Iranian Journal of Chemistry and Chemical Engineering
Volume:39 Issue: 2, Mar-Apr 2020

Graphene-modified Cu2O nanocomposite was synthesized under facile microwave irradiation of an aqueous solution and has been investigated as an enzyme-free glucose biosensor. Morphology and crystal structure of the graphene-modified Cu2O nanocomposite were investigated by using electron microscopy and X-Ray Diffraction (XRD) analyses. Also, the electrochemical performance of the graphene-modified Cu2O nanocomposite for the measurement of glucose concentration in alkaline media was evaluated by using cyclic voltammetry and chronoamperometric measurements. The electrochemical studies revealed that the graphene-modified nanocomposite electrode exhibited a high performance for non-enzymatic oxidation of glucose with a desirable sensitivity. Also, the fabricated graphene-modified biosensor exhibited a wide linear response for glucose detection in the concentrations ranges from 2 µM to 12 mM and a desirable detection limit of 2 µM. Also, the graphene-modified Cu2O nanocomposite provided an appropriate selective response for glucose detection in the presence of high concentrations of ascorbic acid and dopamine.

In this research, pure-phased Ni0.5Cu0.5Cr2O4 synthesis via solid-state method successfully. In the other part, the photocatalytic activity of synthesized Ni0.5Cu0.5Cr2O4 was investigated in various aspects by using Malachite green as a pollutant and compared with the number of previous photocatalysts. The Photocatalysis process is a promising technique for solving many current environmental and energy issues. The environmental pollutant, especially water contaminates, can influence human health, animals, and the ecosystem. Dye as one of the most important pollutants has investigated in this study. In this study, purification and crystal structure of material have been determined by X-Ray powder Diffraction (XRD) method. The results showed that the synthesized Ni0.5Cu0.5Cr2O4 was crystallized in tetragonal structure with space group I 41/AMD. The morphology of obtained materials was modified by Field Emission Scanning Electron Microscope (FESEM). Also, the material was characterized by Fourier-Transform InfraRed (FT-IR) spectroscopy and Thermo Gravimetric Analysis (TGA).

In this research, Cu-phthalocyanine coated hybrid magnetic nanoparticles have been prepared in a simple method and evaluated as an efficient catalyst in the preparation of mono- and bis-pyrano[2,3-d]pyrimidinones and mono- and bis-2-amino-4H-pyrans from the condensation reaction of 1,3-dimethylbarbituric acid or 4-hydroxycumarin with malononitrile and mono- and bis-aldehydes under ultrasonic irradiation. The catalyst could be easily recovered in the presence of the external magnetic field and reused five times without significant loss of activity and mass. The magnetic nanoparticles were characterized using Fourier Transform InfraRed (FT-IR) spectra, X-Ray Diffraction (XRD) spectroscopy, Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA). The results showed the spherical structures of hybrid magnetic nanoparticles and the average size is about 37 nm.

Using of nanocomposite membranes composed of polymer and inorganic nanoparticles is a novel method to enhance gas separation performance. In this study, membranes were fabricated from polyester (PE) containing silica (SiO2) nanoparticles and gas permeation properties of the resulting membranes were investigated. Morphology of the membranes, SiO2 distribution and aggregates were observed by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis. Furthermore, thermal stability, the residual solvent in the membrane film, and structural ruination of membranes were analyzed by Thermo Gravimetric Analysis (TGA). The effects of SiO2 nanoparticles on the glass transition temperature (Tg) of the prepared nanocomposites were studied by Differential Scanning Calorimetry (DSC). The results obtained from gas permeation experiments with a constant pressure setup showed that adding SiO2 nanoparticles to the polymeric membrane structure increased the permeability of the membranes.

