نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران
2 گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران.
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objectives: Soil contamination with heavy metals, mainly due to human activities, has been considered as a severe environmental problem in recent decades. Nickel (Ni) is one of the heavy metals which its concentration increased through industrial development. Recently, the use of nanoparticles for immobilization of heavy metal such as nickel in soil has gained attention due to their unique sorption properties and cost-effectiveness. Therefore, the aim of this research was to study the effect of different nanoparticles on the distribution of chemical forms of nickel in soil contaminated with nickel.
Materials and Methods: A composite soil sample was taken from the surface layer (0–30 cm depth) of a calcareous soil from the agricultural farms of the College of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran and then it was contaminated with a concentration of 200 mg/kg of nickel from the source of nickel nitrate (Ni(NO3)2.6H2O). A factorial experiment with a completely randomized design was conducted with two factors including nanoparticle types (nano-clay montmorillonite, common reed nano-biochar, and zero-valent iron nanoparticle), and level of their application (0, 0.5, and 1% w/w) for 90 days in three replications under incubation conditions in the laboratory of the Soil Science Department at Shahid Chamran University of Ahvaz. The different chemical forms of nickel were also determined utilizing sequential extraction procedure (26).
Results: The results showed that using nanosorbents at both application amounts of 0.5% and 1% caused a significant decrease in available nickel (DTPA-extractable). Applying of nano adsorbents, especially nano biochar, significantly reduced the concentration of exchangeable and carbonate fractions of nickel in the soil and increased the concentration of organic, exchangeable and residual forms of nickel. The concentration of exchangeable fraction of nickel in zero-valent iron nanoparticle, nano clay, and nano biochar treatments decreased by 45.86, 50.50 and 54.39 %, respectively, compared to the control treatment at the 1% application level. The concentration of nickel bonded with carbonates and residual nickel in reed nanobiochar at the level of 1% decreased and increased by 60.61 and 25.64%, respectively, compared to the control treatment. The value of nickel stability index (IR) in the soil increased significantly (P ≥ 0.05) with the application of nanosorbents compared to the control, which indicates an increase in the amount of nickel in the stable fractions (organic matter and Fe & Mn oxides fractions). Also, the nickel mobility factor in the control soil was significantly higher than the soil treated with zero-valent iron nanoparticle, nanoclay and nano biochar, which indicates the decrease in the amount of mobile nickel with the use of nanosorbents in the soil.
Conclusions: The application of nanosorbents in nickel contaminated soil caused a decrease in nickel in exchangeable and carbonate forms and increased forms of bonded Ni with organic matter and iron and manganese oxides compared to the control soil. In general, the results of this research showed that the use of nanosorbents, especially nano biochar, can immobilize nickel in contaminated soil. Using of nano biochar to contaminated soil, due to its high pH, high organic carbon, and high specific surface area, leads to a decrease in the mobility of nickel in contaminated soil.
کلیدواژه‌ها [English]
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