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Removing wastewater pollutants using semiconducting-based heterogeneous photocatalysis is an advantageous technique because it provides strong redox power charge carriers under sunlight irradiation. In this study, we synthesized a composite of reduced graphene oxide (rGO) and zinc oxide nanorods (ZnO) called rGO@ZnO. We established the formation of type II heterojunction composites by employing various physicochemical characterization techniques. To evaluate the photocatalytic performance of the synthesized rGO@ZnO composite, we tested it for reducing a common wastewater pollutant, para-nitro phenol (PNP), to para-amino phenol (PAP) under both ultraviolet (UV) and visible light irradiances. The rGO x @ZnO (x = 0.5–7 wt%) samples, comprising various weights of rGO, were investigated as potential photocatalysts for the reduction of PNP to PAP under visible light irradiation. Among the samples, rGO 5 @ZnO exhibited remarkable photocatalytic activity, achieving a PNP reduction efficiency of approximately 98% within a short duration of four minutes. These results demonstrate an effective strategy and provide fundamental insights into removing high-value-added organic water pollutants.

Fully exploiting the properties of graphene will require a method for the mass production of this remarkable material. Two main routes are possible: large-scale growth or large-scale exfoliation. Here, we demonstrate graphene dispersions with concentrations up to ∼0.01 mg ml −1 , produced by dispersion and exfoliation of graphite in organic solvents such as N-methyl-pyrrolidone. This is possible because the energy required to exfoliate graphene is balanced by the solvent–graphene interaction for solvents whose surface energies match that of graphene. We confirm the presence of individual graphene sheets by Raman spectroscopy, transmission electron microscopy and electron diffraction. Our method results in a monolayer yield of ∼1 wt%, which could potentially be improved to 7–12 wt% with further processing. The absence of defects or oxides is confirmed by X-ray photoelectron, infrared and Raman spectroscopies. We are able to produce semi-transparent conducting films and conducting composites. Solution processing of graphene opens up a range of potential large-area applications, from device and sensor fabrication to liquid-phase chemistry. Fully exploiting the properties of graphene will require a method for the mass production of this remarkable material. The dispersion and exfoliation of graphite in organic solvents can produce graphene monolayers with a yield of about 1% by weight. Moreover, these samples are free from defects and oxides, and can be used to produce semi-transparent conducting films and conducting composites.

Self-cleaning surfaces revolutionizing the technology world due to their novel property of cleaning themselves, and its multi-functional self-cleaning surfaces exhibit at least one or more functional properties (transparent, conducting, anti-bacterial, anti-corrosion, etc.) This review article focuses on the fundamentals of wettability, material parameters controlling surface wettability and three different paths to realization of self-cleaning surfaces, i.e., (i) super-hydrophobic, (ii) super-hydrophilic and (iii) photocatalytic. The subsequent part of the article mostly focuses on the super-hydrophobic path towards realizing self-cleaning surfaces. In the super-hydrophobic path, the objective is to make the surface extremely repellent to water so that water droplets slide and ‘roll off’ from the surface. The next section of the review article focuses on the role of additive manufacturing in the fabrication of super-hydrophobic micro-structures. Amidst the different fabrication processes of self-cleaning surfaces, additive manufacturing stays ahead as it has the manufacturing capacity to create complex micro-structures in a scalable and cost-effective manner. A few prominent types of additive manufacturing processes were strategically chosen which are based on powder bed fusion, vat photopolymerization, material extrusion and material jetting techniques. All these additive manufacturing techniques have been extensively reviewed, and the relative advantages and challenges faced by each during the scalable and affordable fabrication of super-hydrophobic self-cleaning surfaces have been discussed. The article concludes with the latest developments in this field of research and future potential. These surfaces are key to answer sustainable development goals in manufacturing industries. Graphical abstract

