Norfloxacin (NOF) is an environmentally harmful and ubiquitous aquatic pollutant with extensive production and application. In this study, a novel composition named carbon-based composite photocatalytic material of zinc oxide and zinc sulphide (ZnO/ZnS@BC) was successfully obtained by the impregnation-roasting method to remove NOF under UV-light. Scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive spectrometer characterised the composition. ZnO/ZnS was successfully decorated on the surface of biochar (BC). The pH, the ZnSO 4 /PS ratio, and ions and quenchers, were investigated. High removal efficiency was obtained with a pH of 7 and a ZnSO 4 /PS ratio of 1:1, and the removal ratio of NOF reached 95% within three hours; the adsorption and degradation ratios reached 46% and 49%, respectively. Fe 2+ promoted the degradation of NOF, whereas other ions inhibited it, with NO 3 − showing the strongest inhibitory effect. Three reactive species (tert-butanol, quinone, and ammonium oxala) were identified in the catalytic system. The decreasing order of the contribution of each reactive species was: O 2 − > ·OH − > h + . Additionally, a recycling experiment demonstrated the stability of the catalyst; the catalytic degradation ratio of NOF reached 78% after five successive runs. Therefore, ZnO/ZnS@BC possessed strong adsorption capacity and high ultraviolet photocatalysis ability.

In the present work, a series of magnetically separable Fe 3 O 4 /g-C 3 N 4 /MoO 3 nanocomposite catalysts were prepared. The as-prepared catalysts were characterized by XRD, EDX, TEM, FT-IR, UV-Vis DRS, TGA, PL, BET and VSM. The photocatalytic activity of photocatalytic materials was evaluated by catalytic degradation of tetracycline solution under visible light irradiation. Furthermore, the influences of weight percent of MoO 3 and scavengers of the reactive species on the degradation activity were investigated. The results showed that the Fe 3 O 4 /g-C 3 N 4 /MoO 3 (30%) nanocomposites exhibited highest removal ability for TC, 94% TC was removed during the treatment. Photocatalytic activity of Fe 3 O 4 /g-C 3 N 4 /MoO 3 (30%) was about 6.9, 5, and 19.9-fold higher than those of the MoO 3 , g-C 3 N 4 , and Fe 3 O 4 /g-C 3 N 4 samples, respectively. The excellent photocatalytic performance was mainly attributed to the Z-scheme structure formed between MoO 3 and g-C 3 N 4 , which enhanced the efficient separation of the electron-hole and sufficient utilization charge carriers for generating active radials. The highly improved activity was also partially beneficial from the increase in adsorption of the photocatalysts in visible range due to the combinaion of Fe 3 O 4. Superoxide ions (�O 2 −) was the primary reactive species for the photocatalytic degradation of TC, as degradation rate were decreased to 6% in solution containing benzoquinone (BQ). Data indicate that the novel Fe 3 O 4 /g-C 3 N 4 /MoO 3 was favorable for the degradation of high concentrations of tetracycline in water.

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