Sugarcane bagasse/kapok fiber-based filters for simultaneous demulsification and removal of Li⁺ ions from the waste of lithium grease production

Author(s)

Sandrini, Daiana M. F. ; Fuentes, Dairon P. ; Oliveira, Pedro, V ; Petri, Denise F. S.

• Document type: Journal article
• Source: Separation and Purification Technology; v. 361, p. 15-pg., 2025-01-10.

Abstract

Low-cost amphiphilic adsorbents were successfully prepared by combining raw microparticles of kapok fiber (KF) and sugarcane bagasse (SB) in a 1:1.65 mass ratio. The addition of hydroxypropyl methylcellulose (HPMC) or carboxymethyl cellulose (CMC), along with polydopamine (PDA), facilitated the molding of the filters and enhanced compatibility among the particles. These filters were employed to treat an industrial oil-in-water (O/ W) emulsion waste stabilized by lithium 12-hydroxystearate. The milky emulsion percolated through fixed-bed columns packed with either HPMC-SB/KF or CMC-SB/KF filters. The adsorption of Li+ ions on the adsorbents was evaluated using inductively coupled plasma optical emission spectrometry and pH measurements. The pH of the raw waste decreased from 9.2 to 4.4, indicating that Li+ ions were exchanged with H+ from the SB carboxylic acid groups, destabilizing the emulsion. Oil droplets and 12-hydroxystearic acid adsorbed on the hydrophobic surface of KF, resulting in a transparent eluate, especially when the HPMC-SB/KF filter was used. For the CMCSB/KF filter, Li+ ions exchanged with Na+ ions (the CMC counter-ions), leading to less demulsification. The HPMC-SB/KF and CMC-SB/KF filters removed 83.7 % and 99.7 % of Li+ ions from the waste, respectively. Li+ ions adsorbed on the CMC-SB/KF filters were desorbed using 3 mL of 1.0 mol/L HCl, producing a solution with a Li+ concentration 3.5 times higher than that of the original waste. The breakthrough curve for the CMC-SB/KF filters indicated adsorption capacity (q0) of 3.97 mg/g. The combination of HPMC-SB/KF and CMC-SB/KF filters demonstrated high efficiency in simultaneously demulsifying and removing Li+ ions from lithium grease production waste. (AU)

• FAPESP's process: 18/13492-2 - Synthetic and natural scaffolds applied to regenerative medicine
• Grantee: Luiz Henrique Catalani
• Support Opportunities: Research Projects - Thematic Grants