tailieunhanh - INTERFACIAL APPLICATIONS IN ENVIRONMENTAL ENGINEERING - CHAPTER 6
Loại bỏ các kim loại nặng từ Media Nước bởi Ion Exchange với Y zeolit Kim loại nặng (HM) là một thuật ngữ chung chung áp dụng cho nhóm của kim loại và kim với một mật độ nguyên tử lớn hơn cm g 6 3 và bao gồm các yếu tố như Cu, Cd, Hg, Ni, Pb, Zn, Co, Al, và Fe [1,2]. Ô nhiễm và độc tính kết hợp với kim loại nặng cũng được thành lập, với bằng chứng cho thấy tác động có hại cho sức khỏe, sinh thái và công cộng [3,4]. Sự hiện diện của. | 6 Removal of Heavy Metals from Aqueous Media by Ion Exchange with Y Zeolites MARK A. KEANE University of Kentucky Lexington Kentucky . I. BACKGROUND POLLUTION BY HEAVY METALS Heavy metals HM is a general collective term applied to the group of metals and metalloids with an atomic density greater than 6 g cm 3 and includes such elements as Cu Cd Hg Ni Pb Zn Co Al and Fe 1 2 . The pollution and toxicity associated with heavy metals is now well established with mounting evidence of adverse ecological and public health impacts 3 4 . The presence of heavy metals in water has an appreciable effect on acidity 5 and the resultant decrease in pH is known to adversely affect fish stocks and vegetation 6 . These pollutants reach the environment from a vast array of anthropogenic sources as well as natural geochemical processes. Heavy metal ions in solution are toxic to humans if the concentration is sufficiently high and Health Agency guidelines set maximum acceptable HM concentrations in drinking water that are typically less than 3 mg dm 3 7 8 . This chapter focuses on Fe Co Ni Cu Cd and Pb as six representative HM pollutants. Iron is found naturally in large concentrations in soil and rock normally in an insoluble form but it can as a result of a series of naturally occurring complex reactions be converted to soluble forms that often result in water contamination 7 . Excess iron in groundwater can also arise from the use of iron salts as coagulants during water treatment or as a byproduct of pipe corrosion 1 . Iron is very unlikely to cause a threat to health at the concentrations typically recorded in water supplies but excessive amounts can certainly have detrimental effects. The presence of cobalt as a water pollutant can be due to a leaching from rock soil or the result of commercial activities relating to agriculture or the mining metallurgical electronics industries or as a byproduct of electroplating and pigment paint production 6 9 . Nickel and copper are .
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