Bio‐cleaned lignin‐based carbon fiber and its application in adsorptive water treatment

Abstract Although an agricultural byproduct, lignin can be a felicitous choice serving as a carbon fiber precursor upon bio‐cleaning with Pseudomonas fluorescence . In this study, carbon fiber produced from electrospun bio‐cleaned lignin (Bio‐KLB) was demonstrated to be a novel efficient adsorbent for methylene blue in wastewater treatment. Bio‐cleaning effectively changed lignin from un‐electrospinnable to easily‐electrospinnable by removing impurities. Bio‐KLB carbon fiber mats showed average fiber diameter of 278.95 ± 49.89 nm, and randomly dispersed fiber mats showed average elastic modulus of 1532.87 ± 439.63 MPa and tensile strength of 16.72 ± 5.21 MPa. Adsorption of methylene blue on Bio‐KLB carbon fibers was analyzed at pH = 9, where optimal adsorption and decent reusability were observed. Kinetic adsorption was fitted well with pseudo‐first‐order model while adsorption isotherms were fitted to both Langmuir and Freundlich models. The highest adsorption capacity was 548.65 mg/g based on Langmuir model. The results provide clear evidence that electrospun bio‐cleaned lignin‐based carbon fibers can be a strong alternative material for dye treatment.