Study On Adsorption And Regeneration Performance Of Expanded Activated Carbon Composite Of Modified Titanium Dioxide

Carbon-based nanostructured materials have a unique structure and excellent adsorption capacity,and are often used in the research of removing various pollutants.However,the development of carbon-based adsorbent materials mainly is faced with two problems:?1?They have limited ability to adsorb pollutants,?2?they cannot be used multiple times when the adsorption reaches equilibrium.In order to solve the problem described above,many researchers continuously improve the capacity of adsorption,and make them achieve the effect of multiple recycling through a series of methods.In this paper,the following research work has been done on the current problems of carbon-based adsorption materials:?1?Preparation method and study on adsorption properties of expanded activated carbon?EX-AC?.I tried to use corn and expanded corn as raw materials respectively to prepare activated carbon by making use of phosphoric acid activation.The results show that the EX-AC's surface area increased by 131%than that of unexpanded activated carbon?AC?,and the adsorption capacity of methyl orange increased by 73.24%,its maximum adsorption capacity is 127.05mg/g.and I also explored a series of factors affecting the adsorption effect of EX-AC on methyl orange,the experimental results are as follows:All experiments were completed under the condition of dosage of 1g/L.When the concentration increased from100mg/L to 150mg/L,the removal rate decreased by 23.62%,when the temperature risen from 20?to 50?,the maximum adsorption capacity increased by 9.5%,when the pH of the solution risen from 4.5 to 9.5,the removal rate dropped by 14.7%,when the chloride ion concentration increased from 0 to 0.5mol/L,the removal rate decreased by 7.3%.After fitting the kinetic equations and thermodynamic equations to the experimental data,it was found that the adsorption of EX-AC is very close to the quasi-second-order adsorption kinetics.Otherwise EX-AC's adsorption process is very close to the Langmuir equation,and its gibbs free energy is negative in this process,indicating that the adsorption process can be spontaneous.In addition,I tested the adsorption capacity of EX-AC for chloramphenicol,it was found that the EX-AC's adsorption rate of 80mg/L reached 97.14%,and the maximum adsorption value was 97.68mg/g.?2?Preparation of titanium dioxide photocatalytic material thiourea modified?S_X-TiO₂?.In this chapter,the mixed solution was prepared by titanium tetrachloride and different quality thiourea,and adding ammonia to the mixture until it is neutral,and then let precursor calcine at high temperature in muffle furnace.Results show that when the ratio of titanium tetrachloride to thiourea is 4:3,the S₃-TiO₂ composite material showed excellent catalytic degradation of methyl orange under visible light.The forbidden energy of S₃-TiO₂ is only2.4ev,which is much smaller than pure TiO₂.Using mercury lamp as the light source,investigated the photocatalytic performance of S₃-TiO₂,its degradation performance of methyl orange reached 96%within 130 minutes.·O₂^-?h⁺?·OH all have a great influence on the catalytic process,of which·O₂^-has the largest effect.After 4 cycles of experiments,the removal capacity of methyl orange will degrade slightly.?3?The EX-AC and S₃-TiO₂ were compounded in a certain proportion by ultrasonic-calcination.The results show that when the ratio of EX-AC to S₃-TiO₂ is 4:1,the composite not only retains excellent adsorption performance,but also has the ability of photocatalytic regeneration.The regeneration rate reaches 79.8%after 12 hours of ultraviolet.After four cycles experiment,the adsorption and regeneration ability are stable.