جستجوی مقالات مرتبط با کلیدواژه "اکسید گرافن" در نشریات گروه "آب و خاک"

Wheat is considered the most important grain and one of the vital food products in Iran. After nitrogen, phosphorus is the most important nutrient required by plants and holds a high priority for the growth, yield and quality of plants. However, due to the introduction of phosphorus in various reactions in the soil, a small amount of consumed phosphorus fertilizer is removed by the plant and the rest of it is left in a non-absorbable form in the soil. The efficiency of using phosphorus fertilizers and the availability of this nutrient is considered as a limiting factor for the production of agricultural products in calcareous soils with alkaline reaction of Iran. Since graphene and its oxidized form, with large amounts of active oxygen groups and high specific surface area, have been proposed by many studies as non-toxic and biocompatible materials in the production of compounds with improved efficiency of using nutrient, therefore to increase the efficiency of phosphorus consumption in soil, in this study, phosphorus was loaded on graphene oxide (GO-P). The present study aims to assess the influence of this compound as a source of phosphorus and its mixing with triple superphosphate fertilizer (GO-P-TSP) compared to triple superphosphate soluble fertilizer (TSP) on the amount of water retention of fertilizers in soil and phosphorus concentration in aerial parts of wheat plant.

Methods and Materials:

Graphene oxide was prepared based on the modified Hamers method. Then graphene oxide was adjusted to certain pH and iron sulfate as a source of iron ions was added to the graphene oxide suspension with vigorous stirring. The mixture was stirred for one hour and then centrifuged for 30 minutes. Then the supernatant was removed and the residue of the compound was dry frozen. In the next step, pH was adjusted with sodium hydroxide (NaOH) solution. Then a certain weight of potassium dihydrogen phosphate salt (KH2PO4) was added to the above suspension. The mixture was stirred for one hour and centrifuged for 30 minutes. After centrifugation, the supernatant was removed and the remains of the phosphorus composition based on graphene oxide were dry frozen. Loading tests were performed in three replicates. pH, EC, bulk density, total concentration of phosphorus and iron and X-ray diffraction spectroscopy (EDS) analysis were measured in the sample of phosphorus composition based on graphene oxide. Then three fertilizer formulations were selected, which included (1) triple superphosphate fertilizer, (2) synthesized phosphorus fertilizer based on graphene oxide, and (3) mixing graphene oxide-phosphorus compound with triple superphosphate fertilizer in a ratio of 50:50% phosphorus.To investigate the water retention behavior of fertilizers in the soil, dried samples of the three studied fertilizer formulations was added into a sandy soil completely and weighed. At the same time, dried sandy soil without fertilizer was placed in another beaker as a control.Then each beaker was added distilled water and weighed. The beakers were weighed once every three days at room temperature until they reached constant mass. The water-retention behavior of the soil was calculated.In order to investigate the effect of three fertilizer formulations on phosphorus availability, soil with low amount of phosphorus was selected and physical and chemical properties of the soil sample were measured at a depth of 0-30 cm. A greenhouse experiment on wheat planting was conducted using a randomized complete design with 3 replications. The treatments included three fertilizer formulations at three fertilization levels (10, 15, and 20 mg kg-1) with 3 replications. The control treatment was performed without phosphorus fertilizer. Plants were harvested 72 days after planting, washed with distilled water and dry with tissue paper. The samples were air-dried and then oven dried at 70˚C to a constant weight in a forced air-driven oven. After harvesting, the weight of fresh and dry matter and phosphorus concentration in the soil and aerial parts of the plant were measured. Statistical data were analysed using SAS software (9.4) and the mean values were compared using LSD tests (at 1 and 5% level).

The composition of phosphorus based on graphene oxide (GO-P) in powder form had 35.5% of total P2O5, 31.1% of soluble in water P2O5, 19.6 of total iron and 15.28% of total potassium. The result of EDS analysis confirmed the loading of phosphorus on graphene oxide. The pH of the phosphorus composition based on graphene oxide was 5.8, approximately 2.5 units higher than triple superphosphate fertilizer. The bulk density of the compound (GO-P) was significantly lower than triple superphosphate fertilizer. The EC of the compound (GO-P) was similar to the EC of the triple superphosphate fertilizer. Soil water retention with synthesized phosphorus fertilizer based on graphene oxide (GO-P) was higher than soil (control) and other compounds added to soil. Experimental results showed that the addition of prepared fertilizer formulas (GO-P and GO-P-TSP) increased water retention in the soil for a longer period of time, while in the soil without adding fertilizer and triple superphosphate treatment, respectively, from 10 and 11 days, the absorbed water completely evaporated. Therefore, the combination of soil with GO-P and GO-P-TSP compared to the soil without fertilizer and the combination of soil with triple super phosphate (TSP) fertilizer had better water retention behavior. The greenhouse experiment results of wheat planting showed that all treatments were significant (P<0.01). Among all the treatments and measured levels, the control treatment showed the lowest value. The highest concentration of phosphorus in aerial parts of wheat (0.31%) and in soil after harvesting (9.5 mg kg-1), fresh (10.6 g per pot) and dry weight (2.03 g per pot) of aerial wheat plants were related to the treatment of phosphorus compounds based on graphene oxide at the level of 20 mg kg-1.

