Kailas L. Wasewar

Reactive extraction of lactic acid using alamine 336 in MIBK: equilibria and kinetics.

Lactic acid is an important commercial product and extracting it out of aqueous solution is a growing requirement in fermentation based industries and recovery from waste streams. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid-amine (solvent) system used. Equilibria for lactic acid extraction by alamine 336 in methyl-iso-butyl-ketone (MIBK) as a diluent have been determined. The extent to which the organic phase (amine +MIBK) may be loaded with lactic acid is expressed as a loading ratio, z=[HL](o)/[B](i,o). Calculations based on the stoichiometry of the reactive extraction and the equilibria involved indicated that more lactic acid is transferred to the organic phase than would be expected from the (1:1) stoichiometry of the reaction. The extraction equilibrium was interpreted as a result of consecutive formation of two acid-amine species with stoichiometries of 1:1 and 2:1. Equilibrium complexation constant for (1:1) and (2:1) has been estimated. Kinetics of extraction of lactic acid by alamine 336 in MIBK has also been determined. In a first study of its kind, the theory of extraction accompanied by a chemical reaction has been used to obtain the kinetics of extraction of lactic acid by alamine 336 in MIBK. The reaction between lactic acid and alamine 336 in MIBK in a stirred cell falls in Regime 3, extraction accompanied by a fast chemical reaction occurring in the diffusion film. The reaction has been found to be zero order in alamine 336 and first order in lactic acid with a rate constant of 1.38 s(-1). These data will be useful in the design of extraction processes.

Intensification of enzymatic hydrolysis of penicillin G: Part 1. Equilibria and kinetics of extraction of phenyl acetic acid by Alamine 336

Abstract Equilibrium and kinetic studies for the extraction of phenyl acetic acid (PAA) by Alamine 336 in different diluent are reported. Kerosene as a diluent yields a much higher equilibrium constant than methyl isobutyl ketone. The theory of extraction accompanied by a chemical reaction has been used to obtain the intrinsic kinetics of extraction by Alamine 336 in kerosene. The reaction has been found to be zero order in Alamine 336 and first order in PAA with a rate constant of 0.9 s −1 .

Removal of fluoride from aqueous solution: status and techniques

Abstract Presence of various hazardous contaminants like fluoride, arsenic, nitrate, sulfate, pesticides, heavy metals, and other elements in ground water or surface water make the water unsafe and dangerous for the drinking purpose. The presence of any of these elements in drinking water in excess to the permissible limit is harmful for the human life. Fluoride is one of the elements which is very important for health especially for the children during teeth formation as well as harmful for human health if present in water more than permissible limit. Absence or insufficient amount of fluoride in drinking water causes dental caries during teeth formation of children whereas the presence of excess fluoride in drinking water causes dental and skeletal fluorosis. Therefore, maintaining of fluoride concentration within the safe limits is very important. The presence of excess fluoride in drinking water is a global problem. Excessive fluoride concentrations have been reported in ground waters of more than 27 ...

Design of experiments for Malachite Green dye removal from wastewater using thermolysis – coagulation–flocculation

Abstract Thermolysis – coagulation–flocculation was used for reduction of colour and chemical oxygen demand (COD) of aqueous basic dye Malachite Green. Statistical design of experiment was used for thermolysis experiments which resulted of 69.57% and 70.59% maximum reduction of COD and color, respectively at the optimum conditions of 95 min treatment time, 82°C treatment temperature, and pH 11.02. MgCl2 was used as coagulant for coagulation–flocculation. About 98% of color and 90% of COD were reduced at a final pH of 10.89 and a coagulant dose of 3 g MgCl2 l−1 of dye solution. The optimum conditions for coagulation–flocculation process were determined by varying a single factor while keeping other factors fixed at a specific set of conditions. Coagulation–flocculation after thermolysis at the optimal operating conditions resulted in a reduction of 91.26% COD and 98.78% color at final pH 10.89 but at a much lesser coagulant dosage of 500 mg l−1. Compared to only coagulation–flocculation, combined process o...

REACTIVE EXTRACTION OF PROPIONIC ACID USING TRI-n-OCTYLAMINE

Reactive extraction of propionic acid using tri-n-octylamine (TOA) in 1-decanol and 2-octanol was studied. Physical and chemical extractions from aqueous solution of acid were presented. The extraction of propionic acid from aqueous solutions using TOA in 1-decanol and 2-octanol, respectively, resulted in a degree of extraction as high as 92%. The effect of temperature was studied and it was found that as the temperature was raised from 305 to 353 K, KE decreased from 30.11 to 11.85 and 19.44 to 10.23 in the case of 30 and 40% TOA, respectively, in 1-decanol and 28.57 to 11.32 and 21.99 to 8.70 in the case of 30 and 40% TOA, respectively, in 2-octanol. TOA in both diluents was found to be more effective at pH values less than 4. Increasing the pH from natural pH to 7 was found to severely affect the extraction. Different salts (NaCl, Na2SO4, K2HPO4) and substrate sources (lactose and dextrose) were selected to study their effects on the reactive extraction of propionic acid. The presence of salts lowers the extraction, but substrate sources were found to have no effect on the extraction of propionic acid using TOA in either diluent. Six model solutions were prepared containing various concentrations of salts and substrate to get a real view of extraction. Extraction from the model solutions was lower than that observed in the aqueous solutions. However, the values are still high enough to have a sustainable extraction.

