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Full-Text Articles in Nanoscience and Nanotechnology

Study On The Use Of Mgal Hydrotalcites As Solid Heterogeneous Catalysts For Biodiesel Production, João F. Gomes Dec 2011

Study On The Use Of Mgal Hydrotalcites As Solid Heterogeneous Catalysts For Biodiesel Production, João F. Gomes

João F Gomes

This paper, reports experimental work on the use of new heterogeneous solid basic catalysts for biodiesel production: double oxides of Mg and Al, produced by calcination, at high temperature, of MgAl lamellar structures, the hydrotalcites (HT). The most suitable catalyst system studied are hydrotalcite Mg:Al 2:1 calcinated at 507 ºC and 700 ºC, leading to higher values of FAME also in the second reaction stage. One of the prepared catalysts resulted in 97.1 % Fatty acids methyl esters (FAME) in the 1st reaction step, 92.2 % FAME in the 2nd reaction step and 34 % FAME in the 3rd reaction …


Notice On A Case Study On The Utilization Of Wind Energy Potential On A Remote And Isolated Small Wastewater Treatment Plant, João F. Gomes Aug 2011

Notice On A Case Study On The Utilization Of Wind Energy Potential On A Remote And Isolated Small Wastewater Treatment Plant, João F. Gomes

João F Gomes

Small wastewater treatment plants (WWTP) are frequently located, by necessity, in remote and isolated sites, which increases the difficulty of its energy supply. Some of them are located near the seaside, in environmental sensible zones, and due to tourism activity of these sites, seasonal effects related with population size fluctuation can occur, which can originate certain inefficiencies concerning WWTP design and energy supply. The objective of this paper is to describe a step by step procedure for evaluation of the wind potential of sites that are dependent of in-situ energy generation, as well as, a case study on the utilization …


Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan May 2011

Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan

Journal of Electrochemistry

A simple and efficient electrochemical route was developed for the synthesis of flaked spindle-like CuO nanocrystals using aqueous electrolyte and Cu sacrificial anode (graphite as the cathode) in an undivided cell at a constant potential mode under room temperature. The morphologies, structure and component of CuO nanocrystals obtained were characterized by SEM, XRD, respectively. Flaked spindle-like CuO nanocrystals were successfully used to modify a GC electrode to detect H2O2 with cyclic voltammetry (CV) and amperometric (AC).The results showed that products were pure monoclinic CuO nanocrystals. The linear range for the determination of hydrogen peroxide is from 1.0 μmol?L-1 to 1.0 …


Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen May 2011

Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen

Journal of Electrochemistry

CO2 reduction on Cu(111) single crystal surfaces was studied using DFT calculations on the reaction energies and the minimum energy paths. The results indicated that the possible reaction paths for CO2 reduction on Cu(111) surface are CO2(g) + H* → COOH* → (CO +OH)*, (CO + H)* → CHO*, CHO + H → CH2O* → (CH2 + O)*, CH2* + 2H* → CH4 or 2CH2* → C2H4. On Cu(111) surface, the reaction rate is controlled by steps of CH2O* → (CH2 + O)*, CO2(g) + H* → COOH → (CO +OH)* and (CO + H)* → CHO*. In addition, the …


Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng Feb 2011

Electrocatalytic Oxidation Of Hydrazine At Rutin Carbon Nanotubes Modified Electrode, Hong-Fang Zhang, Qing-Lin Sheng, Jian-Bin Zheng

Journal of Electrochemistry

The electrochemical behavior and electrocatalytic oxidation of hydrazine on rutin multiwall carbon nanotubes modified glassy carbon electrode were studied by cyclic voltammetry.The experimental results indicated that the electrode exhibits good electrocatalytic activity to hydrazine at a reduced oxidation potential of 262 mV.The amperometric response of the modified electrode showed linear increase after successive addition of hydrazine in the concentration range of 2.5×10-6~1.0×10-4 mol·L-1 with a detection limit of 5×10-7 mol·L-1.


