The Transmission Kinetics Study Of Germanium In Black Soil-Vegetables System

Germanium is broadly applied as important semiconductor and super conductor, germanium is also important material in oil-industry. The waste of these industries consists of lots of germanium. Plants absorb heavy metals from soil, people can absorb heavy metal through food chain. Heavy metal not only have effect on the growth , the harvest and quality of the plant of the plants ,but also on the health of people .Nowadays vegetables especially leaves-vegetables have become one of the important food in lots of countries, the consumption of which grows rapidly .The law of germanium translocation and accumulation in vegetables and soil added of that germanium system were also studied.A new method , microwave plasma torch atomic emission spectroscopy (MPT-AES),was used to determine trace elements germanium in vegetables and soil. The samples were wet ashed and then dissolved by HNO3-H3PO4-H2O2 hydrochloric acid. Some experimental parameters are discussed and optimized. Microwave power is 80W, negative high pressure is 800V, wave length is 265.118nm,support gas is 0.50L/min, carrier gas is 0.90L/min. The recoveries are in the range of 92.77%~95.60%, and the RSD is less than 4.00%.The merits of the method are high sensitivity, rapidity less gas consumption and so on.The effective factors on absorption of germanium in black soil were also studied. The results showed that time, organic matter, temperature and pH have effect on the absorption of germanium. The absorption quantity increased with time prolonged and reached balance when it was two hours and half. Organic matter added can greatly increased the capacity of germanium absorption. With temperature increasing, the germanium absorption decreased. The isothermal germanium absorption data obtained all fitted with : Langmuir, Freundlich and Temkin equation, and the conventional Langmuir equation seemed to be the best one to describe the sorption data as judged by its very significant correlation coefficients. The correlation coeffecient is 0.9985~0.9992.The order of absorption maximum(X_m) is 15℃ >25 ℃>35℃;The order of absorption parameters(K) is 15℃>25℃>35℃; The absorption capacity of 15℃ is strongest, the absorption quantity is biggest. The result of the adsorption kinetics and thermodynamics behavior of germanium absorbed by black soil in water solution showed that the absorption precession could fit for Banum model. The result of the activation energy of adsorption (E_y), the activation enthalpy of adsorption( △H_y), the activation free energy of adsorption, the activation entropy of adsorption( △S_y) showed that the absorptionprecession was a exothermic chemical precession. The reaction can't go along freely and can make the system more legitimate. Under the same pH, germanium absorption quantity increased with increasing germanium concentration. Under the same germanium concentration, the order of germanium was: pH9>pH6>pH3. Within pH3~pH9, the linear Freundlich isotherm was found to be more suitable than other isotherms in describing germanium absorption characteristics of black soils. The correlation coefficient is 0.9957-0.9993.In this paper, the effect of germanium on vegetables such as Chinese spring cabbage, cherry-radish and pease at cabinet and pot culture system outdoors were studied. The law of germanium translocation and accumulation in vegetables were also studied. The results showed that concentration of germanium in soil can increase the vegetables growth but high germanium content can inhibit the growth or have the toxicity. The effect of germanium on different vegetables is different. The effect of germanium on different organs of the same vegetable was also different.High germanium content such as 50mg/kg can prolong the time of germination; lOOmg/kg can inhibit germination and the percent of germination was low. Low concentration of germanium such as lOOmg/kg resulted in young plant perished. High germanium content have obvious inhibitation and toxicity influence. When germanium content exceed 50mg/kg, the leaves of pease began to become yellow, slim gradually and flat pean-pot was more ,the root began to present brown, break and even bad dead with the period extention of growth. The root of cherry-radish became aging and hard ,it was root vitality was repressed seriously that the plant make less use of the nutrition of the soil and cause obvious output reduction.The germanium content of low level have promotive function on the growth of cherry-radish and pease, making them long power prosperous, biomass increasing. When the germanium content is 30mg/kg, the biomass of root, stem, leaves, pean-pot of pease is 3.83%, 21.82%, 16.73%, 11.91% more than the contrast. The total biomass is 14.16% more than the contrast. The change of the root of cherry-radish is obvious than the above part. When germanium content is 30mg/kg, the biomass of the above part is 80g/pot, was 12.80% more than the contrast. The biomass of the root is 64.72g/pot, is 66.09% more than the contrast. The total biomass of cherry-radish is 35.68% more than the contrast. The germanium content above 30mg/kg have repressive or toxicitive effect on the growth of cherry-radish and pease. When germanium content is lOOmg/kg, the biomass of root, stem, leaves and pean-pot ofpease each pot were decreased by 16.33%, 17.49%, 16.06% and 12%. The biomass of the above part cherry-radish was 50.60g/pot, decreased by 6.17%; the biomass of the root was 22.70g/pot, was decreased by 44.09%. The germanium content of 5,10,30,50mg/kg all have promotive effect on the growth of Chinese spring cabbage. But when germanium content above 50mg/kg, germanium began to have repressive effect on Chinese spring cabbage, the biomass decreased. When the germanium lOOmg/kg, the biomass was 143.63g/pot, decreased by 11.95%. As the yield decrease by 10%, the critical germanium concentration of in soil are: pease: 92.42mg/kg; cherry-radish: 62.40mg/kg; Chinese spring cabbage: 96.43mg/kg.The regulations of germanium concentration was: Pease: root > stem >leaf>pean-pot; cherry-radish: root > above part; Chinese spring cabbage: root > leaf. The enrichment parameters of different vegetables was different: pease > cherry-radish > Chinese spring cabbage. And different organs of the same vegetables was also different. These lie on the varieties of vegetables and the structure characteristic of different organs. These were also one of the presentation of the type of the vegetables. On the other hand, the germanium content of the soil was also an important factor on the content of vegetables.The study can offer basis for the resolving of pollution problem by irrigation with industrial water contained germanium, and also can help the work of the restoration and resumption of abandoned germanium mine lands. This paper can support for the study of germanium environmental and ecologic effect.