微电解技术处理难降解工业废水的研究进展

介绍了铁碳微电解技术处理工业废水的作用机理。综述了铁碳微电解技术的研究进展。针对该技术在处理不同工业废水时普遍存在的堵塞、短路、死角、铁屑结块等问题,介绍了研发的新型纳米铁碳微电解复合材料及新工艺,并对铁碳微电解技术今后的研究方向进行了展望。     

内电解法治理洗涤水煤气废水过程中氰化物行为的研究

文中通过对洗涤塔排出废水、凉水塔前后废水中氰化物形态、内电解池灰渣中络合氰化物、内电解主要电极反应和氰化物迁移转化、末级处理所用离子交换树脂及其再生洗脱等的研究;讨论了在内电解过程中氰化物的行为。     

微电解技术在工业废水处理中的应用进展

概述了近年来传统铁碳微电解法在难降解工业废水预处理、污泥处理和重金属去除、低浓度废水处理等领域的研究进展,介绍了通过在铁碳微电解体系中投加其他金属以催化反应的改性微电解法的废水处理效果,以及微电解与电场强化、微波强化、Fenton氧化、生物处理、物化法等其他工艺联合技术在废水处理中的应用现状,探讨了相关微电解技术存在的问题及未来的发展方向。     

一种三维三相电化学反应器

该发明公开了一种三维三相电化学反应器。该反应器包括集水槽、电解室、布气及给水分配室，所述集水槽与电解室、电解室与布气及给水分配室之间设有布气板，布气板为多孔有机玻璃筛板，布气板上平铺有微孔膜，电解室两边靠近侧板处设有两道竖立平行的凹槽，在两个凹槽内插入两个电极，电解室内填充电极材料。该反应器电解效率高，微孑L膜可随时更换、透气性好，且拆装清洗方便。     

内电解-Fenton氧化法降解活性艳蓝X-BR机理

以蒽醌染料活性艳蓝X-BR为研究对象,进行了内电解-Fenton氧化法降解蒽醌染料机理的研究。通过紫外-可见分光光度计、傅立叶变换红外光谱仪、高效液相色谱仪、离子质谱仪等分析检测仪器对反应过程中间产物进行了分析,并通过对各种谱图的解析,推断出了活性艳蓝X-BR在内电解-Fenton氧化法处理降解过程中的反应历程。     

臭氧氧化-三维电极电解联用技术深度处理造纸废水

采用臭氧氧化-三维电极电解联用技术深度处理造纸废水,通过单因素及正交实验法确定了最优工艺条件,并探讨了反应的动力学和机理。实验结果表明:废水处理的最优工艺条件为电极间距1.5 cm、电流密度9mA/cm~2、臭氧曝气量15 mL/min、活性炭填充量22 g/L、反应时间60 min,该工艺条件下,废水的COD去除率达93.70%;臭氧氧化-三维电极电解联用技术对废水中COD的去除过程符合一级反应动力学方程;臭氧氧化和三维电极电解间存在协同效应。     

催化铁内电解-生物处理耦合技术的机理及研究进展

催化铁内电解技术(简称催化铁技术)是同济大学城市污染控制国家工程研究中心自主研发的新型废水处理方法。介绍了催化铁-生物处理耦合技术的机理,总结了近年来该技术的研究进展,并在此基础上指出了该技术目前存在的问题及发展方向。对于催化铁-生物处理耦合技术而言,考察在实际应用中的影响因素、完善催化铁的后续处理、深入分析反应机理及可控路径、探索与不同处理工艺的兼容性、提高长期运行的稳定性等是今后需重点关注的研究内容。     

微电解—芬顿氧化工艺预处理高浓度松香改性酚醛树脂生产废水

为了降低松香改性酚醛树脂生产废水的COD并改善其可生化性,采用微电解—芬顿氧化工艺对该废水进行预处理.研究了pH、微电解反应时间、曝气、双氧水投加量等对微电解和芬顿氧化处理效果的影响,考察了COD去除率和BOD5/COD值的变化趋势.实验结果表明:曝气条件下,调节废水pH为4、进行2次微电解、微电解反应时间各2.0 h...     

