The kinetic activity value of adsorbent is the main basis for the design of adsorption system.
The adsorption rateThe adsorption process often takes a long time to reach equilibrium, and the contact time is limited in the actual production process.Therefore, the amount of adsorption depends on the adsorption rate, and the adsorption rate is related to the adsorption process, the adsorption process can be divided intoThe adsorption process often takes a long time to reach equilibrium, and the contact time is limited in the actual production process.Therefore, the amount of adsorption depends on the adsorption rate, and the adsorption rate is related to the adsorption process, which can be divided into the following steps
(1) External diffusion, the adsorbate from the main air flow through the air film around the particles to the outer surface of the adsorbent; (2) Internal diffusion, the adsorbate from the outer surface through micropores to the surface of the adsorbent micropores
(3) adsorption, the adsorbent reached the microporous surface of the adsorbent is adsorbedhttps://www.yrdcarbon.com/
(4) The desorbed adsorbate diffuses to the main body of the gas phase through internal and external diffusionPhysical adsorption process is generally controlled by internal and external diffusion, chemical adsorption is controlled by both surface dynamics and internal and external diffusion.Because of the complexity of the adsorption process and many influencing factors, it is difficult to derive the rate theoretically, so it is generally determined by experience or model experiment.Acid-base modification is to use acid, alkali and other substances to treat activated carbon, according to the actual need to adjust the surface functional groups of activated carbon, make it change, improve its ability of adsorption of metal ions, so as to achieve the desired adsorption effect.Acid-base modification of activated carbon is usually carried out to improve the adsorption effect of activated carbon on metal ions represented by copper ions. The commonly used modifiers include HC1, NaOH and citrate 3.It was found that by acid-base modification of common coal activated carbon, the ash content of the activated carbon could be greatly reduced and the specific surface area of the activated carbon could be increased
Electrochemical modification is to change the electrical and chemical properties of activated carbon surface by using micro electric field, so as to improve the adsorption selectivity and performance.It does not need to add chemical agents, does not need to heat, does not cause pollution to the environment, low energy consumption, only a few hundred millivolts, easy to operate.The results show that the adsorption equilibrium of activated carbon is dependent on the electric potential: the adsorption amount of activated carbon increases with the increase of the potential, and the adsorption speed is accelerated;Arpolarity polarization is beneficial to the adsorption of chloroform by activated carbon, while cathodic polarization inhibits the adsorption of chloroform by activated carbon 3-341]. Activated carbon heteroatom carrier and compound modificationActivated carbon has very high stability and good activity, these two basic properties become the activated carbon as a catalyst or catalyst carrier conditions.By introducing certain heteroatoms and compounds on the surface of activated carbon by liquid phase deposition, the adsorption performance of activated carbon can be increased by using the binding effect between these substances and adsorbents.compounds, which has the advantages of increasing the reaction rate and increasing the adsorption capacity.Yang Quanhong et al. 'Using FESO;Activated carbon material was modified.activated carbon suppliers south africa