Recycling of waste sludge: preparation and application of a sludge based activated carbon

With the rapidly increasing industrial and agricultural development, a large amount of sludge is continually produced from extensive water treatment. Sludge treatment is now an important environmental issues. Utilization of sludge as a primary resource is an efficient method to address this issue. Sludge based activated carbon (SBAC) materials have high adsorption performance and can effectively remove environmental pollutants including typical organic pollutants and heavy metals through physical and chemical processes. Therefore, developing efficient SBAC materials is important and valuable. The preparation, modification and application of SBAC materials has gained widespread attention. This paper provides a review of the research on SBAC preparation and modification, and its utilization in the removal of environmental pollutants. We include an evaluation of the following: conventional and new methods for the preparation of SBAC; effective methods to for improve SBAC performance via physical and chemical modification; the correlation of their physico-chemical properties of SBAC with pollutant removal efficiency as well as the detail of removal mechanisms. SBAC has a better adsorption performance than commercial activated carbon in some aspects. Furthermore, it is a cost-effective technique and has a wide range of raw materials. However, there are still some limitations in the research to date, and suggestions for further research are highlighted.