Browsing by Author "Deepak Yadav"

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Advanced thermally stable, self-sustaining NiCo2O4 catalyst for CNG emissions in lean burn environment
(Elsevier Ltd, 2019) Deepak Yadav; Pratichi Singh; R. Prasad
Compressed Natural gas (CNG) has considerable potential as a “clean” fuel for motor vehicles. Though, CNG is cleaner fuel, vehicles running on it emit primary pollutants such as carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC) predominantly methane (CH4). US EPA greenhouse gas legislation and Euro VI have imposed strict emission regulations with special emphasis to control greenhouse gases (GHG), demanding vehicles to use advanced after-treatment technologies in order to control GHG emissions. NiCo2O4 catalyst prepared by nano-casted nitrate precursor followed by reactively calcination was used for the SCR of NO emission from Compressed Natural gas vehicles (CNGVs) using CO–CH4 as reductant. Catalyst is self-sustained as it is as redox catalyst which works efficiently in the presence of CO–CH4 reductant inherently present in the gas stream. The experimental results showed that NiCo2O4 catalyst was highly active reducing 96.5% NO at 400 °C. Being an active redox catalyst, NiCo2O4 also facilitates simultaneously oxidation of CO and CH4 to the extent of 95% within the same range of temperature. Therefore, NiCo2O4 catalyst can be suggested for the complete emission control of CNG fueled vehicles. It is very sturdy catalyst as despite a high CH4 oxidation temperature the catalyst showed a stable behavior over a 50 h run. Finally, the above mentioned catalyst can pave the way for the current CNG tail-pipe-technology challenges. © 2019 Hydrogen Energy Publications LLC
Environmental and health impacts of contaminants of emerging concerns: Recent treatment challenges and approaches
(Elsevier Ltd, 2021) Deepak Yadav; S. Rangabhashiyam; Pramit Verma; Pardeep Singh; Pooja Devi; Pradeep Kumar; Chaudhery Mustansar Hussain; Gajendra Kumar Gaurav; Kuppusamy Sathish Kumar
In the past few decades, new contaminants of emerging concern (CECs) in the air, water, and soil have gained significant attention due to their adverse impact on human health and the environment. The sources of CECs have been identified in different forms from domestic and industrial activities such as personal care products and pharmaceuticals. It has been established that aqueous medium plays a major role in the dissemination of various contaminants, like drinking water, reservoirs, lakes, rivers and waste with water medium. There remains inadequate technology for the treatment of CECs in the wastewater systems. Though different techniques have advanced for the treatment of CECs, they still pose a severe threat to human health and disturb the ecological balance. In this review, the characteristics, recent technologies, risk assessment and management of CECs have been discussed. The primary aim is to highlight the new innovative and cost-effective technologies for the remediations of CECs in all forms. Biochar is readily and economically available in abundance and an economical adsorbent with 100% adsorptive removal for H2PO4−. The bibliometric analysis also performed to understand the emerging research trends on the treatment techniques, which can help in developing a guiding pathway to modern research in academia and industry. © 2021 Elsevier Ltd
Erratum: Studies on H2-assisted liquefied petroleum gas reduction of NO over Ag/Al2O3 catalyst (Bulletin of Chemical Reaction Engineering & Catalysis (2018) 13:2 (227-235) DOI: 10.9767/bcrec.13.2.1307.227-235)
(Diponegoro University, 2020) Pratichi Singh; Deepak Yadav; Pooja Thakur; Jitendra Pandey; R. Prasad
An error appeared in Corresponding Author in a paper entitled “Studies on H2-Assisted Liquefied Petroleum Gas Reduction of NO over Ag/Al2O3 Catalyst” published in Bulletin of Chemical Reaction Engineering & Catalysis. The Corresponding Author is corrected to be: * Corresponding Authors. Tel: +919415268192. Email: rprasad.che@itbhu.ac.in (R. Prasad) Tel: +917505072607. Email: dyadav.rs.che13@iitbhu.ac.in (D. Yadav). © 2020 BCREC Group. All rights reserved
MnCo2O4 spinel catalysts synthesized by nanocasting method followed by different calcination routes for low-temperature reduction of NOx using various reductants
(Elsevier Ltd, 2018) Deepak Yadav; Pratichi Singh; Ram Prasad
The present state of the art to control the vehicular NOx emissions, uses costly VWTi catalysts with urea solution as reductant, which work at higher temperature >200 °C. The present investigation is therefore, devoted to design a detailed experimental work to synthesize low cost and improved low-temperature SCR activity of MnCo2O4 catalyst by comparing preparation methods, calcination strategies and using different reductants in a wide range of temperature 50–450 °C. The catalysts were prepared by co-precipitation (CP) and nanocasting (NC) methods. For selection of the best catalyst, its precursor was calcined in stagnant air, flowing air and under reactive calcination (RC) in CO-air mixture. The SCR of NO was studied using various reductants (H2, LPG and H2-LPG) in a tubular reactor under the following conditions: 200 mg catalyst, 500 ppm NO, 8% O2, 1000 ppm LPG, 1% H2, 0.1% NH3 in Ar with a total flow rate of 100 mL/min. The inlet and outlet of the reactor were analyzed with the help of NO/NO2/NOx analyzer and gas chromatography. The catalysts were characterized by XRD, XPS, BET, SEM-EDX and FTIR. The catalyst prepared by NC method followed by RC route (Cat-R) exhibited the best NO reduction of 98.7% below 200 °C with H2-LPG-SCR. The exceptionally high activity with high N2 selectivity and good stability of Cat-R under the laboratory conditions were found. Characterization signified that the catalyst which exhibited oxygen deficient, higher surface area and the higher rate of LPG oxidation consequently have better SCR activity. © 2017 Hydrogen Energy Publications LLC
