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Carbon induced non-radical based peroxymonosulfate (PMS) activation has exhibited several advantages over radical process for eliminating organic pollutants in complicated water matrices. However, the relationship between configuration and composition of carbon and non-radical mechanism, which is important for designing high-efficiency carbon catalysts, remains elusive. In this work, the nitrogen doped carbon spheres (NCSs) with superior PMS activation ability were prepared from low-cost chitosan via two-step hydrothermal carbonization-pyrolysis method for organic pollutants removal. The carbon structure and nitrogen species of NCSs were tuned via changing hydrothermal temperature to explore their correlation with their PMS catalytic mechanism. Results showed hydrothermal carbonization boosted the content of pyridinic N, graphitic N and sp

Microbially induced phosphate precipitation (MIPP) is an advanced bioremediation technology to immobilize heavy metals in soil. In this study, an indigenous bacterial strain LRP3, identified as Rahnella sp., was isolated from Cu-contaminated dark brown soil in the mining area. Strain LRP3 could produce phytase and alkaline phosphatase to degrade phytic acid, which released soluble phosphate to the bacterial culture. Due to the metabolism of bacterial growth, the pH value of bacterial culture was increased. The minimum inhibitory concentration of Cu (II) to bacterial growth in solution was up to 130 mg/L. The bacterial culture could rapidly precipitate Cu (II) in solution through MIPP. The analysis results of Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transform-Infrared Spectrometer (FTIR), and X-ray Diffraction (XRD) revealed that the precipitate form by bacterial culture was rod-shaped Cu3(OH)3PO4 crystal with a diameter of 10 μm. The bacterial culture decreased the content of DTPA-Cu of 83 mg/kg soil in the soil by 58.2%, 61.5% and 75.8% after 5, 10 and 30 days of incubation, respectively, at the temperature of 25 °C. The results indicate that MIPP-based bioremediation by Rahnella sp. LRP3 is a practical, environmental friendly technology for the cleaning-up of copper-contaminated soil.

Hydrothermal carbonation carbon (HTCC) is emerging as a promising alternative for photocatalytic removal of contaminants from water. However, the catalytic activity of HTCC is limited by its poor charge transfer ability, and its photocatalytic mechanism remains unclear. Herein, a unique photosensitization-like mechanism was firstly found on Fe modified HTCC (Fe-HTCC) derived from glucose for effective removal of organic pollutants. Under visible light illumination, the organic pollutant coordinated with Fe-HTCC enabled electrons transfer from its highest occupied molecular orbital (HOMO) to conduction band (CB) of Fe-HTCC, which not only oxidized pollutant itself, but also generated oxygen-centered radical for reducing O2 into O2•- towards pollutant removal. The degradation kinetic constant of sulfamethoxazole (SMX) over Fe-HTCC was about 1024.4 and 20.5 times higher than that of HTCC and g-C3N4, respectively. The enhanced performance of Fe-HTCC was originated from dual role of Fe modification: one is to boost the electron-deficient C sites which prefer to coordinate with amino or hydroxyl of pollutants; the other is to enhance the linkage of discrete polyfuran chains in Fe-HTCC for effective electron transfer from pollutant to Fe-HTCC. This work provides new insight into the synthesis and mechanism of HTCC-based high-efficiency photocatalyst for water decontamination.

The silicon-doped BiVO(4) film was fabricated by modified metalorganic decomposition (MOD) method. XRD analysis indicated that the crystal size of the BiVO(4) film was decreased from 32.4nm to 23.9nm by doping Si. The measurements of FT-IR spectra and the water contact angle showed that doping Si could elevate the surface hydrophilicity of the BiVO(4) film. The phenol elimination rate on the Si-doped BiVO(4) film electrode in the photoelectrocatalytic process was 1.84 times as great as that on the BiVO(4) film electrode. The enhanced photoelectrocatalytic performance was attributed to the decrease of the crystalline size and the enhancement of the hydrophilic performance.

Ag particles were doped on BiVO 4 film by photoreduction technique. XRD analysis indicated that the chemical state of the Ag particles was metallic Ag. TEM observation confirmed that the sizes of the Ag particles were 10–20 nm. The investigation of the phenol degradation demonstrated that the photocatalytic (PC) degradation rate of the phenol on the Ag doped BiVO 4 film was enhanced by 1.61 times in PC process and by 42.7 times in photoelectrocatalytic (PEC) process compared with that of the BiVO 4 film. The transportation of the electrons from the BiVO 4 to Ag driven by the schottky barrier formed between Ag and BiVO 4 can increase the charge carrier separation, and consequently enhance the PC performance. The enhancement of the PC ability in PEC process could be attributed to the simultaneous movements of the photogenerated electrons to external circuit and the photogenerated holes to the Ag particles deposited on the BiVO 4 film. In 4 h, the elimination efficiency and the TOC removal efficiency of phenol on the Ag doped BiVO 4 film in PEC process were 94.1% and 61.0%, respectively.