Preparation of biochar catalyst with saccharide and lignocellulose residues of corncob degradation for corncob hydrolysis into furfural

This paper presented a novel process for production of furfural by hydrothermal degradation of corncob over biochar catalyst, in which it was prepared with the recycling degradation solution and lignocellulosic solid residues. The biochar catalyst was papered by lignocellulose residues and concentrated saccharide solution, and then impregnated in 0.5 mol/L sulphuric acid at room temperature for 24 h assisted by the ultrasonic vibration. In the system of recycling, 8.8 % lignocellulose residues and 100 % concentrated saccharide solution from corncob hydrolysis have been recycled. Hydrolysis of corncob was carried out at 180 °C for duration of 170 min over the biochar catalyst. The experimental results have shown that the furfural yield of up to 37.75 % and overall corncob conversion rate of 62.00 % could be achieved under optimum operating conditions for the catalysts preparation and the corncob hydrolysis. It is believed that the acid density of 4.27 mmol/g of biochar catalyst makes the SO₃H groups cleave β-1,4 glycosidic linkages effectively and hydrolyze the cellulose and hemicellulose to water-soluble sugars, as well as to facilitate dehydration of xylose to give the product of furfural.     

Formation of persistent chlorinated aromatic compounds in simulated and real fly ash from iron ore sintering

Effects of carbon concentration and Cu additive in simulated fly ash (SFA) and real fly ash (RFA) on the formation of polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), chlorobenzenes, and polychlorinated biphenyls which were all regarded as persistent chlorinated aromatics in iron ore sintering were investigated. In the annealing process of SFA with various carbon contents, the yield of chlorinated aromatics and the I-TEQ obtained their maximum at 10 wt% carbon content. Active carbon in SFA acted as the carbon source as well as an adsorbent which led to higher production of PCDD/F in solid phase at 10 wt% carbon content. The increase of carbon content will be beneficial on the formation of 2,3,7,8-Chloro-substituted PCDF compared with 2,3,7,8-Chloro-substituted PCDD. In addition, the CuCl₂·2H₂O was a much more powerful catalyst in the formation of chlorinated aromatic compounds compared with elementary Cu, since it served as both a catalyst and a chlorine donor. However, the RFA behaved similarly with SFA with elementary Cu in the formation of chlorinated aromatic compounds. The effect of carbon content and copper additives on formation of 2,3,7,8-chloro-substituted congeners displayed similar characteristics with the tetra- to octa-PCDD/F isomers and even the total PCDD/Fs.     

The implementation of a measurement system for brushless DC motor parameters

Most of the energy conversion in industrial devices and equipment is completed by the motor. The acquirement of motor parameters becomes very important for designing the motor drives. The aim of this paper is to design and implement a motor measurement system. Through the processing of an Advanced RISC Machines (ARM) microcontroller, the various parameters of motors such as input voltage, input current, input power, motor speed, and motor torque can be obtained. Consequently, the torque constant, load torque, viscous friction, and the inertia of the motor are calculated and achieved. The motor parameters can be commanded and displayed in the designed human interface of a PC via USB communication. The hardware system designed in this system includes an ARM microcontroller, an inverter, a voltage sensor, a current sensor, a torque sensor, and power supply. The software programming is developed under the Visual Studio 2012 environment development platform using the C language. Finally, the prototype of the motor measurement system is completed and verified. The experimental results for the motor parameters and torque/speed characteristic are demonstrated and show the feasibility of the complete designed system.     

超疏水沸石咪唑酯骨架材料ZIF-90的制备及其气体吸附性能

以自制沸石咪唑酯骨架材料ZIF-90为原料,自制2,3,4,5,6-五氟苄胺为修饰剂,通过后修饰法制备了超疏水ZIF-90,采用SEM、XRD、FTIR等技术对其进行了表征,并进行了气体吸附性能测试。表征结果显示:制备的超疏水ZIF-90晶体结构和形貌良好;水接触角高达152.1°;修饰剂分子与ZIF-90晶体上的自由醛基成功发生缩胺反应。气体吸附实验结果表明:当相对压力小于0.02时,超疏水ZIF-90的CO_2吸附量较ZIF-90明显增大,CO_2/N_2和CO_2/CH_4的理想吸附选择系数由修饰前的15.76和4.88分别提升至33.28和17.13;超疏水ZIF-90具有优异的憎水性能。     

