Study On Preparation Of High-performance Activated Carbon Fiber Based On Biomass

The preparation of high-performance activated carbon fibers based on loofah sponge fibers(HP-ACF) were studied and water-soluble phenol-formaldehyde resin was used as the impregnating agent in the study. Physical and chemical properties of HP-ACF and HP-ACF function in DCB wastewater treatment were studied.Orthogonal test was arranged according to Heating rate, pre-oxidation temperature, pre-oxidation time, activation temperature and activation time. Through the orthogonal test, the optimal preparation conditions were determined. the optimal preparation conditions were the heating rate of 8 ? /min, the pre-oxidation temperature of 200?, the pre-oxidation time of 2 h, the activation temperature of 850?, the activation time of 90 min. HP-ACF was finally prepared under the optimal preparation conditions. By thermogravimetric analysis of loofah sponge, water-soluble phenol-formaldehyde resin, impregnated loofah sponge was studied. The probable reactions between water-soluble phenol-formaldehyde resin and luffa sponge were analyzed.Characterization of surface physical and chemical properties was done with samples from orthogonal test and LSF-ACF-P. scanning electron microscopy(SEM);Nitrogen adsorption- desorption isotherms and XRD were applied to characterize the physical properties on the surface. Fourier infrared spectrum(FTIR) was applied to characterize the surface chemical properties. The results showed that with electron microscope, the surface of ACF has generated class graphite layer structure. Nitrogen adsorption- desorption isotherms of ACFs were the same and were belonged to the?isotherm according to IUPAC. Micropores were the major pores of ACFs. At the same time, there are a few in the hole of ACFs. HP-ACF was the product under the optimal preparation conditions, with a huge specific surface area of 422.47 m2/g, average pore diameter of 1.820 nm and total pore volume of 0.192 cm3/g. It was proved that luffa sponge activated carbon fiber contained carbonyl groups, phenolic hydroxyl groups and aromatic cyctic structures through FTIR tests. From XRD curves, it was inferred that the structure of cellulose, hemicellulose and lignin was damaged, the molecules inside rearranged and amorphous carbon materials were finally prepared. Through universal testing machine test the compressive strength of high-performance ACF, and compressive strength of 0.246 MPa. It is visible that high-performance ACF has certain compressive capacity.HP-ACF was applied in DCB wastewater treatment. The influencing factors of the adsorption of DCB wastewater as temperature, pH, and dosing quantity were studied. The results showed that the adsorption of DCB wastewater by HP-ACF was exothermic reaction and the best adsorption temperature is 25?.pH?5,it is ideal for the removal rate of HP- ACF to DCB wastewater,pH>5,the removal rate of HP-ACF to DCB wastewater fell sharply. In 20 mg/L DCB wastewater treatment, when dosing quantity is 1 g/L, the removal rate of activated carbon fiber for DCB tend to the maximum, the removal rate of 98.29%. DCB adsorption isotherms were described respectively with Langmuir adsorption isothermal model and Freundlich adsorption isothermal model. The correlation coefficient of the fitting of two adsorption isotherms was above 0.95. Using the Langmuir adsorption isotherm model fitted results more consistent. Pseudo first-order model and the pseudo second-order model were introduced to fit the HP-ACF's adsorption of DCB wastewater. And the R2 of Lagergren pseudo second-order model was 0.9821. The R2 of Lagergren pseudo first-order model was 0.9534.The pseudo second-order model can better describe HP-ACF's adsorption of DCB wastewater. The HP-ACF after adsorption were regenerated by heating in NaOH solution. After the regeneration, the equilibrium adsorption capacity of ACF and its regeneration efficiency is slightly reduced. Regeneration after four times, the adsorption capacity of ACF is still over 70%.It is visible that high-performance activated carbon fibers have better regeneration effect.