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。2005年，采用感应耦合等离子体原子发射光谱（inductively coupled plasma atomic emission spectroscopy，ICP-AES）测定了5种竹制废弃物与现有生物吸附剂（biosorbents）在不同反应时间、粒径及pH条件下对水溶液中金属离子的去除性能。结果表明，吸附效能随反应时间延长而提升，4~8小时后4种金属离子的吸附过程达到平衡；金属吸附的最佳pH范围为4~6。在5种受试材料中，活性炭（activated carbon）的吸附效果最优，其次为废咖啡渣、废茶叶与树皮，竹材（Dl）的吸附效果最差。通过水萃取处理可显著且简便地提升原竹的金属去除效率，其处理效果甚至优于树皮、废咖啡渣与废茶叶，这是由于水萃取竹材可有效增加其有效容积与比表面积（surface area），释放更多的金属结合官能团（metal-binding functional groups），从而提升金属去除效率。 2006年，为提升竹材的重金属去除性能，研究人员对其开展了化学改性（chemical modification）处理：以毛竹（Phyllostachys pubescens）为原料，经取样、粉碎、过筛、风干后，分别采用氢氧化钠（NaOH）、柠檬酸（citric acid）、酒石酸（tartaric acid）、草酸（oxalic acid）与苹果酸（malic acid）进行改性处理。值得注意的是，氢氧化钠脱纤过程（defiber process）即可提升竹材的金属去除性能：对铜离子（copper ion）的去除率从30%提升至95%，对镉离子（cadmium ion）的去除率从5%提升至49%。在所有受试化学改性剂中，酒石酸改性竹材的改性效果最优，其次为草酸；酒石酸改性竹材对铅离子的去除率可达98%，几乎与商用活性炭（commercial active charcoal）相当。对于镍、铜、镉离子，酒石酸改性竹材的去除能力也较未处理竹材提升了20倍。酒石酸改性竹材是一种具备后续现场试验潜力的吸附材料。 2007年，研究计划开展填充柱（packed column）连续吸附与分批式吸附实验（batch wise experiment）的金属去除性能对比研究，并将采用不同来源的样品。 本研究本年度聚焦竹材对除重金属外的含磷、含氮化合物等污染物的吸附性能，以期缓解此类物质引发的水域富营养化（eutrophication）问题。截至当前试验中期，研究工作主要集中于含磷、含氮化合物检测方法的建立。针对含磷化合物检测方法的筛选，本研究对比了环保署标准方法"NIEA W427.52B"分光光度法/维生素丙法与ICP法，结果显示ICP法的准确度更高（ICP法决定系数r²=0.9978；分光光度法r²=0.9968）且操作更便捷，因此最终选定ICP法用于含磷化合物检测。针对含氮化合物检测方法的建立，本研究对比了"NIEA W419.51A"分光光度法与"NIEA W417.51A"马钱子碱比色法。试验结果表明，"NIEA W419.51A"分光光度法受有机质干扰严重，不适用于竹材吸附试验；而"NIEA W417.51A"马钱子碱比色法操作流程过于繁琐，难以适配大批量试样的检测需求。目前研究正采用离子色谱仪（Ion Chromatography，IC）开展相关检测方法的测试。截至本年度目前节点，本研究已成功建立感应耦合等离子体原子发射光谱（ICP-AES）与紫外-可见分光光度法（UV-VIS）两种分析水样中磷元素的标准校准曲线。针对未处理竹材与重金属吸附性能优异的竹材开展磷酸根离子吸附试验后发现，若要实现磷酸根离子的高效吸附，吸附材料需以带正电荷的官能团为核心；因此，对重金属吸附性能优异的竹材，其对磷酸根离子的吸附效果并未达到预期。后续本研究拟采用负载三价铁的羧基化聚丙烯酰胺（Iron(III)-Loaded Carboxylated Polyacrylamide）对竹材进行改性，以赋予其磷酸根离子吸附能力。