丙烯酸改質水熱合成碳、生物碳、活性碳吸附重金屬之研究

Adsorption on heavy metals by hydrochar, biochar and activated carbon through acrylic acid modification

張晉瑋(Jin-Wei Zhang)

指導教授 ： 趙煥平

中原大學/工學院/環境工程學系/碩士(2019年)

https://doi.org/10.6840/cycu201900595

摘要

本研究以柚木和生薑作為原料，透過簡易的前處理技術製成粉末狀，再分別進行第一步驟水熱合成法製成水熱碳，第二步驟利用水熱碳在800oC缺氧環境下製成生物碳，及使用K2CO3活化水熱碳製成活性碳，並對三種不同型式的碳材料以丙烯酸進行接枝實驗，以提升對重金屬銅、鉛、鎘的吸附能力。所有碳材料經SEM、EDS、XPS、BET、FTIR鑑定其基本性質，在常溫下對三種不同重金屬Cu2+、Pb2+、Cd2+進行吸附實驗，並比較接枝前後之吸附量差異。
經由SEM顯示，部分碳材料接枝後表面均由粗糙面轉變為圓滑面，由EDS、XPS顯示，碳材料內層及表層主要元素為C、O，活性碳含有微量之K存在，經過接枝程序後皆增加了Na、Ce，由BET顯示，屬於低表面積之碳材料經由接枝程序後可增加微量之表面積，屬於高表面積之碳材料則會降低表面積，由FTIR顯示，碳材料表面皆含有COOH基團存在，經由COOH基團的增加可以提供更多錯合能力或離子交換來吸附重金屬。吸附測試結果得知，經過接枝程序之所有碳材料吸附量皆可得到提升，由Langmuir方程式計算出碳材料對重金屬之最大吸附量，接枝前後最佳碳材料排序為水熱碳>活性碳>生物碳，接枝前後重金屬最佳吸附量排序為Cu2+ > Cd2+ > Pb2+。
對Cu2+、Cd2+、Pb2+最佳吸附量依序為169 mg/g、175.4 mg/g、323 mg/g，由吸附實驗結果得知吸附機制主要為錯合能力其次為離子交換。以柚木及生薑兩種原料作比較，以柚木製成之碳材料較佳。

關鍵字

水熱合成碳 ； 生物碳 ； 活性碳 ； 接枝 ； 丙烯酸 ； 重金屬

並列摘要

This study uses teak and ginger as raw materials to synthesize carbonaceous materials. In the first step, the materials were used to synthesize hydrochar through a hydrothermal process. In the second step, the hydrochar was put in an 800oC oven under oxygen-free condition to produce biochar. In the third step, hydrochar is activated using K2CO3 to prepare the activated carbon. The three kinds of carbonaceous materials are grafted with acrylic acid to enhance the adsorption capacity of heavy metals such as copper, lead and cadmium. All carbonaceous materials were characterized by SEM, EDS, XPS, BET and FTIR. The adsorption experiments of three different heavy metals Cu2+, Pb2+ and Cd2+ were carried out at room temperature and pH 5.0 conditions. Langmuir model was used to estimate the adsorption capacities of three heavy metals on the carbonaceous materials.
The SEM images indicated that the surface of carbonaceous materials from rough surface to smooth one after the grafting process. C and O are main element on the produced material through analysis of EDS and XPS. The activated carbon contained trace amounts of K because of activating agent. After the grafting process, the content of Na and Ce obviously increase, which represents a successful grafting reaction. The carbonaceous material can lightly increase the surface area through the grafting process, and the high surface area carbon material reduces the surface area. The result of FTIR analysis indicated that the addition of COOH groups can provide more sites for the complex reaction or ion exchange to adsorb heavy metals. The adsorption test results show that the adsorption amount of all carbon materials can be improved by the grafting procedure. The maximum adsorption capacities of carbonaceous materials for heavy metals follow the order hydrochar > activated carbon > biochar. The optimal adsorption amount of heavy metals before and after grafting was Cu2+ > Cd2+ > Pb2+.
The optimal adsorption capacity on Cu2+, Cd2+ and Pb2+ was 169 mg/g, 175.4 mg/g, 323 mg/g.　The primary adsorption mechanisms were regarded as the complex reaction and ion exchange. Comparing teak with ginger, teak can generate the relatively higher adsorption amount for the heavy metals.

並列關鍵字

hydrochar ； biochar ； activated carbon ； grafting ； acrylic acid ； heavy metals

參考文獻

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