In this paper, structural, magnetic, optical, and photocatalytic properties of core-shell structure Fe3O4@GO nanoparticles have been compared with Fe3O4 nanoparticles in the degradation of methyl blue and methyl orange. For this purpose, GO nanosheets were wrapped around the APTMS-Fe3O4 nanoparticles and then characterized using X-ray Diffraction, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, UV-visible, and Fourier transform infrared spectroscopy. The results show the core-shell nanostructured Fe3O4@GO is formed. As an application for the synthesized structure, degradation of methyl blue and methyl orange as heavy-mass organic pollutants has been measured. While the saturation magnetization of Fe3O4@GO is lower than Fe3O4, but shows better efficiency in the degradation of methyl blue and methyl orange. The obtained catalysts can be quickly separated from the solution under an external magnetic field because of their considerable Ms values, which will be beneficial for their reuse and boosting the overall water treatment efficiency in practical applications.

A series of high-density polyethylene/Cloisite 20A/graphite nanocomposites were prepared via melt blending for the production of polymeric pipes for natural gas transfer. The microstructural, mechanical, thermal, electrical and barrier properties of prepared nanocomposites were investigated. An intercalated morphology was observed for prepared nanocomposites. Improved mechanical properties e.g. over 148 % increase in Young’s modulus were observed by incorporating the nanoparticles into the polyethylene matrix. The thermal analysis showed that the melting point of polyethylene was slightly increased by incorporating both fillers, i.e. Cloisite 20A and graphite in it, and the crystallinity was depended on the type of filler. The results showed that the MFI values decreased by incorporating the fillers into the polyethylene matrix and further decreases were observed by increasing the contents of the filler. It was also found that a considerable amount of electrical conductivity is created in graphite loaded nanocomposites. The natural gas permeability investigations revealed of more than 51 % decrease in the permeability by incorporating 5 wt.% of Cloisite 20A to the polyethylene. It was concluded that the prepared nanocomposites due to their enhanced mechanical, thermal and barrier properties along with the conductive nature are excellent materials to be used in the production of polymeric pipes in natural gas distribution and transportation networks.

The Al, Zr, and Ti modified MCM-41 materials were prepared by the post-synthesis method, and then the Ni-W species were introduced on them by using the co-impregnation method in order to obtain high-performance hydrodenitrogenation (HDN) catalysts. The activity of the catalysts was evaluated by the HDN reaction of quinoline. The optimum HDN activity was observed on the catalyst supported on the Al modified MCM-41. The high performance of the NiW/Al catalyst was due to the higher dispersion of Ni, W species, the more density of acid sites, the more appropriate nature of W species, and the lower reduction temperature of W species. Moreover, the catalysts prepared by co-impregnation method showed better performance than the catalysts prepared by the sequential impregnation method in the HDN of quinoline.

Pure borax and various boron compounds are produced from the solutions in which tincal is dissolved with various reagents. Economically important boron compounds such as boric acid, borax, boric oxide, and refined hydrated sodium borates and perborates are produced from boron-containing ores. The production of boric acid by using nitric acid from tincal is more advantageous because it evaluates by-product NaNO3 as fertilizer production. In this study, the conversion kinetics of tincal to boric acid in nitric acid solutions were investigated by such parameters as particle size, 300-1500 µm; acid concentration,0.5-4 mol/L; solid-to-liquid ratio 0.04-0.10 g/mL; stirring speed 20.93-62.8  s-1, and reaction temperature, 30-60 oC. The conversion was found to increase with decreasing particle size and solid-to-liquid ratio and while it increased with increasing reaction temperature, acid concentration, and stirring speed. The conversion kinetics was examined using the heterogeneous and pseudo-homogeneous reaction models. The experimental results were found to be in better agreement with the correlation given in the following equation and the activation energy being 37.5 kJ/mol.

