Indian Journal of Chemical Technology
Volume 9 Number 6 November 2002
CODEN:ICHTEU 9(5) 471-580 ISSN: 0971-457X
Corrosion behaviour of VTS, STS and DTS inhibitors in formic and
acetic acids 479
Reaction kinetics of formation of dibenz-[b,f]-1,4-oxazepine (CR)
from potassium salt of Schiff’s base 484
Ionization constants of crown dyes 487
Bioremediation of anaerobically digeted post-methanation distillery
spent wash 491
Albumin test strip for quick detection of albuminuria in human 496
Actvated carbon from parthenium as adsorbent: Adsorpation of Hg(II)
from aqueous solution 499
Enzymatic clarification of Beal juice by calcium alginate gel immobilized
PME of Aspergillus oryzae 504
Effect of transition metal cations and anions on the production of citric
acid by Aspergillus niger 508
Cobalt tungsten alloy-electrodeposition and characterization 513
An understanding of the dissolution and passivation of 70/30 cupronickel
Estimation of dielectric constants of some halogenated polymers by
group additive methods 526
Degumming of vegetable oil by membrane technology 529
Comparative study of catalytic activity of immobilized invertase in
Sodium alginate gel on sucrose hydrolysis 535
Removal of trace metals with mango seed powder 543
Corrosion behaviour of VTS, STS and DTS inhibitors in formic and acetic acids
M A Quraishi*, D Jamal & M Luqman
Three organic inhibitors namely, 1- Vanillin thiosemicarbazone (VTS), 1- Salicylaldehyde thiosemicarbazone (STS), 1- Dimethyl aminobenzaldehyde thiosemicarbazone (DTS) were synthesized to investigate their inhibiting actions on corrosion of mild steel (MS) in aqueous solutions containing 20% formic acid and 20% acetic acid by weight loss and potentiodynamic polarization methods. All of these compounds have shown good inhibition efficiency (IE) in formic acid solutions. IE of these compounds has been found to vary with the concentration of the compounds, temperature and immersion time. The adsorption of these compounds on the steel surface from the acids has been found to obey Temkin’s adsorption isotherm. The values of activation energy (Ea) and free energy of adsorption (DGads) indicated physical adsorption of these compounds on the steel surface. The potentiodynamic polarization experiments revealed that all the compounds are mixed type inhibitors.
Reaction kinetics of formation of Dibenz-[b,f]-1,4-oxazepine (CR) from potassium salt of Schiff’s base
Bidhan Chandra Bag* & M P Kaushik
The kinetics of formation of dibenz-[b,f]-1,4-oxazepine (CR) from potassium salt of schiff’s base (SB) has been studied at various temperatures. Integral method has been used for the analysis of the data and it has been observed that the reaction follows a unimolecular first order kinetics. The rate constant has been found to be 2.5×10-3 min-1, 2.99×10-2 min-1 and 1.63×10-1 min-1 at 90°C, 120°C and 150°C respectively. The values of activation energy and the frequency factor have also been determined.
Ionization constants of crown dyes
B R Pandya & Y K Agrawal*
The thermodynamic ionisation constants of the synthesised crown dyes are determined in aqueous and aqueous dioxane medium at 25±1°C by pH metric titration techniques. The thermodynamic ionisation constants were also determined in aqueous dioxane medium and in DMF by spectrophotometric method at 25±1°C.
Bioremediation of anaerobically digested post-methanation distillery spent wash
V K Garg* & Renuka Gupta
Anaerobically treated post-methanation spent wash is highly coloured with exceptionally high chemical oxygen demand (COD). An efficient isolate of Pseudomonas sp., viz., RG-2 for decolourisation was isolated from soil collected from distillery premises by enrichment culture method. RG-2 isolate was having considerable decolourisation (34.6 per cent) of 12.5 per cent diluted post-methanation spent wash after 8 days incubation. Addition of glucose to medium was essential to have decolourisation by this isolate. The effect of pH, carbon source, carbon source dose, nitrogen source, incubation period and post-methanation spent wash concentration have also been studied.
