Synthesis, Characterization, and Utilization of a Lignin-Based Adsorbent for Effective Removal of Azo Dye from Aqueous Solution

Xianzhi Meng; Brent Scheidemantle; Mi Li; Yun-Yan Wang; Xianhui Zhao; Miguel Toro-González; Priyanka Singh; Yunqiao Pu; Charles E Wyman; Soydan Ozcan; Charles M Cai; Arthur J Ragauskas

doi:10.1021/acsomega.9b03717

Synthesis, Characterization, and Utilization of a Lignin-Based Adsorbent for Effective Removal of Azo Dye from Aqueous Solution

ACS Omega. 2020 Feb 6;5(6):2865-2877. doi: 10.1021/acsomega.9b03717. eCollection 2020 Feb 18.

Authors

Xianzhi Meng¹, Brent Scheidemantle^{2

3}, Mi Li¹, Yun-Yan Wang⁴, Xianhui Zhao⁵, Miguel Toro-González⁶, Priyanka Singh^{2

3}, Yunqiao Pu⁷, Charles E Wyman^{2

3}, Soydan Ozcan^{8

9}, Charles M Cai^{2

3}, Arthur J Ragauskas^{1

7

4}

Affiliations

¹ Department of Chemical & Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, Tennessee 37996, United States.
² Center of Environmental and Research Technology (CE-CERT), University of California, Riverside, California 92507, United States.
³ Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, California 92521, United States.
⁴ Department of Forestry, Wildlife, and Fisheries; Center for Renewable Carbon, The University of Tennessee Knoxville, Institute of Agriculture, Knoxville, Tennessee 37996, United States.
⁵ Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
⁶ Isotope and Fuel Cycle Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
⁷ Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
⁸ Department of Mechanical, Aerospace, Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States.
⁹ Manufacturing Demonstration Facility, Energy and Transportation Science Division, Oak Ridge National Laboratory, Knoxville, Tennessee 37932, United States.

Abstract

How to effectively remove toxic dyes from the industrial wastewater using a green low-cost lignocellulose-based adsorbent, such as lignin, has become a topic of great interest but remains quite challenging. In this study, cosolvent-enhanced lignocellulosic fractionation (CELF) pretreatment and Mannich reaction were combined to generate an aminated CELF lignin which is subsequently applied for removal of methylene blue and direct blue (DB) 1 dye from aqueous solution. ³¹P NMR was used to track the degree of amination, and an orthogonal design was applied to determine the relationship between the extent of amination and reaction parameters. The physicochemical, morphological, and thermal properties of the aminated CELF lignin were characterized to confirm the successful grafting of diethylenetriamine onto the lignin. The aminated CELF lignin proved to be an effective azo dye-adsorbent, demonstrating considerably enhanced dye decolorization, especially toward DB 1 dye (>90%). It had a maximum adsorption capacity of DB 1 dye of 502.7 mg/g, and the kinetic study suggested the adsorption process conformed to a pseudo-second-order kinetic model. The isotherm results also showed that the modified lignin-based adsorbent exhibited monolayer adsorption. The adsorbent properties were mainly attributed to the incorporated amine functionalities as well as the increased specific surface area of the aminated CELF lignin.