Facile One-Pot In Situ Synthesis and Characterization of a Cu2O/Cu2(PO4)(OH) Binary Heterojunction Nanocomposite for the Efficient Photocatalytic Degradation of Ciprofloxacin from Aqueous Solution under Direct Sunlight Irradiation

Sunlight-driven photocatalytic degradation of ciprofloxacin and organic dyes by biosynthesized rGO-ZrO2 nanocomposites

Aquatic ecology has been greatly threatened by the discharge of effluents of textile and antibiotic industries into natural waters. Herein, an efficient and easily recycled reduced graphene oxide/zirconium oxide nanocomposite has been synthesized using banana peel extract (abbreviated as rGO-ZrO₂ in this work). The X-ray diffraction (XRD), field emission scanning electronic microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy were used to analyze the synthesized material. The as-prepared rGO-ZrO₂ nanocomposite was employed as a photocatalyst for the decomposition of rhodamine blue (RhB) and crystal violet (CV) dyes, and ciprofloxacin (CIP) antibiotic by illumination with direct sunlight. The RhB and CV were degraded to maximum extent of around 86 and 90%, respectively, over the rGO-ZrO₂ nanocomposite after exposure to direct sunlight for 120 min. On the other hand, the degradation of CIP was approximately 93.1% over the rGO-ZrO₂ nanocomposite in 240 min under same experimental conditions. Further studies were performed regarding the role of parameters like pH, catalyst dose, and scavengers, in order to understand the superiority of rGO-ZrO₂ nanocomposite in degrading organic pollutants. Moreover, the intermediate products and plausible CIP degradation mechanisms were examined using liquid chromatography-mass spectrometry (LC-MS). Moreover, the catalyst was easily separated from the solution and demonstrated good stability and reusability. The RhB, CV, and CIP removal efficiency were 80%, 83%, and 88%, respectively, after five cycles.

Multifunctional nanofibrous membranes with sunlight-driven self-cleaning performance for complex oily wastewater remediation

Developing multifunctional, efficient and durable membrane for long-term usage for treating complex oily wastewater is highly desirable but still a challenge due to the severe membrane fouling. Herein, a hierarchical structured superhydrophilic/underwater superoleophobic nanofibrous with antifouling and visible-light-induced self-cleaning performance was manufactured by a facile combination of electrospun silver/β-cyclodextrin/polyacrylonitrile (Ag/β-CD/PAN) nanofibers and then the in-situ growth of a zinc oxide (ZnO) layer. The formed micro/nano sized hierarchical structure greatly increased the roughness and improved the underwater superoleophobic ability of the membrane. Therefore, the resultant ZnO/Ag/β-CD/PAN membrane displays splendid separation performance for oil/dye/water complex emulsions and high flux recovery (>90%). Meanwhile, the permeation flux of a variety of oil/water emulsions was higher than 619 L m^-2h^-1 with a separation efficiency above 99.7% under the action of gravity. Furthermore, the as-fabricated membrane exhibits excellent stability towards different harsh conditions (e. g. corrosive solution, high temperature, UV irradiation and ultrasound washing). The robust mechanical and chemical stability, outstanding separation capabilities as well as excellent flux recovery capabilities makes the self-cleaning membrane a good candidate for the remediation of complex oily wastewater.

Magnetic, thermally stable, and superhydrophobic polyurethane sponge: A high efficient adsorbent for separation of the marine oil spill pollution

Herein, we demonstrated a facile method for the fabrication of magnetic and superhydrophobic polyurethane sponge with water contact angle of 159° as an adsorbent for cleanup the marine oil spill pollution. For this aim, a polyurethane sponge was coated with carbon black (CB), hexagonal boron nitride (h-BN)@Fe₃O₄, and acrylic resin and then characterized by different techniques. Owing to the chemical and thermal stability of h-BN and CB, the modified sponge was stable under corrosive conditions (pH = 1-14 and salt solutions) and at different temperatures (-12 °C-105 °C). In addition to common oils and organic solvents, we also used the real spilled oils containing monoaromatics and polyaromatics in the water surfaces of the Persian Gulf for investigation of adsorption efficiency of sponge in a real condition. The oil adsorption capacity of this sponge was in the range of 64-176 g g^-1. Also, this adsorbent can separate high amount of oil or organic solvents up to 66,400 times of its own weight from the oil-water mixture in a continuous separation. The results confirm that modified sponge can be used more than 20 times for oil spill cleanup without considerable reduction of its adsorption capacity. Consequently, the modified sponge is a promising candidate material for use in a real oil-water separation process.