Design of Experiments (DoE) is a powerful guiding tool that can help researchers to identify the main variables that affect the performance characteristics. The present paper elaborates on the optimization and prediction of reaction parameters like type of plastic, catalyst, and temperature using Taguchi’s L9 orthogonal array method with three levels and three parameters to obtain the highest yield of plastic oil. To determine the effect of each parameter, the Signal to Noise (S/N) ratio was calculated based on the experiments conducted. In this investigation, contributions of reaction parameters were analyzed by Analysis of Variance (ANOVA) using statistical software Minitab-16. Based on the investigation, the reaction parameters like type of plastic: Low-Density Polyethylene (LDPE), catalyst: Silica alumina (SA), and temperature: 500°C are optimized to get the better yield of oil. Based on the confirmatory trial, the oil yield of about 95.4%, the gas yield of about 3.4%, and solid residue as 1.2% were obtained, which is better than the normal trails.

A novel Schiff base was synthesized by the reaction of piperonal and anthranilic acid, which was further utilized in the synthesis of five novel complexes by reaction with different metal salts ultrasonically. Time for the reaction was greatly reduced through ultrasound irradiations and the yield of reactions was also high as compared to the conventional methods using reflux conditions. The synthesized Schiff base and its metal complexes were characterized by spectroscopic techniques like UV-Visible, IR, and 1H NMR. The synthesized compounds were tested for their antibacterial and antioxidant activity. Good results were obtained in the case of antibacterial activities.

A new binuclear complex of [{NiCl(6-mbipy)}2(μ-Cl)2] (1) was prepared from the reaction of NiCl2.6H2O and 6-methyl-2,2'-bipyridine (6-mbipy)  in a mixture of methanol and acetonitrile. Suitable crystals of 1 for X-ray diffraction measurement were obtained by slow evaporation of the resulted green solution at room temperature. Complex 1 was characterized by spectral methods (IR, UV–Vis, and luminescence), elemental analysis (CHN), and single-crystal X-ray diffraction. The structure of 1 is centrosymmetric binuclear complex and each Ni(II) cation is five-coordinated in a slightly distorted square-pyramidal configuration. In this binuclear complex, the Ni…Ni distance is 3.533(1)Å. Furthermore, the luminescence emission of the title complex was blue-shifted and is stronger than that of free 6-methyl-2,2'-bipyridine ligand. Thermal stabilities of this complex was also studied by thermogravimetric analysis.

Colloidal Gas Aphrons (CGA), consist of gas bubbles with diameters ranging from 10 to 100 micron, surrounded by a thin aqueous surfactant film. This fluid combines certain surfactants and polymers to create the systems of microbubbles. The function of surfactant in CGAs is to produce the surface tension to contain the aphrons. Also, a biopolymer needs to be considered in the formulation as a viscosifier as well as a stabilizer. The aphron-laden fluid appears to be particularly well suited for drilling through depleted zones. The unique feature of aphron based fluids is to form a solid free, tough, and elastic internal bridge in pore networks or fractures to minimize deep invasion using air microbubbles. This microenvironment seal readily cleans up with reservoir flow back as production is initiated, thereby reducing the cost associated with stimulation processes. This paper presents a comprehensive, comparative study of rheological behavior and filtration properties of CGA based drilling fluids with various concentrations of polymer and surfactant. Laboratory evaluations showed that the CGA based fluid is one of the ideal engineering materials which can control and kill the loss circulation, save cost and increase productivity in which rheological characteristics and filtration properties of them are greatly influenced by the level of polymer and surfactant concentration.

The main standard method for gold karat determination is the cupellation method. However, this method is not sufficiently accurate to determine gold karat in the presence of insoluble Platinum–Group Metals (PGMs), such as Ir, Ru, and Rh. In this study, for the first time, a complementary method that can be used coupled with the reference cupellation method is presented for the highly accurate determination of gold karat containing PGMs. According to this method, gold metal was separated from the PGMs by dissolving parted cornets in aqua regia and then, its selective precipitation using an aqueous solution of SO2 gas as a reducing agent. The gold amount in alloys containing PGMs was determined using the suggested strategy with an excellent recovery, high accuracy (average relative error=0.12%) and precision (SD=0.6 for n=3). The optimized volume of aqueous SO2 solution was 35 mL that provides a gold recovery as high as 99.7% with enough big grain size and high purity (999.0‰). The proposed strategy was successfully used to determine the gold amount in secondary gold jewelry containing Ir, Rh, and Ru (a gold recovery of 99.9% with a relative error of 0.07 was obtained). The obtained karat was comparable with the other methods. Accordingly, the proposed method will be a promising simple and available assay for gold alloys containing PGMs, which could be used routinely in most cupellation labs all over the world.

