高级氧化技术在造纸废水处理中的研究进展

高级氧化技术是近几年很受关注的废水处理新技术，用其处理造纸废水的研究也在广泛展开。从这种技术的机理、研究现状及存在问题出发，阐述了这些新方法在造纸废水处理中的实验研究及应用的可能性。     

石墨极板电氧化法处理靛蓝染料废水初步研究

采用惰性材料石墨为阳极的电氧化法处理靛蓝染料废水。研究了进水浓度、不同电解质的作用对处理效果的影响，获得了COD去除率大于90％、色度去除率大于95％的处理效果。     

Cr元素对铁合金抗热强碱磨损腐蚀性能的影响

测定了10钢、20Cr5、20Cr11含铬铸钢和185Cr13、295Cr26高铬铸铁在85℃的质量浓度为303g蛐L的NaOH溶液中的腐蚀速率、电位鄄时间曲线、静态及冲刷条件下的电化学曲线。实验结果显示,铬钢和铬铸铁在静态浸泡中,电位都经历过高—低—高的变化,表明其腐蚀历程相似。在静态条件下,含铬量高的铬钢和铸铁腐蚀失重大于含铬量低的材料。在冲刷条件下,由失重法获得的总失重和由极化曲线计算得到的腐蚀失重均显示含铬高的铸铁抗磨损腐蚀性能优于含铬量相对低的铸铁。增加铬含量,对合金抗热强碱的纯腐蚀有不利的影响,但却有利于材料抗热强碱介质的磨损腐蚀。     

“三合一”微生物燃料电池的产电特性研究

为了降低内阻,尽可能提高微生物燃料电池的输出功率,提出了一种将阳极、质子交换膜和阴极热压在一起的"三合一"膜电极形式的微生物燃料电池,并考察了其在接种厌氧污泥条件下对乙酸自配水的产电特性.该"三合一"电池在稳定运行条件下电池内阻约为10～30Ω,远低于现已报道的其它形式的微生物燃料电池的内阻.目前该"三合一"型微生物燃料电池最大输出功率密度约300 mW·m-2,库仑效率约50%.试验结果表明,在一个间歇运行周期中,电池内阻增加是引起输出电压降低的最主要原因.同时在不同的外阻条件下,需要降低极化的重点不同.     

超声振动强化膜分离过程机理的研究

膜分离过程中的浓差极化现象是影响膜分离效果的主要因素之一 ,本文探索了利用超声振动的方法来强化膜分离反应过程。首先建立了其动力学模型 ,然后通过试验对其强化机理进行了深入的探讨 ,以达到经济、高效地提高膜分离效果的目的。     

废水脉冲电解处理节能高效的原因分析

将脉冲电源和直流电源分别作为废水电解处理的电源,试验探明其对废水电解处理的电能消耗和COD去除率的影响,并分析废水脉冲电解处理节能高效的原因。试验结果表明,脉冲电流相对直流电流能够更加有效减缓电极的极化,降低电极过电位,使电能消耗降低15%-35%;在脉冲电解处理废水过程中电流效率稳定、Fe^2＋能够有效扩散到废水中,使去污效果增强5%-7%。     

Recent advances in the electrochemical oxidation water treatment: Spotlight on byproduct control