The highest concentration of phosphorus in aerial parts of wheat was related to the treatment of phosphorus compound based on graphene oxide at the level of 20 mg kg-1. Therefore, with more research in the future to produce "nutritious plants" in sustainable, efficient and flexible agricultural systems, we can benefit from technologies based on carbon materials.

The utilization of traditional micronutrients faces certain constraints, such as the significant retention of micronutrients in the soil. This can occur due to robust adsorption reactions to clays and organic matter, or the formation of insoluble compounds in the soil. These factors greatly diminish the effectiveness of micronutrient fertilizers. The environmental concerns and limited effectiveness linked to conventional fertilizers motivate the pursuit of innovative fertilizers with delayed release and enhanced performance. A possible solution that has been explored for these issues is the utilization of slow-release fertilizers (SRFs) or controlled-release fertilizers (CRFs). These fertilizers deliver vital nutrients to plants at a slower pace compared to conventional fertilizers. The release mechanisms of these CRFs are dependent on either diffusion through their coating or gradual hydrolysis. Yet, soil characteristics like moisture level, pH, ion concentration, and temperature also play a role in influencing nutrient release through hydrolysis or diffusion. Hence, there exists a potential disparity between the speed at which micronutrients are released into the soil and the necessary pace of nutrient absorption by crops. Graphene oxide (GO) stands out as a common material for crafting slow-release fertilizers (SRFs). Given GO's strong affinity for metal ions and its role in ferrying therapeutic compounds, it's logical to envision GO being effectively employed as a transporter for plant micronutrients. In this study, we introduce an innovative approach to tackle these constraints, showcasing the utility of GO sheets as novel carriers for efficiently loading plant micronutrients. This technique finds application in creating advanced fertilizers that enable gradual and sustained release.

In this document, we present the creation of a novel carrier system using sheets of graphene oxide (GO). These sheets are capable of efficiently carrying plant micronutrients, allowing for a controlled and gradual release. To demonstrate this idea, we utilized zinc (Zn) and copper (Cu) as examples of micronutrients, loading them onto the GO sheets to formulate a fertilizer based on GO. We verified the chemical composition and successful loading of both nutrients onto the GO sheets using techniques such as X-ray photoelectron spectroscopy and thermogravimetric analysis.

The prepared Zn-graphene oxide (Zn−GO) and Cu-graphene oxide (Cu−GO) fertilizers showed a biphasic dissolution behavior compared to that of commercial zinc sulfate and copper sulfate fertilizer granules, displaying desirable fast and slow micronutrient release. A visualization method and chemical analysis were used to assess the release and diffusion of Cu and Zn in soil from GO-based fertilizers compared with commercial soluble fertilizers to demonstrate the advantages of GO carriers and show their capability to be used as a generic platform for macro- and micronutrients delivery. The results of kinetic rate of adsorption show a significant increase in adsorption of both ions at the beginning of the process (first 10 min), with slow increase after 10−20 min and reaching the maximum after 120 min. In the case of ZnSO4 and Zn−GO granules, similar amounts of Zn were recovered at >9 mm from the granules, 28 and 25%, respectively. In soil with CuSO4 granules, 29 % of the fertilizer Cu was recovered at >9 mm, whereas in soil with Cu−GO granules, 18 % of the fertilizer Cu was recovered in this zone. A pot trial demonstrated that Zn and Cu uptake by lettuce was higher when using GO-based fertilizers compared to that when using standard zinc or copper salts.

The findings revealed that solid pellet forms of micronutrient fertilizers (Zn−GO and Cu−GO) exhibited a notable capacity for nutrient retention (over 10%). This capacity is attributed to GO's substantial surface area and numerous oxygen binding sites on its surface and edges, facilitating the binding of micronutrient ions. The carrier based on GO exhibited a two-phase nutrient release profile, enabling the supply of micronutrients through both rapid release (approximately 40% within 5 hours) and gradual sustained release. This release pattern is highly advantageous for crops, as it meets the high nutrient demands during seedling establishment and provides a slower, continuous release during later growth stages. The impressive nutrient retention and favorable release properties of GO-based carriers make them an attractive choice for loading various nutrients (both macro and micro) and their combinations. Consequently, they have the potential to serve as versatile carriers, ushering in a new era of advanced Slow-Release Fertilizers (SRFs).