NISCAIR Online Periodicals Repository Collection: IJCT Vol.16(4) [July 2009]

Mn recovery from medium grade ore using a waste cellulosic reductant

Title: Mn recovery from medium grade ore using a waste cellulosic reductant

Authors: Hariprasad, D; Dash, B; Ghosh, M K; Anand, S

Abstract: Medium grade siliceous manganese ore containing 38.22% Mn was leached in sulphuric acid medium using shredded newspaper as reducing agent. Objective of the present study was to investigate the effectiveness of ligno-cellulosic base wastes such as used newspaper as a reducing agent. The experimental parameters chosen for this study were: H₂SO₄ concentration (2-5% v/v), temperature (60-90^oC), reductant to ore ratio (0.4-1) and ore particle size (57 – 274 µm). Optimum conditions for >90% extraction were: 90^oC, 5% H₂SO₄ (v/v), reductant to ore ratio 0.5, 8 h, 10% pulp density and ore particle size -100 m. Newspaper was found to be equally effective as a reducing agent for low grade ore (15.83% Mn) also wherein the amount of reductant and acid needed were proportional to Mn content of the ore. The leach solution was enriched to 87 g/L by recycling process. The enriched solution was purified by pH adjustment to 4.7 using 20% lime slurry. MnSO₄.H₂O was crystallized from purified solution. A schematic flow-sheet has been included.

Page(s): 322-327

Adsorption behaviour of Pb(II), Cd(II) and Zn(II) on NALCO plant sand

Title: Adsorption behaviour of Pb(II), Cd(II) and Zn(II) on NALCO plant sand

Authors: Mohapatra, M; Khatun, S; Anand, S

Abstract: Present investigation evaluates the adsorption of Pb(II), Cd(II) and Zn(II) ions on plant sand of National Aluminum Company, Orissa, India. The XRD pattern and FTIR spectra showed goethite, alumina and silica as the major phases in the sand. Effects of various parameters such as time, pH, temperature, metal ions and adsorbent concentrations were studied. The adsorption followed pseudo second order kinetics for all the three cations. The proton stoichiometry was dependent on the nature of the metal ion showing the order Zn(II)>Cd(II)>Pb(II). The adsorption was found to be in the order Zn(II)>Cd(II)> Pb(II) with loading capacities of 47.79, 42.2 and 22.8 mg g^-1 of plant sand sample. The adsorption data was fitted to various models. The thermodynamic parameters (Δ)G⁰, (Δ)H⁰ and (Δ)S⁰ have been evaluated. The XRD patterns of Pb(II) adsorbed plant sand sample showed that the crystallinity of silica phase was affected with the appearance of (110) plane and disappearance of (011) plane. It also disturbed the (110) plane of goethite. Cd(II) adsorbed sample showed disappearance of (011) plane of silica phase and transformation of alumina phase Al₂O₃ to σ-Al₂O₃. The adsorption of Zn(II) showed prominence of (110) plane of goethite with disappearance of σ-Al₂O₃ phase.

Page(s): 291-300

Enzymatic synthesis of fructose ester from mango kernel fat

Title: Enzymatic synthesis of fructose ester from mango kernel fat

Authors: Dandekar, P P; Patravale, V B

Abstract: Fructose ester as a biosurfactant was successfully synthesized from the fatty acid fraction (olein fraction) of Mango Kernel Fat (MKF). The synthesis was carried out by reaction of sugar and fatty acid fraction in presence of the enzyme lipase from Candida rugosa which acted as a biocatalyst. Phosphate buffer (pH 7.0) was used as the reaction medium to realise maximum enzymatic action. The product was separated from the reaction medium by liquid- liquid extraction. Maximum conversion (36.52 %) was achieved at fructose to olein fraction molar ratio of 1 : 10 (mol/L), with the lipase concentration of 4g/L, at a temperature of 30^oC at the end of 3 days. The presence of an ester band in the synthesized ester was confirmed by Fourier Transform Infrared (FTIR) analysis. Identity of the product was further confirmed by NMR studies and a colour identity test for the ester group.

Page(s): 317-321

Removal of fluoride from low TDS water using low grade coal

Title: Removal of fluoride from low TDS water using low grade coal

Authors: Borah, L; Dey, N C

Abstract: Defluoridation of ground water using low grade Assam coal as an adsorbent is studied by batch sorption experiments. Effect of the variables, like quantity of adsorbent, contact time, particle size of the adsorbent are examined to establish the optimum conditions. The results show that the low grade Assam coal, collected from Tirap colliery of the North Eastern coalfield, after pretreatment, can be used as an effective adsorbent in removing fluoride from ground water. The optimum conditions for the efficient removal of fluoride are observed to be (i) quantity of adsorbent = 1.25 g in 100 mL water, (ii) contact time = 60 min, (iii) particle size of adsorbent = —72 BSS or lower.

Page(s): 361-363