The cell potential of the cell containing two ion-selective electrodes (ISE), Na-ISE | NaClO4 (m), PEG 4000 (Y), H2O (100-Y) | ClO4-ISE has been measured at temperatures of (288.15, 298.15, and 308.15) K as a function of the weight percentage Y of PEG 4000 in a mixed solvent at a 1 Mpa and the standard state for measured activity coefficients will be a solution of the salt in pure water. Y was varied between (0 and 25) wt.% in five-unit steps and the molality of the electrolyte (m) was between 0.05 mol kg-1 and almost saturation. The values of the standard cell potential were calculated using routine methods of extrapolation together with extended Debye-Hückel and Pitzer equations. The results obtained produced good internal consistency for all the temperatures studied. Once the standard electromotive force was determined, the mean ionic activity coefficients for NaClO4, the Gibbs energy of transfer from the water to the PEG 4000-water mixture, and the primary NaCl hydration number were calculated.

The current study is aimed to utilize the microwave for isolation of colorant from neem bark and its application onto chemical & bio-mordanted cotton fabric. For the purpose, aqueous, acid and organic media have been employed to isolate the colorant and to make its application onto surface modified and bio-mordanted cotton fabric followed by microwave treatment up to 6min. It is found that using optimum extraction and dyeing conditions, acceptable fastness properties have been rated when 9% of Al & Fe, 7% of tannic acid as pre chemical, 7% of acacia, 9% of henna, 7% of pomegranate & 5% of turmeric extract as pre bio mordants. Similarly, 5% of Al, 9% of T.A, 7% of pomegranate, and turmeric extract as post-mordants have been employed. It is recommended that isolation of colorant & dyeing under MW treatment has not only improved the natural dyeing process but also the addition of herbal-based bio-mordants have made the dyeing process more sustainable & ayurvedic. So it is concluded that microwave treatment has not only explored the coloring potential of neem bark but also made possible use of bio-mordants for making process more green with excellent color characteristics under reduced optimal conditions.

In contemporary research, “Heterostructure” assemblies play an important role in energy conversion systems, wherein the composite assemblies facilitate faster charge carrier transport across the material interfaces. The improved/enhanced efficiency metrics in these systems (electro/photo-electrochemical processes/devices) is due to synergistic interaction and synchronized charge transport across material interfaces. Herein, we report Type-I Heterostructure consists of N, S doped TiO2, and Fe2O3 for electrochemical crystal violet dye degradation studies. Synthesized N-S codoped TiO2/Fe2O3 composite heterostructured assemblies were fabricated on Titanium (Ti) substrate and used for electrochemical analysis. Complete decolorization was achieved with all the fabricated electrodes and a higher rate of degradation was achieved with the composite electrode (Ti/TiO2/Fe2O3) in comparison to individual electrodes (bare Ti, Ti/TiO2, Ti/Fe2O3). Further, a probabilistic mechanism of degradation is proposed in support of the hypothesis. The outcomes of the present work will have a profound effect on doped semiconductor heterostructure assemblies in the degradation of complex dye molecules of industrial outlets.

