化学激发循环流化床粉煤灰的研究

利用扫描电镜、激光粒度分析、X-衍射分析等测试手段,对循环流化床粉煤灰的理化性质和微观结构进行分析。比较了5种激发剂对循环流化床粉煤灰的激发效果,结果表明Na2SiO3·9H2O的激发效果最好。     

High nitrite accumulation and strengthening denitrification for old-age landfill leachate treatment using an autocontrol two-stage hybrid process

An autocontrol two-stage hybrid process was developed to treat landfill leachate. Biological nitrogen removal with nitrification and denitrification via nitrite pathway was split into two stages. The first stage was designed for the high nitrite accumulation and was composed of two hybrid bed reactors (Hybrid I and Hybrid II) and a coagulation–flocculation reactor having effective volumes of 120 L and 80 L, respectively. The second stage was designed for strengthening denitrification and included a single 80 L reactor. The carriers of the hybrid bed reactors were composed of fixed multiple flexible carriers and suspended particle carriers. Dissolved oxygen (DO), pH value, oxidation–reduction potential (ORP) and temperature were used as online fuzzy control parameters of the automatic control system. The concentration of nitrite in Hybrid I and Hybrid II could reach 411 mg L⁻¹ and 604 mg L⁻¹, respectively. Ammonia removal has reached maximal rates of 0.061 kgNH₄⁺-N (m³ h)⁻¹ and 0.041 kgNH₄⁺-N (m³ h)⁻¹, respectively. A maximum nitrite removal rate of 0.211 kgNO₂⁻-N (m³ h)⁻¹ was observed during the strengthening denitrification. The running time of one cycle was not fixed and was actually controlled by the system. The results indicated that the running period was more closely related to influent ammonia concentration than influent COD concentration. The aeration times could be shortened and the energy could be saved. The autocontrol two-stage hybrid process is therefore an economical and effective way for landfill leachate treatment.     

Solid fuels in chemical-looping combustion

The feasibility of using a number of different solid fuels in chemical-looping combustion (CLC) has been investigated. A laboratory fluidized bed reactor system for solid fuel, simulating a chemical-looping combustion system by exposing the sample to alternating reducing and oxidizing conditions, was used. In each reducing phase 0.2 g of fuel in the size range 180–250 μm was added to the reactor containing 40 g oxygen carrier of size 125–180 μm. Two different oxygen carriers were tested, a synthetic particle of 60% active material of Fe₂O₃ and 40% MgAl₂O₄ and a particle consisting of the natural mineral ilmenite. Effect of steam content in the fluidizing gas of the reactor was investigated as well as effect of temperature. A number of experiments were also made to investigate the rate of conversion of the different fuels in a CLC system. A high dependency on steam content in the fluidizing gas as well as temperature was shown. The fraction of volatiles in the fuel was also found to be important. Furthermore the presence of an oxygen carrier was shown to enhance the conversion rate of the intermediate gasification reaction. At 950 °C and with 50% steam the time needed to achieve 95% conversion of fuel particles with a diameter of 0.125–0.18 mm ranged between 4 and 15 min depending on the fuel, while 80% conversion was reached within 2–10 min. In almost all cases the synthetic Fe₂O₃ particle with 40% MgAl₂O₄ and the mineral ilmenite showed similar results with the different fuels.     

天然沸石负载La2O3-ZnO-TiO2光催化降解活性艳红K-2BP

利用80目天然斜发沸石作载体制备La₂O₃(0.5%)-ZnO(20%)-TiO₂/沸石复合光催化剂,以20 W紫外灯为光源,在自制的光催化反应器中降解活性艳红K-2BP,考察了光照时间、空气通入量、催化剂用量、溶液初始浓度、H₂O₂与Fe³⁺投加量等对活性艳红K-2BP光催化降解率的影响。结果表明,当溶液初始浓度为60 mg/L,催化剂投加量为12 g/L,通气量为1 200 mL/min,光照2.5 h,活性艳红K-2BP的降解率可达99.2%;H₂O₂和Fe³⁺投加量为4 mL/L和3 g/L时,光照1 h活性艳红K-2BP降解率分别为100%和97.2%。紫外可见吸收光谱显示,LZTZ光催化剂可有效降解印染废水。     

沸石吸附废水中磷污染物的研究

含磷化学物质的普遍使用以及目前很低的污水处理率,导致含磷废水大量排放,水体富营养化和水污染日益严重.采用中国地质大学材料学院合成的13X沸石,作为一种新型磷吸附剂,研究其在不同吸附时间、水体pH值、沸石用量和振荡速度等条件下,对水体中磷的吸附规律.研究表明,该沸石作为废水除磷吸附剂具有很好的发展前景.     

改性沸石对2,4-二氯苯酚的吸附性能研究

采用溴化十六烷基三甲铵(HDTMAB)制备了改性沸石，并研究了其吸附性能的影响因素，包括HDTMAB的加入量、有机污染物的初始质量浓度、溶液的pH值等，绘制了改性沸石吸附2，4-DCP的吸附等温线并得到了饱和吸附容量。结果表明，改性沸石对2，4-二氯苯酚(2，4-DCP)具有很好的吸附效果，实验条件下对2，4-DCP的去除率可达90％以上。     

改性沸石对镉(Ⅱ)的交换性能研究

在静态条件下,从p H、温度、浓度等方面考察了改性红辉沸石对Cd2+离子交换能力的影响以及Cd2+离子与其他重金属阳离子共存的影响,同时也考察了改性沸石对模拟废水的重金属去除效果。结果表明,改性红辉沸石对Cd2+的去除率达到99%以上,且同时也能使Pb2+,Zn2+,Cu2+离子达到国家标准排放。     

改性沸石去除水中低浓度氨氮的研究

分别利用无机盐、无机酸和稀土对天然沸石进行了改性处理,并从理论上阐述了不同方法对沸石进行改性的机理,提出了改性沸石的最佳制备方法,并采用X衍射的分析手段观察化学处理对载体的影响,探讨了改性沸石对NH4 吸附动力学以及再生实验.研究表明,3种方法均不同程度地提高了沸石去除氨氮的能力,其中利用无机盐改性的沸石的效果最佳,对NH4 的吸附动态符合Freundlich方程,与传统的化学凝聚法和生物法相比,具有工艺简单、高效、经济等优点.无机盐改性沸石制备最佳条件是:溶液中钠离子浓度为0.8 mol/L,在水浴温度70～75 ℃时,按固液比1∶50投加沸石,浸渍时间为2 h,过滤后滤饼在100 ℃下干燥1 h.     

添加剂对喷雾-喷动床半干法烟气脱硫性能的影响

研究了3种添加剂(NaOH、CaCl2、NaCl)对喷雾-喷动床半干法烟气脱硫性能的影响,并分析了添加剂增进脱硫效果的机理。试验结果表明：3种添加剂都能显著提高脱硫率,NaOH的效果最佳,CaCl2次之,NaCl较差。     

新型内循环生物流化床反应器氧传质特性研究

实验对新型内循环生物流化床几种结构的氧传质系数进行比较 ,从而选出最优结构。在此基础上考察了空气流量、固含率、曝气装置对该反应器氧传递特性的影响。实验结果表明挡板尺寸大 ,距反应器底部近 ,气量大氧传质效果好。同时 ,固含率影响氧传递效果。