This study focuses on synthesizing a composite material of Ag/ZnO/BiOCl using Ag, ZnO, and BiOCl as raw materials. The material was prepared by loading Ag and BiOCl onto ZnO nanofilms, aiming to enhance the photocatalytic degradation of ciprofloxacin (CIP). Optimization of the photocatalytic degradation process through single-factor experiments revealed that under conditions of an initial CIP pH of 9, an Ag/ZnO/BiOCl dosage of 1 g/L, and an initial CIP concentration of 5 mg/L the conversion efficiency of CIP reached 98.79% after 150 min of exposure to a 250 W xenon lamp simulating sunlight. Furthermore, the composite material maintained a conversion efficiency of 86.17% for CIP even after five cycles of reuse, demonstrating its excellent stability. The optical properties, elemental composition, valence state, crystallinity, and morphology of the samples were analyzed using techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), UV–visible diffuse reflectance spectroscopy (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results indicate that the introduction of Ag expanded the light response range of ZnO, while the addition of BiOCl improved the separation efficiency of electron–hole pairs in the composite nanomaterial. The photocatalytic mechanism was further elucidated through radical scavenging experiments, confirming that ·OH and h⁺ are the main active species in the degradation process.

With the advancement of China’s agricultural modernization and scientific and technological progress, there has been a substantial increase in corn production, resulting in significant agricultural waste of materials such as corncobs. Conventional incineration methods fail to efficiently utilize the recyclable resources present in corncobs. In this investigation, corncob biochar film (CBC) was synthesized through the pyrolysis of corncob. Single-factor and orthogonal experiments were used to determine the conditions needed to prepare biochar film with the best Cr(VI) adsorption effect. The experiments showed that at a heating rate of 5 °C/min, pyrolysis temperature of 500 °C and pyrolysis time of 120 min, the Cr(VI) removal rate of prepared biochar film reached 73.55% and the adsorption capacity was 18.39 mg/g. Meanwhile, the factors affecting the removal of Cr(VI), including pH value, initial concentration of Cr(VI) solution, dosage of adsorbent, adsorption kinetics and isothermal adsorption, were analyzed in detail. The structures of CBC before and after Cr(VI) adsorption were analyzed by SEM, FTIR, XRD, XPS, and BET. These findings demonstrate the efficacy of corncob biochar film in Cr(VI) removal.

Biochar, a carbon-dense material known for its substantial specific surface area, remarkable porosity, diversity of functional groups, and cost-effective production, has garnered widespread acclaim as a premier adsorbent for the elimination of heavy metal ions and organic contaminants. Nevertheless, the application of powdered biochar is hindered by the challenges associated with its separation from aqueous solutions, and without appropriate management, it risks becoming hazardous waste. To facilitate its use as an immobilization medium, biochar necessitates modification. In this investigation, sodium alginate, celebrated for its superior gelation capabilities, was amalgamated with polyvinyl alcohol to bolster mechanical robustness, thereby embedding biochar to formulate sodium alginate biochar microspheres (PVA/SA-FMB). A meticulously designed response surface methodology experiment was employed to ascertain the optimal synthesis conditions for PVA/SA-FMB. Characterization outcomes unveiled a highly developed surface abundant in functional groups and confirmed the successful incorporation of iron ions. Adsorption trials revealed that at a temperature of 25 °C and a pH of 2, the adsorption capacity of PVA/SA-FMB for Cr(VI) was 13.7 mg/g within the initial 30 min, reaching an equilibrium capacity of 26.03 mg/g after 1440 min. Notably, the material sustained a Cr(VI) removal efficiency exceeding 90% across five cycles, underscoring its rapid and effective Cr(VI) eradication performance. Kinetic and isothermal adsorption analyses suggested that the adsorption of Cr(VI) adheres to a pseudo-second-order kinetic model and the Freundlich isotherm, indicative of monolayer adsorption dominated by reaction mechanisms. X-ray photoelectron spectroscopy (XPS) analysis inferred that the adsorption mechanism predominantly encompasses electrostatic attraction, redox processes, and complex formation.

In this study, an innovative Ag/ZnO/BC nanofilms composite material was synthesized by loading zinc oxide and silver on biochar nanofilms using a combination of hydrothermal and calcination methods using zinc oxide, silver and biochar as raw materials. Subsequent characterization analysis confirmed the successful synthesis of Ag/ZnO/BC nanofilms photocatalysts, and the Ag/ZnO nanocomposite particles were effectively loaded on the biochar nanofilms (BC). The composite exhibited robust photocatalytic removal under visible light irradiation under simulated wastewater conditions with an ammonia nitrogen concentration of 50 mg/L. The photocatalytic removal of ammonia and nitrogen pollutants in the composite was achieved by the use of Ag/ZnO nanoparticles. Specifically, the degradation of ammonia nitrogen pollutant reached a peak efficiency of 83.28%. Notably, the photocatalyst maintained over 80% degradation efficiency after four cycles, highlighting its sustained photocatalytic activity and stability. In conclusion, this study elucidated a feasible method to fabricate metal oxide–biochar thin-film composites with excellent adsorption and photocatalytic properties, thus providing a promising pathway for the remediation of organic wastewater, especially wastewater containing ammonia and nitrogen pollutants.

In this paper, reduced graphene oxide (RGO) was prepared by a modified Hummers method and chemical reduction method, and an RGO/TiO₂ NTs (RGO/TiO₂ nanotubes) photoelectrode was prepared by the electrochemical deposition method. The as-prepared RGO/TiO₂ NTs were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and their photocatalytic activities were investigated by measuring the degradation of methylene blue (MB) under simulated solar light irradiation. The SEM and XRD results indicated that the original tubular structure of TiO₂-NTs was not changed after RGO modification. The surface of the TiO₂ NTs photoelectrode was covered with a non-uniform, flake-shaped reduced graphene oxide film. The thickness of the RGO/TiO₂ NTs was increased to about 22.60 nm. The impedance of the RGO/TiO₂ NTs was smaller than that of the TiO₂ NT photoelectrode. The optimal preparation conditions of RGO/TiO₂ NT photoelectrodes were investigated by using a single factor method and response surface method. The best preparation conditions were as follows: deposition potential at 1.19 V, deposition time of 10.27 min, and deposition temperature at 24.94 °C.

In this study, g-C₃N₄/BiOI/tourmaline composites were synthesized by loading BiOI and tourmaline on g-C₃N₄ nanofilms using g-C₃N₄, BiOI, and tourmaline as raw materials, aiming to optimize the photocatalytic degradation of amaranth red dye wastewater (AR). Single-factor experiments were conducted to optimize the degradation process. The findings indicate that a degradation rate of 95.88% can be achieved for AR within 150 min of light exposure, given a g-C₃N₄/BiOI/tourmaline dosage of 1 g/L, an initial pH level of 3 for the AR, and an initial AR concentration of 10 mg/L. Upon repeating the experiment for five cycles, the composite exhibited 83.10% activity, demonstrating its stability. Various analytical techniques were employed for material characterization: X-ray diffractometry (XRD) to ascertain the crystalline structure, field-emission scanning electron microscopy (FESEM) to evaluate morphology, X-ray photoelectron spectroscopy (XPS) for elemental analysis, ultraviolet–visible diffuse reflectance spectroscopy (UV-vis DRS) for optical properties, and photoluminescence (PL) spectroscopy to analyze the recombination of excited electrons and holes. Free radical masking experiments further elucidated the photocatalytic mechanism, revealing that the primary active species in the degradation process is the superoxide anion (O₂⁻). This research offers a novel approach to address the limitations of n-type metal-free semiconductor photocatalysts.