• Byproduct formation mechanisms during electrochemical oxidation water treatment. • Control byproduct formation by quenchers. • Process optimization to suppress byproduct formation. Electrochemical oxidation (EO) is a promising technique for decentralized wastewater treatment, owing to its modular design, high efficiency, and ease of automation and transportation. The catalytic destruction of recalcitrant, non-biodegradable pollutants (per- and poly-fluoroalkyl substances (PFAS), pharmaceuticals, and personal care products (PPCPs), pesticides, etc.) is an appropriate niche for EO. EO can be more effective than homogeneous advanced oxidation processes for the degradation of recalcitrant chemicals inert to radical-mediated oxidation, because the potential of the anode can be made much higher than that of hydroxyl radicals (E_OH = 2.7 V vs. NHE), forcing the direct transfer of electrons from pollutants to electrodes. Unfortunately, at such high anodic potential, chloride ions, which are ubiquitous in natural water systems, will be readily oxidized to chlorine and perchlorate. Perchlorate is a to-be-regulated byproduct, and chlorine can react with matrix organics to produce organic halogen compounds. In the past ten years, novel electrode materials and processes have been developed. However, spotlights were rarely focused on the control of byproduct formation during EO processes in a real-world context. When we use EO techniques to eliminate target contaminants with concentrations at μg/L-levels, byproducts at mg/L-levels might be produced. Is it a good trade-off? Is it possible to inhibit byproduct formation without compromising the performance of EO? In this mini-review, we will summarize the recent advances and provide perspectives to address the above questions.     

电袋复合除尘器高效捕集微细粉尘 PM2.5的机理探讨

电袋复合除尘器捕集粉尘除了静电凝并作用外,滤袋表面的二次粉尘层和一次粉尘层中粉尘颗粒之间的微米级间隙,以及滤料纤维层中纤维间距的微距,加上荷电粉尘层形成的（内）电场力和（或）外加电场的作用,使微细粉尘发生极化、库伦和电场吸附,是实现高效捕集微细粉尘PM2.5的重要机理。     

An assessment of the effectiveness and impact of electrokinetic remediation for pyrene-contaminated soil

The effectiveness of electrokinetic remediation for pyrene-contaminated soil was investigated by an anode-cathode separated system using a salt bridge. The applied constant voltage was 24 V and the electrode gap was 24 cm. Two types of soil （sandy soil and loam soil） were selected because of their different conductive capabilities. The initial concentrations of pyrene in these soil samples were 261.3 mg/kg sandy soil and 259.8 mg/kg loam soil After treatment of the sandy soil and loam soil for seven days, 56.8% and 20.1% of the pyrene had been removed respectively. Under the same power supply voltage, the removal of the pollutant from the sandy soil was greater than that from the loam soil, due to the higher current and lower pH. Further analysis revealed that the effectiveness of electrokinetic remediation was affected by the energy expenditure, and was associated with changes in soil properties.     

Electrochemical oxidation of 1H,1H,2H,2H-perfluorooctane sulfonic acid (6：2 FTS) on DSA electrode：Operating parameters and mechanism

The 6:2 FTS was the substitute for perfluorooctane sulfonate(PFOS) in the chrome plating industry in Japan. Electrochemical oxidation of 6:2 FTS was investigated in this study. The degradabilities of PFOS and 6:2 FTS were tested on the Ti/SnO2–Sb2O5–Bi2O3anode. The effects of current density,potential,and supporting electrolyte on the degradation of 6:2 FTS were evaluated. Experimental results showed that 6:2 FTS was more easily degraded than PFOS on the Ti/SnO2–Sb2O5–Bi2O3anode. At a low current density of 1.42 mA/cm2,6:2 FTS was not degraded on Ti/SnO2–Sb2O5–Bi2O3,while the degradation ratio increased when the current density ranged from 4.25 to 6.80 mA/cm2. The degradation of 6:2 FTS at current density of 6.80 mA/cm2 followed pseudo first-order kinetics with the rate constant of 0.074 hr-1. The anodic potential played an important role in the degradation of 6:2 FTS,and the pseudo first-order rate constants increased with the potential. The surface of Ti/SnO2–Sb2O5–Bi2O3was contaminated after electrolysis at constant potential of 3 V,while the fouling phenomenon was not observed at 5 V. The fouled anode could be regenerated by incinerating at 600°C. The intermediates detected by ultra-performance liquid chromatography coupled with a triple-stage quadrupole mass spectrometer(UPLC–MS/MS) were shorter chain perfluorocarboxylic acids. The 6:2 FTS was first attacked by hydroxyl radical,and then formed perfluorinated carboxylates,which decarboxylated and removed CF2 units to yield shorter-chain perfluorocarboxylic acids.