沉淀—树脂吸附法处理对氨基偶氮苯盐酸盐生产废水的研究

对氨基偶氮苯盐酸盐（ＰＡＢＳ）是生产染料的重要中间体。在ＰＡＢＳ生产过程中，排放出高浓度（ＣＯＤ４万～８万ｍｇ／Ｌ）、高色度（４万～８万）、高毒性（含苯胺和对氨基偶氮苯）和高氯（Ｃｌ－４万～１０万ｍｇ／Ｌ）的废水。利用中和沉淀—大孔吸附树脂吸附法进行了处理工艺的小试研究。结果表明，废水色度去除率达到９９９％，降到２０以下；出水中基本不含对氨基偶氮苯（ＰＡＢ）；出水中苯胺的浓度降到３ｍｇ／Ｌ。ＧＣ／ＭＳ分析的结果表明，乙醇脱附液中苯胺是最主要的有机物，所以利用该工艺能实现苯胺的回收。     

GROUND WATER NITRATE REDUCTION IN GIANT CANE AND FOREST RIPARIAN BUFFER ZONES1

ABSTRACT: Ground water contamination by excess nitrate leaching in row‐crop fields is an important issue in intensive agricultural areas of the United States and abroad. Giant cane and forest riparian buffer zones were monitored to determine each cover type's ability to reduce ground water nitrate concentrations. Ground water was sampled at varying distances from the field edge to determine an effective width for maximum nitrate attenuation. Ground water samples were analyzed for nitrate concentrations as well as chloride concentrations, which were used as a conservative ion to assess dilution or concentration effects within the riparian zone. Significant nitrate reductions occurred in both the cane and the forest riparian buffer zones within the first 3.3 m, a relatively narrow width. In this first 3.3 m, the cane and forest buffer reduced ground water nitrate levels by 90 percent and 61 percent, respectively. Approximately 40 percent of the observed 99 percent nitrate reduction over the 10 m cane buffer could be attributed to dilution by upwelling ground water. Neither ground water dilution nor concentration was observed in the forest buffer. The ground water nitrate attenuation capabilities of the cane and forest riparian zones were not statistically different. During the spring, both plant assimilation and denitrification were probably important nitrate loss mechanisms, while in the summer nitrate was more likely lost via denitrification since the water table dropped below the rooting zone.     

Production of hydrogen by steam gasification of dehydrochlorinated poly(vinyl chloride) or activated carbon in the presence of various alkali compounds

Steam gasification of dehydrochlorinated poly(vinyl chloride) (PVC) or activated carbon was carried out in the presence of various alkali compounds at 3.0 MPa and 560°C–660°C in a batch reactor or in a semi-batch reactor with a flow of nitrogen and steam. Hydrogen and sodium carbonate were the main products, and methane and carbon dioxide were the minor products. Yields of hydrogen were high in the presence of sodium hydroxide and potassium hydroxide. The acceleration effect of the alkali compounds on the gasification reaction was as follows: KOH > NaOH > Ca(OH)₂ > Na₂CO₃. The rate of gasification increased with increasing partial steam pressure and NaOH/C molar ratio. However, the rate became saturated at a molar ratio of NaOH/C greater than 2.0.     

刺激性气体HCl在不同尺度火灾实验中的释放行为

火灾是一种灾害性燃烧现象 ,给人员和财产安全带来极大损失。氯化氢 (HCl)是火灾烟气中阻碍人员逃生的最重要的刺激性气体之一。以典型的小尺度和大尺度实验为例 ,分析了加热程度和通风供氧对常用有机材料起火后释放HCl的影响 ,发现不论小尺度还是大尺度 ,HCl的形成只与燃烧过程有关 ,与氧化过程无关 ,HCl的生成率不随通风情况不同而改变。实验中影响HCl释放的主要因素是热 (辐射加热热流密度或温度 )。当超过CCl键发生断裂的温度后 ,继续升温HCl释放速率不发生改变 ,出现稳定释放阶段。在反映HCl释放过程不同尺度间存在共性 ,因此 ,利用小尺度的结果进行释放规律内在机理的探索是合理的方法     

亚甲蓝湿式氧化影响因素研究

以湿式氧化技术对亚甲蓝水溶液进行处理,用水样COD去除率评价处理效果.考察了反应时间、温度、氧分压、搅拌速度、进水pH值以及进水浓度对处理效果的影响,并进行机理分析.实验确定的最佳操作工艺条件为:反应温度210℃、氧分压2.0 MPa、搅拌速度880 r/min、进水pH=11.30.在此条件下,COD为2 000mg/L的亚甲蓝水溶液,反应90min时COD去除率达93.2%.     

二安替比林甲烷分光光度法测定氯化镁中钛的含量

用盐酸溶解氯化镁样品,以抗坏血酸和焦磷酸钠共同作掩蔽剂,在酸性介质中用二安替比林甲烷分光光度法测定氯化镁中钛的含量,给出了合理的实验条件.     

