Preparation Of Hollow Silica Microspheres Modified By Potassium Permanganate And Study On Its Removal Of Antimony(?) In Water

With the mining of antimony ore and the increasing demand and use of antimony-containing products,antimony will inevitably be caused to enter the environment,especially the antimony mining area and the surrounding water,atmosphere and soil are seriously polluted.Antimony that enters the environment may be absorbed by the human body after migration and transformation and enrichment in the food chain,which poses a potential threat to human health.At present,there are many methods for removing antimony in water.Among these methods,the adsorption method is widely used due to its advantages such as low running cost,good treatment effect and wide application range.There are many types of sorbents.As a non-toxic and biocompatible inorganic material,hollow silica microspheres?HSS?have a unique cavity porous structure that gives them advantages such as large specific surface area and large pore volume.Rich in hydroxyl groups,it is easy to be functionally modified,and has been studied by many scholars for adsorption and removal of pollutants in water.Therefore,in this thesis,HSS was selected as the adsorbent,and in combination with the existing research results,HSS was prepared by a two-step method and compared with the dual template method.The effects of ammonia concentration,hydrolysis time,and stirring speed on the morphology and particle size of HSS were studied.By changing the conditions of the synthesis process to control its morphology,the best synthesis process parameters of monodispersed hollow silica microspheres with controllable particle size were achieved.On this basis,the hollow silica microspheres were modified with potassium permanganate solution.The static adsorption experiment was used to study the effect of the amount of adsorbent added,the initial pH value of the solution,the adsorption time,the initial concentration on the removal of Sb???on the hollow silica microspheres before and after modification and the adsorption of Sb???on adsorbent was analyzed from the perspective of kinetics and adsorption equilibrium.The main findings are as follows:1.From the aspect of product morphology and performance,the two-step method and the dual template method can control the particle size of the product in different ranges.The two methods control the particle size of the silicon spheres at the micron level and sub-micron level,respectively.The product of dual template method has better sphericity,higher specific surface area,and higher purity.From the perspective of synthesis process and cost,the synthesis cycle of the two-step method is shorter,the process is simpler and more economical.2.When the hydrolysis time of phenyltrimethoxysilane is between 3and 5 minutes,regular spherical silica microspheres can be obtained and the average particle size of the microspheres decreases with the increase of the hydrolysis time.When the ammonia concentration is in the range of2.36mol/L to 2.90mol/L,the average particle size of the microspheres gradually increases with the increase of ammonia concentration at first.When the ammonia concentration reaches a certain value?2.47mol/L?,it begins decrease.The morphology of the product is the best at a rotation speed of 260 rpm,with a regular spherical shape and a uniform particle size.However,it is difficult to ensure the product's appearance and narrow particle size distribution at other rotation speeds.3.The number of oxygen-containing functional groups on the surface of hollow silica microspheres modified with KMnO₄?KMnO₄/HSS?increases.So the adsorption capacity of HSS is improved to a certain extent.The results of adsorption experiments of Sb???in water by HSS and KMnO₄/HSS show that at the pH range of 3.0 to 10.0,with the increase of pH,the adsorption effect significantly decreased.In 100mL solution with initial concentration of 0.43mg/L,the removal rate gradually increases with the increase of the dosage of adsorbent.When the adsorption time t is about 2h,it's reaches an adsorption equilibrium state basically,and the removal rate no longer increases significantly.The adsorption process of Sb???in water by HSS and KMnO₄/HSS is more consistent with the Langmuir isotherm model.The theoretical saturated adsorption capacities of HSS and KMnO₄/HSS are 33.43mg/g and37.04mg/g,respectively.Kinetic studies show that the adsorption process of Sb???by HSS and KMnO₄/HSS is more in line with the quasi-second-order kinetic model.