Abstract:

Carrier material is the foundation for the construction of immobilized system, in which the pore structure directly affects the immobilized biomass and the degradation results. In this study, different pore sizes of polyurethane foam were synthesized and were used to immobilize Alcaligenes sp. DN25 for phenol degradation. The results showed that the biomass on the polyurethane foam with pore network structure reached the maximum value of (0.0253±0.0010) g when the pore size was 150 μm. Phenol of 1160 mg·L^-1 was completely degraded by the PUF-immobilized cells within 48 h, while the freely suspended cells were completely inhibited. It was found that the equilibrium adsorption rate of 900 mg·L^-1 phenol by the PUF carrier was 56.1% within 12 h. Furthermore, phenol degradation by the PUF-immobilized cells under the conditions of initial pH at 6.0—9.0 and NaCl concentration of 0—4.0% were investigated, respectively. There were not significant differences in phenol degradation under the conditions of initial pH and NaCl concentrations. In addition, the removal rate of 500 mg·L^-1 phenol can still be maintained at 100% after the repeated use of 11 batches of immobilized cells, reflecting the enhancement of the PUF-immobilized cell system on both the phenol treatment concentration and system stability.

Key words: foam, immobilized, degradation, pore size, phenol

摘要：

载体材料是构建固定化体系的基础，其中孔结构直接影响固定化的生物量及降解结果，开展了制备不同孔径聚氨酯泡沫材料并考察其固定化产碱杆菌DN25降解苯酚的研究。结果表明，孔隙结构的聚氨酯泡沫材料在孔径均值为150 μm时所固定的生物量达到最大值（0.0253±0.0010） g，固定化细胞能在48 h内完全降解1160 mg·L^-1苯酚，而游离细胞则完全受到抑制，并且发现载体材料PUF在降解前12 h内吸附苯酚的平衡吸附率为56.1%。进一步研究固定化细胞在初始pH6.0~9.0，NaCl浓度0~4.0%条件下降解900 mg·L^-1苯酚的情况，固定化细胞对苯酚的去除率受pH、NaCl浓度的影响不显著。并且，固定化细胞重复使用11个批次对500 mg·L^-1苯酚的去除率仍能保持100%，反映了PUF-固定化细胞体系对苯酚处理浓度和系统稳定性两方面的强化作用。

关键词: 泡沫, 固定化, 降解, 孔径, 苯酚