IIT-Hyderabad professor Chandra Shekhar Sharma bags award

Professor Chandra Shekhar Sharma from the department of chemical engineering, Indian Institute of Technology, Hyderabad (IIT-H), has won the prestigious Young Scientist Platinum Jubilee Award, instituted by the National Academy of Sciences, India. He has been selected for his work on electrospun nanofibers and nanostructured carbon materials which can be used in environmental protection and healthcare. Professor Chandra Shekhar and his team recently introduced female sanitary napkins, using electrospun nanofibers (biodegradable polymer). Most sanitary napkins use non-biodegradable superabsorbent polymers (SAP) to increase their commercial value. However, they cause health hazards and also environmental problems. The product will soon hit the market after field trials. Furthermore, the team has also received a grant from the department of science and technology under the nano mission programme. The team has also developed an inexpensive way of creating electrodes. The award, started in 2005, is given to scientists in the field of physical, chemical and biological sciences

Effect of Current Collector and Pyrolysis Temperature on the Electrochemical Performance of Photoresist Derived Carbon Films

SU-8, an epoxy based negative photoresist has been demonstrated as a potential precursor to fabricate thin films and three-dimensional micropatterned arrays in glassy carbon. However, the use of silicon wafer as a substrate cum collector limits their use in real battery devices. In accordance with the commercial lithium ion battery architecture and also owing to enhanced conductivity, we have successfully demonstrated the use of stainless steel (SS) wafer as a current collector to prepare binder free SU-8 derived carbon thin films. Standard carbon microelectromechanical systems (C-MEMS) process parameters were tuned to obtain a uniform, crack-free carbon thin film on SS wafer upon pyrolysis. Further, we varied the final pyrolysis temperature to examine its effect on the microstructure and composition as characterized with X-ray diffraction, Small angle X-ray scattering, Raman spectroscopy and CHNS-O elemental analyzer respectively. The microstructural changes in the carbon films at different pyrolysis temperature were then correlated with their electrochemical performance as investigated using galvanostat charge/discharge experiments, impedance spectroscopy and cyclic voltammetry. Selection of an appropriate current collector and optimizing the pyrolysis temperature yielded excellent cyclic stability and coulombic efficiency with 400 mAh g−1 reversible capacity after 100 cycles, nearly double to as reported in the literature

IIT Hyderabad develops sanitary napkins that absorb better

Chandra Shekhar Sharma from the Department of Chemical Engineering, IIT Hyderabad and his team turned to nanotechnology to produce cellulose-based nanofibre for use as an absorbent core in sanitary napkins. They chose cellulose acetate biopolymer and subjected it to electrospinning to synthesise fibre of nanoscale size

Photoresist Derived Carbon Films as High Capacity Anodes for Lithium Ion Battery

An epoxy-based negative photoresist (SU-8) was spin-coated on stainless steel (SS) wafers followed by two-step pyrolysis in inert atmosphere to yield dense carbon films to be used as anodes for lithium (Li) ion batteries. The selection of SS wafer substrates was in accordance with commercial Li ion battery architecture. Cyclic voltammograms confirm the passive layer formation by electrolyte decomposition in the initial cycle. Galvanostatic charge/discharge experiments in the range 0.01-3 V performed at a C-rate=0.1 C confirms the reversible intercalation of Li ions and shows higher gravimetric reversible capacity for these photoresist-derived carbon films on SS wafer substrates than graphite (400 mAh/g vs. 372 mAh/g for graphite). This high reversible capacity may be attributed to high disorder in photoresist derived-carbon as characterized by X-ray diffraction and Raman spectroscopy

IIT Hyderabad uses activated jamun to remove fluoride from water

“Besides testing the activated jamun seed powder in the lab we also tested it using groundwater taken from Nalgonda village, which is one of the worst fluoride-affected villages in India. After two hours of contact time, we were able to reduce the fluoride content from 3.2 milligram per litre to less than 1.5 milligram per litre, which is the WHO limit,” says Dr. Sharma

A review on battery technology for space application

This review article comprehensively discusses the energy requirements and currently used energy storage systems for various space applications. We have explained the development of different battery technologies used in space missions, from conventional batteries (Ag–Zn, Ni–Cd, Ni–H2), to lithium-ion batteries and beyond. Further, this article provides a detailed overview of the current development of lithium batteries concerning their different electrode and electrolyte system, which needs special consideration for enabling their use for space application. This review also provides an outlook on the battery technology development for interplanetary space missions enlisting the research emphasis to be directed to meet the special energy requirements during various stages of such missions. This review is an attempt to provide a one-step comprehensive overview for any researchers, scientists, batteries manufacturers, and space agencies to first understand the current requirements critically and, accordingly, the solutions to prepare a future roadmap to develop highly efficient, next-generation advanced energy storage systems to mitigate the technical challenges and at the same time, minimizing the cost associated

A noble metal-free candle soot derived carbon electrocatalyst for simultaneous H2 generation and wastewater treatment

Electrocatalytic water splitting to produce green hydrogen is a promising approach for clean energy generation. However, the commercial aspect of this approach is limited due to catalysts cost and feedstock. Thus design of an inexpensive and noble metal-free (Pt, Rh, Ir etc.) catalyst is desirable. Moreover, wastewater as a feedstock for hydrogen generation is not explored to its full potential for green hydrogen generation, which otherwise is also a problem to be managed especially in developing countries. In the present work, we have investigated an inexpensive catalyst i.e. candle soot-derived carbon as an electrocatalyst for H2 generation from textile wastewater utilizing methylene blue as a model pollutant. The carbon catalyst is synthesized from the candle soot and is characterized for its structural and morphological properties. Carbon soot coated onto the nickel foam (CS@NF) proves as an efficient hydrogen evolution catalyst due to its excellent electrical conductivity and large active surface area. CS2.5@NF (with the loading of 2.5 mg cm−2) shows an overpotential and Tafel slope of 117 mV and 43.85 mV/dec, respectively in an acidic medium containing textile pollutants. Under optimal condition, ∼62% degradation is achieved within ∼90 min, along with the stable hydrogen production of ∼0.158 mmol per hour. These preliminary findings demonstrate the potential usage of an inexpensive non-noble metal free catalyst for simultaneous wastewater treatment as well as hydrogen generation

Sustained drug release from multi-layered sequentially crosslinked electrospun gelatin nanofiber mesh

The aim of this study is to develop electrospun gelatin nanofibers based drug delivery carrier to achieve controlled and sustainable release of hydrophobic drug (piperine) for prolonged time. To accomplish this, we devised some strategies such as sandwiching the drug loaded gelatin nanofiber mesh with another gelatin nanofiber matrix without drug (acting as diffusion barrier), sequential crosslinking and finally, a combination of both. As fabricated multilayered electrospun nanofibers mesh was first characterized in terms of degradation study, morphology, drug-polymer interactions, thermal stability followed by studying their release kinetics in different physiological pH as per the gastrointestinal tract. Our results show that with optimized diffusional barrier support and sequential crosslinking together, a zero order sustained drug release up to 48 h may be achieved with a flexibility to vary the drug loading as per the therapeutic requirements. This work lays out the possibility of systematic design of multilayer nano-fiber mesh of a biopolymer as a drug delivery vehicle for hydrophobic drugs with a desired signature of zero order release for prolonged duration