木質纖維材料化學改良對於過濾系統之影響(3/4)-Removal of pollutants from Agueoues Solutions by Lignocellulose Wastes

The ability of five spices of bamboo waste and known biosorbents to remove metal ions from aqueous solutions at different reaction time, particle size and pH values was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) in 2005. The results showed that the adsorption efficacy increased with reaction time and after 4~8h, the adsorption of four metal ions reached equilibrium. The optimum pH for metal adsorption is at the range of 4~6. Among these five compared materials, activated carbon was the most effective, and then was exhausted coffee, exhausted tea and bark, and the last was bamboo (Dl). The metal removal efficiency of raw bamboo can be greatly and easily improved by water extracted treatments and the results are even better than those of bark, exhausted coffee and tea. This is because bamboo extracted with water can effectively increase its available volumes and surface area and more metal-binding functional groups were released, resulted in better metal removal efficiency. Chemical modification was conducted in 2006 to improve the heavy metal removal ability of bamboo. Phyllostachys pubescens was sampled, grounded, sieved, air-dried, and then treated by NaOH, citric acid、tartaric acid、oxalic acid and malic acid.
It is interesting to find that the removal ability of bamboo has already been improved in the defiber process by NaOH: from 30% to 95% (copper ion); from 5% to 49% (cadmium ion). Among all testing chemical agent, tartaric acid modified bamboo showed the best improving ability, and then oxalic acid. The Pb removal ability of tartaric acid modified bamboo (98%) was almost equal to commercial active charcoal (100%). As to nickel, copper, cadmium removal ability, tartaric acid modified bamboo also showed 20 times greater than untreated bamboo. Tartaric acid modified bamboo is a potential material to the follow-up field test.
In 2007, the comparison of metal-removal ability between continuous adsorption on a packed column and batch wise experiment will be conducted. Samples from different fields will also be adopted.
本年度探討竹材對重金屬以外如含磷化合物與含氮化合物等污染物之吸附效果，以期減少此二物質所造成水域環境“優養化”(eutrophication)之現象。截至期中，主要在進行含磷化合物與含氮化合物偵測方法之確立。針對含磷化合物偵測方法之選用，曾比較環保署(NIEA W427.52B)分光光度計/維生素丙法與ICP兩種偵測法，其中以ICP法之準確度較高（ICP法r20.9978；分光光度計法r2為0.9968）、操作較為便利，故最後選定為ICP法。此外對於含氮化合物偵測方法之確立，曾比較NIEA W419.51A分光光度計法及NIEA W417.51A馬錢子鹼比色法。試驗解果顯示此NIEA W419.51A分光光度計法受有機物質之干擾甚為嚴重，不試用於竹材吸附試驗；而NIEA W417.51A馬錢子鹼比色法過程過於繁複，不利於多量試材之進行。目前正以離子分析儀（IC）測試中。本年度截至目前為止，已成功建立“感應藕合電漿原子發射光譜”(ICP-AES)及“紫外線-可見光分光光譜(UV-VIS)兩項分析水樣品中磷元素之標準檢量線。針對未處理竹材及對重金屬吸附效果極佳之竹材進行磷酸鹽離子吸附試驗，結果顯示若欲吸附磷酸鹽離子，則材料應以帶有陽電荷之官能基為主，因此，對重金屬吸附效果極佳之材料，反而對磷酸鹽離子吸附不若預期理想。後續本試驗擬將竹材加以（Iron(III)-Loaded Carboxylated Polyacrylamide）改良，使具有吸附磷酸鹽離子能力。