Phenol electrooxidation on Fe-Co3O4 thin film electrodes in alkaline medium

Fe-Co₃O₄ thin film with different amounts of Fe have been used for the electro-oxidation of phenol in alkaline medium at room temperature. The electrodes were prepared by coating stainless steel supports with successive layers of the oxides, obtained by thermal decomposition at 673 K. The electrolysis was carried out at constant potential and the phenol disappearance, during the electrolysis, was monitored by UV-Vis absorbance measurements between 250 and 500 nm. After 3 h of electrolysis, the intermediates were identified by comparing the HPLC data and UV-Vis spectra to those from pure standards. The results indicate that the same oxidation products are formed on the different prepared electrodes, namely the decomposition products of phenol such as benzoquinone, hydroquinone and cathecol in basic medium. Simulated results show clearly the decrease of the amount of phenolic species with the electrolysis time. An enhancement of the phenol removal is observed with the presence of iron in the oxide. Under the operating conditions, around 30% of the initial phenol has been removed at ca. 3 h and the complete degradation is obtained after 54 h of electrolysis, when Fe-Co₃O₄ thin film with 10% of Fe is used as anode.     

铁炭微电解-Fenton氧化-A/A/O生化等联合工艺处理酚类、硝基苯类废水的探讨

采用酸化沉淀-超滤-铁炭微电解-Fenton氧化-混凝沉淀-A/A/O生化处理等联合工艺处理酚类、硝基苯类废水。设计处理水量:物化预处理2 m^3/h、生化处理3 m^3/h。运行结果表明,该工艺处理效果良好,出水pH6~9,COD≤500 mg/L,SS≤400 mg/L,NH3-N≤50 mg/L,TP≤2 mg/L,酚类≤0.5 mg/L,硝基苯类≤2,盐分≤5000 mg/L,出水水质优于设计指标要求。     

ClO2氧化,混凝沉降法处理煤气洗涤水的研究

根据煤气洗涤水的性质,用ClO2 氧化除酚,SL和PAM混凝沉降除悬浮物的方法处理煤气洗涤水。实验结果表明,经处理后废水中的主要污染物酚、焦油和悬浮物等去除率都很高,该水完全可以满足回用要求。     

包埋活性炭聚氨酯软泡去除废水中苯酚的研究

通过对Pu-Ac吸附剂进行吸附苯酚实验,Pu-Ac吸附剂吸附25mg/L苯酚溶液时确定平衡吸附时间为12h;当pH值在6~7范围内,溶液呈弱酸性时对苯酚的去除率达到最大值;Pu-Ac吸附剂对腐殖酸的吸附去除率低于粉末活性炭;水体中含有的细颗粒泥沙含沙量在0.1~10kg/m3范围内对苯酚的吸附效果基本没有影响;Pu-Ac吸附剂经NaOH强碱溶液再生后,对苯酚的去除率保持在70%左右,可以循环利用。     

靛红褪色光度法测定废水中苯酚

基于KH2PO4-Na2HPO4缓冲介质中,痕量苯酚对高碘酸钾氧化靛红反应有催化作用,建立了测定废水中苯酚的催化动力学方法.优化了试验条件,讨论了缓冲溶液酸度、试剂体积、加热时间和反应温度对试验的影响.方法在0.08 mg/L～2.0 mg/L线性关系良好,检出限为5.3×10-3 mg/L,加标回收率为97.6%～103%,实际样品测定结果与4-氨基安替比林法对照,结果令人满意.     

固定化细胞技术处理含酚废水的研究

固定化细胞技术的关键是所用载体材料的性能。本文力求寻找一种价格低、寿命长、效率高的载体。通过同一菌种在固定状态和游离状态降解含酚废水的实验对比，证明红砖碎粒是一种优良的载体材料。利用正交实验，确定了该菌种在固定时的最佳运行条件。并对游离细胞和固定细胞降解苯酚的过程进行了动力学分析。结果表明，在两种情况下，该菌种降解苯酚的过程均符合Ｍｏｎｏｄ模型。     

大孔阴树脂及其白球对水中低浓度苯酚吸附行为的研究

研究了作为高分子材料的大孔阴树脂及其对应白球对水中低浓度苯酚的吸附行为，详细考察了吸附过程的吸附容量、速度等吸附参数以及ｐＨ、Ｃａ＾２＋、腐殖质等因素对吸附的影响，并对试验结果从理论上进行了分析与探讨。     

