| With the rapid development of economic and society,the demand for fresh water is increasing,which is in inverse proportion to the storage volume,because of water resources losing and pollution.In order to solve the sho rtage of freshwater,the researchers are paying attention to desalination,including an innovative method of capacitive deionization technology(CDI).The key technology of CDI is the manufacture of electrode materials.Carbon materials have the excellent characteristics of acid,alkali and salt resistance,are the preferred materials for desalination electrodes.As a kind of carbon materials,carbon fiber felt is self-supporting and high conductivity.In this paper,three kinds of carbon fiber felt electrodes had been studied: long-cut carbon micron fiber felt,electrostatic-spinning carbon nanofiber felt and hiberarchy carbon fiber felt respectively.In the processes of experiment,the raw materials were prepared to characterization analysis and performance test.For long-cut carbon micron felt(CMF),the surface of CMF was modified by acetone and nitiric acid to obtained hydrophilic and electroconductibility characters.Many properties of material were tested,the contact angle was 40.1 o,the electrical resistivity was 47.1m?·cm,the specific surface area was 9.6185m2/g.The factors affecting capacitive deionization were studied to abtain optimum test plan: the electrodes were placed in a vertical direction;electric adsorption amount of ten pairs of electrodes was better than five and three for the same total mass;1.2V was the best voltage;the electrodes had adsorption effect for 1000mg/L,2000mg/L,3000mg/L,4000mg/L Na Cl solution.Under the concentration of 200mg/L,the percentage of demineralization was 5.14%,the adsorption quantity was 2.05mg/g;under the concentration of 500mg/L,the percentage of demineralization was 9.04%,the adsorption quantity was 9.04mg/g;under the concentration of 1000mg/L,the percentage of demineralization was 8.69%,the adsorption quantity was 17.39mg/g.For electro-spinning carbon nanofiber felt(CNTs/G/CNFs),the technologies were explored.The high voltage was 24 KV,the inside diameter was 0.4±0.01 mm,the rotation speed of drum was 30r/min,the space between two syringe needle was 15 cm during the electrostatic spinning process.The peroxidation temperature was 290? for 1h and the carbonization temperature was 900? for 1h during the heat treatment process.After tests,the contact angle was 126.57o,the electrical resistivity was 1.865 ×10-3?·m,the specific surface area was 223.8m2/g.Under the concentration of 200mg/L,the percentage of demineralization was 24.7%,the adsorption quantity was 8.22mg/g;under the concentration of 500mg/L,the percentage of demineralization was 17.78%,the adsorption quantity was 18.77mg/g;under the concentration of 1000mg/L,the percentage of demineralization was 18.01%,the adsorption quantity was 36.03mg/g.After five times cyclic utilization,the initial effect was the best and the desalination performance reduced slightly.For hiberarchy carbon fiber felt(D-CNTs/ CCNFs),it was considered as flexible electrode,because carbon nanotubes formed a net structure between carbon micronfiber felt and carbon nanofiber felt under the condition of nickel and cobalt catalyst.Then the property of electro-adsorption desalination was studied.Under the concentration of 200mg/L,the percentage of demineralization was 27.22%,the adsorption quantity was 9.04mg/g;under the concentration of 500mg/L,the percentage of demineralization was 19.86%,the adsorption quantity was 20.96mg/g;under the concentration of 1000mg/L,the percentage of demineralization was 18.83%,the adsorption quantity was 37.67mg/g.After five times cyclic utilization,the initial effect was the best and the desalination performance reduced slightly.Above all,we know that those three kinds of electrodes possessed capacitive deionization property.Compared to CMFs and CNTs/G/CNFs,hiberarchy carbon fiber felt was the best under the concentration of 200mg/L,500mg/L and 1000mg/L. |
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