Comparative study of different waste biomass for energy application

Biomass is available in many varieties, consisting of crops as well as its residues from agriculture, forestry, and the agro-industry. These different biomass find their way as freely available fuel in rural areas but are also responsible for air pollution. Emissions from such solid fuel combustion to indoor, regional and global air pollution largely depend on fuel types, combustion device, fuel properties, fuel moisture, amount of air supply for combustion and also on climatic conditions. In both economic and environment point of view, gasification constitutes an attractive alternative for the use of biomass as a fuel, than the combustion process. A large number of studies have been reported on a variety of biomass and agriculture residues for their possible use as renewable fuels. Considering the area specific agriculture residues and biomass availability and related transportation cost, it is important to explore various local biomass for their suitability as a fuel. Maharashtra (India) is the mainstay for the agriculture and therefore, produces a significant amount of waste biomass. The aim of the present research work is to analyze different local biomass wastes for their proximate analysis and calorific value to assess their potential as fuel. The biomass explored include cotton waste, leaf, soybean waste, wheat straw, rice straw, coconut coir, forest residues, etc. mainly due to their abundance. The calorific value and the proximate analysis of the different components of the biomass helped in assessing its potential for utilization in different industries. It is observed that ash content of these biomass species is quite low, while the volatile matter content is high as compared to Indian Coal. This may be appropriate for briquetting and thus can be used as a domestic fuel in biomass based gasifier cook stoves. Utilizing these biomass species as fuel in improved cook-stove and domestic gasifier cook-stoves would be a perspective step in the rural energy and environmental sectors. This is important considering that the cleaner fuel like LPG is still not available in rural areas of many parts of the world.

Extractive Deep Desulfurization of Liquid Fuels Using Lewis-Based Ionic Liquids

A new class of green solvents, known as ionic liquids (ILs), has recently been the subject of intensive research on the extractive desulfurization of liquid fuels because of the limitation of traditional hydrodesulfurization method. In present work, eleven Lewis acid ionic liquids were synthesized and employed as promising extractants for deep desulfurization of the liquid fuel containing dibenzothiophene (DBT) to test the desulfurization efficiency. [Bmim]Cl/FeCl3 was the most promising ionic liquid and performed the best among studied ionic liquids under the same operating conditions. It can remove dibenzothiophene from the model liquid fuel in the single-stage extraction process with the maximum desulfurization efficiency of 75.6%. It was also found that [Bmim]Cl/FeCl3 may be reused without regeneration with considerable extraction efficiency of 47.3%. Huge saving on energy can be achieved if we make use of this ionic liquids behavior in process design, instead of regenerating ionic liquids after every time of extraction.

Effect of sonication time on enhancement of effective thermal conductivity of nano TiO2–water, ethylene glycol, and paraffin oil nanofluids and models comparisons

This paper presents experimental and theoretical determination of the effective thermal conductivity of various base fluids and nano TiO2 composition. Ultrasonically assisted sol–gel method was used for synthesising anatase TiO2 nanoparticles and dispersing them into base fluids using sonication for the synthesis of nanofluids. It is observed that thermal conductivity enhancement is significantly higher than that of base fluid. The thermal conductivity shows an increment with the addition of nanoparticles and confirms a 22% enhancement achievable in base fluids. The effect of base fluids is a complex idea and difficult to understand; lower base fluid viscosities were supposed to contribute higher in enhancement of thermal conductivity, but another important factor; i.e. fluid nanoparticles surface interaction, nanoparticles crystal type also contributes in enhancement. In the further study, as the sonication time increases; an improvement in the thermal conductivity of nanofluids is also observed. Except water-based nanofluids, all others show reasonably good agreement with the data predicted by Bruggeman model and the prediction is in the range of 5%. This study is important since it covers base fluids with a wide range of thermal conductivity and viscosity.

Status of adsorptive removal of dye from textile industry effluent

Abstract Textile industry is the key user of dyes and hence the prime source of water pollution, which risks aquatic as well as human life. There are various physical, chemical, and biological methods for dye removal, but most convincing is adsorption due to its simplicity. The extensive research has been carried out in this field which has brought a wide range of adsorbents in reach of industries. Freshly obtained off beat adsorbents in addition to direct one present have been used. The present paper aims at the broad classification of adsorbents recently introduced to the arena. The division of adsorbents comprises conventional means like activated carbon (commercial and derived), zeolite, and other nonconventional adsorbents as natural material, wastes, or even especially designed adsorbents, which are inexpensive and clean to use. Also, the investigations done regarding adsorption lately have been compared with respect to their results. The efficacy of each operation is under grave discussion. Up to 9...

Comparative Study of the Mechanical and Thermal Properties of Polyamide-66 Filled with Commercial and Nano-Mg(OH)2 Particles

In the present work, polyamide-Mg(OH)2 nanocomposites were prepared via melt intercalation on a twin-screw extruder. Different particle sizes (24, 20, 11 nm) of Mg(OH)2 were synthesized by in-situ deposition technique and its shape and sizes was confirmed on transmission electron microscope (TEM). Nano-Mg(OH)2 was added from 1 to 4 wt% in the polyamide. Properties such as tensile strength, elongation at break, hardness, and flame retardency were studied. These results were then compared with commercial Mg(OH)2-filled composites. There was propounding effect to be observed on properties of polyamide nanocomposites due to uniform dispersion of nano-Mg(OH)2 and commercial Mg(OH)2. Moreover, thermal property like thermal degradation was studied on TGA. Extent of dispersion of nano-Mg(OH)2 was studied along with microcracks generated during tensile testing using AFM. It was found that nano-Mg(OH)2 is thermally more stable compared to that of commercial Mg(OH)2. Besides that, Tg and M.T. are studied on DSC.