Structure and activity of microwave irradiated silica supported Pd-Fe bimetallic catalysts in the hydrodechlorination of chlorobenzene

A series of silica supported Pd–Fe bimetallic catalysts were prepared by conventional as well as microwave heating methods. The catalysts were characterised by nitrogen adsorption (for BET surface area), X-ray diffraction (XRD), temperature-programmed reduction (TPR) and hydrogen chemisorption for their physico-chemical properties and were evaluated for chlorobenzene (CB) hydrodechlorination (HDC) activity. The catalysts prepared with microwave irradiation resulted into higher hydrodechlorination activity compared to their conventionally prepared analogues. These results are explained in terms of differences in the Pd morphology observed during the microwave irradiation

Derivation of the Expanded Form of the BJH Equation and its Application to the Pore Structure Analysis of Mesoporous Adsorbents

The BJH equation, v n = R n ( Δ V ) n − R n Δ t n ∑ i = 1 n − 1 c i A i , used for pore structure analyses via its application to the N 2 desorption isotherms at 78 K of porous materials, has been modified by substituting the value of c i and expanding the last term. The quantity v n is the volume of the pores involved in the nth desorption step and is given in terms of the volume of N 2 , (ΔV) n , exuded from the porous material, the constants R n and c i which depend on the average pore size and average thickness of the physically adsorbed multilayer, Δt n being the decrease in thickness of the multilayer as a result of the nth desorption step and A i the surface area of the set of pores involved in the ith desorption step. A derivation of the modified equation is presented. It has been applied to the N 2 desorption data of bone char used by Barrett, Joyner and Halenda (BJH). The effect of the multilayer thickness (t) values given by Pierce and de Boer on the pore size distribution of bone char has been studied. The pore size distribution data are compared with those obtained by the original BJH and Pierce methods. The pore system conforms very well with the idealised open-ended cylindrical pore model. The expanded BJH equation has also been applied to the desorption isotherms of fresh and sintered silica-alumina cracking catalysts over the entire range of silica/alumina ratios. The multilayer thickness (t) values given by de Boer have been used in the calculations. The pore systems of the catalysts, vacuum-dried at 400°C, are observed to conform to the cylindrical pore model as revealed by the excellent agreement between the cumulative surface areas obtained in P.S.D. calculations and the BET surface areas. The pore systems of the catalysts, sintered at different temperatures in a dry oxygen stream, deviate considerably from the cylindrical pore model. Enlargement of the pores and their nonconformity with the ideal pore model are attributed to modifications of the pore structures brought about by the phenomenon known as ‘self-steaming’ with the water vapour released from the catalysts

Effect of tungsten addition to Pd/ZrO₂ system in the hydrodechlorination activity of CCl₂F₂

The catalytic activity of Pd on W-ZrO2 in the hydrodechlorination of CCl2F2 was studied by varying WO3 content. The TPR results of Pd/W-ZrO2 were related to effects caused by contact with hydrogen. XRD data of spent catalysts shows that there is no change in the structure of zirconia indicating that these catalysts are highly resistant to the corrosive reaction atmosphere. Addition of tungsten to Pd/ZrO2 system led to the formation of CHClF2 (HCFC-22) in the hydrodechlorination of CCl2F2. Thus, the role of WO3 istocatalyze the partial dechlorination of CCl2F2

Abstracts of National Conference on Biological, Biochemical, Biomedical, Bioenergy, and Environmental Biotechnology

This book contains the abstracts of the papers presented at the National Conference on Biological, Biochemical, Biomedical, Bioenergy, and Environmental Biotechnology (NCB4EBT-2021) Organized by the Department of Biotechnology, National Institute of Technology Warangal, India held on 29–30 January 2021. This conference is the first of its kind organized by NIT-W which covered an array of interesting topics in biotechnology. This makes it a bit special as it brings together researchers from different disciplines of biotechnology, which in turn will also open new research and cooperation fields for them. Conference Title: National Conference on Biological, Biochemical, Biomedical, Bioenergy, and Environmental BiotechnologyConference Acronym: NCB4EBT-2021Conference Date: 29–30 January 2021Conference Location: Online (Virtual Mode)Conference Organizer: Department of Biotechnology, National Institute of Technology Warangal, Indi

Abstracts of National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020

This book presents the abstracts of the papers presented to the Online National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020 (RDMPMC-2020) held on 26th and 27th August 2020 organized by the Department of Metallurgical and Materials Science in Association with the Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, India. Conference Title: National Conference on Research and Developments in Material Processing, Modelling and Characterization 2020Conference Acronym: RDMPMC-2020Conference Date: 26–27 August 2020Conference Location: Online (Virtual Mode)Conference Organizer: Department of Metallurgical and Materials Engineering, National Institute of Technology JamshedpurCo-organizer: Department of Production and Industrial Engineering, National Institute of Technology Jamshedpur, Jharkhand, IndiaConference Sponsor: TEQIP-

Multi-messenger Observations of a Binary Neutron Star Merger

International audienceOn 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta