Synergetic effect of photocatalytic oxidation plus catalytic oxidation on the performance of coconut shell fiber biochar decorated α-MnO2 under visible light towards BPA degradation

Renewable Magnetic NH2-MIL-101(Fe) for the Efficient Removal of Bisphenol A from Aqueous Solutions

Bisphenol A (BPA) is extensively utilized as an industrial chemical in the production of certain plastics and epoxy resins. They are frequently found in environmental water and have the potential to cause risks to both the environment and human health. To efficiently remove the endocrine disruptor BPA from aqueous solutions, sea urchin-like magnetic material Fe3O4@PDA@NH2-MIL-101 (Fe) was synthesized via hydrothermal methods. Fe3O4@PDA@NH2-MIL-101 (Fe) has excellent adsorption performance, with a theoretical maximum adsorption capacity of 300.47 mg/g for BPA. The adsorption kinetics of BPA by Fe3O4@PDA@NH2-MIL-101 (Fe) followed the pseudo-second-order kinetic model and Liu's isotherm model. Magnetic separation experiments reveal a high recovery efficiency, maintaining 94.82% of its initial adsorption capacity after five cycles. The primary adsorption mechanisms of Fe3O4@PDA@NH2-MIL-101 (Fe) on BPA included pore filling, hydrogen bonding, π-π interaction, and Lewis acid-base interaction. Additionally, the material showed excellent removal performance of BPA, with a maximum adsorbed amount of 135.27 mg/g for total organic carbon (TOC) in the shale gas fracturing flowback fluid. These findings suggest that Fe3O4@PDA@NH2-MIL-101 (Fe) holds significant potential as an adsorbent for BPA removal from actual wastewater, offering promising prospects for practical applications.

Bi2O2CO3/Bi2O2+xS1-x S-scheme n-n heterojunction with boosted photocatalytic degradation for bisphenol A

Bisphenol A (BPA) is considered to be a typical endocrine-disrupting compounds (EDCs), and its widespread existence in nature is quite harmful to human and ecological environment. The S-scheme n-n heterojunction composite (Bi2O2CO3/Bi2O2+xS1-x) was constructed via a facile two-step chemical precipitation method for the removal of BPA in water environment. The optimal composite catalyst exhibited outstanding catalytic activity for BPA, obtaining approximately 0.00724 min-1 degradation rate constant which was 6.77 and 3.37 times that of the pristine BOC (Bi2O2CO3) and BOS (Bi2O2+xS1-x), respectively. UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), valence band X-ray photoelectron spectroscopy (VB XPS), and Mott-Schottky (M-S) plots were used to analyze the band position of the catalysts, and it was found that the two semiconductors were n-type semiconductors and formed S-scheme heterojunction. Through radical trapping strategies and electron spin resonance (ESR) analysis, the results showed that the hole and superoxide radicals took a major part in the removal of BPA. According to the products detected through high performance liquid chromatography-mass spectrometer (HPLC-MS), two reaction pathways of BPA degradation were deduced.

Design of double Z-scheme Ag-Ag3O4/CuO-CuFe2O4 magnetic nanophotocatalyst via starch-templated microwave-combustion hybrid precipitation method and modified with corona-plasma: Remediation of dye contaminants

Herein, the novel double Z-scheme Ag-Ag3O4/CuO-CuFe2O4 magnetic nanophotocatalyst with nanosphere-on-nanosheet-like morphology was synthesized via the corona-plasma-assisted starch-templated microwave-combustion-precipitation method to remove the dye pollutants. The CuO-CuFe2O4 meso/macroporous nanophotocatalyst was synthesized using a one-pot-stage combustion-microwave process with/without starch as a hard-template. Subsequently, surface modification was carried out by DC corona-plasma discharge technology at various voltages, namely 500, 1000 and 1500 V. Then, the Ag3O4 photocatalyst was deposited on the CuO-CuFe2O4 fabricated with starch-hard-template and treated with 1000 V corona-plasma (denoted as: Ag-Ag3O4/CuO-CuFe2O4 (Starch) 1000 P). The properties of the synthesized nanophotocatalysts were analyzed using various techniques, including X-ray diffraction (XRD), Diffuse reflectance spectroscopy (DRS), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller and Barrett-Joyner-Halenda (BET-BJH), Vibrating Sample Manetometer (VSM), and Photoluminescence (PL). The XRD analysis corroborated the presence of CuO, CuFe2O4 and Ag3O4 in the structure of all samples. The BET-BJH analysis indicates that the specific surface area of the Ag-Ag3O4/CuO-CuFe2O4 (Starch) 1000 P nanophotocatalyst as the best sample is 2 m2/g, higher than other samples. Additionally, the DRS analysis revealed that the band gap of the Ag-Ag3O4/CuO-CuFe2O4 (Starch) 1000 P nanophotocatalyst is about 1.68 eV with the surface plasmon resonance. The performance of the ternary heterostructured Ag-Ag3O4/CuO-CuFe2O4 (Starch) 1000 P nanophotocatalyst was 96.2% and 89.1% in the degradation of the crystal violet (10 mg/L) and acid orange 7 (10 mg/L), respectively, proving its outstanding degradation capacity.

Amino-grafted Biochar as a Novel Photocatalyst for degradation of high concentration dye

Photocatalytic degradation of organic pollution by biochar was a sustainable strategy for waste water remediation, nevertheless, it still suffers drawbacks like low efficiency due to the poor photocatalytic properties of pristine biochar. Herein, amino groups were grafted on the edge sites/defects of biochar by Friedel-Crafts acylation to enhance the degradation of high concentration dye solutions. The results suggested that the amino groups played an important role in imparting photocatalytic properties to biochar. Owing to the strong Lewis basicity and electron-donating ability of amino groups, their interaction with oxygen-containing functional groups/aromatic structures in biochar was improved, which enhanced the electron exchange ability of biochar under visible light irradiation, resulting in excellent degradation performances of high concentration RhB (∼10 times faster than ungrafted biochar). In this work, amino-grafted garlic peel biochar delivered a new idea for the future direction of biochar-based photocatalysis in wastewater remediation.