微小空间内光合细菌与气-液相界面作用的可视化实验

摘要

实验研究了光合细菌在微槽道光生化反应器内的产氢过程以及光合细菌与气-液相界面之间的相互作用.实验发现微槽道内气泡的初始生长点多位于粗糙的侧壁面,气-液相界面内外气体分子的浓差扩散导致气泡不断长大,液体流速增大加快了气泡的生长速率.在某些区域还观察到气泡逐渐缩小直至溶解于液相中的现象;光合细菌会在气-液相界面既存在不可逆吸附现象又存在排斥现象,吸附在气-液相界面的光合细菌会围绕气泡表面运动.同时吸附在气-液相界面的光合细菌增加了气泡的机械强度和稳定性并阻碍气泡的聚合.%The hydrogen production of photosynthetic bacteria (PSB) in a micro-channel photobioreactor was experimentally investigated and the interaction between PSB and gas-liquid interface was observed. It was found that the bubble originated at the rough sidewall surface of the microchannel and grew as a result of the gas molecules transfer across the gas-liquid interface. The bubble growth rate was accelerated by increasing liquid flow rate. It was also observed that a bubble gradually shrank down to dissolve in the liquid phase. Meanwhile, the irreversible adsorption of PSB onto the gas-liquid interface and the mutual repulsion between PSB and gas-liquid interface were revealed. The absorbed PSB did not stick on the bubble surface but slipped around the interface. Furthermore, the absorbed PSB on the gas-liquid interface enhanced the mechanical strength and stability of the bubbles, hence resulting in an impediment to the coalescence of bubbles.