Photocatalytic Poly(vinylidene fluoride) membrane of Ag3PO4/GO/APTES for water treatment

Preparation of thiourea derivative incorporated Ag3PO4 core shell for enhancement of photocatalytic degradation performance of organic dye under visible radiation light

Photocatalysis is a promising technique to reduce hazardous organic pollutants using semiconductors under visible light. However, previous studies have been concerned with the behavior of silver phosphate (Ag3PO4) as n-type semiconductors, and the problem of their instability is still under investigation. Herein, 4,4'-(((oxalylbis(azanediyl)) bis(carbonothioyl)) bis(azanediyl)) dibenzoic acid is synthesized by green method and used to enhance the photocatalytic behavior for Ag3PO4. The incorporated Ag3PO4 core-shell is prepared and characterized via XRD, FT-IR, Raman, TEM and BET. Besides, the thermal stability of the prepared core shell was investigated via TGA and DSC measurements. The optical properties and the energy band gap are determined using photoluminescence and DRS measurements. The photodegradation of methylene blue in the presence of the synthesized Ag3PO4 core-shell under visible light is examined using UV/Vis measurements. The effect of initial dye concentration and contact time are studied. In addition, the kinetic behavior of the selected dye during the photodegradation process shows a pseudo-first order reaction with rate constant of 0.015 min-1 for ZAg. The reusability of the Ag3PO4 core shell is evaluated, and the efficiency changed from 96.76 to 94.02% after three cycles, indicating efficient photocatalytic behavior with excellent stability.

Recent updates on remediation approaches of environmentally occurring pollutants using visible light-active nano-photocatalysts

Photocatalysis emerges as a potential remedy for the issue of an unreliable light source. Recognized as the most dependable and potent energy source sustaining life on Earth, sunlight offers a promising solution. Sunlight is abundant and free, operational costs associated with running photocatalytic system using nanoparticles are often lower compared to system relying on artificial light source. The escalating problem of water pollution, particularly in highly industrialized nations, necessitates effective wastewater treatment methods. These methods aim to combat elevated pollution levels, encompassing pharmaceuticals, dyes, flame retardants, and pesticide components. Advanced oxidation processes within photocatalytic wastewater treatment exhibit substantial promise for removing complex organic pollutants. Doped nanomaterials, with their enhanced properties, enable efficient utilization of light. Coupled nanomaterials present significant potential in addressing both water and energy challenges by proficiently eliminating persistent pollutants from environment. Photocatalysis when exposed to sunlight can absorb photons and generate e- h + pairs. This discussion briefly outlines the wastewater treatment facilitated by interconnected nanomaterials, emphasizing their role in water-energy nexus. In exploring the capabilities of components within a functional photocatalyst, a comprehensive analysis of both simple photocatalysts and integrated photocatalytic systems is undertaken. Review aims to provide detailed explanation of the impact of light source on photon generation and significance of solar light on reaction kinetics, considering various parameters such as catalyst dosage, pH, temperature, and types of oxidants. By shedding light on these aspects, this review seeks to enhance our understanding of intricate processes involved in photocatalysis and its potential applications in addressing contemporary environmental challenges.

Thermal separation of plastic components from waste crystalline silicon solar cells: Thermogravimetric characteristics and thermokinetics

