摘要
燃煤电厂产生的粉煤灰可作为原料合成X型沸石,用于吸附烟气中的CO_(2).通过对沸石材料表面疏水改性,可有效抑制水蒸气对CO_(2)吸附的竞争干扰.本文以粉煤灰为原料成功合成高结晶度的NaX型沸石,并提出用十六烷基三甲氧基硅烷(HDTMS)对其进行疏水改性.同时,考察了改性过程原料配比、反应时间和反应温度对NaX沸石疏水性能和CO_(2)吸附性能的影响.结果表明,NaX沸石和改性后的NaX-HD沸石均保持了较高结晶度.最佳改性条件为HDTMS质量分数12%、反应时间12 h、反应温度80℃,在此条件下改性沸石的水蒸气吸附量较未改性时降低42.3%,同时CO_(2)吸附量仅下降10%,表现出优异的疏水性.疏水改性后的沸石在50°C的CO_(2)/H_(2)O混合气体吸附实验中,CO_(2)吸附量达到0.34 mmol·g^(-1),而未改性NaX沸石的吸附量仅为0.15 mmol·g^(-1),表明HDTMS接枝形成的致密非极性层有效抑制了水分子竞争吸附,提升了CO_(2)在湿态烟气中的选择性吸附能力,为解决工业烟气中水蒸气干扰CO_(2)捕集的关键问题提供了新思路.
X-type zeolite synthesized by coal fly ash generated from coal-fired power plant has been applied for CO_(2) adsorbent in flue gas.The competitive of water vapor on CO_(2) could be suppressed by hydrophobic modification of zeolite surface.In this work,high crystalline NaX zeolite was synthesized by coal fly ash and hydrophobically modified with hexadecyltrimethoxysilane(HDTMS).This study examines the effects of material ratio,reaction time,and temperature on the hydrophobicity and CO_(2) adsorption of NaX zeolite.The results indicate that both NaX and the modified NaX-HD remained high degree of crystallinity.Optimal modification conditions were obtained with HDTMS mass fraction of 12%,reaction time of 12 hours,and reaction temperature of 80℃.Under optimal conditions,the water vapor adsorption capacity of the modified zeolite decreased 42.3%compared to the unmodified sample,while the CO_(2) adsorption capacity decreased only 10%,which demonstrates the excellent hydrophobicity.The CO_(2)/H_(2)O mixed gas adsorption experiments at 50℃show that modified zeolite achieved a CO_(2) adsorption capacity of 0.34 mmol·g^(-1),whereas the value was only 0.15 mmol·g^(-1) for unmodified NaX.This suggests that the dense non-polar layer formed by HDTMS grafting effectively inhibits the competitive adsorption of water molecules,enhancing the selective adsorption capacity of CO_(2) in wet flue gas.In general,the work provides a novel approach to solve the critical issue of water vapor interference in CO_(2) capture from industrial flue gas.
作者
韩晨浩
滕阳
张锴
HAN Chenhao;TENG Yang;ZHANG Kai(Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation,North China Electric Power University,Beijing 102206)
出处
《环境科学学报》
北大核心
2026年第1期310-320,共11页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.U1910215)。
关键词
粉煤灰
沸石
疏水改性
吸附
二氧化碳
fly ash
zeolite
hydrophobic modification
adsorption
carbon dioxide