Photocatalytic degradation of phenol on different phases of TiO(2) particles in aqueous suspensions under UV irradiation

Photocatalytic degradation of phenol on different phases of TiO₂ particles was examined under 400-W UV irradiation. The effects of various operating parameters including TiO₂ dosage, solution pH (4–10), and initial phenol concentration (0.13–1.05 mM) on phenol degradation were investigated. Three forms of TiO₂ photocatalysts such as pure anatase phase, pure rutile phase, and the mixed phase were prepared by sol-gel method and followed annealing at different temperatures. The annealing temperature used were 500 °C, 700 °C and 900 °C for pure anatase phase, the mixed phase, and pure rutile phase, respectively. It was shown that pure anatase TiO₂ exhibited higher photocatalytic activity than the physical mixture of pure anatase and rutile TiO₂. Moreover, the TiO₂ particle with a specific fraction of mixed anatase and rutile phases exhibited better performance than pure anatase TiO₂. Finally, the degradation rate could be satisfactorily fitted by a pseudo-first-order kinetic model.     

Inhibitory effect of high phenol concentration in treating coal gasification wastewater in anaerobic biofilter

In this paper, the inhibition of methanogens by phenol in coal gasification wastewater(CGW)was investigated by both anaerobic toxicity tests and a lab-scale anaerobic biofilter reactor(AF). The anaerobic toxicity tests indicated that keeping the phenol concentration in the influent under 280 mg/L could maintain the methanogenic activity. In the AF treating CGW,the result showed that adding glucose solution as co-substrate could be beneficial for the quick start-up of the reactor. The effluent chemical oxygen demand(COD) and total phenol reached1200 and 100 mg/L, respectively, and the methane production rate was 175 m L CH4/g COD/day.However, if the concentration of phenol was increased, the inhibition of anaerobic micro-organisms was irreversible. The threshold of total phenol for AF operation was 200–250 mg/L. The extracellular polymeric substances(EPS) and particle size distribution of anaerobic granular sludge in the different stages were also examined, and the results indicated that the influence of toxicity in the system was more serious than its effect on flocculation of EPS. Moreover, the proportion of small size anaerobic granular sludge gradually increased from10.2% to 34.6%. The results of high through-put sequencing indicated that the abundance of the Chloroflexi and Planctomycetes was inhibited by the toxicity of the CGW, and some shifts in the microbial community were observed at different stages.     

Effect of dilution rate on dynamic and steady-state biofilm characteristics during phenol biodegradation by immobilized Pseudomonas desmolyticum cells in a pulsed plate bioreactor

Continuous pulsed plate bioreactor (PPBR) was used for phenol biodegradation. Pseudomonas desmolyticum cells immobilized on granular activated carbon was used. Dynamic and steady state biofilm characteristics depend on dilution rate (DR). Lower DR favour phenol degradation and uniform, thick biofilm formation. Exo polymeric substance production in biofilm are favoured at lower dilution rates. Pulsed plate bioreactor (PPBR) is a biofilm reactor which has been proven to be very efficient in phenol biodegradation. The present paper reports the studies on the effect of dilution rate on the physical, chemical and morphological characteristics of biofilms formed by the cells of Pseudomonas desmolyticum on granular activated carbon (GAC) in PPBR during biodegradation of phenol. The percentage degradation of phenol decreased from 99% to 73% with an increase in dilution rate from 0.33 h?1 to 0.99 h?1 showing that residence time in the reactor governs the phenol removal efficiency rather than the external mass transfer limitations. Lower dilution rates favor higher production of biomass, extracellular polymeric substances (EPS) as well as the protein, carbohydrate and humic substances content of EPS. Increase in dilution rate leads to decrease in biofilm thickness, biofilm dry density, and attached dry biomass, transforming the biofilm from dense, smooth compact structure to a rough and patchy structure. Thus, the performance of PPBR in terms of dynamic and steady-state biofilm characteristics associated with phenol biodegradation is a strong function of dilution rate. Operation of PPBR at lower dilution rates is recommended for continuous biologic treatment of wastewaters for phenol removal.