K.M. Meera Sheriffa Begum

Optimization using central composite design (CCD) for the biosorption of Cr(VI) ions by cross linked chitosan carbonized rice husk (CCACR)

The presence of heavy metals in aqueous streams arising from the discharge of industrial effluents into water bodies is one of the most important environmental issues because of their toxic nature and its removal is highly essential. This paper deals with the adsorption studies for the removal of hexavalent chromium ions from aqueous solutions using Schiff based chitosan activated carbonized rice husk composites as adsorbent. The activation and surface properties of the adsorbent were characterized by Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Brauner Emmet and Teller (BET) analyzer. Central Composite Design (CCD) was used to optimize the process variables such as initial metal ion concentration, adsorbent dosage and pH of the solution on the performance of percentage removal and adsorption capacity. The experimental data were validated with different isotherms and kinetic models to evaluate the solute interaction behavior and nature of adsorption.

Removal of Chromium(VI) Ions from Aqueous Solutions and Industrial Effluents Using Magnetic Fe3O4 Nano-particles

The adsorption characteristics of magnetic Fe3O4 nano-particles synthesized by chemical co-precipitation for the removal of chromium(VI) ions from aqueous solutions and tannery effluents have been studied. The composition, size, morphology and magnetic properties of the nano-particles were characterized by FT-IR, XRD, TEM and VSM methods, respectively. Experiments were conducted in batch mode to observe the influence of different parameters such as pH, feed concentration, adsorbent dosage and temperature on the performance of the adsorbent. It was found that when the pH of the system was decreased from 7 to 2, the extent to which Cr(VI) ions were removed increased from 54% to 77%. The adsorption process was found to follow second-order kinetics and the rate constant was evaluated at 30 °C. The Langmuir isotherm was found to provide a good fit to the experimental data. The adsorption capacity of magnetite nano-particles towards Cr(VI) ions at room temperature was 2.9508 mg/g, with the value increasing to 3.4454, 3.7592 and 4.0475 mg/g at 40 °C, 50 °C and 60 °C, respectively. On the basis of the adsorption free energy change of 16.577 kJ/mol obtained at 30 °C, the adsorption mechanism was confirmed as being chemical in nature. The thermodynamic parameters for the adsorption process were also calculated from the experimental data. At an S/L ratio of 0.2 and under optimized conditions of pH, temperature and agitation, the removal of Cr(VI) ions from aqueous solution amounted to 85%. Regression analysis was performed and a correlation between percentage removal and operating parameters obtained.

Studies on biodiesel production from Pongamia oil using heterogeneous catalyst and its effect on diesel engine performance and emission characteristics

ABSTRACT Commercial calcium oxide (CaO) impregnated with 25 wt% potassium iodide (KI) was prepared by wet impregnation method and adopted for transesterification of Pongamia oil using methanol. The synthesized catalyst (KI/CaO) was characterized using different techniques such as X-ray Diffraction, Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller and Scanning Electron Microscopy analysis. Under the reaction conditions of 12:1 methanol:oil ratio, 4 wt% KI/CaO catalyst, 2 h reaction time and at a reaction temperature of 65°C, a maximum biodiesel conversion of 95.7% was obtained. Synthesized biodiesel was characterized by FTIR and H Nuclear Magnetic Resonance Spectroscopy techniques. The performance and emission characteristics of different blends of Pongamia biodiesel and conventional diesel were tested using a single-cylinder, four-stroke IC engine and the results were compared.

Highly biocompatible chitosan with super paramagnetic calcium ferrite (CaFe2O4) nanoparticle for the release of ampicillin

