Preparation of straw activated carbon and its application in wastewater treatment: A review

Plant straw resources are rich, and the annual yield of crop straw is large. To reduce environmental pollution caused by the burning of plant straw and realize maximum resource utilization of straw, the published literature data are analyzed in depth. It was found that the carbon element content in the straw was about 40% and the ash content was low. The straw activated carbon can meet the adsorption standard requirements of wooden activated carbon, which was a good material for the sustainable utilization of activated carbon. The activated carbons prepared from cotton straw and hemp straw have large specific surface area, and the total pore volumes of activated carbon from sunflower straw and hemp straw are obviously higher than that of other straw activated carbon. In order to improve the quality of activated carbon, the effects of various activators are better than that of single activator in the preparation of straw activated carbon. The study found that when the ratio of the initial concentration of pollutants to the adsorbent concentration is 30, the removal efficiencies of heavy metals (Cu(II), Cr(VI) and Fe(III)) aren’t less than 90%. This review will be of great significance to optimize the preparation conditions of straw activated carbon, improve the quality of straw activated carbon and expand the application range of straw activated carbon.