نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه شیمی ، دانشکده علوم ، دانشگاه جیرفت، جیرفت، ایران
2 گروه گیاهپزشکی، دانشکده کشاورزی، دانشگاه جیرفت، جیرفت، ایران
3 گروه گیاهپزشکی ، دانشکده کشاورزی ، دانشگاه جیرفت، جیرفت، ایران
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Agricultural pesticides are significant environmental pollutants that cause serious harm to humans and the ecosystem. Among these pesticides is abamectin, which is used as an acaricide. In this study, needle-like molybdenum trioxide (MoO₃) nanorods were synthesized via the hydrothermal method, and a molybdenum trioxide@graphene oxide (MoO₃@GO) nanocomposite was heterogeneously prepared for the removal of the pesticide abamectin. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (IR). The average size of the MoO₃ nanorods was found to be 110 nm. The adsorption performance of these two materials for abamectin was compared. The results indicated that both adsorbents exhibit high adsorption capacity, with the MoO₃-graphene oxide nanocomposite showing superior adsorption. Key variables such as pesticide concentration, adsorbent dosage, contact time, and pH were investigated. The results demonstrated that the adsorption capacity of MoO₃ nanorods was 95%, while that of the synthesized nanocomposite reached 98%. The adsorption process followed the Langmuir isotherm model. The optimal adsorption conditions were determined as follows: adsorbent dosage of 3 mg, pesticide concentration of 5 ppm, contact time of 15 minutes, and acidic pH.
کلیدواژه‌ها [English]
Extended Abstract
Introduction
Abamectin is a widely used antiparasitic agent derived from the fermentation products of the soil bacterium Streptomyces avermitilis. Initially developed as a veterinary drug in the 1980s, Abamectin is a mixture of two closely related components: Avermectin B1a and Avermectin B1b, with B1a being the more potent isomer. It has since found applications in agriculture and public health. Known for its efficacy against a variety of pests, including nematodes and arthropods, abamectin works by interfering with the transmission of nerve impulses in target organisms, leading to paralysis and death. Its unique mechanism of action, along with its favorable safety profile when used according to guidelines, has made it a valuable tool in integrated pest management (IPM) programs. In summary, abamectin remains a critical component of pest control strategies in both agricultural and veterinary contexts. Its effectiveness against a broad spectrum of parasites, paired with relatively low toxicity to humans and animals, underscores its importance. However, awareness of its environmental impact and adherence to safety standards are essential to ensure responsible use. Continued research will be vital to balance the benefits of abamectin with potential risks, optimizing its role in sustainable pest management while safeguarding ecosystem health.
Materials and methods
to conduct this research, a 1000 ppm solution of abamectin (purchased from Sigma Aldrich) with 97% purity was prepared. Other materials used in the experiments, including 98% sulfuric acid, pure hydrogen peroxide, pure potassium permanganate, pure graphite, and concentrated hydrochloric acid, were also purchased from Sigma Aldrich.
Results and discussion
needle-like molybdenum trioxide nanorods were synthesized using a hydrothermal method, and a molybdenum trioxide@graphene oxide nanocomposite was synthesized heterogeneously. The characterization of the synthesized nanoparticles was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and infrared spectroscopy (IR), with an average size of 110 nanometers for the molybdenum trioxide nanorods. The results of this study compared these two compounds for the adsorption of abamectin toxin. The XRD pattern of graphene oxide shows sharp peaks at 2θ = 11, 26.5, which is indicating that the graphene oxide is not pure and contains some graphite impurities. The XRD pattern of MoO3 shows sharp peaks at 2θ = 12, 23.5, 27, 28.5, 34, 36.5, 39.5, 47, 49, and 59, corresponding to the formation of molybdenum trioxide, which matches the JCPDS pattern 050508. The peak at 12 corresponds to the (020) plane, the peak at 23 corresponds to the (110) plane, the peak at 27 corresponds to the (040) plane, the peak at 28 corresponds to the (021) plane, the peak at 34 corresponds to the (111) plane, the peak at 36 corresponds to the (041) plane, the peak at 39 corresponds to the (060) plane, the peak at 47 corresponds to the (200) plane, and the peak at 49 corresponds to the (210) plane. The XRD pattern of the nanocomplex shows that all the peaks of molybdenum trioxide are covered by the peaks of graphene oxide carefully. The shortening and broadening of peak 11 and the increasing height and broadening of peak 27 confirm that the peaks of molybdenum trioxide are covered by graphene oxide. The removal of molybdenum trioxide peaks at angles higher than 30° is due to the involvement of molybdenum oxide planes with graphene oxide through van der Waals bonding.
Conclusion
The findings showed that both adsorbents have high adsorption capacity, and the molybdenum trioxide and graphene oxide nanocomplex has a greater adsorption capacity. The variables of toxin concentration, adsorbent amount, contact time, and pH in the adsorption process were examined. The results indicated that the adsorption capacity of the molybdenum trioxide nanorods is 95%, and the capacity of the synthesized nanocomposite is 98%. During condition optimization, it was shown that an adsorbent amount of 3 mg, a toxin concentration of 5 ppm, and a contact time of 15 minutes at acidic pH achieved the highest adsorption. In the present study, needle-shaped molybdenum trioxide nanorods were synthesized using a hydrothermal method, and the molybdenum trioxide nanocomposite was synthesized via a heterogeneous method. Both nanocomposite materials were utilized as adsorbents for the adsorption and removal of the pesticide abamectin from the environment. The results indicate that both nanocompounds have the capability to adsorb abamectin, with the molybdenum trioxide@graphene oxide nanocomposite displaying superior efficiency as an abamectin adsorbent. Kinetic and thermodynamic data for the adsorption process were also calculated.
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