Chitosan-modified biochar: Preparation, modifications, mechanisms and applications

The chitosan-modified biochar composite, as a carbohydrate polymer, has received increasing attention and becomes a research hotspot. It is a promising impurity adsorption material, which has potential application value in the agricultural environment fields such as soil improvement and sewage purification. The composite can combine the advantages of biochar with chitosan, and the resulting composite usually exhibits a great improvement in its surface functional groups, adsorption sites, stability, and adsorption properties. In addition, compared to other adsorbents, the composite truly achieves the concept of waste control by waste. In this paper, the preparation method, composite classification, adsorption mechanism, and models of biochar modified by chitosan are introduced, meanwhile, we also review and summarize their effects on the decontamination of wastewater and soil. In addition to common heavy metal ions, we also review the adsorption and removal of some other organic/inorganic pollutants, including (1) drug residues; (2) dyes; (3) phosphates; (4) radionuclides; (5) perfluorochemicals, etc. Moreover, challenges and prospects for the composite are presented and further studies are called for the chitosan-biochar composite. We believe that the composite will lead to further achievements in the field of environmental remediation.

Automated summary

The chitosan-modified biochar composite has attracted increasing attention as a promising impurity adsorption material in the agricultural environment. This composite combines the advantages of biochar and chitosan, exhibiting improved surface functional groups, adsorption sites, stability, and adsorption properties. It has shown potential for decontamination of wastewater and soil from various pollutants including heavy metal ions, drug residues, dyes, phosphates, radionuclides, and perfluorochemicals. Further studies and exploration are needed for the chitosan-biochar composite.