نوع مقاله : مقاله پژوهشی
1 دانشیار بخش زیست شناسی دانشگاه شیراز
2 دانش آموخته کارشناسی ارشد گروه زیست شناسی دانشکده علوم دانشگاه شیراز، شیراز
عنوان مقاله [English]
Experiments were carried out with four concentrations of nickel chloride (0, 10, 80 and 220 mg/l) and a constant concentration of nano-adsorbent Fe3O4 (4 g/l), plus control. The treatments were soluble in plants as alternatives to normal water. The results were statistically analyzed by analysis of variance. The results showed that the least growth by weight was observed for plants with 220 mg Ni treatment. Proline in shoot increased significantly relative to root compared to control. Measurement of nickel heavy metal content by ICP-AES atomic absorption spectrophotometer showed that the concentration of nickel metal increased in the plant as it increase in the water. Inductively coupled plasma atomic emission spectroscopy is a method of emission spectroscopy that excites atoms and ions with a plasma, causing it to emit electromagnetic radiation at wavelengths characteristic of a particular element. Magnetic nanoparticles treatment Fe3O4 showed a significant reduction in nickel concentrations in the plant, indicating that they were successful in removing nickel metal. The results of antioxidant potential showed that concentrations of nickel as heavy metal stress increased the antioxidant and the treatment of nickel with nanoparticles in all three concentrations reduced the antioxidant. The nickel heavy metal in high concentrations is toxic for sunflower plant and the magnetic nanoparticle successfully absorbs the nickel metal up to 99 percent and reduces its toxic effects in the water.
Heavy metals are metallic elements with an atomic density of more than six grams per cubic centimeters. Currently, heavy metal contamination represents a growing
environmental concern across the world. Heavy metals are ubiquitous, highly persistent, non- biodegradable compounds, which tend to bioaccumulate in the food chain. Phytoremediation is the process through which green plants extract, sequester, and detoxify pollutants. This cost-efficient technique has attracted the attention of researchers over the years. Phytoremediation could be accomplished in-situ, while it is also an environmentally friendly approach for the removal of heavy metals from the soil by the use of appropriate plants for this purpose. Nickel is considered an essential element for many living systems that is necessary for plant metabolic activities. But high concentrations of this element are toxic to the plant and may interfere with many of the biochemical and physiological processes of the plants. Sunflower (Helianthus annuus) is a proper option for phytoremediation. Sunflower grows in tropical and mid-tropical areas depending on the type of the hybrid. It is cultivatable in a wide range of climatic conditions. The sustainability of sunflower is caused by its various morphological and physiological features, including the rapid growth (90-150 days depending on the level of environmental factors), having developed roots, resistance to soil salinity, passiveness to the length of the day, and no need for highly fertilized soil to provide satisfactory products. The magnetic nanoadsorbent are a base adsorbent embedded with magnetic particles, which are oxides of metals such as Fe, Co, Ni, and Cu, and can be easily separated from water under a magnetic field. In recent years, the problem of non-compliance of surface water quality has become more frequent. In addition, groundwater pollution in most areas of the country is relatively serious and poses a major threat to the safety of domestic production and water use. Through the statistical analysis of the total national wastewater discharge in recent years, it has been found that the total discharge of sewage shows an increasing trend. Among the many problems of water pollution, the problem of heavy metal pollution is particularly prominent, and groundwater quality and safety are not optimistic. For the treatment of wastewater containing heavy metals, a variety of treatment methods have been derived, such as adsorption and electrolysis. However, traditional adsorbents have many disadvantages, such as poor adsorption effect, high use cost, and difficulty in achieving separation between solid and liquid. Therefore, it is urgent to prepare a new type of adsorbent with high efficiency and low cost. In this study, special groups of magnetic nanomaterials were modified to achieve rapid and efficient removal of heavy metal ions in wastewater and the reuse and recycling of adsorbents. Pure water will become a golden resource in the context of the rising pollution, climate change and the recycling economy, calling for advanced purification methods such as the use of nanostructured adsorbents. However, coming up with an ideal nanoadsorbent for micropollutant removal is a real challenge because nanoadsorbents, which demonstrate very good performances at laboratory scale, do not necessarily have suitable properties in in full-scale water purification and wastewater treatment systems. Here, magnetic nanoadsorbents appear promising because they can be easily separated from the slurry phase into a denser sludge phase by applying a magnetic field. Water is needed for umpteen day-to-day domestic, commercial and industrial activities. Yet, over the years, pollution of water has kept increasing to such an extent where matters have worsened into water stress and water scarcity conditions in many regions of the world. The release of untreated wastewater poses two major global ecological problems. One which encompasses the entire set of the potential damaging and irreversible impacts on the different components of the food web and ecosystems. Accumulation of proline in higher plants is an indication of disturbed physiological condition, triggered by biotic or abiotic stress condition. Determination of free proline levels is a useful assay to monitor physiological status and to assess stress tolerance of higher plants.
This experiment was carried out in a factorial arrangement in a completely randomized design in three replications. The Duncan test was performed for comparison of mean. Determination of ferric reducing antioxidant power (FRAP) analysis was performed. This assay involves the reduction of ferric into ferrous. For this purpose, acetate buffer, ferric chloride and TPTZ (2,4,6-Tri (2-pyridyl)-s-triazine) in 40 mM HCl were initially admixed together to prepare the FRAP reagent. A volume of 2850 μl of the reagent, which was incubated at 37 ◦C (15 min) was added to either the plant extract or control solution (150 μL). In the following stage and after being incubated in the dark for a half-hour, the absorbance of the sample was read at 593 nm. Trolox at a concentration range of 25–800 μM was used, and antioxidant capacity (FRAP) was determined as μM Trolox equivalent (TE)/g DW. Measurement of nickel heavy metal content by ICP-AES atomic absorption spectrophotometer was done. It is used for its ability to detect heavy metals in liquid samples at very low concentrations. The aerial and underground parts of the plant were separated by special shear and measured with a sensitivity scale of 0.001 g.
The results of the measurements indicated that the highest fresh weight (22 g), 80 mg Nickel treated with magnetic nanoparticles, and the lowest fresh weight of the aerial and root (18 g) was related to 220 mg Ni treatment. The nickel heavy metal in high concentrations is toxic for sunflower plant and the magnetic nanoparticle successfully absorbs the nickel metal up to 99 percent and reduces its toxic effects in the water.