自由基对工业化纤废水氧化处理的研究

通过芬顿试剂氧化、次氯酸钠氧化、过氧化氢和光催化氧化方法对化纤废水进行了处理,并通过COD检测、紫外可见光光度计等方法对氧化效果进行分析。结果显示自由基氧化对化纤废水的色度减小非常明显,能使其色度从800多倍减少到10倍以下,COD值从3 550 mg/L降解到100 mg/L以下,透光率的变化率达到98.59%。化学处理工艺的探讨发现在pH值4～6,搅拌速度为1 500 r/min,处理30 min就能使废水的COD去除率达到95.67%;pH为4时过氧化氢的氧化效果最佳。利用过氧化氢和次氯酸钠的氧化获得了自由基氧化处理此类废水的基本原理,即自由基氧化和链式反应的持续发生造成了有机物的降解,少量自由基的生成某种程度上刺激了高级氧化反应的深入,同时极少量自由基的交联可能会湮灭氧化反应,不同类自由基之间形成竞争,可能影响其氧化性能的发挥,因此需要通过控制反应物的种类、用量和有效分离反应中间产物,可以达到高级氧化反应处理此种废水的最佳效果。     

综合管廊燃气舱结构形式对燃气爆炸超压的影响*

为研究地下综合管廊燃气舱结构形式对燃气爆炸超压的影响,采用数值模拟的方法,改变燃气舱高度,通风分区长度和局部开口大小,分析不同情况下的燃气爆炸超压变化规律。结果表明:冲击波传播速度随燃气舱高度的增加而减小,随着高度的增加,超压峰值曲线由“驼峰状”逐渐变为两端高中间低的“盆形”,爆炸过程产生的最大超压与高度成反比关系。超压峰值在340 m处接近0 kPa,延长通风分区并不会增加超压峰值,可以在考虑防火的要求下根据实际情况适当延长通风分区的长度。局部开口的存在使得爆炸气流能够自由泄压,超压峰值与开口的大小成反比关系。     

吸附气泡分离法脱除废水中微量表面活性剂的数学模型

根据Ｒ．Ｌｅｍｌｉｃｈ提出的吸附气泡分离理论，运用集总参数模型，在连续稳态操作条件下研究了废水中微量表面活性剂ＣＴＡ－Ｂｒ的吸附气泡脱除方法，求得了实验条件下吸附塔中表面活性剂浓度的轴向分布函数及该过程的传质扩散参数。结论表明，在该脱除过程中，废水中表面活性剂的涡流扩散系数远比其分子扩散系数大。脱除过程速率主要受气。液界面液膜侧表面活性剂在膜内的分子扩散速率控制。     

湘钢无机废水处理与回用过程反渗透膜脱盐的研究

采用ESPA-99.0/1016.0型反渗透膜装置,对除硬、除碱和混凝沉淀处理后的湘钢炼铁口废水进行了脱盐深度处理的研究。通过调节反渗透过程的压力、进水盐浓度、pH值等条件,考察其对淡水透膜率及脱盐效果的影响。实验结果表明:在反渗透压0.80 MPa下,反渗透膜对废水中的碱度、硬度和可溶性盐类的脱除率均可达到85%以上,出膜淡水/浓水的流量比在0.4以上,淡水透膜率约为30.7%;在进膜废水流量和浓度一定的条件下,随着反渗透膜操作压力的提高,淡水透膜率上升,脱盐效率下降;在操作压力和进膜废水流量一定的条件下,随着进膜废水中可溶性盐类浓度的提高,淡水透膜率下降,脱盐效率上升;进膜废水pH值的改变基本上不影响淡水透膜率和膜的脱盐效果。     

利用高炉瓦斯泥中的锌制备活性氧化锌的研究

利用高炉炼铁瓦斯泥中的锌,采用火法富集和湿法浸取制取活性氧化锌。考察了温度、时间对火法富集产品中氧化锌含量和原料瓦斯泥中锌挥发率的影响,确定了富集工艺的最佳条件为:在氮气氛围下,温度从常温以10℃/min升温至1 000℃并且在1 000℃下保持1 h,得到的富集产品中氧化锌含量82.24%;瓦斯泥中锌挥发率97%。同时考察了温度、氨水用量、碳酸氢铵用量和液固比等因素对氧化锌浸取率的影响。确定的最佳工艺条件为:浸取温度40℃,氨水用量为理论量的2倍,碳酸氢铵用量为理论量的2倍,液固比4∶1,浸取时间2 h,氧化锌浸取率达99.9%。湿法制得的活性前驱体碱式碳酸锌,经煅烧得到纯度为98.4%的活性氧化锌产品,氧化锌的总回收率达95.3%。     

