Removal of Heavy Metal Ions from Aqueous Solutions by Modified Bamboo Wastes

in International Symposium (Abstract oral presentation), 國際研討會(摘要口頭發表)
標題Removal of Heavy Metal Ions from Aqueous Solutions by Modified Bamboo Wastes
出版類型國際研討會(摘要口頭發表)
出版年度2007
AuthorsFu-Lan Hsu, 許富蘭, & Hong-Lin Lee 李鴻麟
會議名稱國際林業研究組織聯盟林產部研討會
出版日期Oct 29 2007 12:0
會議地點圓山大飯店 (台北市)
其他編號0000
中文摘要

Heavy metals, which are not biodegradable and are readily accumulated in living tissues, cause a variety of diseases and disorders. This study aimed to evaluate the ability of chemically and thermally modified bamboo to remove them from aqueous solution. To determine the effect of chemical modification, bamboo, Phyllostachys pubescens, was pulverized, sieved, air-dried, and difibered with 2%/or 8% NaOH and then treated with 0.6M/ or 1.2 M of citric acid, tartaric acid, oxalic acid or malic acid. Around 0.4 grams of treated and untreated powdered bamboo was mixed with 20 mL of each of 10 ppm lead, nickel, copper and cadmium standard solutions. After thoroughly mixing, metal ion concentrations in the filtrate were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and the adsorption capacity was calculated. Results revealed that the heavy metal removal ability of 2% NaOH-treated bamboo was improved due to its defiberation. Approximately 95% copper and 49% cadmium ions were removed by 2%-NaOH treated bamboos, whereas only 30% and 5% corresponding ions were removed by the control bamboos. Tartaric acid and oxalic acid, were the two chemicals having the greatest effect on improving the removal of heavy metals. The heavy metal removal ability of tartaric acid-modified bamboo to remove Pb, around 98%, was almost equal to that of commercial active charcoal (100%). As to nickel, copper, and cadmium removal ability, tartaric acid-modified bamboo was 20 times more effective than untreated bamboo. Tartaric acid-modified bamboo was the candidate material for further follow-up field testing.
To evaluate the effect of thermal modification, powdered bamboo was heated in an oven at 200, 300, 400, 500, 600, 700, 800, 900, or 1000 oC for 60 min. As the heating temperature increased from 200 to 400 oC, the heavy metal removal ability of thermally treated bamboo increased. The less adsorptive parts of bamboo-cellulose and hemicellulose have been gradually removed and the most adsorptive part of bamboo-lignin were exposed may, in parts, contribute to the improved ability. Thermally treated bamboo showed the best ability to remove Pb, followed by Cd, Cu and Ni. Moreover, similar results were observed as temperature increased from 500 to 1000 oC, and the improvement might result from the increase of contact surface through the increasing size of interior mini pores.

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