Effectiveness and potential of straw- and wood-based biochars for adsorption of imidazolium-type ionic liquids.
The growing industrial application of imidazolium-type ionic liquids (ITILs) is likely to result in their release to the environment. Water-soluble ITILs are difficult to remove from wastewaters using traditional adsorbents. In this work, we developed different biochars derived from straw and wood (named as SBB and WBB, respectively) to improve the adsorption effectiveness for removal of ITILs from wastewaters. SBB had high O/C element ratio (0.143), while WBB had high ratio of Vmicro/Vtotal (61.5%) compared with commercial activated carbon (AC). Both of them showed greater adsorption of ITILs than AC with different adsorption mechanisms. FTIR spectra revealed that electrostatic interactions were the dominant driving force in SBB adsorption, while high micropore volume promoted adsorption in WBB. The adsorption of [C2mim][BF4] on SBB and WBB was strongly enhanced by trivalent PO4(3-) anions, suggesting that PO4(3-) anions could be used as promoter to increase the removal efficiency of ITILs from wastewater. Using HCl solution (pH=0.5) as regenerant, SBB and WBB were regenerated with nearly 100% recovery of adsorption capacity over ten consecutive adsorption-desorption cycles. Straw-based biochar and wood-based biochar are efficient sorbents for removal of water-soluble ionic liquids from aqueous solutions.
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Kaishun
K
Shi
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Civil and Environmental Engineering Department, University of California, 5732 Boelter Hall, Los Angeles 90095-1593, USA. Electronic address: ypqiu@tongji.edu.cn.
Yuping
Y
Qiu
Civil and Environmental Engineering Department, University of California, 5732 Boelter Hall, Los Angeles 90095-1593, USA.
Ben Li
Civil and Environmental Engineering Department, University of California, 5732 Boelter Hall, Los Angeles 90095-1593, USA.
Michael K
MK
Stenstrom
D000327:Adsorption; D001673:Biodegradation, Environmental; D002606:Charcoal / Q000737:chemistry*; D007093:Imidazoles / Q000302:isolation & purification*; D052578:Ionic Liquids / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*; D014934:Wood
D007093:Imidazoles; D052578:Ionic Liquids; D014874:Water Pollutants, Chemical; C540010:biochar; D002606:Charcoal
Adsorption; Biochars; Ionic liquids; Removal