Chemical & Biochemical Engineering

In the study of a reaction on a heterogeneous catalyst, external and internal mass diffusion play an important role since they can have an inherent affect on the kinetics of the reaction. Therefore, in the study of intrinsic rates of reaction, the effects of external and internal mass diffusion must be eliminated or considered prior to proper kinetic studies. In this study, the effects of external and internal mass diffusion on the propane dehydrogenation reaction over a Pt/Sn catalyst were investigated. Some experiments were performed in a laboratory scale setup and the required data was gathered. The rate of reaction was considered to be first order based on propane. External diffusion was studied using Mears' criterion and internal diffusion was investigated by the Thiele Module and the Internal Effectiveness Factor, based on experimental data.

h i g h l i g h t s " New capacitance method measures distribution of liquid injected in a fluidized bed. " More atomization gas improves the contact between liquid and fluidized particles. " Increasing the fluidization velocity improves liquid-particle contact. " Increasing the fluidization velocity breaks up wet agglomerates. g r a p h i c a l a b s t r a c t Liquid was sprayed into a fluidized bed for 10 s and formed wet agglomerates that slowly broke up, releasing ''free'' moisture. G(t) is the ratio of total liquid freed from the agglomerates, since the start of the injection, to the total mass of injected liquid. GLR is the mass ratio of the atomization gas to injected liquid. V r is the fluidization velocity.

Uniform distribution of liquid feed on fluidized particles increases the yield of valuable products and improves operability in processes such as Fluid Coking TM and Fluid Catalytic Cracking. The liquid properties and local bed hydrodynamics have a strong impact on the contact between the injected liquid and the bed particles. Several publications addressed parameters which affect the formation of undesired solidliquid agglomerates, such as fluidization velocity, nozzle geometry, ratio of atomization gas to liquid. In this study, the effect of viscosity, wettability, fluidization velocity and atomization gas flowrate on the distribution of liquid feed sprayed into a fluidized bed was investigated with a reliable and fast response capacitance meter. This method was extended to monitor the gradual agglomerate breakup kinetics.

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Incubation of BMG-1 cells with thallium chloride (201Tl) in the range of diagnostic dose did not show a smooth uptake curve and appeared to have an unsuspected deviation in initial phase. In the present study this unexpected phenomenon was explored, using commonly used radionuclides (viz., 201Tl and 131I). Comparison was made with technetium-99m pertechnetate (99mTcO4(-)) and technetium-99m labeled methoxyisobutylisonitrile (99mTc-MIBI) that are known to show conventional 2 phase graph representing inflow and outflow segments. Serial in vitro, ex-vivo and in vivo gamma scintigraphy as well as NMR spectroscopy experiments were conducted to corroborate the results. BMG-1 cells demonstrated a four-phase uptake pattern with 201Tl as compared to a conventional biphasic pattern with 99mTc-MIBI. Flow cytometry data however did not reveal any 201Tl induced cell injury. Further, mice tissue extracts injected with 201Tl also showed a transient depression in its uptake. Scintigraphy experiment...

Incubation of BMG-1 cells with thallium chloride ( 201 Tl) in the range of diagnostic dose did not show a smooth uptake curve and appeared to have an unsuspected deviation in initial phase. In the present study this unexpected phenomenon was explored, using commonly used radionuclides (viz., 201 Tl and 131 I). Comparison was made with technetium-99m pertechnetate ( 99m TcO 4 -) and technetium-99m labeled methoxyisobutylisonitrile ( 99m Tc-MIBI) that are known to show conventional 2 phase graph representing inflow and outflow segments. Serial in vitro, ex-vivo and in vivo gamma scintigraphy as well as NMR spectroscopy experiments were conducted to corroborate the results. BMG-1 cells demonstrated a four-phase uptake pattern with 201 Tl as compared to a conventional biphasic pattern with 99m Tc-MIBI. Flow cytometry data however did not reveal any 201 Tl induced cell injury. Further, mice tissue extracts injected with 201 Tl also showed a transient depression in its uptake. Scintigraphy experiments in rabbits administered with diagnostic dose of 201 Tl and 131 I confirmed the in vitro and ex vivo findings. Further, proton NMR spectroscopy showed decrease in the level of choline at 3 h and 24 h in 201 Tl treated animals as compared to control. Phosphoethanolamine peak firstly decreased at 3 h but reached normal level at 24 h time point. No significant change was observed in the level of betaine. This transient reduction in internalization of 201 Tl and 131 I may represent a hitherto unknown acute effect of low dose radiation, i.e., transient depression in Na + -K + ATPase pump activity without any apparent evidence of cell damage, representing a transient cell membrane dysfunction. The phenomenon may present a mechanistical explanation of 'thyroid stunning' at cellular level and suggest that it may be more universal in nature than suspected till now.

