聚乙烯醇在超临界水氧化体系中的降解

用超临界水氧化法对聚乙烯醇(PVA)废水进行降解研究,分别考察了反应温度、反应压力、氧化剂过氧倍数以及反应时间对PVA废水降解效率的影响,并用GC/MS对液相降解产物进行表征,推测其可能降解途径.结果表明:超临界水氧化法能有效降解PVA废水,随反应温度的升高、压力的增大、反应时间的延长,COD去除率也随之提高.PVA在超临界水氧化体系中降解为烯烃、烯酮、醇和羧酸类中间产物,最终降解为小分子的饱和直链烷烃类液相产物.     

超临界水氧化法在造纸黑液治理中的应用

从超临界水的性质,超临界水氧化法的原理,动力学、工艺和优越性等方面阐述了超临界水氧化法作为一种造纸黑液治理技术具有的广阔应用前景,结合实验讨论了超临界水氧化法在造纸黑液治理中应用的可行性,并对处理过程中可能存在的一些问题及相应的改进措施进行了探讨.     

制浆黑液超临界水氧化过程的动力学研究

采用幂函数模型推导制浆黑液超临界水氧化的反应动力学方程,并利用间歇式超临界水氧化反应器进行制浆黑液超临界水氧化反应实验。通过实验发现,温度和停留时间是影响COD去除率的主要因素,在温度380～540℃,压力25～31MPa,停留时间60～150s,过氧量150%～300%的条件下,制浆黑液的COD去除率为95.0%～99.3%。对实验数据分析得到,超临界水氧化法去除高浓度黑液COD的活化能为15.171kJ/mol,COD和O2的反应级数分别为1.62和0.22,反应速率常数为0.88968。     

高级氧化技术在难降解有机废水处理中的应用

高级氧化技术已经成为处理难降解有机废水的重要手段,在印染、化工、农药、造纸和制药等领域的废水处理工程中得到广泛应用,具有广阔的应用前景.着重叙述了高级氧化技术的基本原理,阐述了化学氧化法、光化学氧化法、臭氧氧化法、湿式氧化法和超临界水氧化法等常用的高级氧化技术在难降解有机废水处理中的应用,同时指出了高级氧化技术未来的研...     

造纸黑液超临界水氧化过程的能流分析与经济评价

超临界水氧化是解决难降解高浓度废水的有效途径,但处理工艺的高能耗成为限制其推广应用的瓶颈问题。采用能流分析的方法,对造纸黑液超临界水氧化过程中的能量消耗和产生情况进行了分析,通过热平衡分析和压力分析,考察了各工艺条件对过程能耗的影响,根据实验结果对过程的经济性进行了评价,在此基础上提出了降低超临界水氧化过程运行成本的措施。     

超临界水氧化技术在环境治理中的应用

超临界水氧化技术在高浓度难降解有机危废处理方面具有反应迅速彻底、反应装置小、无二次污染等优点。从超临界水的性质、氧化反应特性以及基本工艺流程等方面对超临界水氧化过程进行了系统介绍,总结了现阶段超临界水氧化的研究现状,重点阐述了超临界水氧化技术在废水处理、固废处理以及水体保护方面的应用,并展望了超临界水氧化技术的发展趋势,以期为实现超临界水氧化技术的工业化提供指导。     

超临界流体技术在造纸工业中的应用

综述了超临界技术尤其是超临界水氧化法在造纸生产过程、造纸污水和污泥的处理以及废水中痕量有害成分分析等方面的应用.     

超临界水氧化法处理废水

超临界水（Supercritical Watr）具有很多特殊性质。超临界水氧化法（Supercritical Oxidation,SCWO）可以有效除去造纸废水中的有毒物质。     

制浆黑液超临界水氧化资源化治理

采用超临界水氧化技术处理高浓度制浆黑液,既能消除污染,又能产生可供利用的能源,具有很好的经济与社会效益。从超临界水氧化的特点、工艺流程、物能消耗、能量输出等方面对制浆黑液超临界水氧化治理过程进行了介绍,在此基础上对其经济性进行了评价,阐述了提高过程经济性的耦合工艺,对装置的主要污染源进行了分析并提出相应的控制对策,最后就设备开发中存在的问题提出了建议,为实现制浆黑液超临界水氧化资源化治理提供了指导。     

高级氧化技术在造纸废水处理中的应用

高级氧化技术对废水中难降解有机物质有较高的去除效率,因而受到广泛关注.重点介绍了芬顿法与类芬顿法、臭氧氧化法、光催化氧化法、超临界水氧化法、湿式催化氧化法等高级氧化技术的作用机理及其在造纸废水处理中的研究进展,分析并指出了各种高级氧化技术的特点、存在的问题和今后的发展方向.     

超临界水氧化法处理黑液

造纸黑液是一种相当难处理的高浓度工业废水,本文以工业纯氧为氧化剂,用自制的间歇式超临界水氧化系统处理造纸黑液,实验结果表明:选定最佳的实验参数后,超临界水氧化法可使黑液中COD和色度的去除率分别达到99.9%和99.5%。     

氧化沟工艺及其在制革废水处理中的应用

介绍了氧化沟工艺的研究进展。概述了制革废水一级物化处理和二级生化处理的各种方法。由于氧化沟工艺具有耐高有机负荷、耐高毒性负荷、耐高盐负荷冲击能力的特点 ,更适于制革废水的处理。以工程实例阐述了氧化沟工艺处理制革废水所取得的良好效果 ,并指出 :氧化沟工艺作为一种新的废水生物处理技术 ,用于制革废水处理 ,前景广阔。     