县域跨界水污染补偿机制在嘉兴市的探索

嘉兴市构建的县域跨界水污染补偿机制,不仅是一项流域水污染防治制度刨新,而且是浙江省跨行政区水污染补偿政策的重要支撑和有力保障.通过对大量数据的统计分析,提出了3种补偿标准,并运用跨界水污染补偿模型,模拟测算了2个市级断面和2个县级断面的补偿额.模拟测算结果不但能描绘出县域跨界水污染的现状,而且能够明确补偿对象和补偿额,对流域水质根本改善具有重要意义.     

金融危机为中国环境保护事业带来新契机的探讨

由美国次贷危机引发的金融危机已对全球经济产生巨大冲击,也将给世界环境保护工作带来负面效应.客观分析了此次金融危机对中国环境保护带来的挑战和契机,明确指出应充分利用这次契机,除依靠国家宏观经济政策的扶持外,还要通过产业内部调整和完善来积极应对.大力促进中国环境保护事业的新发展.     

不同类型填料的三维电极/Fenton试剂法处理苯酚废水

采用不同类型填料对三维电极/Fenton试剂法处理苯酚模拟废水进行研究.结果表明.不同类型活性炭填料对苯酚去除率有很大影响,粒炭不适合做粒子电极,采用5.0 mm柱炭处理效果较好;采用石英砂与活性炭混合填料的处理效果比单一活性炭填料好,但苯酚去除率提高不明显;电解槽反应器中按比例投加涂膜活性炭和活性炭混合填料能明显提高苯酚去除率;当涂膜活性炭与活性炭体积比为1,2时,苯酚去除率最高,达96.8%.     

GC/MS法测定润滑油基础油中多环芳烃

对润滑油基础油中多环芳烃的气相色谱/质谱(GC/MS)测定方法进行了研究,探讨了样品的提取,固相萃取柱净化等前处理方法,同时也对仪器测定条件进行了优化.结果表明,在检测润滑油基础油中多环芳烃时,经优化的GC/MS法的加标回收率和精密度均达到较满意的水平.     

碳羟基磷灰石对水中Cr(Ⅵ)的吸附性能研究

利用废弃蛋壳为原材料,水热法合成碳羟基磷灰石(CHAP),并利用X射线衍射、扫描电镜、能谱分析手段对其结构进行了表征.将CHAP作为含铬废水的吸附剂,考察了pH、Cr(Ⅵ)初始浓度、吸附时间等对Cr(Ⅵ)吸附行为的影响.结果表明,初始质量浓度为50 mg/L的Cr(Ⅵ)溶液,在常温(22±2) ℃、溶液pH为3.0、CHAP用量为5 g/L时,30 min基本达到吸附平衡,Cr(Ⅵ)去除率为98.3%,饱和吸附容量达29.85 mg/g.CHAP对Cr(Ⅵ)的吸附行为符合Langmuir吸附等温式和Freundlich吸附等温式,相关系数分别为0.998 4和0.922 6.通过10%(体积分数)H2SO4对吸附Cr(Ⅵ)的CHAP进行再生,再生率最高达95.8%.     

颗粒化序列间歇式活性污泥反应器工艺处理化粪池污水

在序列间歇式活性污泥反应器(SBR)中成功培养出适应化粪池污水水质的好氧颗粒污泥.并将其应用于化粪池污水的处理.在好氧颗粒污泥培养的第15天左右,SBR中开始出现细小的颗粒,然后微生物在其上繁殖生长使颗粒逐渐增大而成熟;在第24天时,SBR中絮状活性污泥已基本实现了颗粒化.培养出的好氧颗粒污泥对化粪池污水有稳定的处理效果,在进水完全为化粪池污水时,COD、NH_4~+-N、TN的平均去除率分别为77%、61%、47%.但是,由于化粪池污水COD较低,因此无法维持较高的生物量,在后期的稳定运行过程中MLSS始终维持在2 500 mg/L左右.好氧颗粒污泥的同步硝化反硝化作用是其稳定脱氮的保证.