The present paper describes the preparation, characterization, and performance evaluation of thin film composite (TFC) nanofiltration (NF) membranes having porous polysulfone as base support and polyvinyl alcohol (PVA, degree of hydrolysis 86-87% and molecular weight 125,000) as the final barrier layer. Maleic acid (MA) was used as the cross-linker of PVA. The membranes were characterized by their molecular weight cutoff, FTIR, SEM, and contact angle. The effects of variation of different parameters like concentration of polysulfone, polyvinyl alcohol, maleic acid, and cure time on the membrane performance (flux and rejection of inorganic salts) were studied and the optimum membrane composition was evaluated. From the analysis of flux and rejection data it may be concluded that membranes prepared from 17% PSF, 1% PVA, with MA solution concentration of 0.2% (w/w) cured at a temperature of 125 ± 2°C for 30 min give the optimum balance of flux and rejection (R). Such membranes show differential rejection among the sulfate and chloride salts. For membranes prepared under optimum conditions the average rejections of NaCl and MgSO 4 are 22.8% and 83.8%, respectively; i.e., on an average 60% difference exists between the rejection of MgSO 4 and NaCl. The overall trend of rejection by such membranes is R Na 2 SO 4 > R MgSO 4 > R NaCl > R CaCl 2 ffi R MgCl 2 (R = rejection). The average MWCO of these membranes varies between 250 and 350 Da.

h i g h l i g h t s g r a p h i c a l a b s t r a c t Novel PVA pore-filled polycarbonate proton exchange membrane. Investigation of membrane physiochemical properties with PVA crosslink time. Pore-filled membranes showed very good performance and stability. Microbial fuel cell eliminates Pt catalyst at cathode and Nafion membrane use.

 It has a short-term commercial potential and its economic analysis is quite promising;  The BioGenerator is the first commercially viable biotechnology for energy storage;  It is a power generation technology of which has a negative CO 2 emission.

The thickness and roughness of the functional layer in thin film composite membranes (TFCMs) are important determinants of the membrane performance, whether in reverse osmosis, gas separation or energy applications. This paper describes and compares different techniques for the measurement of these quantities. A new method based on atomic force microscopy (AFM) is developed and compared with techniques based on scanning electron microscopy (FEG-SEM) and profilometry. AFM and profilometry methods allowed a simultaneous determination of thickness and roughness and could be extended for studying the effect of parameters such as support membrane roughness. The methods have been tested on polyamide TFC RO membranes. The membranes were prepared by an interfacial polycondensation technique on polysulfone support, by reaction between mphenylene diamine and trimesoyl chloride in the organic phase. Based on our earlier work which showed the important role of shear on membrane morphology in such syntheses, preparations both with and without shear were employed. The measurement of thickness using AFM was carried out on specially made membranes in which, by the use of a mask, only a part of the PSF was coated with the PA layer. By scanning a region that contains both the covered and the uncovered parts, thickness values could be obtained. In the second technique, the SEM cross sectional images of TFCMs allowed the determination of the distribution of thickness over the area seleted. In the third, a surface profilometer was used to determine the thickness of de-laminated PA films. The thickness distributions and average thicknesses measured from all three methods matched closely. Overall, these techniques are of great potential in TFC and similar membrane characterization.

