Journal de géologie et géophysique
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Sorption Mechanism and Capacity Evaluation of Palygorskite from Iraq to Remove Pb from Aqueous Solution

Salih Muhammad Awadh and Saad Muhi Towfik

The use of the palygorskite of Iraq as an adsorbent for the removal of Pb from aqueous solution was investigated by the mean of batch technique. Iraqi palygorskite was collected from Digma and Akashat Formations (Masstrachtian and Danianage) from the western Iraqi Desert. Palygorskite exists within the clay-rich sediments; therefore it was concentrated by separation from clay fraction. A series of adsorption tests were conducted to analyze the sorption mechanism and capacity of palygorskite. Standard solutions of Pb were prepared with known concentrations (10, 25, 50, 75, 100, 125, 150, 175, 200, 225, and 250 ppm). Each solution was mixed with 1gm of palygorskite, and treated with total volume up to100 ml for 1hr with stirring at temperature of 25°C. The treated palygorskite was then separated by filter paper. Each filtrate solution was subjected to physical and chemical measurements. Solid to liquid ratio, Adsorption equilibrium reaction time, pH and Pb ion concentration are determined. The results of this study revealed that there is negative relat ionship between pH and each of electrical conductivity (EC), total dissolved solids (TDS) and salinity. The pH of the treated solution decreased from 7.2 to 2.37. Electrical conductivity, TDS and salinity in the initial solutions increased and ranged between 960-14000 μs/cm, 482-11900 ppm and 0.2-8.2‰ respectively. The sorption capacity was recorded as 99.5% of 10 ppm solution, whereas it was 22.22% of 250 ppm solution.