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As a potent herbicide capable of contaminating water and soil environments, paraquat, which is still widely used worldwide, is toxic to mammals, algae, aquatic animals, etc. Paraquat was loaded on novel nanoparticles composed of pectin, chitosan, and sodium tripolyphosphate (PEC/CS/TPP). The size, polydispersity index, and ζ potential of nanoparticles were characterized. Further assessments were carried out by SEM, AFM, FT-IR, and DSC. The encapsulation was highly efficient, and there was a delayed release pattern of paraquat. The encapsulated herbicide was less toxic to alveolar and mouth cell lines. Moreover, the mutagenicity of the formulation was significantly lower than those of pure or commercial forms of paraquat in a Salmonella typhimurium strain model. The soil sorption of paraquat and the deep soil penetration of the nanoparticle-associated herbicide were also decreased. The herbicidal activity of paraquat for maize or mustard was not only preserved but also enhanced after encapsulation. It was concluded that paraquat encapsulation with PEC/CS/TPP nanoparticles is highly efficient and the formulation has significant herbicide activity. It is less toxic to human environment and cells, as was evidenced by less soil sorption, cytotoxicity, and mutagenicity. Hence, paraquat-loaded PEC/CS/TPP nanoparticles have potential advantages for future use in agriculture.

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In this study vertically aligned carbon nanotubes (VA-CNT) was grown on anodized aluminum oxide (AAO) substrate. The synthesized AAO-CNT membrane was characterized using Raman spectroscopy, field emission scanning electron microscopy (FESEM), contact angle and BET. The pure water flux, humic acid (HA) (as representative of natural organic matters) rejection and fouling mechanism were also evaluated. The fabricated membrane has pore density of 1.3 × 1010 pores per cm2, average pore size of 20 ± 3 nm and contact angle of 85 ± 8o. A significant pure water flux of 3600 ± 100 L/m2.h was obtained at 1 bar of pressure by this membrane due to the frictionless structure of CNTs. High contact angle exhibited the hydrophobic property of the membrane. It was revealed that HA is primarily rejected by adsorption in the membrane pores due to hydrophobic interactions with HA. Flux decline occurred rapidly through both cross flow and dead end filtration of the HA. Based on the blocking laws, internal pore constriction is dominant fouling mechanism in which HA adsorbs in membrane pores results in pores blockage and flux decline.