Albumin test strip for quick detection of albuminuria in human
Sandeep K Sharmaa, Madhu Balaa, N B Tulsania, Neeta Sehgalb & Ashok Kumara*
In this article, the dry-reagent test strip technique has been discussed for qualitative and semi-quantitative estimation of albumin in urine. The strip method developed in our laboratory is quick, simple, economical and based on indigenous technique. It is based on the principle of “Protein error” in which specific chromogen immobilized onto a pad reacts with albumin present in the urine and changes the colour of the strips from light yellow to blue-green. The change in colour is visible to the naked eyes and can be compared to the colour chart for the estimation of total albumin concentration present in the urine sample.
Activated carbon from parthenium as adsorbent: Adsorption of Hg(II) from aqueous solution
K Kadirvelua, C Sivasankarib, M Jambuligamb & S Pattabhia*
Activated carbon (AC) prepared from parthenium was used to remove Hg(II) from aqueous solution by adsorption technique under varying conditions of agitation time, metal ion concentration, adsorbent dose and pH. Adsorption equilibrium reached within 165 min for all concentrations studied (10 to 50 mg/L). Adsorption is dependents on solution pH, Hg (II) concentration, carbon concentration and contact time. Adsorption followed both Langmuir and Freundlich isotherm models. The adsorption capacity was found to be 10 mg/g of AC at initial pH of 5.0 at 30+2°C for the particle size of 125-250µm. The percent removal increased with pH from 2 to 6 and remained constant up to pH 10.0.
U Ghosh & H Gangopadhyay*
The production of pectin methyl esterase (PME) was investigated on solid substrate fermentation of Aspergillus oryzae. The optimum conditions of PME production were 300C, incubation for 3 days and hydration of wheat bran 50% (w/v). The partially purified PME was then immobilized by 2% sodium alginate by crosslinking with 2% CaCl2 solution, retaining 68% of the activity of free PME. Optimum pH for free and immobilized PME was 3.6 and 4.0 respectively. Optimum temperature was the same for free and immobilized PME. Michaelis constant for free and immobilized PME was 0.7% and 0.6% respectively. The immobilized PME retained about 72% of the initial activity after being used for 10 cycles for the clarification of Bael juice.
Effect of transition metal cations and anions on the production of citric acid by Aspergillus niger
Ar Angumeenala, P Kamalakannana, H J Prabhub & D Venkappayyaa*
Interest in studying the effect of microelements on the metabolism of fungi during the bioconversion has led to this work. The present work reports the production of citric acid starting from glucose by Aspergillus niger. The microelements supplemented were cadmium, lead, chromium and molybdenum. The bioconversion path of Aspergillus niger was TCA cycle. The products of the microbial metabolism namely total titrable acidity, citric acid, succinic acid, malic acid, intracellular proteins, extracellular proteins, amylase activity, lipid and biomass contents were determined periodically. Among the nutritional supplements tried cadmium was found to drive the metabolism of Aspergillus niger to produce more amount of citric acid. Experimentally observed growth stages were used for mathematical modelling to explore kinetic parameters. The values calculated based on the model were found to agree well with the observed ones in the case of lead and cadmium as supplements, whereas in the case of molybdenum and chromium deviations occur between the calculated and observed values. This discrepancy in the values of metabolic products was ascribed to the pH, temperature and other inhibitory products formed during fermentation.
Cobalt tungsten alloy-electrodeposition and characterisation
A Subramaniana, G N Kousalyaa, V S Muralidharanb* & T Vasudevana
Bright Co-W alloy on steel is obtained from the optimised bath with the operating conditions of cobalt sulphate 0.15 M sodium tungstate 24 gpl, ammonium chloride 0.2 M, sodium citrate 0.2 M, dimethyl sulphoxide 0.06 M, pH 8 at 4 Adm-2. The hardness of the alloy deposit is two times that of cobalt deposit. The corrosion resistance in 1.0 M acidic solutions for Co-20% W alloy is in the order of HCl > H2SO4 > HClO4. The deposition of cobalt on platinum takes place from cobalt citrate complex. This citrate complex undergoes successive electron transfer. During the Co-W alloy deposition on platinum, cobalt tungstate complex undergoes reduction to form an alloy. The dissolution of Co-W alloy film occurs from Co-W intermediate phase.
