湿式氧化-催化湿式氧化联用处理定影废水

采用湿式氧化(WAO)-催化湿式氧化(CWAO)两段工艺处理定影废水,重点考察了反应时间、温度、压力、pH等因素对WAO处理效果的影响,并进行了CWAO处理WAO出水氨氮的尝试,取得了较好的效果.实验确定WAO适宜的反应条件:温度为160℃、氧分压为1 MPa、反应时间为2 h、进水pH为4.8.该条件下的CODCr去除率达79%,出水pH为1.4.CWAO处理WAO出水时所选定的反应条件:pH为12.9、温度为250℃、氧分压为3 MPa、反应时间为2 h.采用CWAO和WAO联用的方法处理定影废水,CODCr去除率达99.8%,氨氮去除率达97.8%,pH为5.6.     

国外湿式氧化反应系统的研究开发

简要介绍湿式氧化反应系统的应用历史、反应机理及动力学特征,以及该反应系统的设计及现有反应设备的特点、工业化中面临的难题等。重点介绍了国外主要的已工业化的湿式氧化反应系统,并针对不同反应系统在反应设备、操作条件、处理效果等方面的特点进行比较总结。在小结湿式氧化反应系统研究应用现状的基础上提出了今后研究开发的方向。     

湿式氧化催化剂的研究

摘要叙述了一型湿式氧化催化剂的研制情况和用于处理工业废水的效果,给出了有关小型试验结果。     

Insight into spent caustic treatment: on wet oxidation of thiosulfate to sulfate

Oxidation of thiosulfate to sulfate is often the rate controlling step during wet air oxidation (WAO) of spent caustic from the refinery and petrochemical industry and exhibits high Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). The kinetics of WAO of thiosulfate was studied in the absence and presence of a heterogeneous copper catalyst. Wet oxidation of thiosulfate to sulfate is a free radical reaction exhibiting an induction period. In non‐catalytic oxidation, almost complete conversion of thiosulfate to sulfate was observed in 12 min at 150 °C and in 8 min at 120 °C in the presence of a heterogeneous copper catalyst at 0.69 MPa oxygen partial pressure. The presence of phenol accelerated thiosulfate oxidation. © 1999 Society of Chemical Industry     

Catalytic wet air oxidation of dye pollutants by polyoxomolybdate nanotubes under room condition

In order to develop a catalyst with high activity and stability for catalytic wet air oxidation of pollutant dyes at room condition, a new polyoxometalate Zn_1.5PMo₁₂O₄₀ with nanotube structure was prepared using biological template. The structure and morphology were characterized using infrared (IR) spectra, UV–vis diffuse reflectance spectra (DR-UV–vis), elemental analyses, X-ray powder diffraction (XRD), and transmission electron microscopy (TEM). And the degradation of Safranin-T (ST), a hazardous textile dye, under air at room temperature and atmospheric pressure was studied as a model experiment to evaluate the catalytic activity of this polyoxomolybdate catalyst. The results show that the catalyst has an excellent catalytic activity in treatment of wastewater containing 10 mg/L ST, and 98% of color and 95% of chemical oxygen demand (COD) can be removed within 40 min. And the organic pollutant of ST was totally mineralized to simple inorganic species such as HCO₃⁻, Cl⁻ and NO₃⁻ during this time (total organic carbon (TOC) decreased 92%). The structure and morphology of the catalyst under different cycling runs show that the catalyst are stable under such operating conditions and the leaching tests show negligible leaching effect owning to the lesser dissolution. So this polyoxomolybdate nanotube is proved to be a heterogeneous catalyst in catalytic wet air oxidation of organic dye.     

