Kinetic Study on Removal of Sulphur Mustard on Granular Activated Carbon from Aqueous Solution

Sulphur mustard is a powerful blister agent and has been worked as a chemical warfare agent. No specific antidote is available for its wound. Therefore, adsorptive removal is an effective way of removal. Here, adsorptive removal of sulphur mustard from aqueous solution was studied on activated carbon and screened out MeOH : H2O (1 : 1) solution as a good solvent than others used solvent. Adsorption isotherm of sulphur mustard was compared with its hydrolysis in the same solution. Kinetics of sulphur mustard removal on carbon from aqueous solution was found to be slower than hydrolysis and follow pseudo first order kinetics with the rate constant 5.04 X 10–3 min-1 and half life 137.5 min. The hydrolysis of sulphur mustard in MeOH : H2O (1 : 1) solution was found to be following the pseudo first order kinetics with the rate constant 8.68 x10-3 min-1 and half life 79.8 min

Emerging Potable Water Technologies

Water is essential to keep up life, especially safe drinking water is one of the first priorities. As water quality is important, many nations endeavor to guard the water and to increase access to potable water. Fortification of water supplies from contamination is the earliest stripe of defence. Water purification is very important aspect, presently there are number of drinking water technologies available mostly based on ion exchange, ultra filtration and reverse osmosis techniques, but still about five million people die annually from water born diseases. The objective of this review is to provide direction on the chemical safety of drinking-water and also monitoring of chemicals in drinking-water. Water treatment potential technologies can solve diverse drinking water issues in case of chemical contamination, which is the second objective. The purpose of this review is to make survey of currently available and future emerging technologies for drinking water. Several purification techniques have been adopted to meet the standards. There is a necessity of wide-ranging global approach to tackle the problem of water pollution devastating thousand of lives annually rather than to develop nuclear and biological weapons. This document will also be useful to public health authorities, those responsible for setting standards and for surveillance of drinking-water quality, and to water supply agencies responsible for water quality management

Pressure Swing Adsorption Based Air Filtration/Purification Systems for NBC Collective Protection

The respiratory protection against chemical warfare agents (CWA) has become a worldwide security concern in light of the many recent international threats utilising CWA. Till date the carbon filtration was adequate to protect the soldiers from the threats of CWA. With the advent of further advancements in the CWA a new threat is looming large that is known as the carbon breakers. pressure swing adsorption (PSA) is a well-established gas separation technique in air separation, gas drying, and hydrogen purification separation. Recently, PSA technology has been applied in the area of chem-bio defence by virtue of its unique advantages. This article reviews recent advances and developments in the field of PSA based purification, separation, and its use in defense sector. This emerging and advanced PSA technology can provide regenerative nuclear, biological and chemical (NBC) collective protection for ground vehicles, aircraft, ships and shelters. This PSA technology challenges threat scenario developed which includes nerve, blood and blister agents, as well as a “carbon breaker” agent, and proved that this technology will be a viable concept for future NBC collective protection systems. New technological breakthroughs and greater sophistication of PSA technologies will transform the collective protection based PSA technology in real field sense, addressing the escalating threat of CWA. We conclude this review with future prospects and challenges associated with PSA technology

Respiratory Protection Against Chemical and Biological Warfare Agents

Chemical and biological warfare (CBW) agents pose unavoidable threat, both to soldiers and civilians.Exposure to such deadly agents amidst the CBW agents contaminated environment can be avoided bytaking proper protective measures. Respiratory protection is indispensable when the soldiers or civiliansare surrounded by such deadly environment as contamination-free air is needed for respiration purposes.In this context, an attempt has been made to review the literature for the past five decades on developmentof various protective devices for respiratory protection against aerosols, gases, and vapours of CBWagents. This review covers structural, textural, and adsorption properties of materials used in gas filtersand mechanical filters for the removal of CBW agents.Defence Science Journal, 2008, 58(5), pp.686-697, DOI:http://dx.doi.org/10.14429/dsj.58.169

Synthesis and Characterisation of Ligand Free Cadmium Imprinted Polymer for Sensing of Cd(II) from Aqueous Solution

Cadmium(II)-imprinted polymer [Cd(II)-IIP] was synthesized without using the conventional complexing ligand to reduce unnecessary step for complexing Cd(II). During synthesis of Cd(II)-IIP, the complete removal of Cd(II) from the polymer was confirmed using EDAX and AAS. Synthesized polymers ([Cd(II)-IIP], non-imprinted polymer (NIP) and polymer with cadmium (CdP) were also characterized and compared. SEM analysis of Cd(II)-IIP indicated the changes in surface morphology after imprinting, the polymer looked like a flaky material in comparison with NIP and CdP. BET surface area of Cd(II)-IIP (68 m2/g) was found to be more than that of NIP (24.6 m2/g) and CdP (17 m2/g). Cd(II)-IIP formed a complex with Cd(II) in the solution through carbonyl oxygen of the acrylamide as confirmed by FTIR. TGA analysis showed less char yield for Cd(II)-IIP than NIP. Cd(II)-IIP was further explored for the fabrication of ion selective electrode (ISE), which on binding with Cd(II) gave higher potential than NIP-ISE. Interference study was also performed using Cd(II)-IIP as such and also with fabricated ISE with Cd(II)-IIP using different cations such as Pb(II), Zn(II), Mn(II), Hg(II), and found that imprinted polymer showed more selectivity towards Cd(II) in aqueous solutions

