ADSORPTIVE REMOVAL OF BISPHENOL-A

Abstract

In the past few years, the research on the endocrine disrupting chemicals (EDCs) has been increased with great interest in the area of environmental science and technology owing to the reason that these chemicals (EDCs) have various properties such as estrogenic, antiestrogenic or antiandrogenic and hence their existence leads to the potential damage the endocrine systems of human beings and wildlife. One of the ECDs such as Bisphenol A [2, 2-bis (4- hydroxyphenyl) propane] or BPA is of the important concern due its adverse potentiality to the human health and environment. BPA is mainly used in the manufacturing of resins and polycarbonate plastics. There is chance of entering the BPA into water bodies while manufacturing plastic products, leaching from plastic products, disposed at the landfill sites, and many routes. Thus it causes contaminating the various sources of water such as ground water, surface water, etc. and poses danger to fecundity and reproductive health of human beings and aquatic animals. In this work Bisphenol-A removal from aqueous solution onto low cost adsorbent- Rice husk ash and granular activated carbon was carried out. Variable considered for the study were pH, adsorbent dose, initial concentration and time. The optimum value of these parameters were found as pH6, adsorbent dose30 gil and time 3h for RHA and pH=6, adsorbent dose30 g/l, and time 2h for GAC .At optimized condition the removal efficiency and adsorption uptake of Bisphenol-A onto RHA were found to be 74% and 2.4 mg/g, respectively. Adsorption capacity of RHA and GAC was compared. BET surface area of RHA and GAC was found to be 21.6 m2/g and 137.8 m2/g, respectively. Kinetic study was carried out by employing pseudo first and pseudo second order model and possibility of intra particle diffusion controlling the adsorption mechanism was also investigated. Adsorption equilibrium data were fitted for Freundlich, Temkin model. Positive value of AH° suggest that the adsorption process was endothermic. Change in the entropy was found to be positive. Negative values of AG JS indicates that the adsorption process is feasible and spontaneous.