不同湿热预处理条件对餐厨垃圾厌氧发酵产氢的影响

采用湿热水解技术处理餐厨垃圾,研究不同湿热预处理温度与时间下餐厨垃圾w(VS)(VS为挥发性固体)、ρ(CODs_Cr)(CODs为溶解性化学需氧量)、ρ(TOC)、ρ(TN)等指标的变化,以评价湿热预处理对餐厨垃圾厌氧产氢效能的影响. 在此基础上,结合厌氧产氢动力学分析,确定厌氧发酵产氢的最佳湿热预处理条件. 结果表明:湿热预处理温度、时间对餐厨垃圾可浮油脱出量、w(VS)具有显著影响. 餐厨垃圾湿热预处理后ρ(CODs_Cr)、ρ(TOC)、ρ(TN)变化情况与w(VS)呈负相关. 餐厨垃圾经90℃湿热预处理30min后,可浮油脱出量为37.5mL/kg,w(VS)/w(TS)为95.12%,最大比产氢量达242.1mL/g,最大产氢速率为12.46mL/h,累积产氢率达0.88mol/mol,厌氧产氢启动时间为12.85h. 说明对餐厨垃圾进行适度的湿热预处理可有效提高有机物溶解性与生物可利用效率,进而提高厌氧发酵累积产氢量与产氢速率. 综合能耗、产出等因素,湿热预处理温度90℃,处理时长30min,为餐厨垃圾厌氧发酵产氢的最佳湿热预处理条件.      

环境中氟喹诺酮类抗生素残留检测和去除研究进展

环境样品中的氟喹诺酮类抗生素(FQs)残留浓度低,干扰因素复杂,其检测需要采用多个预处理步骤,固相萃取回收率和重现性好,在实际样品预处理中常采用。检测方法包括毛细管电泳分析法、酶联免疫吸附法以及LC与ECD、FLD、UV、MS联用等。毛细管电泳法速度快,敏度低,检出限高;酶联免疫吸附法检测速度快,但存在交叉反应。高效液相色谱联用质谱检测(HPLC-MS/MS)灵敏度高,选择性好,是比较理想的分析方法。FQs污染物降解方法包括污泥吸附、光降解和高级氧化。光降解和高级氧化技术成本较高,反应副产物可能存在环境风险。污泥颗粒吸附FQs效果好,吸附FQs后,污泥颗粒可通过高温碳化活化制备活性炭,使FQs在高温下得到较彻底降解的同时,实现污泥的资源化利用,是较具前景的去除FQs的方法。     

温和湿热预处理对稻秸理化特性及生物产沼气的影响

为考察温和湿热预处理提高秸秆产气速率的可行性,以水稻秸秆为原料,在湿热预处理温度80℃、物料含水率60%条件下,通过分析湿热处理前后稻秸理化特性及厌氧生物产气特性的变化,研究不同湿热预处理时间对秸秆预处理及产沼气效果的影响.结果表明,温和湿热预处理促进了稻秸有机物的溶出,预处理后稻秸水浸提液pH值有较大幅度下降,而COD、TVFA和乙酸含量均大幅度增加,与对照组相比,T1、T2和T3处理秸秆水浸提液COD浓度分别增加了47.19%、55.18%和60.62%,TVFA浓度分别增加了22.34%、33.98%和50.12%,乙酸浓度分别增加了19.52%、34.02%和49.37%,并且乙酸占TVFA百分比均超过85%以上,差异显著性分析表明,处理T1水浸提液各理化特性指标与对照组相比呈极显著差异,而不同温和湿热预处理之间无显著差异;对稻秸纤维素组分破坏效果明显,但不同预处理时间对秸秆木质纤维组分破坏效果影响不大;厌氧发酵产气的结果表明,温和湿热预处理可明显提高稻秸厌氧生物产沼气,发酵20 d平均容积产气率可提高12.53%以上,累积TS产气率可提高36.17%以上.可见,温和湿热预处理提高秸秆厌氧生物产沼气效果是可行的,考虑到工程应用中预处理能耗成本因素,湿热预处理时间以T1处理(即6 h)为宜.     

Research progress on hydrothermal dissolution and hydrolysis of lignocellulose and lignocellulosic waste

Ethanol production from lignocellulosic waste has attracted considerable attention because of its feasi- bility and the generation of valuable products. Previous studies have shown that pretreatment and hydrolysis are key processes for lignocellulose conversion. Hydrothermal process is a promising technique because of its efficiency to break down the lignocellulosic structures and produce fermentable hexoses. Most studies in this field have therefore focused on understanding these processes or optimizing the parameters, but commonly reported low yields of fermentable hexoses. The inability to produce high yields of fermentable hexoses is mainly attributed to inadequate information on the conversion mechanisms of lignocellulose, particularly the reaction rules of dissolu- tion, which is a limiting step in the entire conversion process. This paper critically reviewed the progress done in the research and development of the hydrothermal dissolution and hydrolysis of lignocellulose. Principles, processes, and related studies on separate dissolution and asynchronous hydrolysis of lignin, hemieellulose, and cellulose are presented. Potential research prospects are also suggested.     

