Keka Sinha

Biosorption of Direct Red 28 (Congo Red) from Aqueous Solutions by Eggshells: Batch and Column Studies

The feasibility of using eggshells as a low-cost biosorbent for the removal of Direct Red 28 (DR 28) from aqueous solutions was studied in batch and dynamic flow modes of operation. The effect of biosorption process variables such as particle size, solution pH, initial dye concentration, contact time, temperature, feed flow rate, and bed height were investigated. Both the Langmuir and Freundlich isotherm models exhibited excellent fit to the equilibrium biosorption data. Optimum pH (6.0), particle size (<250 µm), initial dye concentration (50 mg g−1), temperature (313 K), and contact time (240 min) gave maximum monolayer biosorption capacity of 69.45 mg g−1 which was higher than those of many sorbent materials. Pseudo-second-order kinetic model depicted the biosorption kinetics accurately. Thermodynamic study confirmed the spontaneous and endothermic nature of the biosorption process. Breakthrough time increased with increase in the bed height but decreased with increase in flow rate. Overall, batch and continuous mode data suggest the applicability of eggshells as an environment friendly and efficient biosorbent for removal of DR 28 from aqueous media.

Central composite design optimization and artificial neural network modeling of copper removal by chemically modified orange peel

AbstractThe ability to remove Cu2+ ions from aqueous solution using calcium oxide (Ca(OH)2) treated orange peel was investigated in the present study. Response Surface Methodology (RSM) was applied for the optimization of the process parameters responsible for the reduction of metal ion effect and to evaluate the effects and interactions of the process variables. The optimum reduction of copper was 93.4253% at pH 4.75, 55.5 mg/l copper concentration and 33.91 min of contact time. The deviation between experimental and RSM model equation was very less. Computational simulated artificial neural network (ANN) was formulated to get a good correlation between the input parameters responsible for copper removal and the output parameters (% removal) of the process. The correlation coefficient (R) of ANN is 0.967. The optimization process shows a close interaction between the observational and modeled values of copper removal.

Natural dye from bixa seeds as a potential alternative to synthetic dyes for use in textile industry

Abstract Dye is a substance that has affinity to the substrate to which it is being applied such as textile fibers, foodstuffs and powder. From archeological evidence, it is seen that in India dyeing has been carried out for over 5000 y, which were obtained from animal, vegetable or mineral origin. The greatest source of this dye was mainly from plant kingdom; mainly roots, bark, leave and wood. Dye from Bixa (Annatto) seed is one type of natural dye which can be used as dyeing agent for coloring textile fibers like cotton, wool, silk and for making colorful “Gulal” as well as in food industry. Bixin, the pigment extracted from the red-colored seeds, can be used as coloring agent for this purpose. It is non-carcinogenic in nature and so does not affect human body or environment. An attempt is being made in laboratory scale to extract the natural pigment from the Bixa seeds and its application in different fields such as textiles, colourful powder and food industry.

Biosorption of Congo red and Indigo carmine by nonviable biomass of a new Dietzia strain isolated from the effluent of a textile industry

Abstract A new bacterial strain, PD1, was isolated from the effluent of a textile industry. Phylogenetic analysis based on 16S rRNA gene sequence showed that the strain belonged to the genus Dietzia. The efficacy of the dried bacterial biomass as biosorbent for removal of acid dyes, namely Congo red (CR) and Indigo carmine (IC), from aqueous solutions was studied by performing batch equilibrium tests under different operating parameters such as initial dye concentration, pH, and temperature. The amount of dye adsorbed onto Dietzia sp. PD1 decreased with increasing pH while it increased with increasing temperature. The equilibrium biosorption data showed excellent fit to Langmuir isotherm as compared to Freundlich isotherm. The maximum biosorption capacity, calculated using the Langmuir model, were 170.34 and 188.71 mg g−1 for CR and IC, respectively. Analysis of kinetic data showed that the biosorption processes followed pseudo-second-order kinetics. The numerical value of the thermodynamic parameters (ΔG...

Assessment of water quality index using cluster analysis and artificial neural network modeling: a case study of the Hooghly River basin, West Bengal, India

AbstractRiver Hooghly, considered as an important tributary of the River Ganga, has been affected by indiscriminate discharging of polluted and untreated sewage sludge and industrial waste into the waterways. The assessment of water quality for natural river waters was done using a water quality index (WQI), developed by DELPHI and the Council of Ministers of the Environment methods. These two methods reflect the quality of the water measured with respect to its pollution level. Multivariate statistical techniques, such as cluster analysis, were applied to the data-set on water quality of the Hooghly River (India) which was generated during the years 2002–2008 controlling at eight different sites for five parameters. The relationships among the stations are highlighted by cluster analysis to characterize the WQI. The study represents a computer-simulated artificial neural network model for the evaluation of the relationship between the different parameters of water bodies collected at different stations a...

INatural Blue Dye from Clitoria Ternatea: Extraction and Analysis Methods

An increased environmental awareness of health hazards caused by synthetic dyes has led to revival of natural dyes. Dyes obtained from natural sources have emerged as important substitutes for synthetic dyes. Color-yielding plants such as butterfly pea flowers have been used to study color extraction and can be used as dyeing material for coloring industry. Analytical studies, such as UV–VIS spectrophotometer analysis and dye concentration analysis, are performed on extracted dye using flower petals. In this study, aqueous extractions of dye from flowers were carried out in the following conditions to obtain optimization characterization: time of extraction (30-180 minutes), temperature (60-90°C), amount of flowers (0.1-2gm) and pH (2-10). It was observed that dye concentration increases gradually at higher temperature and for longer time.