Palanisamy Thanikaivelan

Collagen based magnetic nanocomposites for oil removal applications

A stable magnetic nanocomposite of collagen and superparamagnetic iron oxide nanoparticles (SPIONs) is prepared by a simple process utilizing protein wastes from leather industry. Molecular interaction between helical collagen fibers and spherical SPIONs is proven through calorimetric, microscopic and spectroscopic techniques. This nanocomposite exhibited selective oil absorption and magnetic tracking ability, allowing it to be used in oil removal applications. The environmental sustainability of the oil adsorbed nanobiocomposite is also demonstrated here through its conversion into a bi-functional graphitic nanocarbon material via heat treatment. The approach highlights new avenues for converting bio-wastes into useful nanomaterials in scalable and inexpensive ways.

Recent Trends in Leather Making: Processes, Problems, and Pathways

Leather processing has emerged as an important economic activity in several developing countries. Awareness of environmental problems has increased considerably and during recent years protecting environment has become a global issue. Currently the leather processing industry is going through a phase change due to global environmental regulations. The article summarizes the current leather processing methods with their rationale and environmental problems. It has been revealed that pretanning and tanning processes contribute 80–90% of the total pollution load (BOD, COD, TS, TDS, Cr, S2−, sludge, etc.). Further, toxic gases like ammonia and hydrogen sulfide are also emitted. Volatile organic compounds, heavy metals, and carcinogenic arylamines from posttanning and finishing operations are also creating severe concern. Apart from this, a great deal of solid wastes like lime sludge from tannery and chrome sludge from effluent treatment plants are being generated. Advanced processing techniques as well as effluent treatment strategies for combating environmental and human health risks are reviewed in detail. The leather processing industry in various countries, however, is facing a serious challenge from the public and government. This is in spite of the implementation of several advanced processing techniques and treatment systems. Hence, there is a need to revamp leather processing methods anew for the sustainability of leather industry. Some of the novel concepts in leather processing are briefly mentioned and discussed.

An improved product-process for cleaner chrome tanning in leather processing

Abstract Severe restrictions imposed by the pollution control authorities on the disposal of chromium, total dissolved solids and chlorides in tannery effluents have forced the tanners to look for low-waste, high exhaust chrome tanning salts. An improved chrome syntan with more than 90% uptake of chrome has been developed. The new product serves both as tanning and retanning agent and can be applied directly to delimed pelts thus eliminating the conventional pickling stage in the leather processing. This modified process helps to reduce the chemical oxygen demand (COD), total dissolved solids (TDS) and chlorides in the spent tan liquor by 51, 81 and 99%, respectively. The product offers full, soft leathers having shrinkage temperature comparable to conventional chrome tanned skins. Since the developed product is highly reactive, it saves time and reduces the water requirement when compared to the conventional chrome tanning method. Thus the novel product/process developed not only has advantages in reducing pollution loads but also seems to be techno-economically viable.

Optical bifunctionality of europium-complexed luminescent graphene nanosheets.

Graphene is an intriguing two-dimensional material, which could be modified for achieving tunable properties with many applications. Photoluminescence of graphene due to plasmonic emission is well-known, however, attempts to develop strong luminescent graphene have been difficult. Synthesis of a graphene-based material with a dual optical functionality, namely quenching the fluorescence of organic dyes while maintaining its own self-luminescence, is an interesting and challenging proposition. Here, we demonstrate this optical bifunctionality in a lattice-modified luminescent graphene, where europium(III) cations are complexed with graphene through oxygen functionalities. After excitation at 314 nm, a hypersensitive red emission is observed at 614 and 618 nm showing the complexation of europium(III) with graphene. We demonstrate dual functionality of this graphene by the quenching of luminescence of Rhodamine-B while displaying its own hypersensitive red emission. The decay lifetime observed through the time-resolved spectroscopy confirms its potential for applications in biosensing as well as optoelectronics.