GROUND-WATER TEMPERATURE FLUCTUATIONS AT LYONS FERRY FISH HATCHERY,WASHINGTON1

ABSTRACT: The well field serving the Lyons Ferry Fish Hatchery has experienced reduced water temperatures following continued, periodic withdrawal of large volumes of water. In January 1985, the well field temperature was 49°F, which is less than the optimal 52°F for raising salmon and steelhead trout. The aquifer supplying the hatchery is in hydraulic and thermal connection with the Snake River and a flooded embayment of the Palouse River. Ground-water temperatures in the well field cycle on an annual basis in response to changes in surface water temperature and pumping rate. Numerical simulation of the well field, using a simplified mixing cell model, demonstrates the coupling of well field hydraulics and aquifer thermal response. Alternative pumping schedules indicate that it is feasible to adjust ground-water pumping to effectively store heat in the aquifer during the summer months when surface water temperatures are elevated. Sensitivity analysis of this model indicated that the primary controls of the system's thermal response are the volume of the aquifer assumed to contribute to the well field and temperature of the overlying surface water body.     

负载型纳米Bi2WO6/AC的制备及在可见光下降解邻硝基苯酚

采用水热法在160℃条件下以活性炭(AC)为载体合成了光催化剂Bi2WO6/AC,用X射线衍射仪(XRD)、电子扫描电镜(SEM)对催化剂进行了表征.同时,以邻硝基苯酚为目标污染物,在可见光照射下,讨论了催化剂用量、溶液的pH、污染物初始浓度等因素对催化剂光催化活性的影响.结果表明,当[Bi2WO6/AC]=5 g·L-1、pH=5[邻硝基苯酚]0=100 mg·L-1时,催化剂可见光降解活性最好,60 min后邻硝基苯酚的降解率可达到99.81%.     

提升光电编码器湿热环境适应性方法研究

目的研究提升光电编码器湿热环境适应性的方法。方法对某型军用电子装备中,光电编码器湿热环境适应性低的原因进行分析,并制定相应的工艺改进方法。结果根据分析可知,潮气进入光电编码器内部和芯线接头处是造成故障率高的原因,拟定了相应的解决方法。由验证试验结果可知,实施工艺改进方法后,光电编码器内部和芯线接头处再无潮气进入。结论经过验证,改进的工艺方法非常有效,光电编码器在湿热环境下的适应能力得到了极大提高。     

可降解有机物湿解实验及产物分析

湿解是环境友好的新型有机废物处理工艺,湿解实验在反应温度450K,反应时间1h的工况下,对杂草和马粪进行湿解,并分析了两种物料的湿解产物。结果表明:杂草和马粪经湿解处理后,分别得到了18.8%和16.3%的原料转化率,有机质转化率均超过了95%,可为土壤提供丰富的有机质;两种湿解液中所含物质基本上均集中在166.7~428.9及1122~1622的两组质荷比范围内,湿解液呈弱酸性,其中奎尼酸、柠檬酸和L-苹果酸含量丰富。     

餐厨垃圾水热炭化产物分配规律及液固产物特性研究

以实采餐厨垃圾为对象,探究了3种反应强度("温和"180℃-1h、"中等"220℃-2h和"剧烈"260℃-4h)下餐厨垃圾水热炭化三相产物分配规律及液固产物特性.结果表明,反应强度显著影响产物分配.随反应强度提升,固相产物(水热炭)产率先上升后下降;液相产物(炭化液)产率先降低后趋于稳定;而气相产物产率持续上升.但无...     

Impact of hydrothermal process on the nutrient ingredients of restaurant garbage

In order to recover the nutrient resource from restaurant garbage, a complete trial with 2 factors on 5 levels of experiments was carried out. The temperature and heating time are the main factors influencing on hydrothermal process （HP） by which improves the degradability and digestibility of the restaurant garbage favorably to make animal feeds or fertilizer. The results showed the variation of protein, saccharide, and oil in the garbage. It showed that protein dissolved and liquefied during hydrothermal process, which made organic nitrogen in solid phase transfer to liquid phase. After heating at 180℃ for 60min, organic nitrogen in liquid phase began to transform into ammonia. It also showed that hydrothermal process could promote the dextrinization, dissolution of the starch and its hydrolysis to reducing sugar, due to that starch in the restaurant garbage decreases and reducing sugar increases. When the temperature reached 140℃, the reducing sugar started to decrease due to chemical reactions. The cellulose was stable at 100-180℃. The floatable oil increased markedly in the hydrothermal process. The suitable condition for de-oil was observed at 160℃ heating for 80 min. Furthermore, the extraction of grease from the solid phase accords with first-order reaction dynamic model.