Bio derived nanocellulose possesses versatile properties, which are very worthwhile for advanced functional applications. Nanocellulose i.e. nanofibers and nanocrystals can be applied in the form of solution, suspension, ink or nanomaterials in composites, nanocomposites, coatings and films. These forms of nancellulose are found for the development of hydrogels, aerogels, electrodes, adsorbents, packaging films, membranes, nanopapers, filters, supercapacitors, electrodes, electrolytes, rheology modifiers, food additives, scaffolds, and biomaterials/formulations for biomedical and tissue engineering. This paper, categorically reviews and discusses the potential of composite, nanocomposite and hybrid materials obtained from nanocellulose for water Electronic supplementary material The online version of this article (

This paper emphases on the preparation, characterization and application of heterogeneous cation- and anion-exchange membranes. Membranes were made by solution casting method from the blends comprises of ion-exchange resins and eco-friendly polymer binder polyvinyl alcohol (PVA). Dimensional stability of membranes in water was controlled by crosslink density of binder. Physicochemical and electrochemical characteristics of ion-exchange membranes such as ion-exchange capacity (IEC), swelling (%), water uptake (%), surface electrical resistance, and transport number have been optimized by varying the resin:binder ratio. Thermal properties of the membranes were studied using the thermogravimetric analysis and differential scanning calorimetry to evaluate the thermal degradation pattern/stability and transition temperature, i.e., Tg of ionic membranes. The morphology of membrane samples were studied using scanning electron microscope. Heterogeneous ion-exchange membranes (HIXM) prepared...

Landfill leachate is considered a complex, high strength industrial wastewater. Landfill leachate treatment is a major challenge due to high and variable contaminant concentrations such as Chemical Oxygen Demand (COD), ammonia, and Total Dissolved Solids (TDS). Traditionally landfill leachate has been hauled or pumped to Publicly Owned Treatment Works (POTW) for disposal. The ongoing development of more stringent discharge criteria, especially for nutrients, have required many landfills to employ pretreatment for indirect discharge to the sewers or secondary treatment (or more) for direct discharge to the natural environment. Biological leachate treatment is a proven technology for organics and ammonia removal in young and mature leachate. Biological Nitrogen Removal technology, more specifically, the Anoxic/Aerobic processes have been implemented in order to achieve nitrification and denitrification and reduce the oxygen demand. This paper presents two Case Examples of landfill Leachate Treatment Facilities (LTF) for biological removal of organics and nitrogen. One Case Examples involves the optimization of an on-site LTF to accommodate drastic changes in the leachate as a result of changes in landfill management practices. The second Case Example involves the upgrades to an existing on-site LTF to accommodate higher flows as well as achieving nitrification and denitrification for higher organics and nitrogen removal.

The thermal treatment of crop oils was investigated with the aim to produce a renewable, liquid fuel suitable for use in wick-based lighting systems. Specific objectives include reducing fuel viscosity and improving wickability in traditional flat cotton wicks. Pyrolysis and visbreaking processes were the two methods of thermal treatment that were studied. Visbreaking was a semi-batch process carried out in a stirred tank reactor at temperatures ranging from 300 to 500 °C. Pyrolysis utilized a continuous system with a mechanically fluidized bed reactor at temperatures ranging from 400-650 °C. Initial testing with soybean oil feedstock demonstrated that pyrolysis was the superior process for the application due to its greater severity. Organic liquid yields of up to 93 wt% were observed, with reduction in viscosity as high as 96%. Wickability of the fuel was greatly improved as demonstrated with dedicated testing. Product yields and properties were heavily reliant on reaction temperature in both processes. Feedstocks representing a wide spectrum of crop oil composition were tested with pyrolysis. The proportion of saturated chemical bonds was found to have a negative impact on the product quality at low temperatures. Highly saturated oils required increased temperatures to produce liquid product. Fuels produced from the thermal treatment of crop oils can provide up to 60 wt% in blends with kerosene to produce a successful lamp fuel.