膜电解技术处理含氯及重金属的废酸

采用离子交换膜电解技术处理铜冶炼过程产生的含氯及重金属的废酸。考察了废酸处理工艺、电解温度、电解时间、电流密度和催化剂的添加等条件对处理效果的影响。实验结果表明：采用先沉淀重金属后脱氯的废酸处理工艺，氯离子和铜离子的去除效果均较好;当以钛盐为催化剂时，在电解温度为40 ℃、电解时间为2.0 h、电流密度为825 A/m²的最佳工艺条件下，处理后废酸中的氯离子质量浓度为0.22 g/L，氯离子去除率为98.59%，铜离子质量浓度为0.45 g/L，铜离子去除率为95.08%，其他重金属大部分也得到有效去除。净化后的废酸可回用至铜冶炼的生产过程中。     

从洗涤水煤气废水的内电解灰渣中提取亚铁氰络合物的研究

内电解法去除洗涤水煤气废水中游离氰的机理之一是,游离氰转变为亚铁氰化铁络合物沉积于内电解灰渣中。双试剂提取法是从洗涤水煤气废水的内电解灰渣中提取亚铁氰化铁的有效方法。用 X 射线衍射仪对所提取的结晶进行相分析的结果表明,该结晶主要为亚铁氰化铁。     

Determination of the Thermal Efficiency of Pre-boilover Burning of a Slick of Oil on Water

The burning rate of a slick of oil on a water bed is calculated by a simple expression derived from a one-dimensional heat conduction equation. Heat feedback from the flame to the surface is assumed to be a constant fraction of the total energy released by the combustion reaction. The constant fraction (χ) is named the burning efficiency and represents an important tool in assessing the potential of in situ burning as a counter-measure to an oil-spill. The total heat release, as a function of the pool diameter, is obtained from an existing correlation. It is assumed that radiative heat is absorbed close to the fuel surface, that conduction is the dominant mode of heat transfer in the liquid phase and that the fuel boiling temperature remains constant. By matching the characteristic thermal penetration length scale for the fuel/water system and an equivalent single layer system, a combined thermal diffusivity can be calculated and used to obtain an analytical solution for the burning rate. Theoretical expressions were correlated with crude oil and heating oil, for a number of pool diameters and initial fuel layer thickness. Experiments were also conducted with emulsified and weathered crude oil. The simple analytical expression describes well the effects of pool diameter and initial fuel layer thickness permitting a better observation of the effects of weathering, emulsification and net heat feedback to the fuel surface. Experiments showed that only a small fraction of the heat released by the flame is retained by the fuel layer and water bed (of the order of 1%). The effect of weathering on the burning rate decreases with the weathering period and that emulsification results in a linear decrease of the burning rate with water content.     

Calculation of carbon balances for evaluation of the biodegradability of polymers

Establishing carbon balances has been proven to be an applicable and powerful tool in testing biodegradability of polymers. In controlled degradation tests at a 4-L scale with the model polymer poly(-hydroxybutyrate) (PHB), it was shown that the degree of degradation could not be determined with satisfactory accuracy from CO₂ release alone. Instead, the course of degradation was characterized by means of establishing carbon balances for the degradation of PHB withAcidovorax facilis and a mixed culture derived from compost. Different analytical methods for determining the different carbon fractions were adapted to the particular test conditions and compared. Quantitative determination of biomass and residual polymer were the main problems in establishing carbon balances. Amounts of biomass derived from protein measurements depend strongly on assumptions of the protein content of the biomass. Selective oxidation of biomass with hypochlorite was used as alternative, but here problems arose from insoluble metabolic products. Determination of soluble components with the method of chemical oxygen demand (COD) also includes empirical assumptions but seems acceptable if the dissolved carbon fraction is in the range of some 10% total carbon. Results confirm both analytical assays and theoretical approaches, in ending up at values very close to 100%, within an acceptable standard deviation range under test conditions comparable to standard test practice.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.     