Activated Carbon Fabric: An Adsorbent Material for Chemical Protective Clothing

Activated carbon fabric or fiber (ACF) is a novel carbonaceous material with exceptionally high adsorption rate and larger adsorption capacity, that has emerged as a rising star in the field of adsorbents. ACF has many advantages over other commercial porous storage materials such as granular activated carbon and powdered activated carbon in terms of adsorption capacity, well defined microporous structure, stability, flexibility and ease of lamination to various substrates. In the last few years, activated carbon fabrics have gained greater choice of interest for use as an adsorbent material in several fields including nuclear, biological and chemical (NBC) protection suit. Viscose rayon, acetate, polyacrylonitrile, pitch, and phenolic based materials are mainly used as precursors for preparation of ACF. ACF or fibres are generally prepared by process comprising stabilisation, carbonisation and activation of precursors. Reviews recent advances and developments in the field of ACF and their utility as an adsorbent material in various fields including NBC scenario. ACF with unmatchable pore structure and surface characteristics at present, with continued innovations and attention to its key challenges, it is expected that ACF will play a pivotal role in diverse environmental, defence, and civil applications

Dynamic Adsorptive Removal of Toxic Chemicals for Purification of Water

To determine the efficiency of carbon column for the removal of toxic chemicals from water, the adsorption of phenol in concentration range from 0.600 glt to 1.475 gll was studied on activecarbon of 80 CTC grade, 12 X 30 BSS particle size, 1280 m2/g surface area, and of coconut shell origin, under dynamic conditions at space velocity from 0.318 min-' to 4.24 min-' at 25 'C. The carbon column of 100 cm length and 2 cm diameter was found to be removing phenol from the aqueous solution of concentration 1.475 gll up to 84 min at 0.678 min-' space velocity at 5.0 ppm phenol breakthrough concentration. However, no phenol was observed in carbon-treated water after 80 min. The service life of carbon column (100 cm lengthX25 cm diameter) was assessed through the water purification system developed at the Defence Laboratory, Jodhpur and was determined to be 4.095 days with twoas factor of safety for 10 ppm initial concentration of phenol at 0.678 min-' space velocity (corresponding to water flow rate). Effects of carbon bed length, water flow rate, and the phenol concentration were also studied

Template free synthesis of PbS nanoparticles by sol-gel facile method under IR radiation at room temperature

Lead sulfide (PbS) nanoparticles have been synthesized from the precursor of lead nitrite tetrahydrate [Pb(NO3)2.4H2O] and thiourea [CH4 N2S] at room temperature by sol-gel method under the infrared (IR) irradiation. The synthesized PbS nanoparticles have been characterized by XRD, FE-SEM, UV-vis spectrophotometer, and FTIR. The dominant peak (200) in XRD pattern, microstructure and the absorption of PbS have been confirmed the formation of nanoparticles. The crystallite size of PbS nanoparticle has been observed to be 13 nm. The lattice constant

A comparative study of numerical approximations for solving the Smoluchowski coagulation equation

In this work, numerical approximations for solving the one dimensional Smoluchowski coagulation equation on non-uniform meshes has been analyzed. Among the various available numerical methods, finite volume and sectional methods have explicit advantage such as mass conservation and an accurate prediction of different order moments. Here, a recently developed efficient finite volume scheme (Singh et al., 2015) and the cell average technique (Kumar et al., 2006) are compared. The numerical comparison is established for both analytically tractable as well as physically relevant kernels. It is concluded that the finite volume scheme predicts both number density as well as different order moments with higher accuracy than the cell average technique. Moreover, the finite volume scheme is computationally less expensive than the cell average technique

Effect of growth temperature and RF power on structural and optical properties of sputtered deposited PbS thin films

Lead sulphide (PbS) nanocrystalline thin films have been grown from sputtering with the variation of growth temperature and RF-Power. The intensity of single dominant peak (200) in XRD-pattern increases by increasing the growth temperature from 175 oC to 200 oC and RF power from 80 W to 100 W, respectively. The crystallite size and the strain of as-deposited PbS thin films have been calculated from XRD-peak profile analysis. Microscopic surface and cross-section images show the improvement in thin films growth in terms of alignment of grains and thickness. The band gap of PbS thin films has been determined from UV-Vis absorption spectra, where the band gap decreases from 1.98 eV to 1.72 eV as the growth temperature and power increased from 175 °C and 80 W to 200 °C and 100 W