Search results for "METHANE"

Progress in palladium-based catalytic systems for the sustainable synthesis of annulated heterocycles: a focus on indole backbones

2012

BIOVERT+LDJ; A survey highlighting the most recent palladium catalytic systems produced and their performances for progress in direct synthesis of indole backbones by heterocarbocyclization of reactive substrates is provided. The discussion is developed in relation with the principles of sustainable chemistry concerning atom and mass economy. In this respect, the general convergent character of the syntheses is of particular interest (one-pot, domino, cascade or tandem reactions), and the substrates accessibility and reactivity, together with the final waste production, are also important. This critical review clearly indicates that the development of ligand chemistry, mainly phosphines and…

Cover Picture: Metal‐ and Reagent‐Free Highly Selective Anodic Cross‐Coupling Reaction of Phenols (Angew. Chem. Int. Ed. 20/2014)

2014

Use of green alternative solvents in dispersive liquid‐liquid microextraction: A review

2021

Dispersive liquid-liquid microextraction is one of the most widely used microextraction techniques currently in the Analytical Chemistry field, mainly due to its simplicity and rapidity. The operational mode of this approach has been constantly changing since its introduction, adapting to new trends and applications. Most of these changes are related to the nature of the solvent employed for the microextraction. From the classical halogenated solvents (e.g., chloroform or dichloromethane), different alternatives have been proposed in order to obtain safer and non-pollutants microextraction applications. In this sense, low density solvents, such as alkanols, switchable hydrophobicity solvent…

Landfill gas upgrading with countercurrent water wash.

2006

A pilot-scale countercurrent absorption process for upgrading landfill gas to produce vehicle fuel was studied using absorption and desorption units and water as absorbent. The height-to-diameter ratio of the absorption column used was 3:1 instead of the more conventionally used 20:1 ratio, and a higher pressure was used along with a lower water flow rate. The effects of pressure (10-30 bar) and water and gas flow-ratios on the upgrading process were studied. Methane content in the product gas increased to near or above 90% with both gas flows (50 and 100 l/min) used at over 20 bar pressure with 10 l/min water flow and at 30 bar pressure with 5l/min water flow. Carbon dioxide content with t…

Mechanically-biologically treated municipal solid waste as a support medium for microbial methane oxidation to mitigate landfill greenhouse emissions.

2005

The residual fraction of mechanically-biologically treated municipal solid waste (MBT residual) was studied in the laboratory to evaluate its suitability and environmental compatibility as a support medium in methane (CH(4)) oxidative biocovers for the mitigation of greenhouse gas emissions from landfills. Two MBT residuals with 5 and 12 months total (aerobic) biological stabilisation times were used in the study. MBT residual appeared to be a favourable medium for CH(4) oxidation as indicated by its area-based CH(4) oxidation rates (12.2-82.3 g CH(4) m(-2) d(-1) at 2-25 degrees C; determined in CH(4)-sparged columns). The CH(4) oxidation potential (determined in batch assays) of the MBT re…

Greenhouse gases from wastewater treatment — A review of modelling tools

2016

Nitrous oxide, carbon dioxide and methane are greenhouse gases (GHG) emitted from wastewater treatment that contribute to its carbon footprint. As a result of the increasing awareness of GHG emissions from wastewater treatment plants (WWTPs), new modelling, design, and operational tools have been developed to address and reduce GHG emissions at the plant-wide scale and beyond. This paper reviews the state-of-the-art and the recently developed tools used to understand and manage GHG emissions from WWTPs, and discusses open problems and research gaps. The literature review reveals that knowledge on the processes related to N2O formation, especially due to autotrophic biomass, is still incompl…

High emissions of greenhouse gases from grasslands on peat and other organic soils

2016

Drainage has turned peatlands from a carbon sink into one of the world's largest greenhouse gas (GHG) sources from cultivated soils. We analyzed a unique data set (12 peatlands, 48 sites and 122 annual budgets) of mainly unpublished GHG emissions from grasslands on bog and fen peat as well as other soils rich in soil organic carbon (SOC) in Germany. Emissions and environmental variables were measured with identical methods. Site-averaged GHG budgets were surprisingly variable (29.2 ± 17.4 t CO2 -eq. ha-1  yr-1 ) and partially higher than all published data and the IPCC default emission factors for GHG inventories. Generally, CO2 (27.7 ± 17.3 t CO2  ha-1  yr-1 ) dominated the GHG budget. Nit…

Estimation of biogas produced by the landfill of Palermo, applying a Gaussian model

2008

Abstract In this work, a procedure is suggested to assess the rate of biogas emitted by the Bellolampo landfill (Palermo, Italy), starting from the data acquired by two of the stations for monitoring meteorological parameters and polluting gases. The data used refer to the period November 2005–July 2006. The methane concentration, measured in the CEP suburb of Palermo, has been analysed together with the meteorological data collected by the station situated inside the landfill area. In the present study, the methane has been chosen as a tracer of the atmospheric pollutants produced by the dump. The data used for assessing the biogas emission refer to night time periods characterized by weak…

THE INFLUENCE OF LANDFILL FEATURES AND SIDE SLOPES ON METHANE EMISSION RATES

2011

Sanitary landfills for Municipal Solid Waste (MSW) disposal have been identified as one of the most important sources of methane (CH4) emissions; indeed, MSW contains a certain amount of biodegradable organic matter which undergoes anaerobic degradation resulting in the production of the so called landfill gas (LFG), which main component is typically represented by CH4. In general, LFG will escape through any faults in the landfill capping or in the LFG collection system. If the capping is not damaged, low quantities of LFG will be emitted through the permeable material that covers the disposed waste. On the other hand, some zones of the capping are often more permeable than others (e.g. si…

Greenhouse gases from wastewater treatment plant: towards a new protocol for field measurements

2015

Greenhouse gases (GHGs) emission from wastewater treatment plants (WWTPs) represents an increasing interest in the water industry at the present moment. The biological processes needed for treating wastewater have been found responsible for the unintentional generation of GHGs, such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The quality and quantity of a GHG emitted from a WWTP can significantly vary with the wastewater treated, the process configuration, and the strategies employed in process control. In the recent past, efforts for monitoring and accounting for GHGs emissions from WWTPs have considerably increased, and classifications of emission type were proposed t…