Recycling of Waste Sludge: Preparation and Application of Sludge-Based Activated Carbon

With the rapidly increasing industrial and agricultural development, a large amount of sludge has been produced from much water treatment. Sludge treatment has become one of the most important environmental issues. Resource utilization of sludge is one of the important efficient methods for solving this issue. Sludge-based activated carbon (SBAC) materials have high adsorption performance and can effectively remove environmental pollutants including typical organic matter and heavy metals through physical and chemical processes. Therefore, developing efficient SBAC materials is important and valuable. At present, preparation, modification, and application of SBAC materials have gained widespread attention. This paper provides a review of the research on SBAC preparation and modification and its utilization in removing environmental pollutants. It included the following topics present in this review: conventional and new methods for preparation of SBAC were clearly present; the effective methods for improving SBAC performance via physical and chemical modification were reviewed; and the correlation of their physic-chemical properties of SBAC with pollutants' removal efficiencies as well as the removal mechanisms was revealed. 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 drawbacks to its research; thus, some suggestions for further research were given in this review.