The multiple chemical modifications were carried out to achieve N-doping and pore-making to modify sludge-based activated carbon (SACU–PF′). SACU–PF′ possessed abundant functional groups and high adsorption capacity of Cd2+.

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Based on the characteristics of persulfate (PS) activation that can quickly and effectively remove organic pollutants in water, a new catalytic material of carbon nitride supported Fe-Co diatom (FeCo@N-C) was prepared for PS activation to degrade orange II (OII). The XRD pattern showed that eight characteristic diffraction peaks, including CoFe2O4 diffraction absorption peaks. The FT-IR inferred that C-N/C=N, C=O, and O-H functional groups may exist. SEM observed the surface morphology of the synthetic material, and Fe and Co can be successfully loaded on the synthetic material. The activation effect of FeCo@N-C activator on PS was significantly improved, and the decoloration removal rate reached 81.66% at 20 min, 57% higher than the PS alone, FeCo@N-C activator had a good pH and temperature adaptability. FeCo@N-C activator could promoted the production of free radicals which can degrade OII efficiently.

Sludge activated carbon (SAChdc) was prepared by high dehydration & carbonization equipment and used for adsorption phosphorus in wastewater. The sludge can be dehydrated until water content below 60%, then carbonized by the high dehydration & carbonization equipment. The SAChdc used as absorbent in phosphorus of wastewater treatment. The experimental results showed that the adsorption capacity of phosphorus could reach 4.598 mg/g, and adsorption rate was above 91%, the pseudo-second-order kinetic equation and Freundlich isotherm model could describe the phosphorus adsorption process of SAChdc. SAChdc prepared and used as absorbent realized the sludge harmless and resource utilization.

In the present study, the cyanobacterial char (ACC) prepared from Chaohu cyanobacteria was used as a nanoscale carrier for zero-valent iron (NZVI) to synthesize a highly efficient activation material designated as cyanobacterial char-supported nanoscale zero-valent iron (NZVI@ACC), which was subsequently used for activating peroxymonosulfate (PMS) to degrade the orange II (OII) dye. The XRD and XPS results revealed that NZVI was anchored onto the ACC through coordination bonding, thereby forming a stable structure. The SEM and TEM observations revealed that the NZVI was embedded in the sheet structure of the ACC. The NZVI@ACC had a larger specific surface area (42.249 m2/g), and also magnetism, due to which its components could be separated through an externally applied magnetic field. Using this NZVI@ACC/PMS system, the rate of degradation of OII (100 mg/L) reached 98.32% within 14 min. The OII degradation reaction using the NZVI@ACC/PMS system followed first-order kinetics. The activation energy of this degradation reaction was 17.34 kJ/(mol·K). Quenching and EPR experiments revealed that both SO4·– and ·OH were produced in this reaction, with SO4·- playing the major role in the reaction. The theoretical calculations revealed that SO4·- attacked the 12 (N) of OII, which destroyed and degraded the structure of OII. The presence of halogen ions in the actual dye-containing wastewater samples inhibited the OII degradation by the NZVI@ACC system to different degrees, and the inhibition effect followed the order: I- > Br- > Cl-.