Thermal treatment is a mainstream technique to separate plastic components from waste crystalline silicon (c-Si) photovoltaic (PV) modules. In this study, the thermogravimetric analysis (TGA) was conducted for a better understanding of the characteristics of plastic components mainly poly(ethylene-co-vinyl) acetate (EVA) binder and polyfluoroethylene composite membrane (TPT) backsheet in waste c-Si PV panels through thermal treatment at four different heating rates (5-20°C·min-1) under nitrogen and air conditions, respectively. The thermal process of the EVA binder whether in a nitrogen or air atmosphere could be divided into two phases, which were 300-400°C and 400-515°C in nitrogen with the total weight loss reached 99.64%; the two phases in the air were 270-405°C and 405-570°C with the total weight loss was 99.68%. The thermal weight loss of TPT in nitrogen has only one phase occured between 380°C and 520°C, and the weight loss rate is about 83%. There are two weight loss phases in the air atmosphere, which the first phase starts from 265°C to 485°C and the second phase ends at 635°C with a final weight loss reaching 97%. Furthermore, the Kissinger-Akahira-Sunose (KAS) method was chosen to calculate the pyrolysis kinetic parameters. The activation energy for EVA in nitrogen (261.16 kJ·mol-1) was higher than in air (209.04 kJ·mol-1), also the TPT in nitrogen (188.28 kJ·mol-1) higher than in air (172.21 kJ·mol-1). That indicated that the thermal decomposition of EVA binder was accelerated at first phase in nitrogen, but there is little difference in air atmosphere. Moreover, the activation energy of PVF of the TPT backsheet in the first phase was lower than that in the second phase. This study provides the fundamental basis to develop efficient thermal separation for the plastic components EVA and TPT in waste PV panels.Implications: This study mainly aims to explore the thermal separation of plastic components of waste c-Si panels for heating treatment, so that developing an accurate heat treatment approach that is efficient to implement for the separation of secondary raw material i.e., glass and silicon wafer from end-of-life PV panels. Therefore, this research findings have significant implications for providing the basic data support for waste PV panels management recycling standards, specifications, or policy documents.

Modified poly(vinylidene fluoride) nanomembranes for dye removal from water - A review

Water contamination due to soluble synthetic dyes has serious concerns. Membrane-based wastewater treatments are emerging as a preferred choice for removing dyes from water. Poly(vinylidene fluoride) (PVDF)-based nanomembranes have gained much popularity due to their favorable features. This review explores the application of PVDF-based nanomembranes in synthetic dye removal through various treatments. Different fabrication methods to obtain high performance PVDF-based nanomembranes were discussed under surface coating and blending methods. Studies related to use of PVDF-based nanomembranes in adsorption, filtration, catalysis (oxidant activation, ozonation, Fenton process and photocatalysis) and membrane distillation have been elaborately discussed. Nanomaterials including metal compounds, metals, (synthetic/bio)polymers, metal organic frameworks, carbon materials and their composites were incorporated in PVDF membrane to enhance its performance. The advantages and limitations of incorporating nanomaterials in PVDF-based membranes have been highlighted. The influence of nanomaterials on the surface features, mechanical strength, hydrophilicity, crystallinity and catalytic ability of PVDF membrane was discussed. The conclusion of this literature review was given along with future research.

Preparation and Characterization of Polyethersulfone-Ultrafiltration Membrane Blended with Terbium-Doped Cerium Magnesium Aluminate: Analysis of Fouling Behavior

In this study, various techniques, including X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS) mapping, X-ray photoelectron spectroscopy (XPS), and water-contact-angle goniometry (WCAG), were used to characterize the crystalline structure and morphological properties of terbium-doped cerium magnesium aluminate (Ce0.67Tb0.33MgAl11O19 or CMAT) in powder form. The results demonstrated that CMAT was successfully synthesized with a particle size of less than 5 µm and a fully evident distribution of elements, as revealed by the SEM images. This was further confirmed by the XRD and HRTEM images. XPS analysis confirmed the presence of all necessary components in CMAT. Additionally, WCAG results showed that the contact angle of CMAT was more hydrophilic with a value of 8.4°. To evaluate its performance, CMAT particles were dispersed in a Polyethersulfone (PES) solution and used to modify a PES ultrafiltration membrane through a phase-inversion method. The resulting membranes were characterized by SEM, atomic force microscopy (AFM), thermogravimetric analysis (TGA), WCAG, and permeability performance and fouling experiments. The addition of CMAT to the PES membranes did not have a significant effect on the structure of the SEM images of the top layer and cross-section of surface properties. However, increasing the concentration of CMAT improved the membrane surface roughness in AFM, and the modified membranes had the ability to resist fouling. The addition of CMAT did not lead to significant energy loss, indicating that the heat flux loss observed can indeed be explained by the amount of C-OH on the PES membrane’s surface. The contact angle of the membranes became more hydrophilic with increasing concentration of CMAT from PES G0 to PES G7. The PES origin membrane showed a higher permeation than the membranes mixed with CMAT, and the modified membranes with CMAT displayed significant fouling resistance.

