Electronics environmental impact

Of major concern are the health and environmental impacts of the abundant chlorinated and brominated hydrocarbons (ref. 2). These materials have numerous industrial applications as pesticides, solvents, propellants, refrigerants, plastics, fire retardants and extinguishers, disinfectants for drinking water, pharmaceuticals and electronic chemicals. Many chemical manufacturers utilize chlorinated and brominated organics as intermediates. It is estimated, for instance, that almost 85 % of the pharmaceuticals produced in the world require chlorine at some stage of synthesis. 

In addition, these precious and special metals have very low concentrations in ores mining, smelting, and refining these metals therefore have a particularly large environmental impact. Recovering these metals from defunct electronic equipment would result in a fraction of the effect on the environment [20]. 

Xing GH, Chan JKY, Leung AOW, Wu SC, Wong MH (2009) Environmental impact and human exposure to PCBs in Guiyu, an electronic waste recycling site in China. Environ Int 35 (l) 76-82. doi 10.1016/j.envint.2008.07.025... 

Another advantage cited for organic electronics is their perceived low environmental impact and high expected consumer safety. This assumption is generally based on the notion that plastics are easily recycled and are considered safe to humans and animals. However, the materials used are often completely new compositions with poorly understood health and safety attributes. The assumption that all plastics are completely safe for humans is inaccurate, as is exemplified by recent concerns about the toxicity of polyvinyl chloride (PVC).39 In contrast, most inorganic nanoparticle materials are already on the consumer market and have extensive historical data on their safety in a variety of applications. Some materials, such as zinc oxide, are even considered reasonably safe for ingestion and therefore are commonly used in food and cosmetics. However, the health effects and interactions of nanoparticles on the human body are still a topic of debate.40... 

Nitrite reductases (NiRs)—enzymes found in several strains of denitrifying bacteria— catalyze the one-electron reduction of nitrite anion to nitric oxide (Equation 1). - In addition to the importance of this process in the global nitrogen cycle (Figure 1), further incentive for the study of the denitrification process is provided by its environmental impact, ranging from the production of NO as a pollutant and NjO as a potent greenhouse gas, to lake eutrophication due to farm runoff that contains high concentrations of nitrates and nitrites. 

The environmental impact of waste disposal and of chemical use in Europe has led to three legislative actions that, in today s global economy, greatly affect flame-retardant use and research. These actions go by the acronyms of RoHS (Reduction of Hazardous Substances), WEEE (Waste Electrical and Electronic Equipment), and REACH (Registration, Evaluation, Authorisation, and Restriction of Chemical substances). These actions are discussed in detail in Chapter 22, but need to be mentioned here as they are clear examples of how changing regulations affect flame-retardant use, selection, and new fire-safety developments. The first one, RoHS, refers to how new items are manufactured, and specifically bans chemicals and elements of environmental and toxicological concern in Europe. One fall-out item of RoHS is the move from a lead-based solder on circuit... 

WEEE has had a direct affect on flame-retardant use, because flame retardants are used in almost all electrical and electronic equipment to prevent fires from short circuits. This directive lays down rules for disposal and recycling of all electrical and electronic equipment that goes back to the previous incinerator discussion. For flame retardants, this directive affects how the plastic parts, cable jackets, and enclosures are flame retarded. If the plastic cannot be reground and recycled, it must go to the incinerator, in which case it cannot form toxic by-products during incineration. This has led to the rapid deselection of brominated FR additives in European plastics that are used in electronics, or the complete removal of FR additives from plastics used in electronics in Europe. This led, in turn, to increases in electrical fires in Europe, and now customers and fire-safety experts demand low environmental impact and fire safety. However, the existing nonhalogen flame-retardant solutions brought in to replace bromine have their own balance-of-property issues, and so research continues to develop materials that can meet WEEE objectives. 

From an environmental aspect, long print runs of large reports can be counterproductive if the resultant resource utilisation and pollution is taken into account. Criticism of this type can be answered, to some extent, by offering the CER on-line. However, even here the environmental impact of electronic media needs to be considered. 

Chlorinated and brominated materials are burned or thermally treated in a variety of combustion sources including hazardous and municipal waste incinerators, industrial processes, backyard trash burning, and accidental fires. Chlorinated materials are used in a wide range of applications and brominated compounds are fire retardants used in many devices including electronic circuits. Although there has been some research on the reactions of CHCs and BHCs in the past 20 years, too little is known about their reactions considering the magnitude of the environmental impact. Elementary reaction studies of gas-phase reactions of Cj and C2, CHCs, and BHCs are needed to understand their most fundamental reaction properties. Reactions of the chlorinated and brominated benzenes and phenols are important intermediate steps in the formation of PCDD/F. Recent kinetic models indicate that the gas-phase reactions may be quite important and elementary gas-phase reaction studies have been overlooked by researchers. 

Resetirch on thermoelectric materials has experienced a considerable resurgence in the past five years driven by three underlying concerns 1) the environmental impact of freon-based cooling technologies, 2) the generation of electrical power from so-called waste heat in automobiles, and 3) the active cooling of modern electronic device components. 

Battery performance is measured in terms of voltage and capacity. The voltage is determined by the chemistry of the metals and electrolytes used in the battery. The capacity is the number of electrons that can be obtained from a battery. Since current is the number of electrons released per unit time, cell capacity is the current supplied by a cell over time and is normally measure in ampere-hours. Battery specialists experiment with many different redox combinations and try to balance the energy output with the costs of manufacturing the battery. Other factors, such as battery weight, shelf life, and environmental impact also factor into the battery s design. 

The widespread use of metals for different kinds of application (e.g., pigments, coatings, alloys, electronic equipment) leads to the fact that some of the utilized metals (or their compounds) end up in wastes. Metals in wastes can cause severe environmental impacts, particularly with respect to ground-water pollution. 

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