri

Abstract: Pulp and paper mill effluent (COD= 0.7 kg/m³) was treated for the removal of non-biodegradable and toxic compounds by wet air oxidation (WAO) using heterogeneous catalysts. The catalysts include (CuO-ZnO) supported on alumina and ceria as well as lanthanum based perovskites. The activity tests were carried out at 95^oC under atmospheric pressure conditions. A maximum COD reduction of 83 per cent for (CuO-ZnO)/CeO₂ catalyst was obtained in 2 h reaction time at a catalyst conc. of 5 kg/m³ and the initial pH of wastewater sample at 3.0. LaCoO₃ catalyst showed the maximum COD reduction in the basic medium (pH 9.0), whereas the two other catalysts were active in acidic region.

Page(s): 667-671

Alpinia leaf extract: A prospective natural food preservative

Thu, 29 Jul 2004 22:58:59 GMT

Title: Alpinia leaf extract: A prospective natural food preservative

Authors: Sharma, K D; Hashinaga, Fumio

Abstract: Alpinia kumatake leaves, traditionally used for the wrapping of food materials were investigated for their antimicrobial activity against six strains of bacteria, nine strains of moulds and five strains of yeasts. The antimicrobial substance was extracted by using different organic solvents, fractionated, and purified by using silica gel column chromatography and thin layer chromatography. The diethyl ether extract showed higher antimicrobial activity amongst the solvents tried. Both acidic and phenolic fractions had very strong inhibitory effect against bacteria, however, it was poor for yeasts and moulds. The bacterial inhibition of TLC purified substance was 16.25 and 24.38 mm/μg for acidic and phenolic fractions, respectively. The inhibitory effects exhibited by the extracts of Alpinia kumatake leaves showed that there is a possibility of profitable utilization of the plants growing on barren lands for the production of natural food preservatives.

Page(s): 689-693

Synthesis, characterization and applications of a new chelating resin containing nitrosocatechol

Thu, 29 Jul 2004 22:58:59 GMT

Title: Synthesis, characterization and applications of a new chelating resin containing nitrosocatechol

Authors: Pandey, Sachin S; Thakkar, N V

Abstract: A macroreticular polystyrene based chelating ion exchanger containing nitrosocatechol as the functional group has been synthesized. The resin is found to be stable in acidic as well as in basic media. Physicochemical properties of the resin are examined. Sorption capacities of the heavy metal ions on resin are found to be quantitative in the pH range of 1.0 – 7.0. Sorption kinetics of metal ions on the resin is studied. The total sorption capacities of the metal ions as a function of pH were 0.35 mmol/g at pH 4.0, 0.19 mmol/g at pH 5.0 and 0.06 mmol/g at pH 6.0 for Cd(II), Hg(II) and Pb(II) ions, respectively. Under competitive conditions the system shows higher selectivity of Cd(II). The sorption and desorption characteristics for cadmium(II), lead(II) and mercury(II) are studied with a view to utilizing the resin for the removal of cadmium(II), lead(II) and mercury(II) as well as preconcentration of cadmium(II) ions from water samples by column operation.

Page(s): 682-688