K. V. Thiruvengadaravi

Chemometric formulation of bacterial consortium-AVS for improved decolorization of resonance-stabilized and heteropolyaromatic dyes.

A bacterial consortium-AVS, consisting of Pseudomonas desmolyticum NCIM 2112, Kocuria rosea MTCC 1532 and Micrococcus glutamicus NCIM 2168 was formulated chemometrically, using the mixture design matrix based on the design of experiments methodology. The formulated consortium-AVS decolorized acid blue 15 and methylene blue with a higher average decolorization rate, which is more rapid than that of the pure cultures. The UV-vis spectrophotometric, Fourier transform infra red spectrophotometric and high performance liquid chromatographic analysis confirm that the decolorization was due to biodegradation by oxido-reductive enzymes, produced by the consortium-AVS. The toxicological assessment of plant growth parameters and the chlorophyll pigment concentrations of Phaseolus mungo and Triticum aestivum seedlings revealed the reduced toxic nature of the biodegraded products.

Lead(II) Adsorption onto Sulphuric Acid Treated Cashew Nut Shell

In this study, sulphuric acid treated cashew nut shell (STCNS) was used as adsorbent for the removal of lead(II) ions from the aqueous solutions. Adsorption studies were performed by varying the solution pH, contact time, and temperature. Experimental data were analyzed by the model equations such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms and it was found that the Freundlich isotherm model fits best with the experimental data at different temperatures studied. The maximum adsorption capacity of lead(II) on STCNS was determined as 408.6, 432, 446.3, and 480.5 mg/g, respectively, at different temperatures (30, 40, 50, and 60°C). The thermodynamic parameters (ΔGo, ΔHo, and ΔSo) were calculated and the thermodynamic properties of lead(II) ions-STCNS system indicate the exothermic process. Adsorption kinetic constants were determined using pseudo-first-order, pseudo-second-order, and the Elovich kinetic models at various temperatures. The adsorption results clearly showed that the adsorption of lead(II) ions onto STCNS followed pseudo-second-order model and the adsorption was both by film diffusion and by intraparticle diffusion. A single-stage batch adsorber was designed using the Freundlich equation.

Removal of Acid Violet 17 from Aqueous Solutions by Adsorption onto Activated Carbon Prepared from Pistachio Nut Shell

Adsorbents prepared from pistachio nut shell, an agricultural waste biomass, were successfully used to remove Acid Violet 17 from an aqueous solution. The activated carbons PNS1, PNS2, and PNS3 were characterized by scanning electron microscope (SEM), Fourier Transform – Infra Red spectroscopy (FTIR) and (BET). The effect of pH, adsorbent dosage, and temperature on dye removal was studied. Maximum color removal was observed at pH 2. The adsorption increased with the increase in adsorbent dosage. As the adsorption capacity increased with the increase in temperature, the process was concluded to be endothermic. The experimental data were analyzed by the Langmuir and Freundlich isotherm models of adsorption. Equilibrium data fitted well with the Langmuir model. The rates of adsorption confirmed the pseudo-second order kinetics with good correlation values. The results indicated that the activated carbon prepared from pistachio nut shell can be effectively used for the removal of Acid Violet 17 from aqueous solution.

Indigenously acclimatized bacterial consortium for anthracene biotransformation

ABSTRACT A bacterial consortium was screened from the soil exposed to frequent petroleum spills and was employed to degrade and detoxify anthracene at normal operating parameters under static condition. The anthracene degradation was facilitated by the bacterial cells mediated metabolism and biodegradation was confirmed by the different spectral and chromatographic techniques. The distinct products of biotransformation were due to the enzymatic activity of the bacterial consortium.

The Solid Acid Catalyzed Esterification of Free Fatty Acids in Pongamia Pinnata Oil

Abstract Esterification of free fatty acids in Pongamia pinnata oil has been carried out using two different zeolites. Classical optimization of reaction parameters were carried out with H-ZSM 5 and H-Y zeolites. Based on the experimental results, a methanol to oil ratio of 9:1, with 1% by weight catalyst, a reaction time of 1 h and temperature 60°C were selected as the optimum for the esterification reaction. Kinetic studies were undertaken and the reaction was found to fit a pseudo first order kinetics.