This paper presents an innovative approach to addressing critical global challenges in long-term energy planning for low- and middle-income countries (LMICs). The paper proposes and tests an international enabling environment, a delivery ecosystem, and a community of practice. These components are integrated into workflows that yield four self-sustaining capacity-development outcomes. Planning long-term energy strategies in LMICs is particularly challenging due to limited national agency and poor international coordination. While outsourcing energy planning to foreign experts may appear to be a viable solution, it can lead to a reduction in government agency (the ability of a government to make its own informed analysis and decisions). Additionally, studies commissioned by external experts may have conflicting terms of reference, and a lack of familiarity with local conditions can result in misrepresentations of on-the-ground realities. It is argued here that enhancing national agency and analytical capacity can improve coordination and lead to more robust planning across line ministries and technical assistance (TA) providers. Moreover, the prevailing consulting model hampers the release and accessibility of underlying analytics, making it difficult to retrieve, reuse, and reconstruct consultant outputs. The absence of interoperability among outputs from various consultants hinders the ability to combine and audit the insights they provide. To overcome these challenges, five strategic principles for energy planning in LMICs have been introduced and developed in collaboration with 21 international and research organizations, including the AfDB, IEA, IRENA, IAEA, UNDP, UNECA, the World Bank, and WRI. These principles prioritize national ownership, coherence and inclusivity, capacity, robustness, transparency and accessibility. In this enabling environment, a unique delivery ecosystem consisting of knowledge products and activities is established. The paper focuses on two key knowledge products as examples of this ecosystem: the open-source energy modeling system (OSeMOSYS) and the power system flexibility tool (IRENA FlexTool). These ecosystem elements are designed to meet user-friendliness, retrievability, reusability, reconstructability, repeatability, interoperability, and audibility (U4RIA) goals. To ensure the sustainability of this ecosystem, OpTIMUS is introduced—a community of practice dedicated to maintaining, supporting, expanding, and nurturing the elements within the ecosystem. Among other ecosystem elements, training and research initiatives are introduced, namely the Energy Modelling Platform for Africa, Latin America and the Caribbean, and Asia-Pacific as well as the ICTP Joint Summer School on Modelling Tools for Sustainable Development. Once deployed via workflows, the preliminary outcomes of these capacity-development learning pathways show promise. Further investigation is necessary to evaluate their long-term impacts, scalability, replication, and deployment costs.

Over 80% of wastewater worldwide is released into the environment without proper treatment. Whilst environmental pollution continues to intensify due to the increase in the number of polluting industries, conventional techniques employed to clean the environment are poorly effective and are expensive. MXenes are a new class of 2D materials that have received a lot of attention for an extensive range of applications due to their tuneable interlayer spacing and tailorable surface chemistry. Several MXene‐based nanomaterials with remarkable properties have been proposed, synthesized, and used in environmental remediation applications. In this work, a comprehensive review of the state‐of‐the‐art research progress on the promising potential of surface functionalized MXenes as photocatalysts, adsorbents, and membranes for wastewater treatment is presented. The sources, composition, and effects of wastewater on human health and the environment are displayed. Furthermore, the synthesis, surface functionalization, and characterization techniques of merit used in the study of MXenes are discussed, detailing the effects of a range of factors (e.g., PH, temperature, precursor, etc.) on the synthesis, surface functionalization, and performance of the resulting MXenes. Finally, the limits of MXenes and MXene‐based materials as well as their potential future research directions, especially for wastewater treatment applications are highlighted. 2D nanomaterials, especially MXenes have recently seen exciting developments in research and development, and their application in wastewater treatment has drawn wider attention. This review examines state‐of‐the‐art strategies employed in synthesis, functionalization, and characterization of surface functionalized MXenes. Furthermore, engineering strategies like composition design, and how surface protection influence their properties as adsorbents, photocatalysts, and membranes in wastewater treatment are discussed.

Pollution by heavy metals such as lead is a major concern, since exposure to these metals can lead to various adverse health effects. In this work, nanofibers composed of CuO (CuONFs) were developed as a novel and promising material for Pb(II) adsorption. There have been no previous reports concerning the production of polyacrylonitrile nanofibers modified with copper sulfate pentahydrate, followed by calcination, to be utilized as a Pb(II) adsorbent. The nanofibers were obtained using the centrifugal spinning method and then were characterized before and after a calcination step using analytical techniques. Adsorption parameters were investigated, including pH, contact time, adsorbate concentration, and temperature. Satisfactory Pb (II) adsorption was reached at 298 K, pH 5.8, and a maximum adsorption of 151.34 mg g−1 was achieved, predicted by the Hill model. The kinetic data proved that Pb (II) adsorption better fitted the pseudo-second-order model, while the Hill model was confirmed to best fit the equilibrium data. Thermodynamic parameters demonstrated that the lead adsorption was favorable, spontaneous, and exothermic. The CuONFs maintained 97.51% of their initial adsorption capacity after two adsorption/desorption cycles. The results showed that CuONFs have excellent potential as an adsorbent for Pb(II), while also showing high stability during reuse.

