Nanomaterials have gained huge applications ever since their discoveries, especially in the field of electronics, medicine, research, and environmental cleanup. Nanomaterials have a high surface area‐to‐volume ratio along with high surface energies making them suitable for such wide applications. Carbon nanotubes (CNTs) and carbon nanocomposite (CNC) materials are remarkable nanomaterials that have become the backbone of most industries these days. Both materials have gained huge attention in the last decade by the scientific community. CNTs come in two variants, i.e., single‐walled CNTs (SW‐CNTS) and multiwalled CNTs (MW‐CNTs). Due to their wider applications, CNT synthesis is currently emerging with the advancement in technology. Currently, CNTs are being synthesized by chemical as well as physical approaches. The current review article focuses on the vital research and application for the synthesis of CNTs depending on the quality of the nanotube materials. Controlled routes to their organization and assembly are also discussed in detail over here. The aim is to provide recent advances in the synthesis methods, of CNTs, their current applications, future applications, and the potential of agrowaste and industrial waste for the synthesis of CNTs and nanomaterials.

Environmental nanotechnology has developed rapidly over the past few decades due to the fast advancement of nanotechnology and nanomaterials (NMs). Due to their nanoscale size, NMs are receiving immense attention in research and development worldwide. Their nano size has led to better catalysis, high reactivity, and high adsorption capacity. In wastewater treatment, nanotechnology has significant potential to improve the performance and efficiency of water decontamination; more effectively, it provides a sustainable way to keep water supplies safe. Numerous studies have found that removing harmful components from wastewater by employing nanoparticles in conjunction with various treatment methods is effective. The purpose of the current investigation is to conduct a review of the envisioned applications of various NMs in the treatment of wastewater. These NMs include carbonaceous NMs, metal-containing nanoparticles, and nanocomposites, all of which will be reviewed and highlighted in depth.

4-Dimensional Printing (4DP) is the latest concept in the pharmacy and biomedical segment with enormous potential in dosage from personalization and medication designing, which adopts time as the fourth dimension, giving printed structures the flexibility to modify their morphology. It can be defined as the fabrication in morphology with the help of smart/intelligent materials like polymers that permit the final object to alter its properties, shape, or function in response to external stimuli such as heat, light, pH, and moisture. The applications of 4DP in biomedicines and healthcare are explored with a focus on tissue engineering, artificial organs, drug delivery, pharmaceutical and biomedical field, etc. In the medical treatments and pharmaceutical field 4DP is paving the way with unlimited potential applications; however, its mainstream use in healthcare and medical treatments is highly dependent on future developments and thorough research findings. Therefore, previous innovations with smart materials are likely to act as precursors of 4DP in many industries. This review highlights the most recent applications of 4DP technology and smart materials in biomedical and healthcare fields which can show a better perspective of 4DP applications in the future. However, in view of the existing limitations, major challenges of this technology must be addressed along with some suggestions for future research. We believe that the application of proper regulatory constraints with 4DP technology would pave the way for the next technological revolution in the biomedical and healthcare sectors.

The green, cost-effective and sustainable synthesis of nanomaterials has been a key concern of scientists and researchers. In this view, MNPs were prepared using a sapota plant leaf extract and the surface of the magnetite nanoparticles was engineered with unsaturated fatty acids. The first report on the effect of unsaturation on the size and magnetic properties of magnetite nanoparticles (MNPs), prepared by the co-precipitation method, has been studied by coating surfactants on MNPs based on their unsaturation from zero to three (lauric acid, oleic acid, linoleic acid, linolenic acid). The size effect and magnetic properties of MNPs coated with a surfactant have been studied in comparison with uncoated magnetite nanoparticles. After the surface modification of the magnetite particle, it is necessary to check whether the magnetic property has been restored or not. Therefore, the magnetic property was studied. The presence of a surfactant on the surface of MNPs was confirmed by Fourier-transform infrared spectroscopy (FTIR), which was later confirmed by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The atomic structure was studied by X-ray diffraction (XRD) and the size of uncoated and surfactant-coated MNPs was determined by transmission electron microscopy (TEM) and the Scherrer equation by following XRD data. The magnetization property was analyzed by a vibrating sample magnetometer (VSM) at 10, 100 and 300 K and both bared and surfactant-coated MNPs exhibited a superparamagnetic nature at room temperature. The saturation magnetization (M_s) study shows that MNPs coated with a surfactant have a lower saturation magnetization value in comparison to uncoated NPs, confirming surface layering. Because the magnetic fluid has been stabilized in the aqueous medium, the double-layer model is expected to prevail.

In 21st century, organic and domestic wastes and discharges from varied chemical and manufacturing industries to water bodies become a critical issue and challenge for the researchers, engineers and policy makers. Advanced oxidation processes (AOPs) are efficient, sustainable, economically viable and green techniques to elimination on-degradable organic pollutants by biological and traditional processes. A number of research articles have been published from the past two decades on the wastewater treatment using various advanced oxidation processes. The main objective of this review paper is to provide the quick view for researchers, academicians and scientists in the area of wastewater treatment using various types of AOPs, which incorporate green principles involves in the processes for removal of different pollutants and contaminants including dyes, phenols, pesticides, herbicides etc. from wastewaters, with emphasis on the degradation efficiency of various photocatalysts. The formation reactions of •OH radical and the mechanisms of degradation of various organic pollutants in the wastewater is also discussed. This review covers various types of advanced oxidation processes, viz., ozone-based processes, photocatalysis and Fenton-based reactions.