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Biodiesel, an alternative to fossil fuels, consists of alkyl, usually methyl, esters of fatty acids (FAME). Conventionally, it is mostly obtained by homogeneous base catalyzed methanolysis of edible oils. Despite the significant advantages, the main drawbacks of this process are the high requirements in terms of the quality of the raw materials and environmentally unfavorable processes of catalyst separation and products purification. For these reasons, the researches of biodiesel synthesis are aimed at developing new processes that are economically and environmentally acceptable. In this paper processes of FAME synthesis, their advantages, disadvantages and opportunities for improving are analyzed, in order to develop processes suitable for industrial applications. The main aim was to present an overview of the researches in developing biodiesel synthesis providing a high FAME yield, which are environmentally-friendly and economically acceptable. Heterogeneously catalyzed process has most often studied, aiming at developing catalytic active, stable and cheap catalysts as well as at process improvement. The developments of enzyme and noncatalytic processes are mainly aimed at reducing production costs and increasing the FAME yield under mild reaction conditions, respectively. Generally, the perspectives of biodiesel synthesis include the use of continuous processes and suitable reactor systems.

This paper presents the development of standardization in the field of energy efficiency, based on a review of available literature on this topic. The paper discusses the development of standardization of energy efficiency of household appliances, energy efficiency in buildings, energy efficiency in transport, standardization related to the use of renewable energy and energy management system standardization. The aim of this paper is to showcase the course of development and important events in the development of standardization in the field of energy efficiency, as well as to present an analysis of published articles on the topic of standardization of energy efficiency in prominent international journals. In research and formation of conclusions, analysis and synthesis methods are used.

The paper describes the real appearance of a new class of light sources. The technology progress allows the light emitting diodes (LED) to be applied for an in- and outdoor lightning. The special, high power diodes (HPLED) have too many advantages comparing to classical light sources and it is quite reasonable to expect their mass application in the indoor and outdoor lighting. The article contains a brief theoretical aspect of optics, explanations of the classical light sources parameters and typical examples. The performances of standard and high power LED are also included as well. The conclusions made at the paper end predict the massive usage LED for the lightning in a near future.

Electrolytic treatment of wastewater is a technique in which wastewater is treated by applying electric current through electrodes in the electrochemical reactor. This is actually a combination of many processes such as anodic oxidation, electro-coagulation and electro-flotation. The paper presents the influence of current density (5, 10, 20 mA/cm2) on the efficiency and reaction rate degradation of cyanide from cyanide wastewater in an electrochemical reactor with electrodes made of steel and stainless steel for 60 minutes of reaction time. This paper presents of a significant effect of current density and an.

The results obtained during the recycling of spent nickel based catalysts that generate in the oil hydrogenation process are presented. Nickel based catalysts are used for selective hydrogenation of the highly active plants oils. The used catalysts are classified in the H11 category of hazardous materials; they are deposited on the site and are potentially dangerous to the environment. Laboratory experimental research defined optimal conditions (temperature, time and solid-liquid ratio) and technological process of catalysts recycling. Hazardous waste is being converted to the category of non-hazardous, and extracted nickel as nickel-sulphate represents commercial product. The degree of recovery of nickel is higher than 95%.

The overview and analysis of the most important standards in the field of energy efficiency drives, in our country and abroad, are presented in the paper. Special attention is paid to standards relating to the efficiency and control motor speed.