用活性炭吸附除去和回收废气中丙烯酸甲酯

考察了不同平衡浓度和吸附温度下丙烯酸甲酯在3种活性炭(AC、Y2、C5)上的吸附情况及水蒸气存在对吸附的影响.研究表明,丙烯酸甲酯在这些活性炭上的吸附平衡数据均可较好地用Langmuir-Freundlich方程描述;在313K和丙烯酸甲酯平衡体积分数为149×10-6～3412×10-6时,活性炭AC均有最大的平衡吸附量.而当丙烯酸甲酯的体积分数低于149×10-6时,活性炭Y2在该温度下有最大的平衡吸附量.该结果与AC有丰富的微孔和中孔,Y2有较小的平均孔径密切相关.在该温度下,吸附质穿透定量活性炭床层所需时间的对数与其入口浓度的对数呈较好的线性关系.在相对湿度低于40%时,丙烯酸甲酯在活性炭上的饱和吸附量不小于干燥条件下的93%.活性炭吸附剂的再生和吸附于活性炭上丙烯酸甲酯的回收在453K下即可较好实现.活性炭AC对丙烯酸甲酯的吸附性能经过6次吸附(313K)/脱附(573K)循环使用未发现变化.

Elimination and recovery of methyl acrylate from waste gas by adsorption/desorption on activated carbons

The adsorption of methyl acrylate (MA) on three kinds of activated carbons (AC, Y2, C5) was investigated to evaluate its dependency on initial concentration of the adsorbate, temperature and relative humidity. The experimental results obtained at adsorption equilibrium conditions can be described well by Langmuir-Freundlich equation. The saturated adsorption amount of MA on the AC at 313 K is always the highest among those obtained on the three activated carbons when the initial concentration of MA ranges from 149×10(~-6) to 3 412×10(~-6) in volume ratio. Nevertheless, when the MA concentration is lower than 149×10(~-6), Y2 gives the maximum adsorption amount at equilibrium. The pore properties of activated carbons have much effect on their adsorption capacity. The adsorption capacity of AC and Y2 at different conditions can be well associated with their specific pore structure. A linear correlativity in logarithm between initial concentration of the adsorbate and the 1% breakthrough time at 313 K was obtained over the activated carbons. The results indicate that more than 93% of the adsorption capacity can remain when the adsorption of MA on AC is conducted at the conditions with the relative humidity of 40%. The regeneration of activated carbon and the recovery of the MA can be performed by heating the absorbent to 453 K after adsorption. No change in adsorption capacity can be observed after the adsorption (313 K)-desorption (573 K) is cycled for six times.