Batch and bulk removal of hazardous dye, indigo carmine from wastewater through adsorption

An inexpensive adsorption method has been developed for the removal of indigo carmine, a highly toxic indigoid class of dye from wastewater. Waste materials--bottom ash, a power plant waste and de-oiled soya, an agricultural waste--have been used as adsorbents. Attempts have been made through batch and bulk removal of the dye and both the adsorbents have been found to exhibit good efficiency to adsorb indigo carmine. Under batch technique effect of temperature, pH, concentration, dosage of adsorbents, sieve size of adsorbents, etc. have been observed. The dye uptake on to both the adsorbents is found to validate Langmuir and Freundlich adsorption isotherms models. Different thermodynamic parameters, like Gibb's free energy, enthalpy and entropy of the on-going adsorption process have also been evaluated. Batch technique has also been employed for the kinetic measurements and the adsorption follows a first order rate kinetics for both the adsorbents. The kinetic investigations also reveal for both the adsorbents film diffusion and particle diffusion mechanisms are operative in the lower and higher concentration ranges, respectively. Under the bulk removal, indigo carmine has been adsorbed through the column beds of bottom ash and de-oiled soya and more than 90% of the dye material has been recovered by eluting dilute NaOH solution through exhausted columns.     

Process development for the removal and recovery of hazardous dye erythrosine from wastewater by waste materials-Bottom Ash and De-Oiled Soya as adsorbents

Erythrosine is a water-soluble xanthene class of dye. It is widely used as colorant in foods, textiles, drugs and cosmetics. It is highly toxic, causes various types of allergies, thyroid activities, carcinogenicity, DNA damage behaviour, neurotoxicity and xenoestrogen nature in the humans and animals. The photochemical and biochemical degradation of the erythrosine is not recommended due to formation of toxic by-products. The present paper is an attempt to remove erythrosine from wastewater using adsorption over Bottom Ash-a power plant waste and De-Oiled Soya-an agricultural waste. Under the batch studies, effect of concentration of dye, temperature, pH of the solution, dosage of adsorbents, sieve size of adsorbents, etc., have been studied for the uptake of the dye over both adsorbents. The adsorption process verifies Langmuir and Freundlich adsorption isotherms in both the cases and based on the data different thermodynamic parameters have been evaluated. Batch studies also include kinetic measurements, rate constant study, mass transfer behaviour and establishment of mechanistic pathway for both the cases. For the bulk removal of the dye column operations have been carried out and breakthrough capacities of the Bottom Ash and De-Oiled Soya columns have been calculated. Attempts have also been made for the recovery of the adsorbed dye from exhausted columns by eluting dilute NaOH and more than 90% of the dye was recovered.     

Improved low energy adaptive clustering hierarchy and its optimum cluster head selection

ABSTRACT

Wireless sensor networks (WSNs) play a vital role in present-day world, which are being used in different types of applications and occupy an important part in networking domain. The main objective of WSNs is to sense and collect the information from a given area of interest and provide the gathered data to the sink. WSN comprises of number of sensor nodes with batteries of limited energy for communication and computational activities, which are not possible to recharge the batteries after their deployment in the region of interest. Therefore, saving battery energy and utilising the limited power to the optimum level for extending network lifetime became the main factor of WSN. Hence, optimum cluster head (CH) selection will make the network to support longer lifetime and balanced energy consumption during its lifetime. Our proposed protocol selects the optimum CH and found out to be more efficient than the existing low energy adaptive clustering hierarchy. The simulated output shows better network lifetime and in some other performance metric.     

Design and evaluation of acrylate polymeric carriers for fabrication of pH-sensitive microparticles

Colon-targeted microparticles loaded with a model anti-inflammatory drug were fabricated using especially designed acrylic acid–butyl methacrylate copolymers. Microparticles were prepared by oil-in-oil solvent evaporation method using Span 80 as emulsifier. Microparticles were found to be spherical in shape, hemocompatible and anionic with zeta potential of ?27.4 and ?29.0?mV. Entrapment of drug in the microparticles was confirmed by Fourier transform infrared (FTIR) spectroscopy. However, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) revealed amorphous nature of microparticles due to the dilution effect of amorphous polymer. The microparticles released less than 5% drug at pH 1.2, while more than 90% of the drug load was released at pH 7.4. This suggested the colon targeting nature of the formulations. In experimentally developed colitis in Wistar rats, the microparticle formulation showed significant reduction (p?相似文献   

Sorption of Tertiary Butyl Mercaptan to Indoor Materials in Contact with Air or Water

This study reports sorption of the malodorant 2-methyl-2-propanethiol, commonly known as tertiary butyl mercaptan (TBM), to selected indoor materials. The phase distribution of TBM in gas-solid and aqueous-solid systems was evaluated using batch reactors. Sorbents used in the study included two carpets, two wallpapers, a soil, and granular activated carbon (GAC). Sorption was studied for gaseous and aqueous TBM concentrations spanning three orders of magnitude and contact times ranging from 1 to 28 days. The phase distribution data were plotted and fitted using linear and Freundlich relationships. Results indicated that all solids sorbed environmentally significant quantities of TBM, with the likelihood of producing concentrations above the odor threshold during subsequent remediation using mechanical ventilation. TBM retention by sorbents was greater from air than from water. The malodorant partitioned readily into wallpapers and slowly into the carpet materials. Sorption was nonlinear in the case of GAC and the nonlinearity appeared to increase with sorption contact time. GAC sorbed TBM strongly from both air and water.     

The stochastic queue center problem

This paper considers the Stochastic Queue Center problem, which seeks to locate a single facility with a center-type objective in an M/G/1 queue operating environment. The objective function that we consider is to minimize a positive weighted linear function of the square of the average response time and the variance of the response time to a call. The Stochastic Queue Center problem is discussed on both a discrete and a network location topology. When potential facility locations are restricted to a finite set of discrete points, an efficient algorithm is developed to solve for the optimal facility location parametrically in the arrival rate. By exploiting convexity properties of the objective function, we develop an efficient finite-step algorithm to find the Stochastic Queue Center on a network. The major conclusion of this work is that incorporating the variance term in the objective function has a major impact on the choice of the optimal location. We illustrate the results with an example drawn from a potential application of the model for locating an emergency transport center serving different municipalities in Camden County, NJ.     

Effect of iron alloying in evolution of nanostructure and microstructural stability in nickel

Nanocrystalline materials show many interesting properties such as high strength and hardness due to nanosized grains and high density of interfaces. In this context, the present work reports the effect of Fe (iron) addition in Ni (nickel) on nanostructure retention during the annealing of Ni-Fe alloy (with 0, 18.5, 28.5 and 43 wt% Fe) at 450 °C for 16 h. Furthermore, effect of annealing on the deformation mechanism was investigated. The integral breadth method revealed the decrease in grain size with increase in wt% Fe in Ni. The strain rate sensitivity exponent which is a signature of operating deformation mechanism showed a higher value (0.10803) in case of Ni-18.5 wt% Fe during nanoindentation. However, Ni-0 wt% Fe, Ni-28.5 wt% Fe and Ni-43 wt% Fe were characterized by a relatively low strain rate sensitivity exponent (between 0.02069 and 0.10803). Results indicated the presence of Hall-Petch relationship up to 18.5 wt% Fe and inverse Hall-Petch relationship above 18.5 wt% Fe.