A Titanium-Supported Nanoporous Pd Electrocatalyst For Methanol Oxidation, Feng-Juan Niu, Qing-Feng Yi Feb 2011

A Titanium-Supported Nanoporous Pd Electrocatalyst For Methanol Oxidation, Feng-Juan Niu, Qing-Feng Yi

Journal of Electrochemistry

Titanium-supported nanoporous palladium electrode(nanoPd /Ti) was prepared by a hydrothermal process in the presence of the ligand EDTA and using formaldehyde as reducing agent.SEM images showed that the size of Pd particles was about 60 nm and the Pd particles were connected with each other to form a three-dimensional network structure.Cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were applied to evaluate the electrocatalytic activity of the nanoPd/Ti electrode towards methanol oxidation in alkaline solution.CV results showed that the nanoPd /Ti electrode presented high anodic peak densities and a low onset potential for methanol oxidation.Also nanoPd /Ti electrode showed excellent CO tolerance …


Study On The Glycerolysis Reaction Of High Free Fatty Acid Oils For Use As Biodiesel Feedstock, João F. Gomes Jan 2011

Study On The Glycerolysis Reaction Of High Free Fatty Acid Oils For Use As Biodiesel Feedstock, João F. Gomes

João F Gomes

Biodiesel is the main alternative to fossil diesel and it may be produced from different feedstocks such as semi-refined vegetable oils, waste frying oils or animal fats. However, these feedstocks usually contain significant amounts of free fatty acids (FFA) that make them inadequate for the direct base catalyzed transesterification reaction (where the FFA content should be lower than 4%). The present work describes a possible method for the pre-treatment of oils with high content of FFA (20 to 50%) by esterification with glycerol. In order to reduce the FFA content, the reaction between these FFA and an esterification agent is …


Design Of A New Test Chamber For Evaluation Of The Toxicity Of Rubber Infill, João F. Gomes Jan 2011

Design Of A New Test Chamber For Evaluation Of The Toxicity Of Rubber Infill, João F. Gomes

João F Gomes

A test chamber was projected and built (according to ISO 16000-9 Standard) to simulate atmospheric conditions experienced by rubber infill (when applied in synthetic turf pitches) and measure accurately the airborne emissions of pollutants such as dusts and volatile organic compounds (VOC), as well as pollutants present in leacheates. It should be pointed out that standard ISO 16000-9 is only concerned with the determination of the emission of VOC from building products and furnishing (not specific of synthetic turf materials), while other standards are concerned with the emission of leacheates only. This procedure is to be considered as a technical …


What Is A Chemical Engineer ?, João F. Gomes Jan 2011

What Is A Chemical Engineer ?, João F. Gomes

João F Gomes

No abstract provided.


On The Toxicological Effects Of Airborne Nanoparticles From Welding Processes, João F. Gomes Jan 2011

On The Toxicological Effects Of Airborne Nanoparticles From Welding Processes, João F. Gomes

João F Gomes

No abstract provided.


Nanosized Molecular Sieves Utilized As An Environmentally Friendly Alternative To Antioxidants For Lubricant Oils, Eng-Poh Ng Dr. Jan 2011

Nanosized Molecular Sieves Utilized As An Environmentally Friendly Alternative To Antioxidants For Lubricant Oils, Eng-Poh Ng Dr.

Eng-Poh Ng

Lubricants play a significant part in current environmental considerations since they are an integral and indispensable component of modern technology. The production, application and disposal of the lubricants have to follow increasingly strict requirements for protecting the environment and living organisms. In this respect, molecular sieve (LTL type zeolite) is investigated as a potential environmentally friendly alternative to traditional antioxidant additives for lubricant oils. Accelerated oxidation experiments using pure base oil and additivated base oil in the presence of the LTL molecular sieve are carried out in parallel, and the oxidation processes are monitored by FT-IR spectroscopy, spectrophotometry, chromatography, total …