In the present study, the removal of lead (II) ions from aqueous solutions was investigated by powdered Henna. Henna is a herbal material that can dramatically adsorb metal ions. Adsorption experiments were carried out in a batch system at room temperature. Then, the equilibrium concentration of each sample was analyzed by atomic adsorption device. The effects of various parameters such as time, initial concentration, adsorbent amount, and pH were investigated. pH, initial concentration, and adsorbent amount showed sharp effects on the adsorption rate. The effect of time on the process was not considerable, as well. The optimum operating conditions were found at pH of 4.78, time of 49.47 min, lead (II) initial concentration of 93.5 mg/L, and adsorbent amount of 1 g led to 97.8% removal of lead (II). Furthermore, Langmuir and Freundlich adsorption isotherms were investigated for the lead (II) adsorption process on Henna. The results showed that Langmuir's isotherm model is more suitable for this process (R2=0.947).

Mesoporous TiO2-SiO2 nanocomposite (TS) was synthesized via sol-gel method and Amino-functionalized using 3-(aminopropyl) triethoxysilane. prepared amino-functionalized TiO2-SiO2 (NH2TS) was evaluated for eliminating radioactive Th(IV) ion in comparison with (TS). The prepared nanocomposites were characterized using FT-IR,  XRD, DSC-TGA, SEM, EDS, BET, and BJH analyses. DSC and TGA analyses revealed that the total organic content of the NH2TS was at about 4%. According to the XRD patterns, synthesized nanocomposites exhibited only the crystalline anatase phase, and the sizes of the anatase crystallites in the prepared TS and NH2TS calculated to be 10.4 and 14.1nm, respectively. Moreover, the pore diameters of TS and NH2TS estimated to be 4.65 and 3.632 nm according to their BJH plot. The kinetic data of Th(IV) uptake process on both of two nanocomposites corresponded well to the pseudo-second-order equation. Adsorption thermodynamic parameters including the standard enthalpy, entropy, and Gibbs free energy revealed that the ion exchange reactions on both of NH2TS and TS nanocomposites were endothermic and spontaneous processes. The results indicated that NH2TS exhibited higher adsorption affinity toward Th(IV) compared to TS. Moreover, based on the Langmuir model, the maximum adsorption capacity of NH2TS nanocomposite towards the Th (IV) was found to be 1000 mg/g.

In this study, the sterol contents of almond kernel oils collected from naturally growing almond trees in Mersin province were determined. Generally, the sterol contents of almond oil samples varied depending on almond types. The major sterols in almond oils wereß-sitosterol, 5-avenasterol and campesterol, followed by 5,24-stigmastadienol, stigmasterol, sitostanol, and cholesterol. While β-sitosterol contents of almond oils varied between 1986 mg/kg (T26) and 3908 mg/kg (T16), 5-avenasterol contents of almond oils samples were in the range between 215.9 mg/kg (T31) and 581.7 mg/kg (T16). In addition, campesterol contents of oils were found from 75.8 mg/kg (T31) to 172.3 mg/kg (T16). Interestingly, all sterol contents (except cholesterol, brassicasterol and 7-campesterol) of T16 almond oil were found higher than those of the other almond types. The current study showed that almond kernels of the investigated almond types from Turkey are potential sources of valuable oil which might be used as edible oil or industrial applications.

In this study, the chemical composition of the essential oil of Teucrium scordium was studied using capillary GC and GC/MS instruments. In addition, the antimicrobial and cytotoxic activities of the oil and methanol extract were evaluated by disc diffusion and MTT assays, respectively. Forty-three volatile components were identified from the oil of aerial parts, representing of 98.1% of total oil. The major constituents were trans-α-bergamotene (52.3%), (Z)-α-trans-bergamotol (18.1%), linalool (3.0%) and piperitenone oxide (2.9%). The best anti-bacterial activity was observed for the methanol extract against Staphylococcus epidermidis with ZI (19.0 ± 0.47) mm and also against Proteus mirabilis with MIC value of 1.25 µg/mL.Investigation of the samples on cell viability of HeLa cells showed good activity for the essential oil with an IC50 value of 5.2 µg/mL. Our results indicated that Teucrium scordium can be considered for further analyses as an effective and safe curing agent for cancer and pathogenic infection therapies.

