Study On The Adsorption Of Natural Zeolite And Modified Zeolite To Selenium(Ⅳ) And Its Reuse In Soil And Plants

This paper uses natural zeolite as a raw material to prepare a modified zeolite.The adsorption capacity of natural zeolite and modified zeolite for selenium(Ⅳ)in solution is studied,and the two are characterized.The reaction contact time and solution are experimentally analyzed.The influence of initial p H value,initial solution concentration and the amount of adsorbent added on the adsorption process.The kinetic model and isotherm model were used to fit natural zeolite and modified zeolite;then the release effect of modified zeolite in aqueous solution and soil was tested;finally,a plant pot experiment was conducted to analyze its effect on selenium-enrichment in pakchoi influences.Experiments show that the adsorption of selenium(Ⅳ)by natural zeolite and modified zeolite is a rapid process,which has the characteristics of "adsorpt apidly and slow equilibrium".The adsorption process is greatly affected by p H.The optimal reaction p H of natural zeolite is 2 and the optimal reaction p H of modified zeolite is 3.The adsorption process of natural zeolite is consistent with the first-order reaction kinetics,indicating that during the reaction process Affected by only one reactant,the adsorption process of modified zeolite and secondary reaction kinetics are more consistent,indicating that more than one reactant is affected in the reaction process;and the reaction process of both is similar to that of the Langmuir adsorption isotherm model.The results are more consistent,indicating that the process of selenium(Ⅳ)adsorption by natural zeolite and modified zeolite is mainly rhenium molecular layer adsorption;the theoretical maximum adsorption amount of natural zeolite is 4.63 mg / g,and the theoretical maximum adsorption amount of modified zeolite is 46.90 mg / g.Compared to natural zeolite,the theoretical maximum adsorption capacity is increased by 10 times.Modified zeolite has better adsorption effect on selenium(Ⅳ).The release experiment of selenium-modified zeolite in aqueous solution shows that no matter how the p H value of the aqueous solution changes,it will not affect the selenium release trend of selenium-modified zeolite in aqueous solution.The overall trend is to decrease and then maintain stability.In the soil release experiment,after adding selenium-modified zeolite to the soil,the selenium(Ⅳ)content in the soil increased,and all reached the selenium-enriched soil standard.At the same soil p H,the more selenium-modified zeolite added to the soil,the more selenium(Ⅳ)is released,but the smaller the release rate of selenium-modified zeolite.When the same amount of zeolite is added,the lower the p H value of the soil,the higher the selenium(Ⅳ)content in the soil,and the greater the release rate of selenium in the selenium-modified zeolite.As the content of selenium-modified zeolite in the soil increases,the selenium content in the soil and plants increases.If 0.06 g / kg ～ 0.13 g / kg selenium modified zeolite is added to the soil,selenium-enriched plants in the standard range can be obtained.In summary,the modified zeolite can be used as a good medium for removing water pollutants and also as an improver for soil improvement,which provides a new idea for the reuse of pollutants.The selenium-modified zeolite may be a potential fertilizer for soil improvement,which provides a better idea for the resource utilization of natural zeolite.