To solve the energy crisis and environmental pollution caused by fossil fuels, the simultaneous pretreatment of wheat straw with laccase and ball-milling was proposed for the first time to achieve efficient conversion of lignocellulose, inspired by the digestive system of termites in nature. FTIR and XRD analysis showed that simultaneous pretreatment could degrade more lignin, reduce the crystallinity of cellulose, and increase the porosity by 26.3%∼80.1% compared with the control, which promoted the subsequent enzymatic hydrolysis. Under the optimal control parameters (ball milling speed of 500 rpm, ball milling time of 12 h, and slurry concentration of 5 wt%), the conversion ratios of cellulose and hemicellulose reached 99.2% and 75.3% in 72 h, representing a 2.5-fold and 4.1-fold increase compared to the control. The exergy efficiencies of pretreatment and enzymatic hydrolysis were 52.7% and 91.3%, respectively, and the overall exergy efficiency of simultaneous pretreatment was 56.6% with standardized exergy loss of 3.0 kJ/kJ monosaccharide. Overall, a new simultaneous pretreatment strategy was proposed in this study to improve the saccharification rate of wheat straw and systematically evaluated the energy efficiency of the process with exergy indexes.
The widespread application of solar-thermal absorbers is currently hindered by their low absorption efficiency and high capital cost. Therefore, many initiatives, including direct absorption solar collectors (DASCs), are currently under way to improve the efficiency of the absorbers. In this regard, the application of TiN-modified h-BN nanosheets in DASCs is studied in this paper. Their superior solar absorptivity and thermal conductivity are based on the plasma plasmon effect of nanoparticles and the high thermal conductivity of h-BN nanosheets, respectively. In the experiment, five different concentrations (20, 40, 60, 80, 100 ppm) of TiN@h-BN composite nanofluids were prepared by a two-step method. The stability and optical properties of the nanofluids were analyzed. In addition, thermal loss and exergic efficiency of photothermal conversion system were analyzed and discussed. Combined with localized surface plasmon resonance (LSPR) of TiN nanoparticles and h-BN light reflection properties, the photothermal conversion of TiN@h-BN composite nanofluids was improved in DASCs. The 80 ppm nanofluid showed the best exergic efficiency, with an average exergic efficiency of 83%. Meanwhile, the photothermal conversion efficiency of 80 ppm TiN@h-BN composite nanofluid reaches the maximum 78%. This work provides new strategies for harnessing the full spectrum of solar energy and controlling the photothermal properties of nanofluids. Graphical Abstract Schematic diagram of photothermal conversion system of TiN@h-BN nanofluids.
危险品化学品经营许可证（带存储）