Water contamination is one of the most urgent concerns confronting the world today. Heavy metal poisoning of aquatic systems has piqued the interest of various researchers due to the high toxicity and carcinogenic consequences it has on living organisms. Due to their exceptional attributes such as strong reactivity, huge surface area, and outstanding mechanical properties, nanomaterials are being produced and employed in water treatment. In this review, recent advances in the use of nanomaterials in nanoadsorptive membrane systems for wastewater treatment and heavy metal removal are extensively discussed. These materials include carbon-based nanostructures, metal nanoparticles, metal oxide nanoparticles, nanocomposites, and layered double hydroxide-based compounds. Furthermore, the relevant properties of the nanostructures and the implications on their performance for water treatment and contamination removal are highlighted. The hydrophilicity, pore size, skin thickness, porosity, and surface roughness of these nanostructures can help the water permeability of the nanoadsorptive membrane. Other properties such as surface charge modification and mechanical strength can improve the metal adsorption effectiveness of nanoadsorptive membranes during wastewater treatment. Various nanocomposite membrane fabrication techniques are also reviewed. This study is important because it gives important information on the roles of nanomaterials and nanostructures in heavy metal removal and wastewater treatment.

In this study, silver nanoparticles (AgNPs) are synthesized through a green approach by employing Rosa indica L. petal (RE) extracts as reducing and stabilizing agents, which are extracted using three different solvents: ethanol (Et), acetone (Ac), and water (Aq). The phase formation of the AgNPs is confirmed using X-ray diffraction (XRD). Morphological analysis is performed using a field-emission scanning electron microscope (FESEM), which reveals that the AgNPs are spherical in shape. The size is estimated using ImageJ software, which is found to be ~12, 18, and 770 nm for RE-Ac-Ag, RE-Et-Ag, and RE-Aq-Ag, respectively. The phytochemicals of Rosa indica L. petals involved in the formation of the AgNPs are studied using Fourier transform infrared spectroscopy (FTIR). Finally, these materials are studied for their antibacterial, antidiabetic, antioxidant, and hemolytic activity, as well as cell toxicity properties. The materials, RE-Ac-Ag and RE-Et-Ag, are found to be more effective than RE-Aq-Ag in inhibiting E. coli (Gram-negative bacteria) and S. aureus (Gram-positive bacteria). Hemolytic studies reveal that all of the samples show concentration-dependent activity up to 50 µg/mL. RE-Ac-Ag and RE-Et-Ag exhibit nonhemolytic behavior, whereas RE-Aq-Ag remains nonhemolytic until 100 µg/mL. The antidiabetic ability of the AgNPs is evaluated using α-amylase inhibition assay (DNSA assay) and α-glucosidase inhibition assay. The results are found to be effective, with IC₅₀ values of α-amylase and α-glycosidase being 50, 50, and 75 µg/mL for RE-Et-Ag, RE-Ac-Ag, and RE-Aq-Ag, respectively. DPPH assay shows that the AgNPs inhibited the antioxidants well, with IC₅₀ values of 40 µg/mL for RE-Et-Ag and RE-Ac-Ag and 60 µg/mL for RE-Aq-Ag. The toxicity study reveals that the AgNPs show size- and concentration-dependent behavior. Overall, it is realized from the findings that RE-Ac-Ag, RE-Et-Ag, and RE-Aq-Ag show size-dependent antibacterial, antidiabetic, and toxicity properties.

This paper reports on the physicochemical, and mechanical characterization of Coccinia Indica (CI) fiber. The Coccinia Indica fiber (CIF) reinforced epoxy composite is fabricated using a compression molding process. The results of the chemical analysis of CIF showed that the fiber contained more cellulose and skimpy lignin, ash, and wax content. Scanning electron microscopy (SEM) analysis revealed that the fiber possessed a multicellular structure. The Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) studies revealed that CIF shows a crystallinity index of 30%. The thermogravimetric analysis (TGA) indicated that the major degradation of fibers occurred in the temperature range of 204.2 °C to 376.3 °C. The various mechanical test results showed that the tensile, flexural and impact strength increased with increase in fiber length and weight percentage. The maximum properties were found at 30 mm fiber length and 35% of fiber loading. The SEM fractography result showed that the predominant mechanism for mechanical failure was due to fiber pull out, matrix fracture and fiber fracture.

Biogenic synthesis of silver nanoparticles (SS-Ag NPs) using the extract of Saccharum spontaneum (SS) via green chemistry route was investigated for their in-vitro cytotoxicity on osteoblast-like cells and bactericidal effect. Synthesized SS-Ag NPs were analyzed using TEM, FTIR, XRD and UV Vis spectroscopy techniques. The biomolecules present in S. spontaneum were responsible for the reduction and capping of silver nanoparticles. A heterogenous mixture of SS-Ag NPs which consists of triangle, hexagonal, spherical and rod-like structures was obtained. Furthermore, the synthesized SS-Ag NPs were tested for in a broad spectrum of antibacterial activity against E. coli, S. aureus, K. pneumonia and P. aeruginosa and it showed significant inhibitory effect. For the first time, the enhancement in the proliferation rate of MG63 cells with SS-Ag NPs is reported.