R. Vinoth Kumar

Performance assessment of an analcime-C zeolite–ceramic composite membrane by removal of Cr(VI) from aqueous solution

This article describes the synthesis of an analcime-C zeolite membrane on a ceramic support by in situ hydrothermal crystallization. A circular shaped ceramic support was firstly fabricated using low cost raw materials by a uni-axial pressing method and sintering process. Subsequently, the zeolite composite membrane was prepared with the repeated coating of analcime-C on the ceramic support through an in situ crystallization technique. The synthesized zeolite composite membrane was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), porosity, average pore size and pure water permeability. The influence of the number of coatings on the characteristics of the zeolite membrane was also explored. The obtained results clearly demonstrate that the porosity, pore size and water permeability of the membrane decrease significantly with the multiple coating of zeolite over the ceramic support. The porosity, average pore size and pure water permeability of the zeolite membranes are estimated to be 38–24%, 285–155 nm and 2.18 × 10−7 to 4.53 × 10−8 m3 m−2 s−1, respectively for various coatings (1–3). Finally, the separation performance of three times coated zeolite membrane was evaluated by removal of chromium(VI) from aqueous solution by ultrafiltration (UF) at various operating conditions (applied pressure, concentration and pH). The maximum rejection of 84% is achieved at an applied pressure of 207 kPa. Moreover, the separation performance of membrane is better as compared to other membranes reported in the literature.

Cross flow ultrafiltration of Cr (VI) using MCM-41, MCM-48 and Faujasite (FAU) zeolite-ceramic composite membranes

This work describes the removal of Cr (VI) from aqueous solution in cross flow mode using MCM-41, MCM-48 and FAU zeolite membranes prepared on circular shaped porous ceramic support. Ceramic support was manufactured using locally available clay materials via a facile uni-axial compaction method followed by sintering process. A hydrothermal technique was employed for the deposition of zeolites on the ceramic support. The porosity of ceramic support (47%) is reduced by the formation of MCM-41 (23%), MCM-48 (22%) and FAU (33%) zeolite layers. The pore size of the MCM-41, MCM-48 and FAU membrane is found to be 0.173, 0.142, and 0.153 μm, respectively, which is lower than that of the support (1.0 μm). Cross flow ultrafiltration experiments of Cr (VI) were conducted at five different applied pressures (69-345 kPa) and three cross flow rates (1.11 × 10(-7) - 2.22 × 10(-7) m(3)/s). The filtration studies inferred that the performance of the fabricated zeolite composite membranes is optimum at the maximum applied pressure (345 kPa) and the highest rejection is obtained with the lowest cross flow rate (1.11 × 10(-7) m(3)/s) for all three zeolite membrane. The permeate flux of MCM-41, MCM-48 and FAU zeolite composite membranes are almost remained constant in the entire duration of the separation process. The highest removal of 82% is shown by FAU membrane, while MCM-41 and MCM-48 display 75% and 77% of Cr (VI) removal, respectively for the initial feed concentration of 1000 ppm with natural pH of the solution at an applied pressure of 345 kPa.

Modelling and optimization of critical parameters by hybrid RSM-GA for the separation of BSA using a tubular configured MFI-type zeolite microfiltration membrane

This paper deals with the fabrication of a MFI-type zeolite membrane via an in situ hydrothermal synthesis technique on a low cost porous tubular ceramic substrate. To formulate the zeolite layer on the porous substrate, the hydrothermal solution was prepared using silicate solutions. The MFI zeolite (as synthesized and calcined) was characterized by X-ray diffraction (XRD), thermogravimetry (TG) and Fourier transform infrared spectroscopy (FTIR) analysis. The fabricated ceramic substrate as well as the zeolite membrane was characterized by field emission scanning electron microscopy (FESEM), porosity and water permeability measurements. The porosity, mean pore size and water permeability of the zeolite membrane were evaluated to be 51%, 0.272 μm and 4.43 × 10−7 m3 m−2 s−1 kPa−1, respectively. The separation efficiency of the membrane in terms of permeate flux and rejection was studied with BSA as a model protein. Three operating parameters, BSA concentration (100–500 ppm), pH (2–4) and applied pressure (68.94–275.79 kPa), were optimized for the better separation efficiency of the membrane using response surface methodology (RSM) followed by a bi-objective genetic algorithm (GA). The non-linear models predicted by RSM were further optimized by a GA. The appropriate optimum conditions were obtained as a BSA concentration of 100 ppm, solution pH of 2 and applied pressure of 275.79 kPa. These predicted conditions were experimentally validated and a higher permeate flux and rejection of BSA were obtained as 4.63 × 10−5 m s−1 and 81.98%, respectively. Further, the separation efficiency of prepared membrane was compared with other membranes used for BSA separation stated in the literature.

