Desorption Behaviors of 4-nitrophenol on Hyper-Cross-Linked Polymer Resin NDA-701
对硝基酚在超高交联吸附树脂NDA-701上的脱附行为研究

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.