硫酸改質活性碳對氨氣吸附能力之研究

Adsorption of NH3 onto Modified Activated Carbon Impregnated with H2SO4

王友利(Yu-Li Wang)

指導教授 ： 童淑珠

崑山科技大學/工程學院/環境工程研究所/碩士(2008年)

https://doi.org/10.6828/KSU.2008.00043

摘要

本研究主要以浸漬法進行活性碳改質，並探討改質前後之活性碳對氨的吸附能力。在改質過程中，探討的操作因子，包括浸漬時間、硫酸浸漬液濃度及漬浸溫度等參數。硫酸浸漬液濃度控制範圍為0.1~ 6 M、浸漬時間1~24 h、操作溫度25~80oC。活性碳樣品製備完成，則檢測活性碳的乾重、孔徑、孔容積及比表面積，以探討浸漬法對活性碳理化性質之影響。結果顯示改質後活性碳表面沉積硫元素的結晶體，致乾重增加及孔容積變小，此外，因酸的侵蝕，致孔徑變大，比表面積降低，這些參數的改變，皆不利於物理吸附的發生。
利用動態吸附系統探討氨氣吸附之效率，以1 %的氨氣、進流量為50 ml/min之條件下進行吸附測試，以貫穿點(breakthrough point)為飽和吸附終點，未改質活性碳吸附2.23 分鐘，最佳改質條件(硫酸3M，浸漬3小時，操作溫度25oC)吸附時間提升為535.09分鐘，增加了約240倍。以FT-IR﹙Fourier Transform Infrared Spectroscopy﹚穿透法檢測活性碳表面官能基，發現隨著含氧官能基的增加吸附能力也相對增加，且吸附後官能基的量也有降低之情形，藉此推測改質後的活性碳乃利用含氧官能基與氨形成氫鍵，進而移除氨氣。

關鍵字

煤質活性碳 ； 硫酸改質 ； 氨氣吸附 ； 官能基 ； 化學吸附

並列摘要

In this study, adsorption of ammonia onto coal activated carbons modified with H2SO4 impregnation was investigated. The effects of modification time, modification temperature and acid concentration on pore surface of activated carbon were studied. These physical properties of activated carbon including BET surface area, porosity, pore size and pore volume, were explored with H2SO4 modification experiments, under different temperature (ranged with 25-80oC), different impregnating time (ranged with 1-24hr) and acid concentrations (ranged with 0.1-6M). The results showed that dry weight increased and pore volume decreased by the accumulation of sulfur element, and pore size increased and specific surface area decreased by corrosion of acid after modifying. Those phenomena are disadvantageous to physisorption occurrence.
The adsorption of NH3 on activated carbon was detected by continuous system with inflow of 50 ml/min, 1% NH3. The adsorption capacity was presented by breakthrough point (as saturation terminal point). The original saturation absorbing time was 2.23 min., but it changed to 535.09 minutes, which was 240 times raised under optimal modification conditions with 3M H2SO4, 25oC and 3 hours impregnation. Besides, the surface functional groups were determined with Fourier transfer infrared spectroscopy (FTIR). The occurrence of chemisorption due to the interaction between NH3 and some oxygen functional groups via hydrogen bonding was confirmed.

並列關鍵字

Coal activated carbon ； NH3 adsorption ； H2SO4 modification ； Functional group ； Chemisorption

參考文獻

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