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In this work, a modification method of H3PO4 plus H2O2 (PHP) was introduced to targetedly form abundant oxygenated functional groups (OFGs) on biochar, and methylene blue (MB) was employed as a model pollutant for adsorption to reflect the modification performance. Results indicated that parent biochars, especially derived from lower temperatures, substantially underwent oxidative modification by PHP, and OFGs were targetedly produced. Correspondingly, approximately 21.5-fold MB adsorption capacity was achieved by PHP-modified biochar comparing with its parent biochar. To evaluate the compatibility of PHP-modification, coefficient of variation (CV) based on MB adsorption capacity by the biochar from various precursors was calculated, in which the CV of PHP-modified biochars was 0.0038 comparing to 0.64 of the corresponding parent biochars. These results suggested that the PHP method displayed the excellent feedstock compatibility on biochar modification. The maximum MB adsorption capacity was 454.1 mg/g when the H3PO4 and H2O2 fraction in PHP were 65.2% and 7.0%; the modification was further intensified by promoting temperature and duration. Besides, average 94.5% H3PO4 was recovered after 10-batch modification, implying 1.0 kg H3PO4 (85%) in PHP can maximally modify 2.37 kg biochar. Overall, this work offered a novel method to tailor biochar towards OFGs-rich surface for efficient adsorption.

Biochars produced from crab shell (CSB), oak sawdust (OB), Jerusalem artichoke tuber (JAB) and sorghum grain (SB) displayed distinguishable adsorption-related characteristics, such as specific surface area (SSA), ash content and acidic oxygen-containing functional groups (AFGs), which linked to the biochar adsorption mechanisms of most pollutants. Herein, PO43–, Cd2+, and nitrobenzene (NB) were employed for adsorption by these biochars to elucidate the dominant factors for the adsorption. Adsorption performance of the three pollutants onto these four biochars varied considerably, as exemplified by the excellent adsorption of PO43– and Cd2+ onto CSB (225.3 and 116.0 mg/g, respectively) as compared with onto the other three biochars (4.2–37.1 mg/g for PO43– and 9.7–41.0 mg/g for Cd2+). OB displayed the best adsorption of NB (72.0 mg/g), followed by SB (39.5 mg/g), JAB (31.1 mg/g), and CSB (23.6 mg/g). The kinetics and isotherm adsorption assessments couple with material characterization suggested that the sorption of selected pollutants on biochars was attributed to the multiple mechanisms involved, including coprecipitation, chemical bonds, cation exchange, physical absorption, and complexation. Further path analysis suggested that AFGs and ash content in biochars were more important than SSA with regards to pollutant removal, especially, with ash playing a crucial role in the removal of Cd2+ and PO43–, and AFGs being mainly responsible for NB adsorption. These findings might offer guidance on the preparation or modification of biochar with a targeted function for pollutant removal through an understanding the dominant factors.

A newly developed PHP (phosphoric acid plus hydrogen peroxide) pretreatment for lignocellulose is integrated to be a multi-product platform for bioethanol, lignin, and ultra-high surface area carbon; the performances of this multi-product strategy are investigated in this work. Based on PHP pretreatment platform, 100.0 g wheat straw yield 16.0 g ethanol from the cellulose fraction, and 7.2 g high purity lignin can be recovered from the derived liquid fraction in pretreatment. Activated carbon (PHPK-800) with ultra-high surface area of 3291 m2 g−1 can be produced from the water-soluble fractions derived from pretreatment. As electrode material for supercapacitor, PHPK-800 displays an excellent specific capacitance of 303.5 F g−1 at 0.5 A g−1, and retains 87.0% of initial specific capacitance with more than 95.0% coulomb efficiency after 5000 cycles. The fabricated symmetric supercapacitor harvests an excellent energy density of 13.2 Wh kg−1 with 199.9 W kg−1 power density. Besides, a superior CO2 adsorption capability of 4.61 mmol g−1 is achieved by activated carbon of PHPK-700. According to these performances, PHP pretreatment platform is promising for converting lignocellulose into bioethanol, lignin and carbons by the biomass full utilization to achieve a more sustainable lignocellulosic refinery.

Trichoderma is cultivated on a solid medium prepared from wheat straw and food waste. The harvested mixture is fully used to prepare high specific surface carbon. The carbon is further assembled into an electrode to assess its electrochemical performance as a supercapacitor. As adjusted by the activation temperature, the carbon derived at 800 °C displays an extremely high specific surface area of 3977.3 m2 g−1, and the carbon derived at 900 °C shows a large pore volume of 2.372 cm3 g−1. Correspondingly, an excellent specific capacitance of 409.7 F g−1 at a current density of 0.5 A g−1 can be achieved in a three-electrode system. The symmetric supercapacitor achieves a high energy density of 11.3 Wh kg−1 with a corresponding power density of 240.0 W kg−1, and exhibits a good capacitance retention of 99.2% after 10000 cycles at the current density of 5 A g−1 in a 6.0 mol L−1 KOH electrolyte. Based on these results, a novel low-cost path for preparing high-performance materials for energy storage applications is achieved from real-world biomass sources and provides new insights to realize the full utilization of biomass waste.

