tailieunhanh - NATURAL ARSENIC IN GROUNDWATER: OCCURRENCE, REMEDIATION AND MANAGEMENT - CHAPTER 23

Ô nhiễm asen trong nước uống là một nguy cơ sức khỏe nghiêm trọng ở các bộ phận khác nhau của thế giới. Trong hiệu quả nghiên cứu hiện tại của oxit nhôm hoạt tính (AA) đã được kiểm tra cho hấp phụ asenit và các ion arsenate từ nước. Hàng loạt thí nghiệm với nhiệt độ và kiểm soát kích động đã được sử dụng để xác định năng lực hấp thụ và hấp phụ động học để loại bỏ asenit và arsenate. Loại bỏ cả As (III) và As (V) đã được tìm thấy để được mạnh mẽ. | Natural Arsenic in Groundwater Occurrence Remediation and Management -Bundschuh Bhattacharya and Chandrasekharam eds 2005 Taylor Francis Group London ISBN 04 1536 700 X A comparative study for the removal of As III and As V by activated alumina Tony Sarvinder Singh . Pant Department of Chemical Engineering Indian Institute ofTechnology New Delhi India ABSTRACT Contamination of arsenic in drinking water is a severe health risk in different parts of the world. In the present study effectiveness of activated alumina AA was examined for the adsorption of arsenite and arsenate ions from water. Batch experiments with temperature and agitation control was employed to determine the adsorption capacity and adsorption kinetics for arsenite and arsenate removal. Removal of both As III and As V was found to be strongly dependent on initial pH of water. Effects of contact time temperature initial concentration of adsorbent dose and adsorbate concentration were studied to establish optimum conditions. The present investigation revealed that arsenate ions adsorb well on activated alumina at pH less then pHZPC and maximum removal was achieved at pH from water. Compared to As V As III ions have high affinity towards activated alumina at pH . The experimental data for adsorption of both As III and As V fitted well to the Freundlich and Langmuir adsorption isotherm and adsorption was favorable. Column experiments revealed that the breakthrough performance strongly depends on bed height and feed flow rate. By taking chemistry of water into consideration this process can be used effectively for the removal of arsenic species. 1 INTRODUCTION Inorganic pollutants in particular heavy metal ions constitute a major class of water contaminants Arsenic is the one of the abundant element in the earth s crust Cullen Reimer 1989 . Arsenite As III and arsenate As V are highly toxic inorganic species that represent a potential threat to the environment and human health. Arsenic