Journal of Nano Research Vol. 66

Abstract: In this study, nanoscale zero-valent iron (nZVI) particles and their composites with powdered activated carbon (nZVI-PAC) and granular activated carbon (nZVI-GAC) were successfully synthesized via a low-cost green approach with the use of green tea extract. The adsorbents were then used to remove Cr and Cu from aqueous solutions, and their adsorption results were fitted with the Freundlich and Langmuir models. The synthesized adsorbents were characterized using XRD, FTIR, and FESEM techniques. The typical peak of Fe⁰ was detected in the XRD patterns of prepared samples, but the presence of organic compounds in green tea extract weakened related peak. The FESEM characterization demonstrated that the nZVI spherical particles had a chain-like structure and ranging in size from 10 to 50nm. The presence of polyphenols peak in the FTIR spectra revealed that the green tea extract was responsible for the reduction of the Fe²⁺ to Fe⁰. The maximum adsorbed amount of Cr and Cu was found to be 5.68 and 6.48 mg/g, which was achieved by nZVI-PAC and nZVI, respectively. The nZVI-PAC and nZVI also showed a higher removal efficiency for Cu and Cr by 62% and 94% for an initial concentration of 100 mg/L, respectively. The results showed that nZVI, nZVI-PAC, and nZVI-GAC could be promising and eco-friendly adsorbents for Cr and Cu removal from aqueous solutions.

Abstract: Nanotechnology can be used to protect plants against Fusarium Dieback and the Laurel Wilt, that are new and lethal insect-vectored diseases that can host over 300 tree species, including avocado trees. The vectors of these diseases are beetles members of the Scolytinae subfamily, notoriously difficult to control because they spend most of their lives hidden within galleries. Nevertheless, when tested on avocado bolts, some insecticides (including permethrin) provided a reduction in the number of entrance holes or beetle emergence, but the persistence of pesticide residues might have been influenced by factors like rainfall and sunlight. The present study aims to encapsulate permethrin in polylactic acid nanospheres, conferring protection against losses by physic and chemical factors, ultimately increasing its persistence. The particle size, zeta potential, and encapsulation efficiency obtained were 393nm, -32mV, and 27%, respectively. After 96 h of exposure to UV-A light, the insecticidal activity of unencapsulated permethrin was severely diminished, having a reduction in mortality in scolytinae beetles from 80% to 40%, while the nanoencapsulated permethrin retained a 70%. The study has concluded the potential advantage of formulating permethrin into nanometric biodegradable spheres, enhancing the persistence of the insecticide while removing the use of toxic organic solvents as vehicle for the active ingredient, reducing the environmental impact.)