The efficient removal of thallium from sintering flue gas desulfurization wastewater in ferrous metallurgy using emulsion liquid membrane

The removal of thallium ions in flue gas desulfurization wastewater from ferrous metallurgic industry was studied by emulsion liquid membrane (ELM) method using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (P507) as carrier, aviation kerosene (AK) as organic solvent, polyisobutylene succinimide (T154) as surfactant, polyisobutylene (PIB) as additive, and sulfuric acid as internal reagent. Some important influence parameters such as concentrations of carrier, surfactant and stripping agent, agitation speed, extraction time, volume ratios of feed solution to emulsion phase and internal phase to membrane phase, and their effects on the removal efficiency of Tl in the ELM process were investigated and optimized. Under the optimum operating conditions of 2% of carrier, 5% of surfactant, 0.5 M of stripping agent, 350 rpm of agitation speed, 12.5:1 of volume ratio of feed solution to emulsion phase, and 3:1 volume ratio of membrane to internal phase, the maximum extraction efficiency of thallium reached 99.76% within 15-min reaction time. The ICP-MS analysis indicated that the thallium concentration in treated wastewater was below 5 μg/L and could meet the emission standard demand for industrial wastewater enacted by the local government of Hunan province of China. Meanwhile, the extraction of impurity ions calcium and magnesium in the ELM system was investigated. The result showed that an acidic environment would be in favor of the removal of Tl from calcium and magnesium contained in wastewater.

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Simulation of the migration and transformation of petroleum pollutants in the soils of the Loess plateau: a case study in the Maling oil field of northwestern China

We developed a coupled water–oil simulation model to simulate the migration and transformation of petroleum-derived contaminants in the soil of the Xifeng oil field. To do so, we used the HYDRUS-2D model, which simulates the diffusion, adsorption or desorption, and microbial degradation of petroleum-derived hydrocarbons in the soil–water system. The saturated soil hydraulic conductivity of petroleum-derived pollutants was 0.05 cm?day^?1, which is about 1 to 2 % of the soil moisture permeability coefficient. Our numerical simulation results show that spilled crude oil was mainly concentrated in the surface horizons of the soil. The organic pollutant concentration tended to be highest nearest to the pollution source. The pollutant migration was generally concentrated within the top 20 to 30 cm of the soil, with the maximum concentration in the top 5 cm of the soil. With passing time, the pollutant accumulation increased and the adsorption and degradation functions reached a dynamic balance with the input rate at depths greater than 30 cm below the soil surface. The oil-derived pollutants totaled 50 to 100 mg?kg^?1 under the dynamic balance condition, which occurred after 20 to 30 years. The petroleum-derived pollutant concentration in the loess soil was inversely correlated with the horizontal distance from the oil well, and the concentration decreased greatly at a distance greater than 40 m from the well.     

煤及其燃烧产物中微量元素的淋滤试验研究

用没ＰＨ值溶液对炉前原煤、灰化灰、底灰、飞灰进行了对比淋滤试验。重点考察了Ａｓ、Ｚｎ、ＰＢ、Ｎｉ、Ｓｒ等５种元素的淋出行为。发现溶液的ＰＨ、淋滤时间,特别是元素的性质及其赋存状态对元素的淋滤难易程度有重要影响,所分析的５种元素中,Ｓｒ以强淋滤为主,Ｐｂ和Ａｓ以强淋滤和中等淋滤为主,Ｎｉ以中等淋滤为主,而Ｚｎ则为难淋滤元素。     

Associations between acute exposure to ambient air pollution and length of stay for inpatients with ischemic heart disease: a multi-city analysis in central China

Environmental Science and Pollution Research - Ambient air pollution (AAP) has been widely associated with increased morbidity of ischemic heart disease (IHD). However, no prior studies have...     

Secular trends in global burden of diabetes attributable to particulate matter pollution from 1990 to 2019

Environmental Science and Pollution Research - Increasing evidence suggests an association between fine particulate matter (PM2.5) exposure and type 2 diabetes mellitus. However, there is still a...