Anthracene Biodegradation by Oleaginous Rhodococcus opacus for Biodiesel Production and Its Characterization

ABSTRACT This study examined biodegradation of anthracene, a model low molecular weight polycyclic aromatic hydrocarbon (PAH) by oleaginous Rhodococcus opacus for biodiesel production. Specific biomass growth rate (µ) in the range of 0.0075–0.0185 h−1 could be attained over the initial anthracene concentration (50–500 mg L−1), along with 68–70.6% (w/w) lipid accumulation. 10% (v/v) inoculum size showed more positive effect than 5% (v/v) inoculum size on both anthracene biodegradation efficiency and lipid accumulation by R. opacus. 1H and 13C nuclear magnetic resonance (NMR) spectroscopy of the bacterial lipids revealed 82.25% saturated fatty acids content. Furthermore, the transesterified bacterial lipids predominantly consisted of methyl palmitate (32.4%) and methyl stearate (25.9%) as the major fatty acid methyl esters (FAMEs). Overall, this study revealed a very good potential of the bacterium for the production of biodiesel from PAH-containing wastewater.

Removal of FeCl3 from aqueous solution by ultrafiltration using ordered mesoporous MCM-48 ceramic composite membrane

ABSTRACT Mesoporous MCM-48 membrane was prepared on a low-cost circular-shaped ceramic support by a hydrothermal crystallization technique. The characteristics of MCM-48 powder and composite membrane were evaluated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), porosity and water permeation test. The porosity and pore size of the composite membrane were found to be 22% and 0.142 µm, respectively. The MCM-48 composite membrane was investigated for the separation potential of FeCl3 from aqueous solution and a maximum rejection of 86% was obtained for a feed concentration of 250 ppm at lower pH 2.

Separation of BSA through FAU-type zeolite ceramic composite membrane formed on tubular ceramic support: Optimization of process parameters by hybrid response surface methodology and biobjective genetic algorithm

ABSTRACT In this study, Faujasite (FAU) zeolite was coated on low-cost tubular ceramic support as a separating layer through hydrothermal route. The mixture of silicate and aluminate solutions was used to create a zeolitic separation layer on the support. The prepared zeolite ceramic composite membrane was characterized using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), particle size distribution (PSD), field emission scanning electron microscopy (FESEM), and zeta potential measurements. The porosity of ceramic support (53%) was reduced by the deposition of FAU (43%) zeolite layer. The pore size and water permeability of the membrane were evaluated as 0.179 µm and 1.62 × 10−7 m3/m2 s kPa, respectively, which are lower than that of the support (pore size of 0.309 µm and water permeability of 5.93 × 10−7 m3/m2 s kPa). The permeate flux and rejection potential of the prepared membrane were evaluated by microfiltration of bovine serum albumin (BSA). To study the influences of three independent variables such as operating pressure (68.94–275.79 kPa), concentration of BSA (100–500 ppm), and solution pH (2–4) on permeate flux and percentage of rejection, the response surface methodology (RSM) was used. The predicted models for permeate flux and rejection were further subjected to biobjective genetic algorithm (GA). The hybrid RSM-GA approach resulted in a maximum permeate flux of 2.66 × 10−5 m3/m2 s and BSA rejection of 88.02%, at which the optimum conditions were attained as 100 ppm BSA concentration, 2 pH solution, and 275.79 kPa applied pressure. In addition, the separation efficiency was compared with other membranes applied for BSA separation to know the potential of the fabricated FAU zeolite ceramic composite membrane.

Petroleum Versus Biorefinery-Based Platform Chemicals

Globally, biomass resources are gaining attention due to the rapid depletion and imminent danger of the complete exhaustion of fossil fuels. Therefore biorefineries, the equivalent of petroleum refineries, for the generation of transportation fuel and other chemicals are being set up, and technologies for their upgradation are being developed. However, it is necessary to clearly understand the fundamental differences between petroleum refineries and biorefineries. This chapter presents an overview of comparisons between petroleum refinery and biorefinery. It provides information about feedstock availability, which is one of the important and foremost fundamental differences between the two refinery types. Moreover, there are various biorefinery platforms: these platforms can produce a variety of products, including biofuels, chemicals, and other value-added products. This chapter seeks to expound the range of products of biorefinery, its nature, and the extent of environmental pollution along with the sustainability of bio-based products.

Malic and Succinic Acid

Abstract This chapter contributes to the understanding of the potential C4 platform chemicals (malic and succinic acid) for the production of polymer and biodegradable plastics. Various methods of malic acid production from renewable materials, its commercial potential, and its application in the production of renewable polymers are discussed. Bio-based succinic acid has the potential to be a platform chemical. In addition, it can be used as a feedstock for polybutylene succinate production, and thus the market for succinic acid is anticipated to grow due to an increasing attention toward biodegradable products. Therefore this chapter also addresses succinic acid bioproduction and its commercial application in the production of biodegradable plastics.