| 对硝基酚在超高交联吸附树脂NDA-701上的脱附行为研究 |
| 摘要点击 4298 全文点击 2635 投稿时间：2010-06-06 修订日期：2010-08-20 |
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| 中文关键词 对硝基酚 脱附 脱附动力学 固定床脱附 超高交联吸附树脂 |
| 英文关键词 4-nitrophenol desorption desorption kinetics fixed-bed desorption hyper-cross-linked polymer resin |
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| 中文摘要 |
| 通过碱当量选择、 脱附动力学以及固定床吸附-脱附实验，研究了对硝基酚在自制的超高交联吸附树脂NDA-701上的脱附行为，考察了2个温度下不同碱当量比（MNaOH/4-NP）对树脂脱附率的影响；研究了3个脱附温度和3种MNaOH/4-NP值情况下NDA-701的脱附动力学性能；考察了NDA-701的固定床吸附性能和不同脱附剂浓度方案下的动态脱附性能.结果表明，在303 K和333 K温度下，当MNaOH/4-NP<1.2时，NDA-701脱附不完全，其脱附率随温度的增加而增加，但温度对脱附率的贡献随MNaOH/4-NP值的增大而逐渐减小；当MNaOH/4-NP=1.2时，2个温度下NDA-701脱附率均达到100%，说明碱当量是影响NDA-701的脱附热力学性能的关键性因素.脱附动力学符合伪二级动力学模型，脱附温度由303 K增加至333 K，脱附速率常数k2值由0.010 g·(mmol·min)-1增至0.035 g·(mmol·min)-1，当MNaOH/4-NP值达到临界值之后， MNaOH/4-NP值由1.2增至5.0，k2值变化微小，仅由0.038 g·(mmol·min)-1变化至0.044 g·(mmol·min)-1，说明脱附温度能够明显提高其动力学性能，过高的碱当量比对其动力学性能影响甚小，温度是影响NDA-701脱附动力学性能的关键因素；脱附温度为333 K时，以2BV 2%NaOH+5BV蒸馏水为脱附剂，总脱附效率达到100%，与实际工程的脱附方案（脱附剂浓度为1BV 8% NaOH +1BV 4% NaOH +水，温度为353 K）相比，碱量为工程脱附方案的1/3，温度降低20 K，说明树脂吸附法在实际应用中，具备节能减耗的空间. |
| 英文摘要 |
| Desorption behaviors of loaded 4-nitrophenol (4-NP) on hyper-cross-linked polymer resin NDA-701 were studied. The molar ratio of NaOH and 4-NP desorbed (MNaOH/4-NP) selection experiments were carried out at two different reaction temperature(303 K and 333 K). Desorption kinetics characteristic of 4-NP on NDA-701 in the batch and fixed-bed mode were examined at different reaction temperature and MNaOH/4-NP values. The results showed that optimal MNaOH/4-NP values were 1.2 and 100% 4-NP could be desorbed from NDA-701 at two different temperature. When the MNaOH/4-NP was lower than 1.2,the desorption efficiency increases with the increase of temperature,but the function of temperature decrease with increasing of MNaOH/4-NP values for desorption ratio. The information indicated that desorption thermodynamic characteristic of NDA-701 was controlled by MNaOH/4-NP values. Desorption kinetics in the alkaline system can be well described by pseudo-second-order kinetic model,and desorption rate is increased with the increase of desorption temperatures,the k2 value increase from 0.010 g·(mmol·min)-1 to 0.035 g·(mmol·min)-1 when desorption temperature increase from 303 K to 333 K. Nevertheless,higher MNaOH/4-NP values could not promote desorption rate if only MNaOH/4-NP value was larger than the optimal molar ratio of NaOH and 4-NP. When MNaOH/4-NP values increase from 1.2 to 5.0,the k2 value increase from 0.038 g·(mmol·min)-1 to 0.044 g·(mmol·min)-1 merely at 333 K. the results indicated that desorption kinetic characteristic of NDA-701 was controlled by temperature. NDA-701 can be completely recovered using 2 times Bed Volume of 2% NaOH solution at the temperature of 333 K,comparing with field application,implying that more energy and cost can be saved in comparison with the actual desorption process in the industry. |
