磷酸浸渍法制备生物质活性炭吸附氨气

本文研究了磷酸浸渍棕榈壳制备的活性炭用于吸附NH_3。考察了活化温度、H_3PO_4浓度和浸渍时间对活性炭比表面积的影响。本活性炭的氨吸附量不仅仅取决于吸附剂的比表面积,不同于蒸汽法制备的活性炭。在宽温环境下的吸附和解吸实验证明同时发生了物理吸附和化学吸附。化学吸附所导致的氨吸附量与吸附剂表面的氧含量密切相关,化学吸附是由于氨和活性炭表面的一些含氧官能团通过氢键作用而产生的。在此基础上,探讨了磷酸浸渍和化学吸附过程的机理。

Adsorption of ammonia onto biomass - based activated carbons prepared by H3PO4 impregnation

In this paper,preparation of activated carbons from palm shell,a biomass solid waste,by phos- phoric acid(H_3PO_4)treatment and their application for ammonia(NH_3)adsorption were studied.The effects of activation temperature,acid concentration and soaking time on the characteristics of the activated carbon were in- vestigated.Adsorption experiments at a fixed temperature showed that the amounts of NH_3 adsorbed onto the chemically activated carbons,unlike those prepared by steam activation,were not solely dependent on the specific surface areas of the adsorbents.Further adsorption and desorption tests suggested combined physisorptiun and chemisorption of NH_3.The amounts of NH_3 adsorbed by chemisorption were correlated with the contents of ele- mental oxygen present in the adsorbents.Chemisorption was due to the interaction between NH_3 and some oxygen functional groups via hydrogen bonding.Mechanisms for H_3PO_4 impregnation and adsorption processes are pro- posed based on the observed phenomena.