Soil Based Adsorption Media for Permeable Reactive Barriers to Adsorb Lead (Pb<sup>2+</sup>) & Cadmium (Cd<sup>2+</sup>)

Abstract

Groundwater contamination is one of the predominant environmental problems in Sri Lanka and it is suspected as one of the unseen factors of the country’s widespread kidney disease. Heavy metals Cadmium (Cd2+) and Lead (Pb2+) are two potentially harmful contaminants found in polluted groundwater samples in Sri Lanka. Permeable reactive barrier (PRB) is an on-site, costeffective and efficient groundwater heavy metal remediation technique. However, the effectiveness of the PRB system is highly dependent on the characteristics of the reactive materials being used. Accordingly, Rendzina soil (Hunugala series), Reddish Brown earth soil (Nonagama series), Reddish brown latosolic soil (Melsiripura series), and Bog Soil (Wagura series) were selected based on the basic soil properties which were found by previous researchers. Sieve analysis, Atterberg limits, and Procter compaction tests were carried out to determine the physical properties of the selected soils. The batch tests were carried out to determine the absorption rate of heavy metals, namely, Lead (Pb2+) and Cadmium (Cd2+), and to assess the effects of pH, contact time, and initial concentration on the adsorption characteristics of the selected reactive materials. The results reveal that the Rendzima soil is the most suitable reactive material out of all the reactive materials tested.