富拉尔基发电总厂200MW机组除尘器改造

对富拉尔基发电总厂5号炉的设计条件进行了分析，针对燃用低硫煤，飞灰比电阻高，场地较小，除尘效率要求高的情况，在电除尘器的设计上采取有效措施，达到了排放要求。     

Review of the kinetics of alkaline degradation of cellulose in view of its relevance for safety assessment of radioactive waste repositories

The degradation of cellulose (a substantial component of low- and intermediate-level radioactive waste) under alkaline conditions occurs via two main processes: a peeling-off reaction and a basecatalyzed cleavage of glycosidic bonds (hydrolysis). Both processes show pseudo-first-order kinetics. At ambient temperature, the peeling-off process is the dominant degradation mechanism, resulting in the formation of mainly isosaccharinic acid. The degradation depends strongly on the degree of polymerization (DP) and on the number of reducing end groups present in cellulose. Beyond pH 12.5, the OH^- concentration has only a minor effect on the degradation rate. It was estimated that under repository conditions (alkaline environment, pH 13.3-12.5) about 10% of the cellulosic materials (average DP = 1000-2000) will degrade in the first stage (up to 10⁵ years) by the peeling-off reaction and will cause an ingrowth of isosaccharinic acid in the interstitial cement pore water. In the second stage (10⁵-10⁶ years), alkaline hydrolysis will control the further degradation of the cellulose. The potential role of microorganisms in the degradation of cellulose under alkaline conditions could not be evaluated. Proper assessment of the effect of cellulose degradation on the mobilization of radionuclides basically requires knowing the concentration of isosaccharinic acid in the pore water. This concentration, however, depends on several factors such as the stability of ISA under alkaline conditions, sorption of ISA on cement, formation of sparingly soluble ISA-salts, etc. A discussion of all the relevant processes involved, however, is far beyond the scope of the presented overview.     

Study of Aging Characteristics of Ternary Blends of Polyethylenes—II

Six film samples of low-density polypropylene (LDPE)/linear LDPE (LLDPE)/high-density polypropylene (HDPE) with varying ratios of LDPE (20–45 ... wt%) and LLDPE (25–50 wt%) having a fixed amount of HDPE at 30 wt% were prepared by blown film extrusion technique. The samples were aged at four different temperatures, 55°, 70°, 85°, and 100°C, for four different time periods in the interval of between 150 hours and up to 600 hours. The change in the structure of various constituents and the formation of various oxygenated (peroxy and hydroperoxy) and unsaturated groups during thermo-oxidative degradation was discussed by infrared spectroscopy. The visiosity-average molecular weight was found to have decreased slowly in the initial aging hours and temperatures, whereas it decreased by 10% with its previous value tensile strength that is, 100°C when aged for 600 hours. The tensile strength of the sample first increased by 67% at 55°C and 89% at 70°C up to 450 hours, whereas the values increased by 52.5% at 85°C and 33.9% at 100°C when aged for 150 hours and then decreased. The percentage elongation at break increased by 2.7% at 55°C and 10.7% at 70°C for 150 and 300 hours of aging, respectively, whereas the percentage decreased when aged at 85°C and 100°C for up to 600 hours of aging. The values of gel content (percent) increased and initial degradation temperature decreased with aging time and temperature.     

Selection of adsorbents for treatment of leachate: batch studies of simultaneous adsorption of heavy metals

The simultaneous adsorption of copper (Cu), cadmium (Cd), nickel (Ni), and lead (Pb) ions from spiked deionized water and spiked leachate onto natural materials (peat A and B), by-product or waste materials (carbon-containing ash, paper pellets, pine bark, and semi-coke), and synthetic materials (based on urea-formaldehyde resins, called blue and red adsorbents) or mixtures thereof was investigated. The adsorbents that gave the highest metal removal efficiencies were peat A, a mixture of peat B and carbon-containing ash, and a mixture of peat A and blue. At an initial concentration of 5 mg/l for each metal, the removal of each species of metal ion from spiked water and spiked leachate solutions was very good (>90%) and good (>75%), respectively. When the initial concentration of each metal in the solutions was twenty times higher (100 mg/l), there was a noticeable decrease in the removal efficiency of Cu²⁺, Cd²⁺, and Ni²⁺, but not of Pb²⁺. Langmuir monolayer adsorption capacities, q_m, on peat A were found to be 0.57, 0.37, and 0.36 mmol/g for Pb²⁺, Cd²⁺, and Ni²⁺, respectively. The order of metal adsorption capacity on peat A was the same in the case of competitive multimetal adsorption conditions as it was for single-element adsorption, namely Pb²⁺ > Cd²⁺ ≥ Ni²⁺. The results show that peat alone (an inexpensive adsorbent) is a good adsorbent for heavy metal ions.     

