Removal of Cd Ions in Aqueous Solutions with Recycled Crumb Rubber

Cadmium is one of many contaminants in water that causes certain effects in the environment and in humans. Among the characteristics that it possess is that it has the capacity of forming numerous compounds making it hard to remove from the water. Moreover, 4 million tires are discarded annually in Puerto Rico, making it a huge problem for the environment with the urge to find alternative uses. The tires are composed mainly by carbon black, synthetic or natural rubber, fibers and elastomers. The present study indicates that the crumb-rubber inserted to the solutions (as in a batch system) has the ability to adsorb the cadmium from them. Conditions such as Mesh-size (particle size of the crumb rubber), used Cadmium salt, concentration of the aqueous solutions, pH and temperature were evaluated. The results indicate that low concentration solutions at pH 6 with crumb rubber size Mesh-30 (the smallest of the particle sizes) and at 45 Celsius degree achieved a high removal percent. Actual studies consist in the evaluation of the sorption capacity of the crumb rubber in columnar tests and further, desorption studies of the crumb rubber.