The CaFe2O4 nanoparticles (CFNP) were synthesized using the solution combustion method. The CFNP-chitosan-ampicillin was prepared by the ionic gelation method using tripolyphosphate (TPP). The CFNP, chitosan-CFNP, chitosan-CFNP-ampicillin materials were characterized by XRD, FT-IR and TGA analysis in order to evaluate the particle nature and size, the presence of functional groups and their thermal stability. The FESEM and EDAX analysis were performed to understand the surface morphology of the materials and the presence of CFNP in the material, respectively. The vibrating sample magnetometer (VSM) analysis was performed to analyze the magnetic property of the chitosan-CFNP material. The squareness value of 0.1733 obtained by VSM measurements indicates the super paramagnetic nature of chitosan-CFNP. Taguchi orthogonal array method was applied to identify the significant impacting parameters for maximizing the drug encapsulation of chitosan-CFNP. The drug release studies showed that the drug was released rapidly in acidic medium as compared to the basic or neutral medium. The drug release kinetic data were fitted with different linear kinetic model equations and the best fit was obtained with Korsmeyer-Peppas model. The model drug ampicillin release from chitosan-CFNP was tested against staphylococcus epidermis bacteria through disc diffusion method for checking biocompatibility and antibacterial activity.

EMULSION LIQUID MEMBRANE PERTRACTION OF METAL IONS FROM AQUEOUS SOLUTIONS AND ELECTROPLATING EFFLUENT USING ROTATING DISK CONTACTOR

Removal of chromium (III), copper (II), and zinc (II) from synthetic aqueous solutions and electroplating wastewater by an emulsion liquid membrane technique (ELM) was studied using a rotating disk contactor (RDC). Kerosene as diluent, Span 80 as surfactant, di-(2ethyl hexyl) phosphate (D2EHPA) as carrier, and 1 N H2SO4 solution as internal stripping phase were used for emulsion preparation. RDC provides relatively low shear to emulsion and thus minimizes rupture of the ELM. Various hydrodynamic and chemical parameters such as metal ion concentration in the continuous (feed) phase, pH of the continuous phase, carrier concentration, agitation speed, internal stripping agent concentration, and flow rate ratio of continuous phase to dispersed phase (treat ratio) have been experimentally investigated. The results showed that it is possible to remove more than 95% of all metal ions from aqueous solutions with a concentration factor of more than 35 and a removal of 68–74% of three metal ions from the electroplating effluent.

CONTINUOUS FOAM SEPARATION OF HEAVY METAL IONS FROM ELECTROPLATING INDUSTRIAL EFFLUENT

Process industries generate a large amount of waste materials during either production or downstreaming operations. Among many methods available for their separation, foam separation plays a major role, especially when the concentration of undesirable components involved is very low. The success of this technique depends on the stability and characteristics of the foam. This operation is simple with less maintenance as there are no moving parts. In the present study, simultaneous removal of metal ions such as chromium (VI), copper (II), and zinc (II) from electroplating industrial effluent was carried out with sodium lauryl sulfate (SLS) as surfactant in continuous foam column. Enrichment ratios of 3.94, 4.05, and 7.96 with a percentage removal of 59.0%, 63.0%, and 99.2% were obtained for chromium (VI), copper (II), and zinc (II) ions respectively at the optimum operating parameters of 23 cm liquid pool height in column, 0.1 liter per minute (Lpm) of airflow rate, feed flow rate of 4 liters per hour (Lph), 0.1% (w/v) of SLS concentration, pH of 6.0, and at feed concentrations of 32.5, 27.0, and 23.0 ppm for chromium (VI), copper (II), and zinc (II) ions respectively. Enrichment ratio was found to increase with an increase in feed flow rate. With a decrease in concentration of the bulk solution, the separation factor was found to increase. The study indicates the feasibility of continuous foam separation for treating industrial effluents.

Curcumin drug delivery by vanillin-chitosan coated with calcium ferrite hybrid nanoparticles as carrier