The Esterification of Free Fatty Acids in Karanja (Pongamia Pinnata) Oil Using Phosphoric Acid Modified Zeolite

Abstract Use of low-cost raw materials containing high amounts of free fatty acids for the production of biodiesel is a valuable alternative. The production of biodiesel from these kinds of raw materials involves a two-step process. The first step requires esterification of free fatty acids by acid catalysis, followed by base catalyzed transesterification. Karanja is a non-edible oil, with high free fatty acid content, found in abundance in India. Phosphoric acid modified H-Y zeolite was used as a solid acid catalyst for free fatty acid esterification in Karanja oil. The principal parameters of the esterification reaction have been investigated and optimized via the classical method. Kinetic measurements revealed that the esterification followed pseudo first order kinetics.

Eco-Friendly Treatment Strategies for Wastewater Containing Dyes and Heavy Metals

In the present scenario, people are suffering due to the scarcity of freshwater and clean drinking water and it remains a worldwide problem. Fast growth of industries and urban localities and change in lifestyle lead to the increase in the necessity of different kinds of synthetic materials and have led to pollution of water. Water pollution is a major environmental issue faced by the modern world, which leads to ecological disequilibrium that can cause harmful effect on flora and fauna of the ecosystem. Heavy metals and synthetic dyes are the major pollutants to be prioritized in wastewater treatment because of their lethal toxicity. Heavy metal poisoning in human being could have a direct impact on the drinking water, on the very air for breathing, and on the food chain. Synthetic dyes which are in use are highly poisonous and difficult to degrade because of their complex form. At present, researchers are focused on the treatment of wastewater containing toxic and complex organic contaminants. Adsorption is a promising technology for treating wastewater with heavy metal contaminants. Recovery and reusability of the adsorbents make adsorption an eco-friendly and cost-effective technology. Photocatalysis is a highly proven treatment technique for dyes intoxicated wastewater. Conversion of non-biodegradable and complex organic dyes into simple biodegradable molecules by photocatalysis is a greater addition in wastewater treatment. Concentration of heavy metal ions could be measured throughout the treatment process using Atomic Absorption Spectrophotometer (AAS), and for dyes, UV–Visible Spectrophotometer could be employed. Kinetic modeling and adsorption isotherms would pave the way for the better understanding of the rate and nature of the adsorption of heavy metals. Biochemical oxygen demand (BOD), chemical oxygen demand (COD), and eco-toxicity studies are used to monitor the treatment processes.

Modified zeolite as a catalyst for Pongamia pinnata oil esterification in biodiesel production

The solid acid catalyst, Nb/P/ZSM-5 was synthesised and characterised for its nature and morphological features. The catalyst was employed in the esterification of free fatty acids in Karanja (P. pinnata) oil for biodiesel production. Parameters affecting the P. pinnata oil esterification were determined and Nb/P/ZSM-5 catalyst esterified P. pinnata oil was analysed using spectroscopic investigation.

High Permeate Recovery for Concentrate Reduction by Integrated Membrane Process in Textile Effluent.

  The textile dyeing industry consumes a significant amount of high-quality water for processing, which stresses water resources. In recent decades, technologies have been developed to recover water from wastewater. This study describes the high recovery (greater than 92%) of reusable water from an industrial-scale hosiery dye-water recovery facility, consisting of three stages of reverse osmosis and ultrafiltration. The effluent was pre-treated before the membrane process was performed to prevent biofouling. The process performance results in the generation of a consistent water quality that is required for dyeing operations. An average feed flux of 15 l/m2h was maintained in the reverse osmosis membrane by regular chemical dosing and cleaning. The integrated membrane process achieved a permeate with a pH of 6.5 and total dissolved solids (TDS) of 160 mg/l, with no other contaminants, which is of sufficient quality for reuse in the cotton hosiery dyeing process.