scholarly journals Electropositive Promotion by Alkalis or Alkaline Earths of Pt-Group Metals in Emissions Control Catalysis: A Status Report

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 157 ◽  
Author(s):  
Ioannis V. Yentekakis ◽  
Philippe Vernoux ◽  
Grammatiki Goula ◽  
Angel Caravaca
Keyword(s):  
Cost Effective ◽  
Electrochemical Promotion ◽  
Catalytic Performance ◽  
Effective Control ◽  
Status Report ◽  
Alkaline Earths ◽  
Reduction Of Nox ◽  
Electrochemical Promotion Of Catalysis ◽  
Novel Catalyst ◽  
Combustion Processes

Recent studies have shown that the catalytic performance (activity and/or selectivity) of Pt-group metal (PGM) catalysts for the CO and hydrocarbons oxidation as well as for the (CO, HCs or H2)-SCR of NOx or N2O can be remarkably affected through surface-induced promotion by successful application of electropositive promoters, such as alkalis or alkaline earths. Two promotion methodologies were implemented for these studies: the Electrochemical Promotion of Catalysis (EPOC) and the Conventional Catalysts Promotion (CCP). Both methodologies were in general found to achieve similar results. Turnover rate enhancements by up to two orders of magnitude were typically achievable for the reduction of NOx by hydrocarbons or CO, in the presence or absence of oxygen. Subsequent improvements (ca. 30–60 additional percentage units) in selectivity towards N2 were also observed. Electropositively promoted PGMs were also found to be significantly more active for CO and hydrocarbons oxidations, either when these reactions occur simultaneously with deNOx reactions or not. The aforementioned direct (via surface) promotion was also found to act synergistically with support-mediated promotion (structural promotion); the latter is typically implemented in TWCs through the complex (Ce–La–Zr)-modified γ-Al2O3 washcoats used. These attractive findings prompt to the development of novel catalyst formulations for a more efficient and cost-effective control of the emissions of automotives and stationary combustion processes. In this report the literature findings in the relevant area are summarized, classified and discussed. The mechanism and the mode of action of the electropositive promoters are consistently interpreted with all the observed promoting phenomena, by means of indirect (kinetics) and direct (spectroscopic) evidences.

Manganese oxides with hierarchical structures derived from coordination polymers and their enhanced catalytic activity at low temperature for selective catalytic reduction of NOx

2019 ◽  
Vol 48 (43) ◽  
pp. 16395-16401 ◽  
Author(s):  
Byeonggab Ji ◽  
Junhyung Lee ◽  
Seung-Yeop Kwak
Keyword(s):  
Catalytic Activity ◽  
Coordination Polymer ◽  
Manganese Oxides ◽  
Preparation Method ◽  
Catalytic Reduction ◽  
Hierarchical Structures ◽  
Cost Effective ◽  
Catalytic Performance ◽  
Environmentally Benign ◽  
Reduction Of Nox

Hierarchical manganese oxides for enhancing catalytic performance have been successfully synthesized via simple thermal annealing manganese coordination polymer, which is a facile, cost-effective, and environmentally benign preparation method.

scholarly journals Electrochemical promotion of catalysis (EPOC): Perspectives for application to gas emissions treatment

2013 ◽  
Vol 10 (2) ◽  
pp. 226-236
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Supported Catalysts ◽  
Life Time ◽  
Cost Effective ◽  
Electrochemical Promotion ◽  
Gas Emissions ◽  
Simultaneous Control ◽  
Electrochemical Promotion Of Catalysis

Heterogeneous Catalysis and Electrocatalysis can be used very effectively on air pollution control. Air emissions coming either from mobile sources or from stationary sources, including volatile organic emissions, nitrogen oxides, hydrocarbons and carbon monoxide could be well converted to harmless non-pollutants at reasonable temperatures with cost-effective systems utilizing heterogeneous catalysis and suitable catalysts. Some of the disadvantages of conventional heterogeneous catalysts are the high production cost (since most of them are metal supported catalysts), the short life time (due to the catalyst deactivation) and the weakness to control their activity during the catalytic process. A new phenomenon of Solid State Electrochemistry called Electrochemical Promotion of Catalysis (EPOC) combined with classical heterogeneous catalysis could be applied in order to overcome some of the above problems. In this paper we are trying to show with characteristic examples how EPOC could be useful in environmentally important reactions (oxidations, reductions, etc). The results show that EPOC reveals great perspectives in environmental issues and especially in gas emissions treatment technology. The utilization of EPOC could be really useful since we can increase the catalytic activity, alter the selectivity to the desirable products and simultaneous control the reaction rate during a given electrocatalytic process.