Reactive Calcination Route for Synthesis of Highly Active NiCo2O4 Catalyst for Abatement of Cold-Start CO–HC Emissions from LPG Vehicles
(Springer Science and Business Media, LLC, 2017) Pratichi Singh; Deepak Yadav; J. Pandey; R. Prasad
Abstract: An idea of an exotic route of reactive calcination (RC) of a precursor (co-precipitated basic carbonates of nickel and cobalt) for the synthesis of highly active NiCo2O4−δ spinel catalyst (Cat-R) for oxidation of CO and HCs emissions from LPG fueled vehicles is reported in the present paper. The route involved feed of a low concentration of chemically reactive 4.5% CO–air mixture over the precursor at low temperature of 433 K in the beginning and finally increased to 573 K. The precursor was also calcined around 573 K following two other methods: (1) conventionally in stagnant air (Cat-S) and (2) in flowing air (Cat-F) for comparative studies. The catalysts were characterized by XRD, N2 sorption techniques, TPR, SEMEDX and XPS. The formation of spinel structure is confirmed in all the catalysts. The activity measurement showed that total oxidation of lean mixture of CO–LPG occurred at the lowest temperature of 433 K over Cat-R in comparison to Cat-F (451 K) and Cat-S (458 K). The total combustion of the CO–LPG mixture at such low temperature of 433 K was never reported earlier. The remarkable activity of Cat-R over Cat-F and Cat-S in oxidation of CO–LPG mixture is due to the formation of partially reduced NiCo2O4−δ (Cat-R) oxygen deficient structure having the highest surface area smallest crystallites and highly dispersed homogeneous morphology when produced following the RC-route. The activity order of the catalysts produced by various calcination strategies for CO and LPG oxidation was as follows: RC > flowing-air > stagnant-air. Cat-R was also compared with noble metal and the catalytic activity order in the decreasing sequence was as follows: Cat-R > Cat-F > Cat-S > Cat-Pt. Stability test of the catalyst showed that the Cat-R has satisfactory catalytic stability. Thus the Cat-R is the most suitable for abatement of cold-start emissions of CO and HCs from LPG fuelled vehicles. Graphical Abstract: [Figure not available: see fulltext.]. © 2017, Springer Science+Business Media, LLC.
Studies on H2-assisted liquefied petroleum gas reduction of NO over Ag/Al2O3 catalyst
(Diponegoro University, 2018) Pratichi Singh; Deepak Yadav; Pooja Thakur; Jitendra Pandey; R. Prasad
Hydrocarbon-Selective catalytic reduction (HC-SCR) is one of the potential methods to remove NOx emissions from diesel engine, lean burn petrol engines and natural gas engines exhaust. Ag/Al2O3 is a good catalyst for HC-SCR of NOx under lean-burn conditions. Further, addition of small amount of H2 is effective for enhancing HC-SCR activ-ity. This effect is unique to silver and to specific Ag/support combinations, namely, Ag/γ-Al2O3. Various HC reductants, such as: octane, decane, dodecane and propane, have been reported in the literatures. Only a single study on LPG as a reductant over Cu-ZSM catalyst was reported. There was no work reported on H2 assisted LPG over Ag/Al2O3 catalyst. Thus, this gap in the literature is filled with the present investigation of NO reduction over 2 wt.% Ag/Al2O3 catalyst using LPG reductant. The fresh and used catalyst was characterized by various techniques like low temperature N2-adsorption, XRD, XPS and SEM. There was practically no change in the characteristics of the fresh and used catalyst. Two different reductants of CO and LPG were compared for SCR of NO over the cata-lyst without and with H2-assisted. The experiments were performed in a fixed bed tubular flow reactor under the following conditions: 100mg catalyst; 0.13% NO, 2.5% LPG/CO, 1% H2, 10% O2, rest Ar; total flow rate 60 mL/min; temperature ambient 400°C and pressure 1 atm. Around 100% conversion of NO was achieved using LPG reductant. Light off temperature of NO reduction significantly reduced by H2 assisted LPG reductant. The maximum conversion of NO with CO was limited to 35.15% at temperature of 224°C and above. Whereas, 97.79 % NO con-version was achieved at 365°C with LPG reductant. While, the maximum conversions with H2-LPG and H2-CO re-ductants were 100 and 99.46% at 117 and 220°C, respectively. Therefore, H2-LPG-SCR of NOx over 2 wt.% Ag/Al2O3 catalyst system can be used to get 100% reduction at low temperature. Copyright © 2018 BCREC Group. All rights reserved.