US EPA

2067155 

Technical Report 

Effects of pH, Surface Area, and Background Matrices on the Removal of Lead from Aqueous Solutions Using Activated Alumina 

Wootton, P 

1999 

NTIS/02921826_a 

GRA and I 

GRA and I 

The metallic compound lead poses a human health risk and is environmentally toxic. The removal of lead from drinking and waste waters is therefore of great importance. To ensure that the lead concentration is reduced to safe levels, conventional treatment procedures for the removal of lead such as chemical precipitation and ion exchange have been used. These methods often do not yield sufficient removal of lead and can be expensive due to the high costs of required chemicals. Aluminum oxide, Al2O3, has been shown to sorb lead from aqueous solutions by concentrating lead at the particle surfaces. Sorption of lead using aluminum oxide (alumina) is effected by many factors, including PH, available surface area, and background compounds or matrices. Each of these variables significantly impacts both the rate of sorption and the equilibrium amount of lead sorbed on the alumina surface. In this investigation, factors effecting the sorption of lead using alumina were quantified. These factors included the influence of solution pH, alumina surface area (particle size), and presence of background matrices. The specific variables examined were pH solutions that ranged from very acidic ( and lt;3.0) to caustic ( and gt;8.0), alumina particle sizes of and gt;16 (1190 microns) and and lt;200 (74 microns) mesh sizes, and background matrices containing 1.0 mM acetic acid and 0.1 mM sodium chloride. Equilibrium isotherm studies were conducted over the range of variables using known concentrations of alumina and lead in aqueous solutions. The results of this investigation conclude that solution pH plays the most significant role in lead sorption, but alumina particle size and background matrices also decrease the quantity and rate of lead sorption using activated alumina.