Energy-Efficient CuO/TiO2@GCN Cellulose Acetate-Based Membrane for Concurrent Filtration and Photodegradation of Ketoprofen in Drinking and Groundwater

Photocatalytic membranes possessing both photocatalytic and solid-liquid separation capabilities were developed. These materials are based on ternary 1% CuO/TiO2@GCN (1:9) embedded on cellulose acetate (CA) via the phase inversion method. The CA membranes containing 0.1, 0.3 and 0.5 wt% of 1% CuO/TiO2@GCN (1:9) (CTG–100, CTG–300 and CTG–500) were fabricated. The deposition of 1% CuO/TiO2@GCN (1:9) onto the CA membranes and the consequential changes in the materials’ properties were investigated with various characterization techniques. For instance, PXRD, FTIR, and XPS analysis provided evidence that photocatalytic membranes were formed. Electron microscopy and EDX were then used to visualize the photocatalytic membranes and show that the photocatalyst (1% CuO/TiO2@GCN (1:9)) was well dispersed onto the CA membrane. On the other hand, the properties of the photocatalytic membranes were scrutinized, where it was found that the membranes had a sponge-like morphology and that was significantly less hydrophilic compared to neat CA. The removal of KP in water using CTG–500 exhibited over 94% efficiency, while 38% for neat CA was achieved. Water permeability flux improved with increasing 1% CuO/TiO2@GCN (1:9) and hydrophilicity of the membranes. The electrical energy consumption was calculated and determined to be significantly lower than that of the CA membrane. The CTG–500 membrane after every cycle showed self-cleaning ability after operation in drinking and groundwater.

The photoreduction of selenite and selenate on the surface of few layer black phosphorus and a UiO-66 p–n junction heterostructure

The synthesis and characterization of a type-II heterojunction consisting of UiO-66 and few-layer black phosphorus with superior selenium oxyanion photo-reduction efficiency.

Recovery of waste gold for the synthesis of gold nanoparticles supported on radially aligned nanorutile: the growth of carbon nanomaterials

Precious and expensive metals are lost each year through the discarding of old jewellery pieces and mine tailings. In this work, small amounts of gold were recovered by digestion with aqua regia from waste tailings. The recovered gold in the form of HAuCl₄ was then used to deposit Au⁰ onto radially aligned nanorutile (RANR) to form a supported catalyst material. The support material, RANR, was synthesized using the hydrothermal technique whereas the deposition of gold was achieved using the deposition–precipitation with urea method at various loadings. Electron microscopy was used to show that the structure of the support is a sphere formed by multiple nanorods aligned in a radial structure. The Au nanoparticles were observed at the tips of the nanorods. It was confirmed by XRD that the support was indeed a rutile phase of TiO₂ and that the Au nanoparticles had a face-centred cubic structure. The various catalysts were then used to synthesize carbon nanomaterials (CNMs) using the chemical vapour deposition technique. A parametric study varying the reaction temperature, duration and carbon source gas flow rate was conducted to study the effects these conditions have on the structural properties of the resulting CNMs. Here, it was found that mainly carbon nanofibers were formed and that the different reaction conditions influenced their graphicity, width, structure and thermal properties.

A hydrothermal method was used to prepare rutile TiO₂ dandelions. A deposition–precipitation method using urea (DPU) was used to load Au metal nanoparticles in calculated weight percentages and the Au/RANR catalysts where used to synthesise CNFs in a CVD reaction.

AgI loading BiOI composites with enhanced photodegradation efficiency for bisphenol A under simulated solar light

Bismuth oxyiodide (BiOI) is a narrow band gap semiconductor which can be driven by visible irradiation. In order to efficiently separate photo-generated carriers and utilization of visible light, a facile solvothermal approach was used to synthesize a novel AgI loading BiOI 3D hierarchical composite (AgI-BiOI). The AgI-BiOI with Ag and Bi molar ratio of 1:8 (AgI-BiOI (1-8)) showed great enhancement for photocatalytic degradation of bisphenol A (BPA) with pseudo-first degradation rate constant about 3.7 or 14.5 times than that of pristine BiOI or AgI under simulated solar light. This synergistic enhancement for BPA degradation on AgI-BiOI(1-8) is mainly ascribed to enhancing the light absorption intensity and accelerating photo-generated carriers separation due to the formation of AgI-BiOI heterojunction. Free radical quenching experiments proved that positive holes (h⁺) and superoxide (O₂^•-) radicals were dominantly responsible for the degradation of BPA rather than singlet oxygen (¹O₂) or hydroxyl radicals (•OH). The AgI-BiOI(1-8) hardly showed any ecotoxicity to C. elegans through lethal experiments. The luminance bacteria acute toxicity of degradation intermediates of BPA increased before 30 min then reduced significantly with reaction. The good durability and environmental-friendly characteristics make AgI-BiOI(1-8) catalyst to be a good solar light-driven candidate.