ABSTRACT The aim of the present investigation is the development, optimization and characterization of curcumin‐loaded hybrid nanoparticles of vanillin‐chitosan coated with super paramagnetic calcium ferrite. The functionally modified vanillin‐chitosan was prepared by the Schiff base reaction to enhance the hydrophobic drug encapsulation efficiency. Calcium ferrite (CFNP) nano particles were added to the vanillin modified chitosan to improve the biocompatibility. The vanillin‐chitosan‐CFNP, hybrid nanoparticle carrier was obtained by ionic gelation method. Characterizations of the hybrid materials were performed by XRD, FTIR, 1H NMR, TGA, AFM and SEM techniques to ensure the modifications on the chitosan material. Taguchi method was applied to optimize the drug (curcumin) encapsulation efficiency by varying the drug to chitosan‐vanillin, CFNP to chitosan‐vanillin and TPP (sodium tripolyphospate) to chitosan‐vanillin ratios. The maximum encapsulation efficiency was obtained as 98.3% under the conditions of 0.1, 0.75 and 1.0 for the drug to chitosan‐vanillin, CFNP to chitosan‐vanillin and TPP to chitosan‐vanillin ratios, respectively. The curcumin release was performed at various pH, initial drug loading concentrations and magnetic fields. The drug release mechanism was predicted by fitting the experimental kinetic data with various drug release models. The drug release profiles showed the best fit with Higuchi model under the most of conditions. The drug release mechanism followed both non‐Fickian diffusion and case II transport mechanism for chitosan, however the non‐Fickian diffusion mechanism was followed for the vanillin modified chitosan. The biocompatibility of the hybrid material was tested using L929 fibroblast cells. The cytotoxicity test was performed against MCF‐7 breast cancer cell line to check the anticancer property of the hybrid nano carrier with the curcumin drug. Graphical abstract Figure. No Caption available.

A Comparative Study of ANN and CFD Modelling for Pressure Drop Prediction in a Fluidized Bed with Internals

Abstract In the present study, experiments on fluidized beds were conducted by varying hydrodynamic parameters such as air velocity, bed height and internal spacing and these data were used in the development of a model using artificial neural network (ANN) and simulation using computational fluid dynamics (CFD). Staggered rod internals of width 25% and 50% of the column diameter were used. A two-layered feed-forward back propagation ANN model was developed to predict the pressure drop with 15 neurons and it gave a high R2 value of 0.9966. The model prediction and experimental data are in good agreement. The results from CFD studies are also in good agreement with the experimental data. Pressure drop was found to reduce in the presence of internals and it reduced further with a decrease in internal spacing due to continuous splitting of bubbles. The average error in CFD predicted pressure drop is 9.56% and ANN predicted pressure drop is 0.95%.

Clam shell catalyst for continuous production of biodiesel

ABSTRACT Continuous flow transesterification of waste frying oil (WFO) with methanol for the biodiesel production was tested in a laboratory scale jacketed reactive distillation (RD) unit packed with clam shell based CaO as solid catalyst. The physiochemical properties of the clam shell catalysts were characterized by X-ray Diffraction (XRD), Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy (SEM), and Energy Dispersive Atomic X-ray Spectrometry (EDAX). The effects of the reactant flow rate, methanol-to-oil ratio, and catalyst bed height were studied to obtain the maximum methyl ester conversion. Reboiler temperature of 65°C was maintained throughout the process for product purification and the system reached the steady state at 7 hr. The experimental results revealed that the jacketed RD system packed with clam shell based CaO showed high catalytic activity for continuous production of biodiesel and a maximum methyl ester conversion of 94.41% was obtained at a reactant flow rate of 0.2 mL/min, methanol/oil ratio of 6:1, and catalyst bed height of 180 mm.

Studies on Fluidized Beds Using Disc-type Internals and Modelling by ANN

Abstract In the present study, effect of internals and other hydrodynamic variables on pressure drop and expansion ratio were examined. The parameters studied include inlet air flow rate, bed height, spacing of internal, column diameter and percentage open area. Disc promoters of three different percentages of open area (48.03%, 55.15%, 66.26%) were used. The pressure drop was found to increase significantly with increase in bed height and decrease with open area of internals. As the spacing was decreased, the pressure drop increased first and then decreased due to effective breaking of bubbles in the presence of internals. The expansion ratio was seen to decrease significantly with decrease in the internal spacing and decrease in open area of internals. Correlations for pressure drop and expansion ratio have been found using dimensional analysis. The calculated values of pressure drop and expansion ratio were compared with experimental values. Several models have been developed using the Artificial Neural Network (ANN) approach and compared with each other. A high R2 value of 0.9947 with an error of 0.0105 was obtained for the ANN model in the case of pressure drop.