袋式除尘器气流分布数值计算研究

采用结构化/非结构化混合网格技术、多孔介质模型及k-ε两方程湍流模型,对某袋式除尘器及进出口管道内的气体流场进行了数值计算.计算结果表明,合理布置导流板后,袋式除尘器两箱体流量偏差为1.8％;除尘器下游滤袋单元处理气量偏大,中游滤袋单元处理气量较小,最大流量与最小流量偏差为22.3％；靠近除尘器进口处灰斗内存在气流回流特性,易造成粉尘的二次附着现象.     

Effect of Degree of Substitution of Octenyl Succinate Starch on Enzymatic Degradation

Octenyl succinate starch of degree of substitution (ds) 0.03, 0.07, and 0.11 was synthesized in an aqueous medium. These compounds were then tested for the susceptibility to enzymatic degradation. The multiple-enzyme regime of -amylase, amyloglucosidase, and pullulanase was chosen for the evaluation. This combination of enzymes had been proven to degrade 99.5% of unmodified starch to glucose and hence was chosen for this study. It was found that even small amounts of subsituent caused a considerable decrease in the extent of degradation. The net extent of degradation decreased with increasing ds. Surprisingly, the amount of glucose from all three substituted substrates was quite similar, suggesting the effect small amounts of subtituent had on the enzymatic activity.     

Effects of temperature on the release of nutrient elements of solid organic materials under conditions of oversaturation

The effects of temperature on the release of chemical components of six solid organic materials under conditions of oversaturation were investigated in this paper. The six materials were peat moss (PM), weathered coals (WC), charred rice husks (CRH), sawdust (Sd), turfgrass clippings (TC), and chicken manure (CM). Significant differences were observed in the available nitrogen and phosphorus content of the aqueous extracts of organic materials at different temperatures. The available nitrogen content in aqueous extracts of PM and WC at 25 °C was higher than that registered at 15 °C and 35 °C. Available nitrogen content in the aqueous extracts of CRH, Sd, TC, and WC at 35 °C was higher than at 15 °C and 25 °C. The available phosphorus content in the aqueous extracts of organic materials at 35 °C was higher than that available at 15 °C and 25 °C, with the exception of Sd. In addition, the release of available phosphorus in the aqueous solution of organic materials at different temperatures varied constantly for 108 h. The release of potassium (K⁺) and sodium (Na⁺) ions in the aqueous extracts of organic materials was basically steady over time, with the exception of CM. High temperature (35 °C) may significantly hasten the release of K⁺ from organic substrates (except for WC) with low temperatures significantly inhibiting release of K⁺ in Sd and CRH. High temperatures (35 °C) might significantly facilitate the release of Na⁺ in CM and TC. However, no significant differences were manifested in the release of Na⁺ from organic substrates at different temperatures, with the exception of CM and TC. Moreover, no significant differences were observed in the release of calcium, magnesium and iron ions with time, nor were there any significant differences in the contents of iron ions in the aqueous extracts of organic materials at different temperatures. The results indicate that multiple mediums should be pretreated in water for a week before being used for planting. They should be used when all mineral elements of organic materials are steady and ignoring the effect of organic mediums.     

Kinetics of Hydrolytic Degradation of PLA

The chemical recycling of poly(lactic acid) (PLA) to its monomer is crucial to reduce both the consumption of renewable resources for the monomer synthesis and the environmental impact related to its production and disposal. In particular, the production of lactic acid from PLA wastes, rather than from virgin raw materials, it is also possible to achieve considerable primary energy savings. The focus of this work is to analyse deeply the PLA hydrolytic decomposition by means of a kinetic model based on two reactions mechanism. To this end, new experimental data have been gathered in order to investigate a wider temperature range (from 140 to 180 °C) and to extend the water/PLA ratio up to 50 % of PLA by weight. The reported results clearly highlight that more than 95 % of PLA is hydrolyzed to water-soluble lactic acid within 120 min, when it is hydrolyzed within 160–180 °C. Furthermore, the kinetic constant is highly influenced by reaction temperature. The proposed “two reactions” kinetic mechanism complies satisfactorily with the experimental data under analysis.