| Summary: | 博士 === 國立勤益科技大學 === 化工與材料工程系 === 106 === The adsorbent used for recycling waste tires, were prepared by phosphoric acid-activation and nitric acid modification. We investigate the removal effects of the dibenzothiophene. The characteristics of preparing materials are analyzed by BET, XRD, SEM, EDX and Boehm.
The waste rubber is treated with concentrated sulfuric acid to recover the rubber, and the carbon black obtained by the cracking not only can improve the specific surface area and lower the average pore diameter, but also remove impurities such as Si, S and Zn in the tire rubber.To achieve the effect of purified carbon material.
In the phosphoric acid activation method, the effects of phosphoric acid activation temperature and phosphoric acid/carbon black ratio on material properties and adsorption properties were investigated. The adsorbent prepared at an activation temperature of 650 ° C and a phosphoric acid / raw material mass ratio of 2:1 has an optimum DBT adsorption removal rate of 49.4%.
In the surface modification of nitric acid, the optimum DBT adsorption removal rate was 72% when the concentration of nitric acid was 15 M, modification temperature 70 °C and modification time 3 hours. The adsorption performance is mainly affected by the functional groups on the surface of the adsorbent. The functional groups include lactone 0.27 mmol g-1, hydroxyl group 0.48 mmol g-1 and phenol 1.61 mmol g-1. The increase of surface functional groups is beneficial to the activated carbon pair.
In the optimization of adsorption conditions: the optimal adsorption time of activated carbon for DBT is 1 hour; when the amount of adsorbent is 0.2 g, the adsorption desulfurization rate is the highest, and the desulfurization rate is 95%. Moreover, the desulfurization rate of activated carbon to DBT adsorption in simulated oil decreases with increasing adsorption temperature.
The experimental results were fitted the Langmuir isotherm equation and the Freundlich isotherm equation. The results show that the Langmuir adsorption isotherm model is more suitable for the adsorption behavior of dibenzothiophene on activated carbon (R2=0.9933), and the obtained constant qm and b are 254.45 mg g-1 and 0.106 mL mg-1, respectively.
In the adsorption kinetics study, the pseudo-first-order kinetic model and the pseudo-second-order kinetic model were used to fit the experimental results. The results show that the pseudo-second-order kinetic model is more suitable for the adsorption behavior of dibenzothiophene on activated carbon (R2=0.9998). The obtained parameters Cal.qe and K2 are 166.3893 mg g-1 and 0.0188 min-1.
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