基于改性凹凸棒土的强化混凝处理高藻低浊原水工艺

针对水厂低浊高藻水的处理难题,研究了改性凹凸棒土(改性凹土)联合聚合氯化铝(PAC)强化混凝的除藻除浊效果。设计实验原水条件为叶绿素a(chl-a)浓度为98.58~110.35μg/L,浊度(5.6±0.5)NTU。考察了PAC和改性凹土的复配投加量、混凝沉淀时间、pH、投加顺序、搅拌速率等工艺参数对Chl-a和浊度耦合去除效果的影响。结果表明,"PAC+改性凹土"对Chl-a和浊度的去除效果明显优于单投PAC的效果。当PAC投药量12 mg/L,改性凹土投药量10 mg/L,沉淀时间20 min时,对Chl-a和浊度的去除率可分别达到92.5%和89.2%,可至少减少40%的PAC投量,且形成的矾花密实,沉降速度快,去除效率高。最适pH范围为7~8。投加顺序应为先投加改性凹土,混合搅拌转数宜慢速,可控制为50 r/min。     

臭氧氧化法降解聚氯乙烯离心母液废水中3种有机物

以聚氯乙烯离心母液废水中含量较高的3种有机物(聚乙烯醇、异辛醇和α-甲基苯乙烯)作为目标物,考察臭氧氧化工艺对3种有机物的去除效果,同时考察反应时间、臭氧投加量和初始pH对处理效果的影响。实验结果表明,臭氧氧化处理3种废水的最佳反应时间和臭氧投加量分别为:聚乙烯醇25 min,136 mg/L;异辛醇60min,312 mg/L;α-甲基苯乙烯60 min,32 mg/L。在此条件下,3种有机物的去除率分别为98%、85%和95%。此外,碱性条件有助于臭氧氧化工艺对3种有机物的降解。产物分析结果表明,经臭氧氧化,聚乙烯醇断链后进一步反应生成了草酸单乙酯,异辛醇和α-甲基苯乙烯分别生成了和苯乙酮。     

Comparative evaluation of sizing of metal hydride (MH) hydrogen storage tank filled with different alloys

This study presents a comparative analysis of sizing of metal hydride tank filled with different alloys. Alloys include solid solutions and intermetallic compounds of the generic families AB₅, AB₂, AB, A₂B. The effects of the different alloys on the sizing of metal hydride hydrogen storage tanks are complicated and depend on many factors. In this paper, a thermoeconomic optimization analysis with a simple algebraic formula was presented for the estimation of optimum metal hydride tank surface area for heat transfer enhancement. The optimum area of the metal hydride tank filled with commercially available different alloys (LaN₅, Ti_0,98Zr_0,02V_0,43Fe_0,09Cr_0,05Mn_1,5, TiFe, Mg₂NiH₄) was evaluated and compared by the developed method. The optimum net savings and the value of payback were determined for four alloys. It is found that mathematical model can be employed for the determination of optimum metal hydride tank design and increasing net savings according to alloy types. The optimum areas of the tanks filled with four alloys (LaN₅, Ti_0,98Zr_0,02V_0,43Fe_0,09Cr_0,05Mn_1,5, TiFe, Mg₂NiH₄) were calculated as 0.136, 0.130, 0.133, and 0.173 m², respectively. The optimum net savings for tanks filled with four alloys (LaN₅, Ti_0,98Zr_0,02V_0,43Fe_0,09Cr_0,05Mn_1,5, TiFe, Mg₂NiH₄) are about 461.0, 409.3, 419.6, and 979.6 $ and the values of payback are about 1.98, 2.1, 2.17, and 1.37 years, respectively. Excessive area of the metal hydride tank would not be as economical as the optimum tank area. Thermal management of metal hydride tank must be designed for optimum points calculated at which maximum savings occur.     

二氧化钛脱除高温烟气中的氯化氢

HCl是城市垃圾焚烧产生的主要气体污染物之一。将一种新型脱氯剂TiO2引入到垃圾焚烧系统中,并与其他脱氯剂的性能进行比较。研究了不同脱氯剂使用量、不同反应温度和不同HCl气体浓度对TiO2、CaO和CaTiO3脱氯效果的影响。结果显示,TiO2能在高温(800~1 000℃)、高HCl浓度(1 303.6~1 629.5 mg/m3)下获得较好的脱氯效果。与传统的脱氯剂CaO相比,TiO2更适合于高温烟气脱氯,其在1 000℃时的氯容(36.3 mg HCl/g TiO2)几乎是相同情况下的CaO氯容(9.3 mg HCl/g CaO)的4倍。而CaTiO3的脱氯效果不但受到自身分解效率的影响,还受到TiO2和CaO脱氯效果的影响,其脱氯效果较差。