改性氧化钛对羟乙基乙二胺水溶液解吸CO2的强化

Enhancement of CO2 desorption from 2-(2-aminoethylamino)ethanol aqueous solution by modified titanium oxide

羟乙基乙二胺(AEE)水溶液的CO2循环吸收量高(1.2molCO2/molAEE),吸收速度快,稳定性好,但解吸速度慢、解吸量少(0.8mol CO2/mol AEE)是限制该技术广泛应用的主要原因。本文通过向AEE水溶液中添加质量分数为0.05%~0.20%的改性氧化钛(TiO2-MWCNT和TiO2-OH)强化AEE的解吸能力。CO2循环吸收(40℃)-解吸(120℃)实验结果表明改性氧化钛的添加比氧化钛强化CO2解吸效果更好,强化顺序为TiO2-MWCNT>TiO2-OH;其对应的最大解吸速率分别为0.093L/min(质量分数0.15%)和0.083L/min(质量分数0.20%),相对于AEE水溶液,分别提高了32.9%和18.6%;其对应的最大解吸量分别为0.92molCO2/molAEE(质量分数0.15%)和0.88molCO2/molAEE(质量分数0.20%),分别提高了12.2%和9.7%;其对应的CO2循环吸收量分别是0.95molCO2/molAEE(质量分数0.15%)和0.89molCO2/molAEE(质量分数0.15%),分别提高了18.75%和11.25%;5次循环吸收解吸实验结果表明改性氧化钛强化CO2解吸效果稳定,具有较强的化学稳定性。对反应后的改性氧化钛进行XRD、BET、FTIR和SEM表征,结果表明改性氧化钛具有较强的结构稳定性。TiO2-MWCNT和TiO2-OH在促进有机胺溶液解吸CO2方面具有一定的工业应用潜力。

Aqueous 2-(2-aminoethylamino)ethanol(AEE)solution is an efficient CO2 absorbent with a high CO2 capacity of 1.2molCO2/molAEE,high CO2 reaction rate and stable chemical properties.However,the application of this technology is affected by low CO2 desorption rate and desorption loading(0.8 molCO2/molAEE).Modified titanium oxides were found to be able to enhance desorption of AEE aqueous solution at the mass fraction of 0.05%~0.20%.Based on absorption(40℃)-desorption(120℃)experiment results,the performance of modified titanium oxides(TiO2-MWCNT>TiO2-OH)was superior to TiO2 that has been reported.The maximum desorption rates of AEE added with TiO2-MWCNT and TiO2-OH were 0.093L/min(0.15%)and 0.083L/min(0.20%),respectively.Compared with pure aqueous AEE solution,the increase of AEE desorption rate with TiO2-MWCNT and TiO2-OH is 32.9%and 18.6%,respectively.The desorption amounts were 0.92molCO2/molAEE(0.15%)and 0.88molCO2/molAEE(0.20%),which increased by 12.2%and 9.7%,respectively.The cyclic absorption capacity were 0.95 molCO2/molAEE(0.15%)and 0.89molCO2/molAEE(0.15%),which increased by 18.75%and 11.25%,respectively.Five cycle absorption and desorption results showed that the enhancement is durable,which demonstrates stable chemical properties of modified TiO2.The modified TiO2 was characterized by XRD,BET,FTIR and SEM after reaction,which showed stable structure.Above all,TiO2-MWCNT and TiO2-OH are potential to be applied to enhancing CO2 desorption from aqueous AEE solution in industry.