Qiao Sen, Duan Xiumei, Zhou Jiti, Cheng Yingjun, Bhatti Zafar
Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, People's Republic of China,
World J Microbiol Biotechnol. 2014 Jul;30(7):1985-92. doi: 10.1007/s11274-014-1621-4. Epub 2014 Feb 13.
In this study, we developed a novel technique for preparing polyvinyl alcohol (PVA) hydrogel as an immobilizing matrix by the addition of sodium bicarbonate. This resulted in an increase in the specific surface area of PVA_sodium bicarbonate (PVA_SB) hydrogel beads to 65.23 m(2) g(-1) hydrogel beads, which was approximately 85 and 14 % higher than those of normal PVA and PVA_sodium alginate (PVA_SA) hydrogel beads, respectively. The D e value of PVA_SB hydrogel beads was calculated as 7.49 × 10(-4) cm(2) s(-1), which was similar to the D e of PVA_SA hydrogel beads but nearly 38 % higher than that of the normal PVA hydrogel beads. After immobilization with nitrifying biomass, the oxygen uptake rate and the ammonium oxidation rate of nitrifying biomass entrapped in PVA_SB hydrogel beads were determined to be 19.53 mg O2 g MLVSS(-1) h(-1) and 10.59 mg N g MLVSS(-1) h(-1), which were 49 and 43 % higher than those of normal PVA hydrogel beads, respectively. Scanning electron microscopy observation of the PVA_SB hydrogel beads demonstrated relatively higher specific surface area and revealed loose microstructure that was considered to provide large spaces for microbial growth. This kind of structure was also considered beneficial for reducing mass transfer resistance and increasing pollutant uptake.
在本研究中，我们开发了一种通过添加碳酸氢钠制备聚乙烯醇（PVA）水凝胶作为固定化基质的新技术。这使得PVA - 碳酸氢钠（PVA_SB）水凝胶珠的比表面积增加到65.23 m² g⁻¹水凝胶珠，分别比普通PVA和PVA - 海藻酸钠（PVA_SA）水凝胶珠高出约85%和14%。PVA_SB水凝胶珠的扩散系数（Dₑ）值计算为7.49×10⁻⁴ cm² s⁻¹，这与PVA_SA水凝胶珠的Dₑ值相似，但比普通PVA水凝胶珠高出近38%。在用硝化生物质固定后，PVA_SB水凝胶珠中截留的硝化生物质的氧摄取率和铵氧化率分别测定为19.53 mg O₂ g MLVSS⁻¹ h⁻¹和10.59 mg N g MLVSS⁻¹ h⁻¹，分别比普通PVA水凝胶珠高49%和43%。对PVA_SB水凝胶珠的扫描电子显微镜观察表明其具有相对较高的比表面积，并揭示了松散的微观结构，这种结构被认为为微生物生长提供了较大空间。这种结构也被认为有利于降低传质阻力和增加污染物摄取。
