Study On Preparation And Adsorption Properties Of Three Kinds Of Active Carbon Fibers

In this paper,the preparation and adsorption properties of active carbon fibers with different raw materials are mainly studied,and wood residues were modified to improve their adsorption properties,and a low cost and high-performance adsorbent material was obtained.With cotton linter,refined cotton,viscose fiber,three different materials for the preparation of activated carbon fiber.The effects of concentration of phosphate solution,Dipping time of phosphate solution,activation time and activation temperature on the crystal form of active carbon fibers were investigated by X-ray diffraction(XRD)and Specific surface area analysis(BET).The optimum conditions for the preparation of ferrite were determined.Scanning electron microscopy(SEM)analysis showed that the activated carbon fibers prepared under these conditions had good morphology and the surface was showed uneven by steam etching.Three kinds of activated carbon fibers: ACF(a),ACF(b)and ACF(c),which were prepared under the best technological conditions,were adsorbed on two kinds of dyes,Congo red and malachite green.The effects of adsorption time,pH value,adsorbent amount and dye initial concentration on dye removal were elucidated.The main conclusions were as follows:With cotton linter,refined cotton,viscose fiber as raw material by phosphate impregnation,carbonization and activation process of activated carbon fiber preparation,the optimum synthetic conditions were as follows:(1)The hosphate concentration was 5%,(2)The impregnation time was 1 hour,(3)Carbonization at425? for 60 minutes,(4)Activation at 900 centigrade for 30 minutes.Congo red was used as model cationic dye wastewater.The results of the adsorption experiments were as follows: Under these conditions that the room temperature was 297 K,the CR initial concentration was 200 mg/L,the pH was 6,the adsorbent amount of ACF was 0.10 g,the adsorption rate of ACF(a)to Congo red was93.21%,and the equilibrium adsorption amount was 186.43 mg/g;the adsorption rateof ACF(b)to Congo red was 90.09%,and the equilibrium adsorption amount was180.18 mg/g;the adsorption rate of ACF(c)to Congo red was 91.21%,and the equilibrium adsorption amount was 182.43 mg/g.The isothermal adsorption model corresponded well with the Langmuir isotherm;the dynamic adsorption model corresponded well with pseudo-second order kinetic equation.After calcining at 800 centigrade and after 5 times adsorption experiment,ACF can be reused,the CR removal rate was still 90 %,its environmental performance was better.Three compared to cotton as the adsorption of activated carbon fiber prepared better,the maximum adsorption rate,adsorption capacity is the largest.Malachite green was used as model cationic dye wastewater.The results of the adsorption experiments were as follows: Under these conditions that the room temperature was 297 K,the CR initial concentration was 500 mg/L,the pH was 8,the adsorbent amount of ACF was 0.015 g,the adsorption rate of ACF(a)to Malachite green was 95.31%,and the equilibrium adsorption amount was 3177.11mg/g;the adsorption rate of ACF(c)to Malachite green was 95.57%,and the equilibrium adsorption amount was 3185.79mg/g;and the adsorbent amount of ACF(b)was 0.02 g,the adsorption rate of ACF(b)to Malachite green was 95.83%,and the equilibrium adsorption amount was 2395.87mg/g.The isothermal adsorption model corresponded well with the Langmuir isotherm;the dynamic adsorption model corresponded well with pseudo-second order kinetic equation.Three compared to cotton as the adsorption of activated carbon fiber prepared better,the maximum adsorption rate,adsorption capacity is the largest.The adsorbability of the activated carbon fibers prepared from refined cotton is poor,the adsorption rate is the least,and the adsorption amount is the smallest among the three.Compared with two adsorption experiments,it was found that the adsorption effect of activated carbon fiber on malachite green dye wastewater was better.By comparing the adsorption experiments of Congo red and peacock green,it is found that it is beneficial to the adsorption of Congo red under the acidic condition,and it is beneficial to the adsorption of peacock green under the alkaline condition,and the adsorption rate of Congo red is faster,and the overall adsorption effect onCongo red dye and malachite green dye is good as a whole.According to the best process obtained above,the wood waste material was modified and the material A was obtained.The material A was analyzed by specific surface area analysis(BET).The results showed that the surface area of the modified material was more than 100 times larger than that before the modification.Congo red was used as model cationic dye wastewater.The results of the adsorption experiments were as follows: Under these conditions that the room temperature was 297 K,the CR initial concentration was 200 mg/L,the pH was 6,the adsorbent amount of wood residues was 0.10 g,the adsorption rate to Congo red was 94.34%,and the equilibrium adsorption amount was 188.68 mg/g.The isothermal adsorption model corresponded well with the Langmuir isotherm;the dynamic adsorption model corresponded well with pseudo-second order kinetic equation.