Recent Advances in Carbonaceous Photocatalysts with Enhanced Photocatalytic Performances: A Mini Review

Photocatalytic processes based on various semiconductors have been widely utilized in different applications, with great potential for use in environmental pollution remediation and sustainable energy generation. However, critical issues, including low light adsorption capability, wide energy bandgap, and unsatisfactory physicochemical stability still seriously limit the practical applications of photocatalysts. As a solution, the introduction of carbonaceous materials with different structures and properties into a photocatalyst system to further increase the activity has attracted much research attention. This mini review surveys the related literatures and highlights recent progress in the development of carbonaceous photocatalysts, which include various metal semiconductors with activated carbon, carbon dots, carbon nanotubes/nanofibers, graphene, fullerene, and carbon sponges/aerogels. Moreover, graphitic carbon nitride is also discussed as a carbon-rich and metal-free photocatalyst. The recently developed synthesis strategies and proposed mechanisms underlying the photocatalytic activity enhancement for different applications are summarized and discussed. Finally, ongoing challenges and the developmental direction for carbonaceous photocatalysts are proposed.

Synthesis and characterization of polyaniline, polypyrrole and zero-valent iron-based materials for the adsorptive and oxidative removal of bisphenol-A from aqueous solution

One pot synthesis of a polypyrrole, polyaniline and Fe0 nano-composite (Fe0-PPY/PANI) was achieved by polymerizing aniline and pyrrole with FeCl3 followed by the reduction of Fe3+ to Fe0 with NaBH4. PPY/PANI was synthesized the same way as Fe0-PPY/PANI, except that all the FeCl3 was removed by rinsing. The presence of Fe0 was demonstrated using several analytical techniques; this was shown in comparison to materials that are without Fe0. A series of materials were screened as both adsorbents and catalyst for the activation of H2O2 towards bisphenol A (BPA) removal in batch experiments. Polymers performed better than composites containing Fe0 at adsorption, whereas Fe0 based materials were better catalysts for the activation of H2O2. BPA samples were then spiked with other contaminants including sewage water to test the performance of the various adsorbents and Fenton catalysts. PPY/PANI was found to be a better adsorbent than the rest, whereas Fe0-PPY/PANI was the best Fenton catalyst. The adsorption kinetics of BPA onto PPY/PANI was studied; it was found that the process was governed by the pseudo-second-order kinetic model. The adsorption isotherms revealed that the amount of BPA taken up by PPY/PANI increased with increasing temperature and was governed by the Langmuir adsorption isotherm. The mechanism in which Fe0-PPY/PANI and H2O2 degraded BPA was studied, it was found that surface-bound hydroxyl radicals were responsible for the degradation of BPA. It was also shown that the degradation process included the formation of smaller compounds leading to the reduction of the total organic content by 57%.

Resin-gel incorporation of high concentrations of W6+ and Zn2+ into TiO2-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

Incorporating up to 30% of W⁶⁺ and/or Zn²⁺ into TiO₂-anatase influences the lattice structure of TiO₂ thus its photocatalytic efficiency.

An aspirated in-syringe device fixed with ionic liquid and β-cyclodextrin-functionalized CNTs/TiO2 for rapid adsorption and visible-light-induced photocatalytic activity

Dual-functional photocatalyst, IL–CD-CNTs/TiO₂, was fabricated through a facile one-pot solvothermal strategy coupled with an aspirated in-syringe device.

Synthesis of coaxial carbon@NiMoO4 composite nanofibers for supercapacitor electrodes

This work reports the synthesis of coaxial carbon@NiMoO₄ nanofibers for supercapacitor electrode applications. Thin NiMoO₄ nanosheets are uniformly coated on the conductive electrospun carbon nanofibers by a microwave assisted hydrothermal method to form a hierarchical structure, which increases the porosity as well as the conductivity of the electrode. The thickness of the NiMoO₄ can be easily adjusted by varying the precursor concentrations. The high specific surface area (over 280 m² g⁻¹) and conductive carbon nanofiber backbone increase the utilization of the active pseudocapacitive NiMoO₄ phase, resulting a high specific capacitance of 1840 F g⁻¹.

This work reports the synthesis of coaxial carbon@NiMoO₄ nanofibers for supercapacitor electrode applications.