Propolis is a resinous substance collected by bees from plants with a complex and variable chemical composition. Propolis and its fractions possess multiple biological activities. This study focused on a chemical and statistical comparison between four Tunisian Propolis Essential Oils (PEO) and its antioxidant activities. Volatile oils were extracted by hydrodistillation and analyzed by GC-MS. Essential oil yield varied from 0.095% to 0.324%. A total of 59 volatile components were identified mainly dominated by sesquiterpenes and diterpenes hydrocarbons. Six major components were found in all samples collected from the four different locations α-Cedrol, Manoyl Oxide, Manool, Totarol, Tricosane, and Eicosane. The antioxidant activities of Tunisian propolis essential oils have been evaluated using two methods β-carotene-linoleic acid bleaching and DPPH radical scavenging assays and the results were compared with the standard antioxidant (Triolox). PEO from Bizerte region presented a lower IC50 value (30.5 mg/mL) than that of the standard antioxidant Trolox (IC50 = 40.05 mg/mL) indicating high antioxidant capacity using DPPH assay but for the b-carotene-linoleic acid bleaching assay, PEO from Zouarine region had the lowest value of (IC50 = 26.5 mg/mL) compared to standard (IC50 = 31.25 mg/mL). Our findings demonstrated that Propolis Essential Oil (PEO) possess high antioxidant activities and may be suggested as a new potential source of natural antioxidant.

Nowadays rising consumer concern on the safety of synthetic chemical food preservatives is a reason for finding natural new antimicrobial agents, especially among the components of medicinal plants such as Essential Oils (EOs). However, most EOs are sensitive to oxygen, light, and temperature and can be easily degraded. Some EOs have strong taste, flavor, and affect the organoleptic characteristics of foods. Encapsulation can control these unpleasant characteristics. Using yeast cells as encapsulating agents and delivery systems for active ingredients has been widely investigated. Encapsulation in yeast cells has a wide range of advantages such as processes simplicity, commercial availability, low cost-high volume process, and needless of toxic solvents.  In this study, the antibacterial activity of free and encapsulated Zataria multiflora Bioss. Essential Oil (ZEO) in Saccharomyces cerevisiae against Escherichia coli O157:H7 and Listeria monocytogenes as important foodborne pathogens were evaluated. The sensory evaluation of both forms of ZEO in a food model was also done. ZEO was successfully encapsulated into S. cerevisiae cells. Carvacrol and thymol contents in loaded yeasts were determined. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of free and loaded ZEO were studied against Escherichia coli O157:H7 and Listeria monocytogenes; their antibacterial effects in the commercial chicken soup was investigated, and their sensory attributes in the commercial soup were evaluated as well. Our results showed significant decreases in the MIC and MBC values of ZEO in culture media after encapsulation; however, the antibacterial activity of ZEO in commercial chicken soup showed no significant differences after encapsulation (P>0.05). ZEO encapsulation improves its sensory score and hence, decreases its organoleptic effects in food (P<0.01). Considering acceptable sensorial scores of loaded ZEO in yeast cells, this method can practically be applied in food systems as natural biopreservation.

In this study, the effect of 1,2,3-trichloropropane (TCP) as trifunctional monomer on thermophysical properties of synthesized poly(ethylene tetrasulfide) (PETS) is investigated. To this end, different amounts of TCP (0-40 mol. % of halide-containing monomer) were incorporated into the structure of polysulfide polymer via interfacial condensation polymerization. Measurement of gel, fraction showed that by the introduction of only 10 mol. % of TCP, synthesized structure is almost crosslinked. The X-Ray Diffraction (XRD) results revealed that all samples are semi-crystalline whereas the crystallinity of samples strongly depends on the amount of TCP. All samples showed a glass transition temperature (Tg) less than 0 °C followed by melting temperature (Tm). Higher amountof crosslinking monomer resulted in higher Tg while Tm and heat of fusion (ΔHm) were reduced. According to ThermoGravimetric Analysis (TGA) results, all samples exhibited a two-stage degradation process. Although, the introduction of 10 mol. % TCP into the structure of PETS resulted in lower thermal stability of obtained polymer, adding higher amounts of TCP led to the higher thermal stability of polymers.

