Fabrication Of Polyacrylonitrile-based Activated Carbon Fibers Functionalized Sodium Dodecyl Sulfate For The Adsorptive Removal Of Organic Dye From Aqueous Solution

Organic dyes are released into the environment during production and use,which have a great threat to the health of human beings and other organisms.Methylene blue?MB?is one of the representative organic dyes.Activated carbon adsorption was one of the most effective ways to remove MB in natural environment.All the time,few attentions were paid to the reuse of industrial waste.Every year,the wastage rate of polyacrylonitrile?PAN?was as high as 7%.PAN is a common and inexpensive commercial product and recovery of cationic dye.Thus,it was an important meaning to condue the research of the adsorption removal of MB and the reuse of PAN resources.activated carbon was prepared from PAN and modified with twelve alkyl sodium sulfate?SDS?.Then the PAC-SDS was obtained.And the physical and chemical properties of the composite adsorbent were analyzed.The results mainly showed that:?1?The adsorption conditions were optimized and explored by adsorption experiments,and the results showed that the optimal conditions for the PAC-SDS adsorption MB were:in 100mgL 1 MB solution,the optimal dosage of PAC-SDS was 0.01g,initial pH 10 or 11,and the maximum adsorption capacity was 227.82 mg g^-1.?2?The physical and chemical properties of the composite adsorbent were analyzed by FTIR,XPS,BET and SEM.The results showed that the modified activated carbon had more functional groups compared with pristine activated carbon.?3?Under the optimized conditions of pH and dosage,the adsorption kinetics of PAC-SDS at different adsorption time was analyzed.The adsorption process accords with pseudo two order kinetics model,and the correlation coefficient R2 is above 0.998.The amount of MB adsorbed rapidly reached to 210 mg g"1 within the beginning 15 min,then the adsorption of MB onto PAC-SDS was increased only 17 mg g^-1 with the process last a long time until the sorption reached to the equilibrium.The results indicated that the mechanism of MB sorption by PAC-SDS depended on the potential rate-controlling steps due to chemical sorption.?4?Under the optimized conditions of pH and dosage,the adsorption isotherms of PAC-SDS at different initial concentrations were plotted and fitted.Langmuir and Freundlich models were used to analyze the adsorption isotherm.It could be obviously observed that the adsorption process accords with Freundlich model model,and the correlation coefficient R2 is 0.98.The high values of KF indicated that PAC-SDS had a higher adsorption capacity and affinity for MB and the increase of KF with the increase of temperature suggested that high temperature favored adsorption and the adsorption was endothermic in nature.?5?Under the optimized conditions of pH and dosage,thermodynamic analysis of PAC-SDS at different initial concentrations.The sorption of MB onto PAC-SDS was an endothermic and spontaneous process.?6?Under the optimized conditions of pH and dosage,the adsorption effect of PAC-SDS in different electrolyte concentrations was analyzed.The presence of NaCl almost had no effect onto MB removal at low concentrations.However,the removal capacity of MB was decreasing with the concentrations of NaCl increased.?7?Desorption is an important step to reflect the economic value of the adsorbent,desorption study was performed by using spent adsorbent and the regeneration of the PAC-SDS was surveyed by using 0.5 mol L-1 hydrochloric acid desorption as stripping agent.The adsorption ability decreased gradually with the increasing desorption cycles.But the adsorption capacity was still no less that 150 mg g^-1 after sixth cycle.