Background and Aim: Currently, several methods are used to remove heavy metals from aqueous solutions, one of which is the adsorption process. Graphene oxide nanoparticles, due to their high adsorption capacity, have caused major concerns. The current study aimed at assessing the role of these particles in removing Chromium and Lead from aqueous solutions.Materials and Methods: This empirical study investigated the effect of the initial concentration of pollutants, their PH, adsorbent dose, time and temperature on graphen oxide nanoparticles capacity in removing Chromium and Lead from aqueous solutions.Results: Maximum adsorption efficiency occurred at PH=9 with initial concentration of 4 mg/L and at PH=3 with initial concentration of 3 mg/L for Lead and chromium, respectively. Maximum efficiency of Lead and Chromium adsorption by graphen oxide occurred at 0.01 g dosage of the adsorbent and after 15 minutes of contact time, i.e. 90% and 42.33%, respectively. Results showed that adsorption of the two metals was better in accord with Freundlich isotherm. Thermodynamic reaction results revealed that Cr adsorption reaction was exothermic and that of Pb was endothermic.Conclusion: The adsorbent Graphen Oxide has got a favorable role in removal of the two contaminants, Lead and Chromium from aqueous solutions and waste waters.

Background and Objective: Water pollution with heavy metals is one of the most important environmental problems that affect human life and health by causing serious diseases. Therefore, it is necessary to control their presence in the environment. Despite the high use of zinc in industry and the pollution of water resources by effluents containing it and the problems caused 0062002y the presence of this metal in drinking water, a study on the use of chitosan nanoparticles taken from the waste of fish breeding workshops and Shrimp has not been done to optimally remove this metal from water sources. Method: Here, a nanocomposite of chitosan and graphene oxide was synthesized at the University of Jiroft in 2019 and used for removal of zinc metal from industrial wastes. The effects of initial solution pH (2-7), chitosan/graphene oxide bio-sorbent dose (0-1. 5 g/l), initial zinc (II) concentration (10-200 mg/l) and contact time on the uptake capacity of metal (30-420 min) were investigated. Findings: This nanocomposite was exhibited the highest metal ions uptake capacity (89. 2 mg/g) at pH value of 4. 0, biomass dose 0. 01 g/l, metal concentration of 200 mg/l and contact time 420 min. The structural stability and efficient adsorption capacity of adsorbent was proved after four times adsorption– desorption cycles and after that uptake capacity was 19. 35 mg/g. Discussion and Conclusion: The results showed that the synthesized nanocomposite from chitosan and graphene oxide could be used as a potentially good adsorbent to remove Zn2+ simultaneously in aqueous solutions.

More than 22% of the world's agricultural land is saline, and this trend continues to increase with climate changes. Salinity stress causes leaf color change, osmotic stress, ionic toxicity, prevents growth, photosynthesis and plant performance. Due to their size less than micron, metal nanoparticles have a great absorption and transmission power in plants. Salinity stress is a major problem in hot and dry areas under tomato cultivation. For this purpose, investigating the mutual effects of the size and type of zinc oxide and iron oxide nanoparticles on the improvement and change of growth and increasing the resistance to salt stress in tomato plants of the early urbana variety were carried out in the form of a completely randomized and factorial design with 4 replications, at a significant level of 5%. In this research, zinc oxide nanoparticles in 25 and 50 nm sizes, iron oxide in 25 nm sizes and sodium chloride in 0 and 75 mM levels were used. Nanoparticles and salinity treatments were both applied to the plants. The results showed that salt stress led to a decrease in plant growth parameters such as shoot and root length, leaf area, RWC, ion leakage. Also, NaCl led to an increase in the accumulation of prolin and other aldehydes, sodium, iron and zinc. The application of nanoparticles had a slight effect in stress-free conditions, but in stressed conditions, these two nanoparticles alone and especially in combination neutralized the effect of salinity and reduced the damage caused by salinity stress.

In this study, Graphene Oxide- Gold nanoparticles (GO-AuNPs) nanocomposite as novel adsorbent was synthesized by direct reaction between GO and chloroauric acid for removal of amoxicillin from aqueous solution.Nanocomposite (GO-AuNPs) was characteristic by FT-IR spectroscopy. The changes of parameters such as contact time, pH of solution, initial amoxicillin concentration and temperature were measured and investigated by several adsorption experiments various factors affecting the uptake behavior. The adsorption kinetics well described by a pseudo-secondorder rate model.