Probing a Bifunctional Luminomagnetic Nanophosphor for Biological Applications: a Photoluminescence and Time‐Resolved Spectroscopic Study

and core–shell nanocomposites. [ 4 ] All of these materials are either composites or hybrid structures combining luminescent and magnetic materials individually. In these materials, organic dyes or metal complexes were immobilized on a silica layer, which leads to critical problems of leaching and photobleaching. [ 4a ] Alternatively, semiconductor quantum dots such as CdS, CdSe, and CdTe, have been demonstrated to be highly effective for cellular and animal imaging. [ 5 ] However, the use of such colloids for bioimaging applications suffers from additional issues such as toxicity, harmful solvents, and additives, [ 6 ] low light penetration depth, surface-ligand

Molecular mechanics and dynamics studies on the interaction of gallic acid with collagen-like peptides

Abstract Molecular modelling approaches have been used to understand the interaction of collagen-like peptides with gallic acid, which mimic vegetable tanning processes involved in protein stabilization. Several interaction sites have been identified and the binding energies of the complexes have been calculated. The calculated binding energies for various geometries are in the range 6–13 kcal/mol. It is found that some complexes exhibit hydrogen bonding, and electrostatic interaction plays a dominant role in the stabilization of the peptide by gallic acid. The π-OH type of interaction is also observed in the peptide stabilization. Molecular dynamics (MD) simulation for 600 ps revealed the possibility of hydrogen bonding between the collagen-like peptide and gallic acid.

Green solution for tannery pollution: effect of enzyme based lime-free unhairing and fibre opening in combination with pickle-free chrome tanning

Growing global concern on environmental health is forcing all the processing industries to adopt greener and cleaner manufacturing practices. Thus, the leather industry is being pressurized to look for cleaner leather processing. The conventional method of leather making involves do–undo logic. This results in the emission of a huge amount of pollution load such as biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total solids (TS). Currently tanners are looking for design and utilization of cleaner and safer technologies. In this approach, a process has been designed to limit the pH range in leather processing from 13.5–2.8 to 8.0–3.8. An experimental process has been developed by combining enzymatic unhairing, enzyme based fibre opening and pickle and basification free chrome tanning. The experimental tanning process provides comparable leather quality with reduced environmental impact and effluent treatment costs. The process explored also appears to be economically viable.

Green synthesis of copper nanoparticles and conducting nanobiocomposites using plant and animal sources

We report large-scale biosynthesis of copper nanoparticles using an extract of henna leaves as reductant. Due to the substantial electrical conductivity of the calcined copper nanoparticles, we used them to prepare conductive nanobiocomposites utilizing collagen waste. We demonstrate that the nanobiocomposites, when inserted between batteries, illuminate a light emitting diode lamp.

Transforming collagen wastes into doped nanocarbons for sustainable energy applications

Leather industry produces huge quantities of bio-waste that can be used as raw material for the bulk synthesis of carbonaceous materials. Here we report the synthesis of multifunctional carbon nanostructures from pristine collagen wastes by a simple high temperature treatment. Our studies reveal that the nanocarbons derived from the bio-waste have a partially graphitized structure with onion-like morphology and are naturally doped with nitrogen and oxygen, resulting in multifunctional properties. This synthetic route from bio-waste raw material provides a cost-effective alternative to existing chemical vapor deposition methods for the synthesis of functional nanocarbon materials and presents a sustainable approach to tailor nanocarbons for applications such as battery electrodes.

Thermoresponsive magnetic nanoparticle--aminated guar gum hydrogel system for sustained release of doxorubicin hydrochloride.

Hydrogel based sustained drug delivery system has evolved as an immense treatment method for solid tumors over the past few decades with long term theranostic ability. Here, we synthesized an injectable hydrogel system comprising biocompatible aminated guar gum, Fe3O4-ZnS core-shell nanoparticles and doxorubicin hydrochloride. We show that amination of guar gum resulted in attraction of water molecules thereby forming the hydrogel without using toxic crosslinking agents. Hydrogel formation was observed at 37°C and is stable up to 95°C. The prepared hydrogel is also stable over a wide pH range. The in vitro studies show that the maximum de-gelation and drug release up to 90% can be achieved after 20 days of incubation. Studies reveal that the drug and the core-shell nanoparticles can be released slowly from the hydrogel to provide the healing and diagnosis of the solid tumor thereby avoiding several drug administrations and total excision of organs.