Tailoring the surface properties by varying the chemistry and roughness could be of interest for self-cleaning applications. We demonstrate the transformation of hydrophobic ZnO Nano rod (NR) array into superhydrophobic nature by changing the local chemical state and without altering the surface roughness by swift heavy ion (SHI) irradiation. The aligned ZnO NR arrays were irradiated using 150 MeV Ag ions with different fluences from 5E10 to 3E12 ions/cm 2 . The observed static water contact angles of ZnO NRs samples were 103° ± 3°, 152° ± 4°,161° ± 3°, 164° ± 2°, 167° ± 2°,154 ± 3° and 151° ± 2° for the pristine, ion fluencies of 1E11, 3E11, 5E11, 7E11, 1E12 and 3E12 ions cm −2 , respectively. The change in local surface chemistry via formation of surface oxygen related defects due to electronic excitations induced by ion irradiation determine the water dewetting properties. It is found that surface oxygen related defects could be tuned by varying the fluence of the SHIs. Durability tests show that the SHI induced surface oxygen-deficient ZnO NRs have the stable superhydrophobic behavior for more than a year.

The extensive use of organophosphates (OPs) pollutes the environment, leading to serious health hazards for human beings. The current need is to fabricate a sensing platform that will be sensitive and selective towards the detection of OPs at trace levels in the nM to fM range. With this discussed in the present report, an ultra-sensitive immunosensing platform is developed using digestive-ripened copper oxide quantum dots grafted on a gold microelectrode (Au-µE) for the impedimetric detection of parathion (PT). The copper oxide quantum dots utilized in this study were of ultra-small size with a radius of approximately 2 to 3 nm and were monodispersed with readily available functional groups for the potential immobilization of antibody parathion (Anti-PT). The miniaturization is achieved by the utilization of Au-µE and the microfluidic platform utilized has the sample holding capacity of about 2 to 10 µL. The developed immunosensor provided a wide linear range of detection from 1 µM to 1 fM. The lower Limit of Detection (LoD) for the developed sensing platform was calculated to be 0.69 fM, with the sensitivity calculated to be 0.14 kΩ/nM/mm2. The stability of the sensor was found to be ~40 days with good selectivity. The developed sensor has the potential to integrate with a portable device for field applications.

Centrifugal spinning was utilized in producing polyacrylonitrile (PAN) nanofibers loaded with extractant di-(2-ethylhexyl) phosphoric acid (D2EHPA) for efficient adsorption recovery of gallium from aqueous solutions. The adsorption experimental data were best fitted by a pseudo-second-order kinetic model and the BET equilibrium isotherm model. Optimal adsorption performance by the PAN/D2EHPA nanofibers exhibited an adsorption capacity of 33.13 mg g−1 for the recovery of gallium at pH 2.5 and 55 °C. The thermodynamic parameters demonstrated that adsorption was endothermic, spontaneous, and favorable. The stability and reusability of the nanofibers was assessed, demonstrating retention of structural and functional integrity for the nanofibers over five cycles of an adsorption/desorption process, whilst retaining adsorption efficiency. The results demonstrate that PAN/D2EHPA nanofibers have excellent potential for utilization in an efficient adsorption process for gallium recovery, offering significant positive environmental impact over conventional liquid–liquid extraction methods.

Pesticides are unavoidable in agriculture to protect crops from pests and insects. Organophosphates (OPs) are a class of pesticides that are more harmful because of the irreversible inhibition reaction with acetylcholinesterase enzyme, thereby posing serious health hazards in human beings. In the present work, a sensitive and selective immuno-sensing platform is developed using gold inter-digitized electrodes (Au-IDEs) as substrates, integrated with a microfluidic platform having the microfluidic well capacity of 10 µL. Au-IDE having digit width of 10 µm and gap length of 5 µm was used in this study. The surface morphological analysis by field-effect scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) revealed the direct information regarding the modification of Au-IDEs with anti-parathion (Anti-PT) antibodies. In SEM analysis, it was seen that the Au-IDE surface was smooth in contrast to the Anti-PT modified surface, which is supported by the AFM studies showing the surface roughness of ~2.02 nm for Au-IDE surface and ~15.86 nm for Anti-PT modified surface. Further, Fourier transform infra-red (FTIR) spectroscopic analysis confirms the immobilization of Anti-PT by the bond vibrations upon the successive modification of Au-IDE with -OH groups, amine groups after modifying with APTES, and the amide bond formation after incubation in Anti-PT antibody. Electrochemical impedance spectroscopy (EIS) was carried out for the electrochemical characterization and for testing the sensing performances of the fabricated electrode. The developed immuno-sensor provided a linear range of detection from 0.5 pg/L–1 µg/L, with a limit of detection (LoD) of 0.66 ng/L and sensitivity of 4.1 MΩ/ngL−1/cm2. The sensor response was also examined with real samples (pomegranate juice) with good accuracy, exhibiting a shelf life of 25 days. The miniaturized sensing platform, along with its better sensing performance, has huge potential to be integrated into portable electronics, leading to suitable field applications of pesticide screening devices.