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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.

Total dissolved nitrogen (TDN), including dissolved inorganic nitrogen (DIN) and dissolved organic nitrogen (DON), plays an important role in numerous environmental processes, such as nutrient cycling and lake and estuary eutrophication. The impact of DIN on environmental processes has been extensively studied. However, the understanding on DON in the environment is largely unknown, as there is no direct method for DON measurement. In practice, DON was determined by subtracting DIN from TDN. Large measurement errors could be induced when DIN becomes dominant in sample. This study was to investigate the impact of two pretreatments of dialysis, dialysis against Millipore water and dialysis against phosphate buffer (4.7 mM H3PO4-5.3 mM KH2PO4, pH 2.2) using a cellulose ester (CE) membrane (100–500 Da molecular weight cutoff), on DON measurement in a broad DIN range from various aquatic ecosystems. Results showed that the removal of NH4-N and NO3-N by both dialysis approaches was highly effective (>80%), but the DON loss by the former was significantly lower than by the latter. This study demonstrated that dialysis against Millipore water with the membrane would be more effective as a sample pretreatment for DIN removal, leading to a reliable and accurate DON measurement.