An understanding of the dissolution and passivation of 70/30 cupronickel alloy
J Mathiyarasu, N Palaniswamy & V S Muralidharan*
Cyclic voltammetric studies carried out on copper, nickel and 70/30 cupronickel in 0.5 M NaCl solutions revealed that the passivation of copper is due to the formation of Cu2O via CuCl2- and that of nickel is due to oxide formation. X-ray diffraction (XRD) and X-ray photoelectron spectral (XPS) studies on cupronickel revealed the presence of partially covered surface with a corrosion film containing essentially Cu2O. Increase of anodic potential resulted in the formation of chloro hydroxy cupric compounds along with nickel oxide. At potential closer to oxygen evolution, divalent and trivalent oxides of nickel species were predominant. The surface film analysis by X-ray fluorescence (XRF) studies revealed the film to contain more copper than nickel at potential below + 200 mV (SCE). However, at higher anodic potentials the amount of nickel exceeded that of copper. The leaching of cupronickel alloy was found to be uniform and not a preferential one for a less noble metal, such as copper.
Estimation of dielectric constants of
some halogenated polymers by
group additive methods
Muneera Beguma, A Varada Rajulub & Siddaramaiaha*
The dielectric constants (e) of some halogenated polymers were estimated by employing four different equations based on the group additive principle. The estimated values were compared with the experimental values. The suitability of individual equations is discussed.
Degumming of vegetable oil by membrane technology
N C Desaia*, M H Mehtab, A M Davec & J N Mehtac
Conventional method of degumming of crude vegetable oil, which involves the treatment of oil with steam followed by acid, is associated with many drawbacks, such as loss of oil, generation of wash waters, poor quality of degummed oil, etc. These drawbacks can be eliminated by the use of membrane technology being energy efficient, ecofriendly, and simple in operation. In order to explore the possibilities of utilizing membrane based separation process for the degumming of crude vegetable oil, this study has been conducted. The findings of the study indicate that membranes can remove phospholipids approximately 90% and above from castor oil, salicorniaseed oil and cottonseed oil. The permeability of membrane depends on the pressure applied. Ultrafiltration membranes exhibit higher permeability comparative to nanofiltration membrane. In addition to removal of phospholipids, membranes can simultaneously remove colour approximately 80% from the oil.
Comparative study of catalytic activity of immobilized invertase in sodium alginate gel on sucrose hydrolysis
C N Khobragade* & S G Chandel
Invertase is an intracellular hydrolytic enzyme widely used in the inversion of sucrose into glucose and fructose. Both glucose and fructose are the primary compounds used as sweeteners in the food processing industries. In the present investigation invertase was immobilized in sodium alginate gel by entrapment method and the catalytic activity of immobilized enzyme was compared with the activity of native enzyme at variable pH and temperatures. Experimental findings revealed that for native enzyme optimum activity was at pH 4.2 and at temperature 30°C, while for immobilized enzyme it was observed at pH 4.8 and at temperature 50°C. Kinetic parameters Km and Vmax as well as catalytic efficiency of invertase was also determined for both the native and immobilized enzyme.
Removal of trace metals with mango seed powder
Dimple C Parekha, Jignesh B Patela, Padmaja Sudhakar*a & V J Koshy*b
Removal of heavy metals like Cu, Cd, Pb from aqueous solution was studied using mango seeds powder. Study was carried out in batch technique as a function of contact time, metal ion concentration and pH of the solution. The sorption process follows Freundlich sorption isotherm. Maximum sorption was observed at acidic pH itself. The method is applied to various synthetic solutions.
The role of AlPO4-11 in the synthesis of bisphenol-A and cinnamic acid
B V Suresh Kumara*, K Byrappaa, K M Lokanatha Raib, S Anandb & R V Raoc
AlPO4-11 was used as catalyst for the synthesis of bisphenol-A by Friedel-Crafts condensation of acetone with phenol in presence of carbon tetrachloride and synthesis of cinnamic acid by Knovenagel condensation of aromatic aldehydes with malonic acid in presence of ethyl alcohol.
Heat Radiation Law—From Newton to Stefan
The understanding and quantification of the phenomenon of heat radiation has gone through many phases, parallel to the interpretation of the concept of heat.