生物接触氧化法处理制革综合废水中的常见问题及对策

探讨了生物接触氧化法处理制革综合废水时常见的出水水质波动大 ,硫化物、三价铬、悬浮物浓度高 ,易产生大量泡沫和曝气效果不理想等问题 ,提出了相应的解决措施。经制革厂运用实践证明 :改进后的生物接触氧化法处理制革综合废水是较为理想的方法     

Effect of water activity on oxidative deterioration of freeze-dried beef

The effect of water activity on lipid oxidation in freeze-dried beef was studied. Analytical indices of the extent of oxidation (thiobarbituric acid (TBA) number and Ex 350Ee320 fluorescence ratio) showed that samples of water activity 0.270 underwent less oxidation during 84 days storage in oxygen at 50°C than samples of lower water activity. Samples stored under nitrogen, irrespective of water activity, did not show any oxidation.     

Oxidation reaction of high molecular weight carboxylic acids in supercritical water

Stearic acid, being a model compound of high molecular weight carboxylic acids, was oxidized in a batch reactor by changing the oxygen supply with an insufficient oxygen supply at a constant reaction time at 420 degrees C. On the basis of the intermediate products identified by GC/MS, NMR, and HPLC analyses and the free-radical reaction mechanism, the oxidation pathways of high molecular weight carboxylic acids in supercritical water are discussed. The reaction of carboxylic acids in supercritical water proceeds with the consecutive oxidation of higher molecular weight carboxylic acids to lower molecular weight carboxylic acids through several major pathways. The attack of the hydroxyl radical occurs not only at the carbons in alpha-, beta-, gamma-positions to a --COOH group but also at the carbons ((omega-1)-carbon and/or omega-carbon) far in the alkyl chain from a --COOH group, which may lead to the formation of dicarboxylic acids.     

氧化沟工艺处理制革废水实例

根据废水水质及处理要求，确定采用氧化沟工艺，在氧化沟前设置了预沉、调节池氧化脱硫和气浮工艺组成的预处理系统，在二沉池后还设置了加药混凝沉淀工艺，以确保处理后水中COD达到一级标排放标准。     

Effects of mineral content of bovine drinking water: Does iron content affect milk quality?

The composition of water given to dairy cattle is often ignored, yet water is a very important nutrient and plays a major role in milk synthesis. The objective of this study was to study effects of elevated levels of iron in bovine drinking water on milk quality. Ferrous lactate treatments corresponding to 0, 2, 5, and 12.5 mg/kg drinking water concentrations were delivered through the abomasum at 10 L/d to 4 lactating dairy cows over 4 periods (1 wk infusion/period) in a Latin square design. On d 6 of infusion, milk was collected, processed (homogenized, pasteurized), and analyzed. Mineral content (Fe, Cu, P, Ca) was measured by inductively coupled plasma mass spectrometry. Oxidative stability of whole processed milk was measured by the thiobarbituric acid reactive substances (TBARS) assay for malondialdehyde (MDA) and sensory analysis (triangle test) within 72 h of processing and after 7 d of storage (4°C). Significant sensory differences between processed milks from cows receiving iron and the control infusion were observed. No differences in TBARS (1.46 ± 0.04 mg of MDA/kg) or mineral content (0.22 ± 0.01 mg/kg Fe) were observed. A 2-way interaction (iron treatment by cow) for Ca, Cu, and Fe concentrations was seen. While iron added directly to milk causes changes in oxidation of milk, high levels of iron given to cattle have subtle effects that initially may not be obvious.     

Effects of hydroxyl radical induced oxidation on water holding capacity and protein structure of jumbo squid (Dosidicus gigas) mantle

Protein oxidation is considered as an important issue in food preservation process. In the present study, the potential influence of protein oxidation on water holding capacity and protein structure of jumbo squid (Dosidicus gigas) mantle was investigated. After the hydroxyl radical oxidation, it was found that the carbonyl, surface hydrophobicity and dityrosine content of myofibrillar protein significantly increased (P < 0.05), while the content of total sulphydryl decreased significantly (P < 0.01). Meanwhile, the fluorescence intensity of squid was weakened, and the maximum absorption peak of fluorescence red shift as the H₂O₂ concentration increased. The sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed that not only the protein cross-linking but also degradation could have occurred. The content of α-helix decreased, the content of β-sheet, β-turn and the unordered structures increased after oxidation. In addition, oxidation resulted in a decrease in water holding capacity. Taken together, oxidation resulted in the damage of the myofibrillar structure, the increase in muscle loss rate and the decrease in water holding capacity.     

Oxidation of 4-chloro-3-methylphenol in pressurized hot water/supercritical water with potassium persulfate as oxidant

4-Chloro-3-methylphenol (c = 2.0 mM), representing a model pollutant, was oxidized in pressurized hot water and in supercritical water in a continuous flow system. Potassium persulfate was used as oxidant in concentrations of 8.0 and 40.0 mM. Contact times (reaction times) were 3-59 s, temperatures 110-390 degrees C, and pressures 235-310 bar. A wide temperature range was tested to determine the range over which potassium persulfate can be used effectively. Good oxidation efficiencies for 4-chloro-3-methylphenol were obtained at both oxidant concentrations and with short contact times at temperatures clearly underthe critical temperature of water; total organic carbon content of the effluent was low under optimized conditions. Corrosion, measured as nickel and chromium concentrations of the effluent, was more severe at oxidant concentration of 40.0 mM. Sulfate was present in the effluent in high concentrations. Sulfate is the limiting factor in the use of potassium persulfate in wastewater treatment and requires further water treatment.