用光催化 meaning in English

photoactivation

Much research work on environment improvement has been done
人们在用光催化治理环境方面做了很多研究。
The main reasons were no oxygen in methane , the high speed of the gas in use and the small pressure difference
实验结果表明，用光催化方法对户用沼气中h _ 2s气体的消除是不实际的。
It was still a technical problem on how to add the air to the reactor in so small pressure difference . in addition , the photocatalytic reaction efficiency was very low at the high speed . the reactor will be large , the price will be very high and the electricity will be enormously consumed during the photocatalytic - oxidation of h2s in the methane
主要原因是沼气中不含氧，使用时气体流速大，压差小，而用光催化氧化方法消除h _ 2s需要有相当量的氧参与，在压差很小的情况下，一次空气的加入存在技术困难；在高气体流速条件下，光催化效率低，若用光催化方法消除h _ 2s ，反应设备庞大，耗电量高，价格昂贵，农民难以负担。