Study of the Removal of Toxic Anions from Contaminated Water Utilizing Natural Kaolinite Clay of Assam

Abstract

Groundwaters of many parts of Assam, a state of north-east India, are contaminated with high levels toxic arsenic, fluoride. The soil of the area also shows high levels of nitrite and nitrate. The presence of arsenic and fluoride in excessive limits in drinking water along with the attendant problems prevailing in many parts of Assam in the North Eastern India is well documented. Recently Dhemaji and Karimganj districts of Assam have been recorded as arsenic affected areas. Both the World Health organization (WHO) and the U.S. Environmental Protection Agency (USPEA) have classified arsenic as carcinogen. The present study observed the effectiveness of natural clay in the removal of these anions from contaminated water. For this purpose clay samples were collected from Longai of Karimganj district of Assam. This study observed the adsorption capacity of the clay minerals with respect to the parameters, adsorbent dosage, concentration, pH and contact time. SEM-EDX characterization shows the presence of kaolinite along with significant amount of iron and quartz in both the samples. XRD and FTIR analysis also reveals the presence of kaolin minerals. The efficacy of the local clay in removing contaminating anions is discussed in the article.