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BACKGROUND Macroalgae has high potential as a bio‐fuel feedstock due to its high carbohydrate content. Conventional aqueous systems require a huge amount of energy to catalyze depolymerization and hydrolysis of macroalgae. Recently various task‐specific ionic liquids (ILs) successfully depolymerized different biomasses, but were thermally unstable. A variety of dicationic acidic ILs (DAILs) connected by oligo‐ethylene glycol (EG) chains bearing hydrogen sulfate (HSO4−) anions were synthesized with better thermal stability and utilized in hydrolysis of macroalgal biomass, Gelidium amansii. RESULTS The structures of DAILs were confirmed by 1H and 13C NMR as well as FT‐IR. EG‐linker chain lengths and dicationic structure increased the thermal stability of DAILs and influenced their catalytic performance for G. amansii hydrolysis. DAILs linked with short oligo‐EG chains afforded higher sugar yields and exhibited faster hydrolysis rates compared with those linked by long oligo‐EG chains (i.e. PEG400 and PEG600). A maximum sugar yield of 67.45 wt% was recovered from G. amansii using [Tri‐EG‐(MIm)2] 2HSO4 DAIL, after 3 min at 120 °C. CONCLUSION The synthesized DAILs showed dual properties as catalyst and reaction medium for hydrolysis of macroalgae in solvent‐less conditions. Shorter oligo‐EG chain linked DAILs exhibited faster reaction rates with higher sugar yields. © 2016 Society of Chemical Industry

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A phosphorus-doped mesoporous carbon (PMC)-filled coating was deposited on polyurethane foam (PUF) via a layer-by-layer assembly method. First, PMC was prepared from bio-sourced saccharose and phytic acid using mesoporous silica KIT-6 as a hard template. The coated PUF was then prepared by alternate dipping into a chitosan (CH) solution and dipping into an alginate-stabilized PMC (AL-PMC) aqueous dispersion. A few layers (three bilayers) of the CH/AL-PMC coating allowed the PUF to self-extinguish when exposed to a butane flame (≈1400 °C). Additionally, this coating layer enabled the foam to pass the UL-94 rating. Cone calorimetry revealed that this coating reduced the peak heat release rate, rate of smoke release, total smoke release, peak CO2 production rate, and peak CO production rate by 56, 48, 29, 35, and 35%, respectively. Using this foam, a flame retardant foam-based triboelectric nanogenerator (FRF-TENG) was fabricated. The FRF-TENG exhibited excellent energy harvesting performance, offering 158 V and 2.26 μA cm–2 open-circuit voltage and short-circuit current density, respectively. Furthermore, the FRF-TENG can be attached on a chair and serve as a self-powered sensor for the detection of back movement and sit-stand motion. This study may provide a promising potential for the design and fabrication of multifunctional smart foams.

d-Galactose (d-Gal) and 3,6-Anhydro-l-galactose (3,6-l-AHG) are valuable sugars that can be derived from Gelidium amansii. Herein, ionic liquid (IL) pretreatment was used to deconstruct the cell wall of G. amansii without producing any side-products from sugar degradation. It is combined with enzymatic saccharification using recombinant agarases to effectively produce d-Gal and 3,6-l-AHG from IL-treated G. amansii. ILs were screened for the biomass pretreatment as well as the antisolvents for dissolved biomass retrieval from the IL. [Bmim]Ac is the most effective solvent (99% dissolution) and methanol as antisolvent (78% reconstituted G. amansii). Using simplex-centroid design, the optimal loading of three β-agarases: Aga2, AgaA7, and Aga50D for the first hydrolysis was determined to be at equal fractions (0.33). Addition of α-neoagarobiose hydrolase AhgI finally produced maximum yields of 56.5% for d-Gal and 33.7% for 3,6-l-AHG. Given the industrial importance of d-Gal and the high market price of 3,6-l-AHG, results demonstrate the potential of combined IL pretreatment and enzymatic hydrolysis using recombinant agarases as a green process for sugar production from red macroalgae.