Synthesis and Characterization of g-C3N4/Ag3PO4/TiO2/PVDF Membrane with Remarkable Self-Cleaning Properties for Rhodamine B Removal

g-C₃N₄/Ag₃PO₄/TiO₂ nanocomposite materials were loaded onto a polyvinylidene fluoride (PVDF) membrane using a phase inversion method to obtain a photocatalytic flat membrane for dye removal. The morphology, structure, and photocatalytic activity of the g-C₃N₄/Ag₃PO₄/TiO₂ nanoparticles and composite membrane were evaluated. The g-C₃N₄/Ag₃PO₄/TiO₂/PVDF membrane exhibited superior morphology, hydrophilic properties, and antifouling performance compared with the raw PVDF membrane. Four-stage filtration was performed to evaluate the self-cleaning and antifouling capacity of the g-C₃N₄/Ag₃PO₄/TiO₂/PVDF membrane. Upon irradiating the composite membrane with visible light for 30 min, its irreversible fouling resistance (Rir) was low (9%), and its flux recovery rate (FRR) was high (71.0%) after five filtration cycles. The removal rate of rhodamine B (RhB) from the composite membrane under visible light irradiation reached 98.1% owing to the high photocatalytic activity of the membrane, which was superior to that of raw PVDF membrane (42.5%). A mechanism of photocatalytic composite membranes for RhB degradation was proposed. Therefore, this study is expected to broaden prospects in the field of membrane filtration technology.

High-performance photocatalytic membranes for water purification in relation to environmental and operational parameters

Growing technologies, increasing population and environmental pollution lead to severe contamination of water and require advanced water treatment technologies. These aspects lead to the need to purify water with advanced smart materials. This paper reviews the recent advances (during the last 5 years) in photocatalytic composite membranes used for water treatment. For this purpose, the authors have reviewed the main materials used in the development of (photocatalytic membranes) PMs, environmental and operational factors affecting the performance of photocatalytic membranes, and the latest developments and applications of PMs in water purifications. The composite photocatalytic membranes show good performance in the removal and degradation of pollutants from water.

Inhibition of SARS-CoV-2 spike protein entry using biologically modified polyacrylonitrile nanofibers: in vitro study towards specific antiviral masks

With the increase in the contagiousness rates of Coronavirus disease (COVID-19), new strategies are needed to protect people and to halt the from the spread of viruses.

Adsorption and reduction of carcinogenic organics by ordered semi-crystalline poly-m-chloroaniline

Poly-m-chloroaniline has been synthesized by chemical oxidative polymerization of m-chloroaniline and confirmed by spectroscopic studies. Powder X-ray diffraction and FESEM studies confirmed ordered arrangement in poly-m-chloroaniline. The peak at lower angle such as 7.09° having d spacing of 12.53 Å shows ordered structure of PmClA which was further confirmed by layered morphology in the FESEM images. FTIR spectra confirm the stretching and vibration mode of polymeric m-chloroaniline ring. BET surface area and pore diameter of PmClA were found to be 121 m2/g and 15.184 nm. Poly-m-chloroaniline was found to have better adsorption capacity toward anionic dyes over cationic dyes. The anionic dye (IC and EY) was 98 and 99% removed in just 25 min, whereas the cationic dye (MG and Rh6G) was 87 and 83% removed in 30 min. Langmuir adsorption isotherm model and pseudo second-order kinetic equation fitted the data best. Mechanism of adsorption has also been proposed. This is suggested that polymeric materials can be used for purification of water. The reduction of aromatic nitro compounds to amino compounds using organocatalyst has been done for the first time.