Two-stage chemical-biological treatment at Thessaloniki greater area WWTP - experiences and potentials

1995 ◽  
Vol 32 (9-10) ◽  
pp. 75-84 ◽  
Author(s):  
A. D. Andreadakis ◽  
G. H. Kristensen ◽  
A. Papadopoulos ◽  
C. Oikonomopoulos
Keyword(s):  
Biological Treatment ◽  
Treatment Plant ◽  
Cost Effective ◽  
Primary Treatment ◽  
Effective Control ◽  
Two Stage ◽  
Effluent Quality ◽  
Filamentous Microorganisms ◽  
Sludge Settling ◽  
The City

The wastewater from the city of Thessaloniki is discharged without treatment to the nearby inner part of the Thessaloniki Gulf. The existing, since 1989, treatment plant offers only primary treatment and did not operate since the expected effluent quality is not suitable for safe disposal to the available recipients. Upgrading of the plant for advanced biological treatment, including seasonal nitrogen removal, is due from 1995. In the mean time, after minor modifications completed in February 1992, the existing plant was put into operation as a two-stage chemical-biological treatment plant for 40 000 m3 d−1, which corresponds to about 35% of the total sewage flow. The operational results obtained during the two years operation period are presented and evaluated. All sewage and sludge treatment units of the plant perform better than expected, with the exception of the poor sludge settling characteristics, due to severe and persistent bulking caused by excessive growth of filamentous microorganisms, particularly M. Parvicella. Effective control of the bulking problem could lead to more cost-effective operation and increased influent flows.

scholarly journals Prevention of Leptospirosis Infected Vector and Human Population by Multiple Control Variables

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Muhammad Altaf Khan ◽  
Saeed Islam ◽  
Sher Afzal Khan ◽  
Ilyas Khan ◽  
Sharidan Shafie ◽  
...  
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Human Population ◽  
Cost Effective ◽  
Farm Animals ◽  
Effective Control ◽  
Multiple Control ◽  
Control Variables ◽  
Control Functions

Leptospirosis is an infectious disease that damages the liver and kidneys, found mainly in dogs and farm animals and caused by bacteria. In this paper, we present the optimal control problem applied to a dynamical leptospirosis infected vector and human population by using multiple control variables. First, we show the existence of the control problem and then use analytical and numerical techniques to investigate the existence cost effective control efforts for prevention of indirect and direct transmission of this disease. In order to do this, we consider three control functions two for human and one for vector population. We completely characterize the optimal control problem and compute the numerical solution of the optimality system using an iterative method.

scholarly journals A Zirconium Metal-Organic Framework with SOC Topological Net for Catalytic Peptide Bond Hydrolysis

2021 ◽  
Author(s):  
Sujing Wang ◽  
Antoine Tissot ◽  
Guillaume Maurin ◽  
Tatjana Parac-Vogt ◽  
Christian Serre ◽  
...  
Keyword(s):  
Active Sites ◽  
Metal Organic Framework ◽  
Cost Effective ◽  
Peptide Bond ◽  
Catalytic Performance ◽  
Wide Range ◽  
Horse Heart Myoglobin ◽  
Metal Organic ◽  
Effective Synthesis ◽  
Organic Framework

<div>The discovery of nanozymes for selective cleavage of proteins would boost the emerging areas of modern proteomics, however, the development of efficient and reusable artificial catalysts for peptide bond hydrolysis is challenging. Here we report the detailed catalytic properties of a microporous zirconium carboxylate metal-organic framework, MIP-201, in promoting peptide bond hydrolysis in a simple dipeptide, as well as in horse-heart myoglobin (Mb) protein that consists of 153 amino acids. We demonstrate that MIP-201 features an excellent catalytic activity and selectivity, a good tolerance toward reaction conditions covering a wide range of different pH values, and importantly, an exceptional recycling ability associated with easy regeneration process. Taking into account the excellent catalytic performance of MIP-201 and its other advantages such as 6-connected Zr6 cluster active sites, the green, scalable and cost-effective synthesis, and an outstanding chemical and architectural stability, our finding suggests that MIP-201 may be a promising and practical alternative to the current commercially available catalysts for peptide bond hydrolysis.</div>

scholarly journals A Zirconium Metal-Organic Framework with SOC Topological Net for Catalytic Peptide Bond Hydrolysis

2021 ◽  
Author(s):  
Sujing Wang ◽  
Antoine Tissot ◽  
Guillaume Maurin ◽  
Tatjana Parac-Vogt ◽  
Christian Serre ◽  
...  
Keyword(s):  
Active Sites ◽  
Metal Organic Framework ◽  
Cost Effective ◽  
Peptide Bond ◽  
Catalytic Performance ◽  
Wide Range ◽  
Horse Heart Myoglobin ◽  
Metal Organic ◽  
Effective Synthesis ◽  
Organic Framework

<div>The discovery of nanozymes for selective cleavage of proteins would boost the emerging areas of modern proteomics, however, the development of efficient and reusable artificial catalysts for peptide bond hydrolysis is challenging. Here we report the detailed catalytic properties of a microporous zirconium carboxylate metal-organic framework, MIP-201, in promoting peptide bond hydrolysis in a simple dipeptide, as well as in horse-heart myoglobin (Mb) protein that consists of 153 amino acids. We demonstrate that MIP-201 features an excellent catalytic activity and selectivity, a good tolerance toward reaction conditions covering a wide range of different pH values, and importantly, an exceptional recycling ability associated with easy regeneration process. Taking into account the excellent catalytic performance of MIP-201 and its other advantages such as 6-connected Zr6 cluster active sites, the green, scalable and cost-effective synthesis, and an outstanding chemical and architectural stability, our finding suggests that MIP-201 may be a promising and practical alternative to the current commercially available catalysts for peptide bond hydrolysis.</div>

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