Prearation And Characterzation Of Organic Acid Chelated Iron Compounds

The growth and development of plant needs many nutrients.In plants,iron is an important microelement and plays a vital role in metabolism process.But in all parts of the world,there is a universal phenomenon that iron deficiency induced chlorosis of leaves,which is harmful to the production of food or cash crops.In addition,iron deficiency chlorosis has brought great economic losses for farmers and hindered the development of agriculture.Iron deficiency chlorosis is a hot spot in the field of plant nutrition.This phenomenon is more serious in the calcareous soil of the Loess Plateau,especially for the perennial fruit trees,which hinders the development of the fruit industry.The common way to solve this problem is the application of inorganic fertilizer,but it did not significantly improve the soil iron deficiency.In recent years,more and more attention has been paid to chelated iron fertilizer and organic compound iron fertilizer.However,due to the high cost and potential harm to the soil,the problem of iron deficiency chlorosis of fruit trees has not been solved well.In this study,two synthetic methods were tested.By comparing the two methods,choosing a more suitable one was used for research and development of natural organic small molecule chelated iron fertilizer,in order to provide a solution to solve the problem of iron-deficiency chlorosis of fruit trees in calcareous soil on the Loess Plateau.Main results were as follows:?1?The water system synthesis method was used in this experiment.The fulvic acid and ferrous sulfate were used as reactants,and finally the fulvic acid iron was obtained.It is proved that fulvic acid really has the ability to chelate ferrous ions.And based on the analysis for the infrared spectra deduce that the carboxyl group of C=O and COO-in the carboxyl group within the 1600-1700 cm^-1 range,or the carboxyl group bound by hydrogen bonds within the 1000-1200 cm^-1 range,is chelated with ferrous ions to produce fulvic acid iron.However,the mechanism of the specific chelation is unknown.In addition,the process of rotating evaporation concentration and freezing drying are time-consuming and laborious,and the output is low,which can not meet the needs of the practical production.So it is necessary to find a more suitable method.?2?In this experiment,the method of solid phase grinding at normal temperature is adopted the fulvic acid and ferrous sulfate were used as reactants,and finally the fulvic acid iron was obtained.It is proved that fulvic acid and ferrous salt react in the process of grinding.Moreover,after the improvement of the experiment,the chelate ratio of the purified product reached 50.24%.So the application is feasible in practice.But it is necessary to further optimize the experimental design and find the best technological process.By analyzing the functional groups of fulvic acid and fulvic acid and ferrous iron chelate products,it is speculated that the reaction between ferrous iron and-OH in carbohydrates within 520-650cm^-1 is possible.However,some of the treated spectra show almost no change in carbohydrates within 520-650 cm^-1.Therefore,more advanced techniques are needed to explore the mechanism.To sum up,by comparing the two methods,solid-phase grinding method is more simple and convenient,and the yield is high.Thus it is more applicable in reality.It was also confirmed by Fourier transform infrared spectroscopy that fulvic acid and ferrous chloride did react.However,it is not clear whether the chelation reaction or the adsorption reaction occurs.Therefore,the reaction mechanism needs to be further explored.