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, 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 m 2 /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 various free radicals (SO 4 · − , ·OH) were produced, with SO 4 · − playing the major role in the reaction. The theoretical calculations revealed that SO 4 · − attacked the 12 (N) of OII, thereby destroying and degrading both azo and hydrogenated azo structures 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 − .
ABSTRACT The activated cyanobacterial carbon (ACC) prepared from Chaohu Lake cyanobacteria was used as a carrier for nitrogen doping to synthesize nitrogen-doped activated cyanobacterial carbon (N@ACC), a highly efficient activation material. N@ACC was found to be an effective catalyst for the degradation of Orange II (OII) dye by activating peroxymonosulfate (PMS). Characterization of N@ACC showed that it had a larger specific surface area (159.12 m 1 /g) than ACC and an average particle size of 3.28 nm. N@ACC also contained various functional groups such as C=O, C=N, and –OH. To optimize the degradation of OII, the reaction conditions of the N@ACC activated PMS system were adjusted. The N@ACC activated PMS system was able to achieve a degradation rate of 98.8% for OII (100 mg/L) within 35 min, which was significantly higher than the rate achieved by the ACC activated PMS system (19.5%). The degradation reaction followed first-order kinetics and indicated a combined free radical mechanism. Compared to ACC, N@ACC contained a higher content of nitrogen, specifically pyridinic and graphitic nitrogen. The results showed that introducing nitrogen would refactor the structure of raw carbon, regulate its properties, and create new active sites for the degradation of pollutants. Moreover, N@ACC does not need metallic elements to improve PMS degradation efficiency. Therefore, the synthesis of N@ACC could be used as a new way to activate PMS.
In this paper, a novel SERS imprinted composite material was successfully synthesized with the aid of surface enhanced Raman scattering technology and molecular imprinting technology, which could be suitable for specific detection of organic dyes in the river. The UIO-66(NH 2 ) was wrapped with a thin layer of polydopamine (PDA), after loading Ag nanoparticles on rough surface, Ag@UIO-66(NH 2 )/PDA was synthesized and applied as the SERS substrate. In order to promote the ability of selective detection property in the practical sample, the molecularly imprinted polymer (Ag@UIO-66(NH 2 )/PDA-MIPs) was proposed. When the concentrations range changed between 10 −8 mol/L and 10 −10 mol/L, the intensity of characteristic peak at 1596 cm −1 exhibited a linear relationship with OII concentrations increasing. The limit of detection was low than 10 −10 mol/L, the correlation coefficient was 0.9985. The prepared SERS substrate could be available to the practical sample detection, which expanded SERS detection fields.
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