Composting leachate, a potential precursor, was attempted to prepare the activated carbons via hydrothermal carbonization plus KOH activation in this work. The obtained carbons were further investigated to check their electrochemical performances as electrode materials of supercapacitor. The carbon material that activated at 700 °C (CL-700) exhibits the highest specific surface area of 2184.9 m2 g−1 and the largest pore volume of 1.55 cm3 g−1 comparing to the activated carbons at other temperatures. In a three-electrode system, CL-700 displayed an excellent capacitance of 228 F g−1 at 0. 5 A g−1, and it was 178 F g−1 even though at a higher current density of 10 A g−1. After 5000 tests on the charge-discharge cycle, CL-700 showed a superior stability with 83.2% capacity retention and almost 100% coulombic efficiency at 5 A g−1. Moreover, CL-700 had a good energy density of 7.1 Wh kg−1 at a power density of 124.9 W kg−1 in a symmetric two-electrode system. Based on the comparison with the currently reported biomass-deriver carbons, the composting leachate can be regarded as a feasible precursor to harvest carbon materials for supercapacitor electrode, which was meaningful to offer a novel path for the valorization of the leachate fraction from bio-wastes.

In order to seek a possible path for utilization bottom ash, the solid waste from biomass incineration for power generation, its basic characteristics were investigated, and removing methylene blue (MB) from aqueous solution was attempted as well. Results indicated bottom ash dominantly contained Si and Ca-related minerals with >35 mineral elements, meanwhile, it was typically characterized by alkalinity (pH of 9.5) and low specific surface area (14.5m2/g). As the only bottom ash was employed for removing MB, removal efficiency was lower than 44%, however, it was greatly improved to 100% as hydrogen peroxide was supplemented (final concentration of 4.0%). Based on the elucidated mechanisms, Fenton-like reaction was triggered by bottom ash, which was dominantly responsible for removing MB, rather than the adsorption by bottom ash. Besides, increasing reaction temperature and duration dramatically promoted MB removal by bottom ash with the aid of hydrogen peroxide (HBA). A great promotion on MB removal from 92.3mg/g to 143.9mg/g was achieved as pH was adjusted from 2.0 to 5.0, indicating MB removal was pH-dependent. The maximum removal of 260.9mg/g was achieved by HBA at a relatively high initial MB concentration of 2000.0mg/L, suggesting a great potential in treating dye wastewater by functionalizing bottom ash with the aid of hydrogen peroxide. Moreover, the released heavy metals and derived by-products from MB removal were acceptable in consideration of their potential environmental risks. Thus, the current work offers a new path to valorize the solid waste in biomass electricity generation plant.

A number of properties and reactions of a new kind of synthetic dicopper oxygen carrier [Cu2(PTB)]X2 (X = ClO4 −, BF4 − and Cl−), where PTB is N,N,N′,N′-tetrakis (2′-benzoimidazolyl methyl)-α,α′-(dimethylene amino)pyridine, are similar to those of coupled binuclear copper proteins and enzymes to a significant extent. The carriers serve as an active site model to mimic hemocyanin and tyrosinase. [Cu2 (PTB)]2+ reacts very easily with O2 and dioxygen adducts have been isolated. Colourless solutions of [Cu2(PTB)]2+ in dimethyl formamide (DMF) show a total absence of absorption in the near ultraviolet and visible region, but with oxygen give a blueish solution with characteristic, multiple absorptions at 320–390, 430 and 535 nm as well as fluorescence emission spectra (ex = 305 nm, em = 360–375, 410–420 nm). With addition of ascorbic acid, the solutions decolourize, the oxy-deoxy cycle can be repeated several times. ESR spectra of [Cu2(PTB)O2]2+ in frozen DMF solution show an axial spectrum around g =...

In out-of-order (OOO) processors, reorder queue (ROQ) has been widely used to implement precise interruption. The full of ROQ will cause the whole processor stall, while a long latency operation, e.g. a load missed in the caches, will almost definitely cause the ROQ full. In this paper, we present a model for estimating the impact of issuing an instruction on the usage of ROQ and memory level parallelism (MLP), and incorporate these considerations in the cost model of instruction scheduling. Preliminary evaluation results are presented to demonstrate the effectiveness of our approach on reducing the time of ROQ full and improving performance