Disadvantages Of Pollutants Essay

A pollutant is a substance or energy introduced into the environment that has undesired impacts, or adversely affects the usefulness of a resource. A pollutant may cause long- or short-term damage by changing the growth rate of plant or animal species, or by interfering with human health.

1.1 Types of pollution

1.1.1 Air pollution:- Air pollution is caused by harmful gases such as carbon dioxide, sulfur dioxide, nitrogen dioxide, carbon monoxide and very small particles of carbon. Most of the pollution is caused by factories and vehicles. Release of hazardous gases such as sulfur dioxide into the air causes acid rain and global warming, which cause increase of temperatures, droughts and irregular rains. The breathing of polluted particle

The mechanism for heavy metal removal by chemical precipitation is presented in Equation ‎1 1 ‎ M+2 + 2(OH) M (OH) Equation ‎1 1

Where, M+2 is the dissolved metal ions, 2(OH) is the precipitant, M (OH) is the insoluble metal hydroxide (precipitate) The disadvantages of this process are it's requiring of a large amount of chemicals to reduce metals to an acceptable level, and slow the precipitation process.

1.2.2 Ion exchange An ion exchanger as resins is a solid, capable of exchanging either cations or anions from the surrounding materials. The disadvantage of this method is that it cannot handle with concentrated heavy metals solution as the matrix becomes easily fouled by organics and other solids in the wastewater. And it is nonselective.

1.2.3 Electrolytic recovery or electro-winning In this process electric current pass through an aqueous metal- solution containing a cathode and an anode plates. Positively charged ions are attracted to the cathode and negative attracted to anode. Its disadvantage is that, the electrodes have to be replaced due to probability of corrosion.

1.2.4 Adsorption on new