摘要
研发新型、高效吸附甲醛的无机材料已成为热点,采用Na_2SiO_3·9H_2O和KOH化学改性工业硅灰制备硅质溶胶,经水热反应合成吸附材料(S),红外光谱分析(FT-IR)和扫描电镜(SEM)结果证实硅灰中的Si—O结构发生变化,形成更多具有层状或架状结构、微观上呈现多孔结构的物质,BET结果表明其平均孔径为37 nm。通过将其与活性炭(C)以及KOH改性活性炭(CA)对甲醛的吸附性能对比发现,S对甲醛的去除率最高(79.3%),且其循环吸附性能优良。3种样品对甲醛的吸附动力学均满足Langmuir一级吸附模型,甲醛的变化规律均符合指数衰减模型C=y_0+A_1exp(-x/t),且y_0与吸附材料的性质密切相关。提出并阐述了3种吸附材料对甲醛的吸附机理,硅灰基吸附材料除了物理吸附,还有-Si-OH与甲醛之间的氢键作用。
Research and development of novel and efficient inorganic materials for adsorption of formaldehyde have attracted much interest recently. In this paper,silica sols were prepared using a compound of Na2SiO3·9H2O and KOH as chemical activator and industrial silica fume powder as a raw material,which transformed into an adsorption material（ S） with a micro-pore structure after a hydrothermal reaction. The results of Fourier infrared spectroscopy（ FT-IR） and scanning electron microscopy（ SEM） confirmed that the Si—O transformed into a more lamellar or frame structure and presented a porous morphology. The BET results showed that the micro-pore diameter reached 37 nm. Comparing with the formaldehyde adsorption performance of activated carbon（ C） and KOH modified activated carbon（ CA）,it was found that S attained the highest ratio of formaldehyde removal（ 79. 3%）. S also maintained an excellent cyclic adsorption performance and its adsorption dynamics conforms to the first order kinetics of Langmuir adsorption theory. The change rule of formaldehyde follows an exponential decay model,C = y0＋ A1exp（-x/t）,and y0 is closely related to the nature of the adsorption material. The adsorption mechanism of three samples for formaldehyde adsorption was proposed and illustrated,the silica fumebased adsorption material maintained physical adsorption and hydrogen bonding interactions occurred between—Si—OH and formaldehyde.
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第4期2407-2412,共6页
Chinese Journal of Environmental Engineering
基金
西安建筑科技大学博士基金资助项目(DB09082)
关键词
甲醛
吸附
机理
活性炭
formaldehyde
adsorption
mechanisms
activated carbon