A mathematical model for the prediction of internal recirculation of complex impinging stream reactors has been presented. The model constitutes a repetition of a series of ideal plug flow reactors and CSTR reactors with recirculation. The simplicity of the repeating motif allows for the derivation of an algebraic relation of the whole system using the Laplace transform. An impinging streams reactor system with one axial and two tangential inlet fluid streams was constructed and considered as a case study. The model predicts satisfactorily the complex and flow rate dependent experimental residence time distribution functions obtained employing a pulse tracer method for different total flow rates of the incoming feed. The variation of the controlling parameters with changing the total inlet flow rate is discussed. The presented model can predict complex internal recirculation streams within the impinging streams reactor system.

We numerically investigate the pulsatile flow and heat transfer of a micropolar fluid through a Darcy-Forchhmeir porous channel in the presence of wall transpiration. We use the central difference approximations for the spatial derivatives, whereas the time integration has been performed by employing the three steps explicit Runge-Kutta method to obtain the numerical solution. It is noted that the Darcy parameter tends to accelerate the fluid, whereas the Forchheimer quadratic drag parameter and the magnetic parameter would reduce the flow velocity. The effect of the steady component of the pressure gradient is to remarkably accelerate the flow whereas that of the oscillatory component is time-dependent. An increase in the Prandtl number tends to almost straighten the temperature profiles.

Freeze-drying is one of the most used methods for preparing scaffolds and is very sensitive to the material and operational parameters such as nucleation temperature, thermal properties of the mold, cooling rate, set freezing point, and slurry height. In the present study, a Finite Element Method (FEM) based code was developed to investigate the effects of such parameters and to eventually predict the microstructure of the scaffold. Similar molds and cooling conditions used in various experimental studies were simulated and compared. The achieved pattern demonstrated how different thermal condition tailored scaffold microstructure. It was shown that nucleation temperature (Tn) was an effective parameter controlling the final structure of the scaffold and influenced pore sizes with different mold materials. Simulation results also showed that by decreasing the rate of cooling, the average pore sizes increased, and a quenching solution led to a randomly distributed pattern of pore sizes. It is also achieved that by increasing the set freezing temperature as well as the height of the solution the pore sizes increased more at the top of the mold. The thermal gradient also illustrated the orientation of the pore in a mold with the thick isolated wall was considerably uniform. This framework can be used to optimize the scaffold structure or any ice templating method.

Biological inhibition of air pollution has vast advantages over physicochemical methods. One of the biggest challenges faced by researchers with traditional bio-filter in controlling Volatile Organic Compounds (VOCs) such as Benzene, Toluene, Ethylbenzene and Xylene (BTEX) is, low degradation rate (elimination capacity) and accumulation of very high biomass. The use of metabolic uncouplers involves uncoupling electron transport from oxidative phosphorylation reactions and thereby ATP production is less efficient, leads to more substrate utilization. So, this research is aimed to study the influence of different metabolic uncouplers on the biodegradation rate of toluene in a biofilm bio-filter reactor. The bio-filter reactor with Pseudomonas putida MTCC 10617 as biofilm in the presence of five different metabolic uncouplers such as Pentachlorophenol (PCP), 2, 4-Dinitrophenol (DNP), 2, 4, 6-Trichlorophenol (TCP), Benzoic Acid (BA) and Malonic Acid (MA) were studied. Results showed that only PCP and TCP increased the Surface Elimination Capacity (SEC) by 87% and 38% respectively. From the SEM analysis, larger and wider air interface cavities were observed in the biofilm subjected to PCP than TCP exposed biofilm. This infers the higher mass transfer in biofilm exposed to PCP.