The water crisis is one of the biggest challengesin the 21st century. With the development of economy, nitrogen and phosphorus and other nutrients discharged into the water, causing water eutrophication, which leading to abnormal algal breeding and deterioration of water quality. At the same time, 40% of countries and regions in the world are facing water shortages now. Thesustainability of water resources is imminent. Therefore, to develop an efficient, low-cost water purification technology is the key to solve the current water crisis.