Recent advancements in sustainable synthesis of zinc oxide nanoparticles using various plant extracts for environmental remediation.

The sustainable synthesis of zinc oxide nanoparticles (ZnO-NPs) using plant extracts has gained significant attention in recent years due to its eco-friendly nature and potential applications in numerous fields. This synthetic approach reduces the reliance on non-renewable resources and eliminates the need for hazardous chemicals, minimizing environmental pollution and human health risks. These ZnO-NPs can be used in environmental remediation applications, such as wastewater treatment or soil remediation, effectively removing pollutants and improving overall ecosystem health. These NPs possess a high surface area and band gap of 3.2 eV, can produce both OH° (hydroxide) and O2-° (superoxide) radicals for the generation of holes (h+) and electrons (e-), resulting in oxidation and reduction of the pollutants in their valence band (VB) and conduction band (CB) resulting in degradation of dyes (95-100% degradation of MB, MO, and RhB dyes), reduction and removal of heavy metal ions (Cu2+, Pb2+, Cr6+, etc.), degradation of pharmaceutical compounds (paracetamol, urea, fluoroquinolone (ciprofloxacin)) using photocatalysis. Here, we review an overview of various plant extracts used for the green synthesis of ZnO NPs and their potential applications in environmental remediation including photocatalysis, adsorption, and heavy metal remediation. This review summarizes the most recent studies and further research perspectives to explore their applications in various fields.

Myrica esculenta Leaf Extract-Assisted Green Synthesis of Porous Magnetic Chitosan Composites for Fast Removal of Cd (II) from Water: Kinetics and Thermodynamics of Adsorption.

Heavy metal contamination in water resources is a major issue worldwide. Metals released into the environment endanger human health, owing to their persistence and absorption into the food chain. Cadmium is a highly toxic heavy metal, which causes severe health hazards in human beings as well as in animals. To overcome the issue, current research focused on cadmium ion removal from the polluted water by using porous magnetic chitosan composite produced from Kaphal (Myrica esculenta) leaves. The synthesized composite was characterized by BET, XRD, FT-IR, FE-SEM with EDX, and VSM to understand the structural, textural, surface functional, morphological-compositional, and magnetic properties, respectively, that contributed to the adsorption of Cd. The maximum Cd adsorption capacities observed for the Fe3O4 nanoparticles (MNPs) and porous magnetic chitosan (MCS) composite were 290 mg/g and 426 mg/g, respectively. Both the adsorption processes followed second-order kinetics. Batch adsorption studies were carried out to understand the optimum conditions for the fast adsorption process. Both the adsorbents could be regenerated for up to seven cycles without appreciable loss in adsorption capacity. The porous magnetic chitosan composite showed improved adsorption compared to MNPs. The mechanism for cadmium ion adsorption by MNPs and MCS has been postulated. Magnetic-modified chitosan-based composites that exhibit high adsorption efficiency, regeneration, and easy separation from a solution have broad development prospects in various industrial sewage and wastewater treatment fields.

Synthesis and characterization of PANI and PANI-indole copolymer and study of their antimalarial and antituberculosis activity.

The preparation of polyaniline (PANI) and its copolymer with indole involved a chemical oxidative polymerization method, with benzene sulfonic acid (BSA, C6H6O3S) used as a dopant and potassium persulfate (PPS, K2S2O8) as an oxidant. The synthesized compounds underwent characterization using FTIR, 1H-NMR, TGA, and GPC techniques, which allowed the calculation of their average molecular weight and polydispersity index (PDI) through the GPC technique. The PDI values of the PANI copolymer with indole in different aniline-to-indole ratios were 1.53, 1.13, and 1.532 for 1:1, 1:2, and 2:1 ratios, respectively. Thermal stability was determined using TGA, revealing that the indole heterocyclic compound increased the inflexibility of the polymer chains in the synthesized PANI copolymer. The structure of the copolymer was further analyzed using 1HNMR and FTIR techniques, which confirmed the existence of benzenoid and quinoid groups in the PANI-indole copolymers, as well as the effect of doping on the polymer chains. The antibacterial and antifungal properties of the copolymers were studied against several bacterial and fungal strains and measured in terms of minimum inhibitory concentration. Results indicated that the inhibition rate of the PANI-indole copolymer on S. pyogenus (MTCC 442) was higher than that of standard drugs and individual PANI. The PANI-indole copolymers also displayed excellent antituberculosis and antimalarial activities, with the synthesized copolymer showing better outcomes than individual PANI.