Mano Misra

Spent Coffee Grounds as a Versatile Source of Green Energy

The production of energy from renewable and waste materials is an attractive alternative to the conventional agricultural feed stocks such as corn and soybean. This paper describes an approach to extract oil from spent coffee grounds and to further transesterify the processed oil to convert it into biodiesel. This process yields 10-15% oil depending on the coffee species (Arabica or Robusta). The biodiesel derived from the coffee grounds (100% conversion of oil to biodiesel) was found to be stable for more than 1 month under ambient conditions. It is projected that 340 million gallons of biodiesel can be produced from the waste coffee grounds around the world. The coffee grounds after oil extraction are ideal materials for garden fertilizer, feedstock for ethanol, and as fuel pellets.

Functionalization of self-organized TiO2 nanotubes with Pd nanoparticles for photocatalytic decomposition of dyes under solar light illumination.

Self-organized, vertically oriented TiO2 nanotube arrays prepared by the sonoelectrochemical anodization method are functionalized with palladium (Pd) nanoparticles of approximately 10 nm size. A simple incipient wetness method is adopted to distribute the Pd nanoparticles uniformly throughout the TiO2 nanotubular surface. This functionalized material is found to be an excellent heterogeneous photocatalyst that can decompose nonbiodegradable azo dyes (e.g., methyl red and methyl orange) rapidly (150-270 min) and efficiently (100%) under ambient conditions using simulated solar light in the absence of any external oxidative radicals such as hydrogen peroxide.

Dye-sensitized photovoltaic wires using highly ordered TiO2 nanotube arrays.

Dye-sensitized photovoltaic wires (DSPVWs) are developed using anodized Ti wires that contain ordered arrays of TiO2 nanotubes. The prototype DSPVW consists of N719 dye-adsorbed TiO2 nanotube arrays around a Ti wire as a working electrode, a platinum wire as a counter electrode, and an organic electrolyte encased in a capillary glass tube. The effect of length of nanotube arrays on the photovoltaic performance of DSPVWs is studied systematically. A solar-to-electric conversion efficiency of 2.78% is achieved with 55 microm long nanotubes under 98.3 mW/cm(2) AM 1.5 simulated full light. The prototype device is capable of achieving a long distance transport of photocurrent and harvesting all light from any direction in surroundings to generate electricity.

Double-Wall Anodic Titania Nanotube Arrays for Water Photooxidation

Vertically oriented double-wall titania nanotube (external diameters of 82 and 206 nm) arrays are synthesized by a sonoelectrochemical anodization technique in combination with a unique room-temperature ionic liquid and organic electrolyte. Compared to similar single-wall nanotubes (0.638 mA/cm(2)) and commercial nanoparticles (0.365 mA/cm(2)), these double-wall nanotube arrays show 2-4 times more photoactivity to split water under solar light illumination to generate hydrogen and oxygen. Partial doping of B and C into the TiO(2) matrix gives rise to these double-wall nanotubes which absorb visible solar light more efficiently than the intrinsic TiO(2). The structural properties of these novel structures have been studied extensively using various spectroscopic, analytical, and electrochemical techniques.

Redox-Induced Enhancement in Interfacial Capacitance of the Titania Nanotube/Bismuth Oxide Composite Electrode

Bismuth oxide (Bi2O3) decorated titania nanotube array (T-NT) composite materials were synthesized by a simple, yet versatile electrodeposition method. The effects of deposition current density and time on morphology evolution of the bismuth oxide phase were analyzed. It was found that an optimum deposition condition in terms of current density and time could be reached to achieve uniform and equiaxed crystal morphology of the deposited oxide phase. The morphology, shape, size distribution, and crystal structure of the bismuth oxide phase were evaluated using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopic techniques. The electrochemical capacitance of the T-NT/Bi2O3 composites was studied by conducting cyclic voltammetry and galvanostatic charge-discharge experiments. These studies indicated that the capacitance behavior of the composite material was dependent on the morphology and distribution of the bismuth oxide phase. The capacitance was greatly enhanced for the composite having equiaxed and uniformly distributed bismuth oxide particles. The maximum interfacial capacitance achieved in this study was approximately 430 mF cm(-2). Galvanostatic charge-discharge experiments conducted on the composite materials suggested stable capacitance behavior together with excellent capacitance retention even after 500 cycles of continuous charge-discharge operation.

A Green Process for Producing Biodiesel from Feather Meal

This paper describes a new and environmentally friendly process for developing biodiesel from commercial feather meal, a waste product of the poultry industry. Currently, feather meal is used as an animal feed, given its high protein content, and also as a fertilizer because of its high nitrogen content. In this work, we have extracted fat from the feather meal in boiling water (70 degrees C) and then transesterified the fat into biodiesel using KOH and methanol; 7-11% biodiesel (on a dry basis) is produced in this process. ASTM analysis of the prepared feather meal biodiesel confirmed that the biodiesel is of good quality and comparable to other biodiesels made from other common feedstocks. Given the amount of feather meal produced by the poultry industry, it is estimated that this process can create 150-200 million gallons of biodiesel in the United States and 593.2 million gallons worldwide.

Self-Ordered Titanium Dioxide Nanotube Arrays: Anodic Synthesis and Their Photo/Electro-Catalytic Applications

Metal oxide nanotubes have become a widely investigated material, more specifically, self-organized titania nanotube arrays synthesized by electrochemical anodization. As a highly investigated material with a wide gamut of applications, the majority of published literature focuses on the solar-based applications of this material. The scope of this review summarizes some of the recent advances made using metal oxide nanotube arrays formed via anodization in solar-based applications. A general methodology for theoretical modeling of titania surfaces in solar applications is also presented.

Synthesis of TaON nanotube arrays by sonoelectrochemical anodization followed by nitridation: a novel catalyst for photoelectrochemical hydrogen generation from water

This communication reports the synthesis of TaON nanotube arrays as efficient visible light driven photocatalysts for photoelectrochemical generation of hydrogen from water.

Light-assisted anodized TiO2 nanotube arrays

Self-assembled arrays of titania nanotubes are synthesized via electrochemical anodization of Ti foils under the presence of UV-vis irradiation. Compared to control samples (anodized without light), the light-assisted anodized samples exhibit larger diameters as well as thicker nanotube walls, whereas the length of the nanotubes remains the same under otherwise similar synthesis conditions. Enhanced photoelectrochemical performance with light-assisted anodized samples under simulated AM 1.5 irradiation is observed by an increase in photocurrent density of 45-73% at 1.23 V (RHE). The enhanced photoelectrochemical performance is correlated to improved charge separation analyzed by Mott-Schottky. A mechanism on the photoeffect during anodization is presented. The morphology and improved properties obtained from the synthesis methodology may also find application in other fields such as sensing and catalysis.

The detection of improvised nonmilitary peroxide based explosives using a titania nanotube array sensor

There is a critical need to develop an efficient, reliable and highly selective sensor for the detection of improvised nonmilitary explosives. This paper describes the utilization of functionalized titania nanotube arrays for sensing improvised organic peroxide explosives such as triacetone triperoxide (TATP). TATP forms complexes with titania nanotube arrays (prepared by anodization and sensitized with zinc ions) and thus affects the electron state of the nanosensing device, which is signaled as a change in current of the overall nanotube material. The response is rapid and a signal of five to eight orders of magnitude is observed. These nanotube array sensors can be used as hand-held miniaturized devices as well as large scale portable units for military and homeland security applications.