Liquid hot water (LHW), an environmental-friendly physico-chemical treatment, was applied to pretreat the sugarcane bagasse (SCB). Tween80, a non-ionic surfactant, was used to enhance the enzymatic hydrolysis of the pretreated SCB. It found that 0.125 mL Tween80 /g dry matter could make the maximum increase (33.2%) of the glycan conversion of the LHW-pretreated SCB. A self-designed laboratory facility with a plate-and-frame impeller was applied to conduct batch hydrolysis, fed-batch hydrolysis, and the process of high-temperature (50°C) fed-batch hydrolysis following low-temperature (30°C) simultaneous saccharification and fermentation (SSF) which was adopted to overcome the incompatible optimum temperature of saccharification and fermentation in the SSF process. After hydrolyzing LHW-pretreated SCB for 120 h with commercial cellulase, the total sugar concentration and glycan conversion obtained from fed-batch hydrolysis were 91.6 g/L and 68.3%, respectively, which were 9.7 g/L and 7.3% higher than those obtained from batch hydrolysis. With Saccharomyces cerevisiae Y2034 fermenting under the non-sterile condition, the ethanol production and theoretical yield obtained from the process of SSF after fed-batch hydrolysis were 55.4 g/L and 88.3% for 72h, respectively, which were 15.5 g/L and 24.7% higher than those from separate fed-batch hydrolysis and fermentation. The result of this work was superior to the reported results obtained from the LHW-pretreated SCB. 相似文献
Silicon-based fertilizers and soil amendments can have direct and indirect positive influences on cultivated plants. The solid forms of Si-based substances, the most widespread in use, are efficient only at high application rates due to their low level of solubility. Several types of Si-based substances such as fumed silica, slags from the iron and steel industry, modified slags, and a Si-rich product were tested using barley and pea as silicon accumulative and non-accumulative plants, respectively, at two application rates. The plants were grown under toxic concentrations of heavy metals in a greenhouse. Si-rich materials high in water-soluble Si had a positive effect at both the low and high application rates, and for both plant species. This type of substance can be regarded as Si fertilizer, demonstrating greater efficiency at a low application rate and lessened efficiency at a high application rate for protection of the cultivated plants against accumulation of the heavy metals.
Nonferrous metal is an important basis material for the development of the national economy, and its consumption directly affects economic development. It has great significance in the effective utilization of nonferrous metals, development of an environment-friendly society, and investigation of the decoupling of nonferrous metal consumption and GDP growth. The decoupling indicators for nonferrous metal consumption and GDP growth (Dr) in China from 1995 to 2010 were calculated in this study, and the results were analyzed. A productive model based on BP neural network was established. Then, the decoupling indicators for nonferrous metal consumption and GDP growth in China for the period of 2011–2020 were predicted. For the period of 1995–2010, the annual average decoupling indicators were <1 for copper, aluminum, zinc, lead, and nickel, except for tin, which was 0.21. The analysis showed that the decoupling of nonferrous metal consumption and GDP growth is in a less optimistic situation to copper, aluminum, zinc, lead, and nickel in China from 1995 to 2010. The annual average decoupling indicator for tin was 0.21, which indicates relative decoupling. For the period of 2011–2020, the predicted decoupling indicators for copper, aluminum, zinc, lead, nickel, and tin were between 0 and 1. This finding indicates the implementation of relative decoupling. However, the total consumption of nonferrous metals did not decouple from GDP growth. 相似文献
A budget for the methane (CH4) cycle in the Xilin River basin of Inner Mongolia is presented. The annual CH4 budget in this region depends primarily on the sum of atmospheric CH4 uptake by upland soils, emission from small wetlands, and emission from grazing ruminants (sheep, goats, and cattle). Flux rates for these processes were averaged over multiple years with differing summer rainfall. Although uplands constitute the vast majority of land area, they consume much less CH4 per unit area than is emitted by wetlands and ruminants. Atmospheric CH4 uptake by upland soils was ?3.3 and ?4.8 kg CH4 ha?1 y?1 in grazed and ungrazed areas, respectively. Average CH4 emission was 791.0 kg CH4 ha?1 y?1 from wetlands and 8.6 kg CH4 ha?1 y?1 from ruminants. The basin area-weighted average of all three processes was 6.8 kg CH4 ha?1 y?1, indicating that ruminant production has converted this basin to a net source of atmospheric CH4. The total CH4 emission from the Xilin River basin was 7.29 Gg CH4 y?1. The current grazing intensity is about eightfold higher than that which would result in a net zero CH4 flux. Since grazing intensity has increased throughout western China, it is likely that ruminant production has converted China's grazed temperate grasslands to a net source of atmospheric CH4 overall. 相似文献