A2O工艺缺氧生物磷去除

A lab-scale anaerobic-anoxic-oxic （A^2O） process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria （DPB）, evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A^2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A^2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen （92.3%, 95.5%, 96% and 79.5%, respectively） could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation.     

载锰氮化碳催化臭氧法降解水中草酸研究

草酸是废水中多种有机物氧化降解的中间产物,与臭氧反应速率很低,难以直接氧化去除。本研究通过热解法煅烧不同摩尔比例的三聚氰胺与醋酸锰(Ⅲ)二水合物,制备出不同负载量的载锰氮化碳催化剂,并研究了不同条件下载锰氮化碳催化臭氧法对草酸的降解效果,考察三聚氰胺与醋酸锰摩尔比、催化剂投加量、p H值、臭氧浓度等因素以及叔丁醇对草酸去除效果的影响。实验结果表明:相对于单独臭氧氧化而言,载锰氮化碳催化臭氧法可以极大的提高草酸的去除率,在投加0.15 g/L三聚氰胺与醋酸锰20∶1的催化剂后,草酸在60 min的TOC去除率可达到89.1%。叔丁醇加入对草酸的去除率影响较小,表明·OH在载锰氮化碳催化氧化草酸的过程中起作用但不是唯一因素。     

Absorption of carbon dioxide in alkanolamines in the presence of fine activated carbon particles

The rates of absorption of CO₂ into water and 0.1 kmol/m³ aqueous solutions of MEA, DEA and AMP were measured in a stirred cell with a flat gas-liquid interface in the presence of fine activated carbon particles. Experiments showed that the rates of absorption increased significantly with increases in the loading of activated carbon up to about 6 kg/m³ and thereafter remained constant.     

Influence of anode material on the electrochemical oxidation of 2-naphthol: Part 2. Bulk electrolysis experiments

The electrochemical oxidation of 2-naphthol has been studied by galvanostatic electrolysis, using a range of electrode materials such as lead dioxide, boron-doped diamond (BDD) and Ti-Ru-Sn ternary oxide anodes. The influence of some operating parameters, such as current density, flow-rate and chloride concentration on naphthol oxidation has been investigated in order to find the optimum experimental conditions. Measurements of chemical oxygen demand, HPLC and total organic carbon have been used to follow the oxidation. The experimental data indicate that on PbO₂ and BDD, naphthol oxidation takes place by reaction with electrogenerated hydroxyl radicals and is favoured by low current density and high flow-rate. On the contrary, on a Ti-Ru-Sn ternary oxide the mineralisation of naphthol occurs only in the presence of chloride ions that act as redox mediators and COD removal is affected by chloride concentration and is not significantly influenced by the current density and mass-transfer coefficient. From a comparison of the results of the three electrodes it has been found that boron-doped diamond gives a faster oxidation rate and better current efficiency.     

γ-Al2O3载体制备中水洗脱氯工艺的连续化

通过正交实验，研究了γ-Al₂O₃载体制备中拟薄水铝石水洗的连续化。方差分析表明，第一阶段洗水的pH是影响脱氯效果的关键因素，初步得出水洗连续化的优化条件。与国内外传统的间歇式水洗相比，收率从80%提高到99.7%，所需洗水量仅为原来的1/3，而处理500 kg物料的生产周期也从10 h缩短到2～3 h。     

粗四氯化钛除钒工艺现状及发展趋势

概述了使用铜丝、有机物、硫化氢和铝粉4种物质除去粗四氯化钛中的杂质钒方法的优缺点,通过比较指出有机物除钒法和铝粉除钒法是较理想的粗四氯化钛除钒方法。最后,对有机物除钒法目前存在的问题及解决方案进行了分析。     

粗TiCl4除钒工艺探讨

研究了粗TiCl4除钒的工艺过程，通过试验比较了各种有机物除钒的效果，结果表明矿物油除钒性能优异。1t粗TiCl4加矿物油2～4kg，反应温度135～138℃，反应时间60min，收率大于95％，质量达到企业产品标准要求。     

同时发生初次和二次成核且为聚结控制的沉淀过程多定态及稳定性分析

The possibility of multiplicity in an isothermal continuous mixed suspension-mixed product removal crystallizer is explored using the bifurcation theory.A process involving agglomeration controlled precipitation is considered in which secondary nucleation occurs simultaneously with primary nucleation.The determinant equations for the existence of multiple steady states are developed and the multiplicity boundaries dependent on the physical and kinetic properties and operational parameters of the process are obtained by resolving these determinant equations.The number of steady states in the precipitator for various multiplicity regions is determined and the linear stability of these steady states is analyzed by using the Routh criterion.     

Low cost coal-based carbons for combined SO2 and NO removal from exhaust gas

The aim of this paper is to show how a cheap carbonaceous material such as low rank coal-based carbon (or char) can be used in the combined SO₂/NO removal from exhaust gas at the linear gas velocity used in commercial systems (0.12 m s⁻¹). Char is produced from carbonization and optionally activated with steam. This char is used in a first step to abate the SO₂ concentration at the following conditions: 100 °C, space velocity of 3600 h⁻¹, 6% O₂, 10% H₂O, 1000 ppmv SO₂, 1000 ppmv NO and N₂ as remainder. In a second step, when the SO₂ concentration in the flue gas is low, NO is reduced to N₂ and steam at the following experimental conditions: 150 °C, space velocity of 900 h⁻¹, 6% O₂, 10% H₂O, 0-500 ppmv SO₂, 1000 ppmv NO, 1000 ppmv NH₃ and N₂ as remainder.It has been shown that the presence of NO has no effect on SO₂ abatement during the first step of combined SO₂/NO removal system and that low SO₂ inlet concentration has a negligible effect on NO reduction in the second step. Moreover, this char can be thermally regenerated after use for various cycles without loss of activity. On the other hand, this regenerated char shows the highest NO removal activity (compared to parent chars, either carbonized or steam activated) which can be attributed to the activating effect of the sulfuric acid formed during the first step of the combined SO₂/NO removal system.