不同添加剂对聚乙烯醇固定化锰氧化细菌的影响

为了研究海藻酸钠、琼脂、碳酸钙、活性炭4种添加剂对聚乙烯醇固定化锰氧化细菌的影响, 通过环境扫描电镜进行观察.结果表明:不加添加剂的聚乙烯醇交联后内部分布不均匀, 结构中存在外致密层;加入琼脂可明显缓解外致密层的形成, 微观孔隙数量增加;加入碳酸钙后聚乙烯醇颗粒直径缩小, 内部孔隙的壁厚较大;碳酸钙和活性炭的加入不利于聚乙烯醇形成微观孔隙;海藻酸钠和琼脂恶化了聚乙烯醇颗粒的水溶膨胀性, 而碳酸钙和活性炭有助于改善水溶膨胀性;当添加剂加入量低于1%时, 4种添加剂都可改善聚乙烯醇的机械强度, 加入过多添加剂会使机械强度下降;加入活性炭有利于提高聚乙烯醇固定锰氧化细菌的活性, 而碳酸钙使固定细菌的机械强度改善最为明显.

Effect of the Co-composite Matters on the Immobilized Manganese-oxidizing Bacteria by PVA

Four kinds of co-composite matters including alginate, agar, calcium carbonate and activated carbon were mixed with polyvinyl alcohol (PVA) for immobilizing the manganese-oxidizing bacteria. The internal structure of the PVA gel beads was tested and analyzed by scanning electron microscope. A dense layer exists in the surface of PVA gel beads with an unequal distribution, and adding agar is useful for overcoming this shortcoming and increasing the number of internal pore. Adding calcium carbonate decreases the diameter of the gel beads and improves the thickness of the internal pore wall. The solution and expansion of PVA beads may be worsen after adding sodium alginate and agar and better with activated carbon and calcium carbonate. All the four kinds of co-composite matters are useful for improving the mechanical strength of the PVA gel beads until the ratio is lower than 1%. Activated carbon and calcium carbonate relate with the improving of the bioactivity and mechanical strength, respectively.