混凝-二次氧化工艺处理压裂返排废液的研究

针对压裂返排产生的返排液COD严重超标,若不妥善处理将严重破坏环境的问题,采用混凝-二次氧化联合工艺处理压裂返排废液。通过试验对比,采用2 000 mg/L的试剂P与1 000 mg/L的试剂PA复配使用作为絮凝剂,以投加量50 mg/L、相对分子质量1 200万的试剂M为助凝剂,进行混凝处理;一次氧化采用氧化剂N,投加量为2 500 mg/L,氧化时间40 min;二次深度氧化采用Fenton试剂,通过正交试验确定p H值为3,H2O2与Fe2+投加量分别为0.2 mol/L、0.075 mol/L,氧化时间45 min。3个阶段的COD去除率分别为23.8%,41.3%,31.0%,总去除率为96.1%,废液COD由2 241 mg/L降至87.4 mg/L。     

催化湿式氧化处理农药废水的研究

利用担载型双金属活性组分催化剂，考察了反应温度、压力、进料空速和V（空气）：V（H2O）（体积比）等反应条件对催化湿式氧化处理某农药废水效果的影响。对于该种废水，在4．2MPa，245℃，空速为2．0h^-1，V（空气）：V（H2O）＝300的反应条件下，废水的COD去除率可达到91．3％。经处理后废水的BOD5／COD＞0．5，说明其可生化性能良好。     

Biodegradability of linear alkylbenzene sulfonates subjected to wet air oxidation

Shake flask experiments were conducted to determine the biodegradability of aqueous linear alkylbenzene sulfonate (LAS) and LAS (1600 mg dm^?3) subjected to wet air oxidation (WAO), to assess the suitability of WAO as a pre‐treatment for biological degradation. The effects of WAO temperature (180–240 °C) and the concentration of the orthophosphoric acid catalyst (0–1.0 mol dm^?3) were investigated. Results showed that a higher WAO temperature increased the biodegradability of the WAO effluent. This was due to a greater removal of both recalcitrant sulfonated organics and organic concentration (TOC and COD). Conversely, greater orthophosphoric acid concentrations decreased the biodegradability of the WAO effluents. This was because the higher acid concentration increased the ionic strength and changed the WAO intermediate and product distribution, inhibiting microbial action. Nevertheless, the effluents from both variations of WAO were still more biodegradable than LAS at equivalent concentrations. However, since higher WAO temperatures can substantially increase capital costs, future work should focus on developing a WAO catalyst that both desulfonates and mildly oxidises LAS at moderate temperatures (200 °C). © 2002 Society of Chemical Industry     

催化湿式氧化处理头孢氨苄废水

采用催化湿式氧化处理头孢氨苄废水,考察反应温度、进水pH及Cl-含量对RCT催化剂性能的影响,并对液体样品及催化剂进行了HPLC、TOC/TN、GC-MS、N2物理吸附-脱附及XRF表征。通过正交实验,得出最佳的工艺条件为:进水pH=4.8,Cl-浓度1 500 mg·L-1,反应温度260℃;对催化剂进行300 h连续寿命考察,废水TOC及TN去除率均超过90%,催化剂稳定性高,活性组分流失较少;废水经催化湿式氧化处理,水中残留的主要有机物均可生化降解。     

生物接触氧化法处理氯碱化工污水

介绍了接触氧化法处理氯碱化工污水的特点及污水场的工艺、运行情况。     

催化湿式氧化技术处理高浓度污染废水的研究进展及应用

催化湿式氧化技术是一种可有效处理高浓度、高毒性以及难生物降解有机废水的方法.作者介绍了催化湿式氧化技术的发展过程,重点分析和归纳了催化湿式氧化技术的工艺流程、催化剂的研究进展和应用领域,分析了该技术存在的技术和应用问题,总结了我国湿式催化氧化技术工业应用的现状,对该技术的研究方向提出了建议.     

臭氧催化氧化深度处理焦化废水的试验研究

针对生化后焦化废水COD_(cr)无法达标的问题,通过中试研究了臭氧催化氧化技术深度处理焦化废水的效果,考察了臭氧投加量、反应时间、pH值、催化剂对COD_(cr)去除率的影响,确定了最佳运行参数。结果表明:连续运行68 d,当进水CODcr为140~200 mg/L,反应时间为1.5 h,臭氧投加量为80mg/(L·h)时,COD_(cr)平均去除率大于60%,出水满足《炼焦化学工业污染物排放标准》(GB 16171—2012)的要求。运行费用仅1.30元/m~3,是强制混凝沉淀技术的1/4~1/2。工艺运行稳定、可靠,催化剂使用前后,比表面积、孔结构等均未发生明显变化,催化剂未发生失活现象。     

高浓度有机废水的均相催化湿式氧化影响因素

乳化液废水的均相催化湿式氧化实验发现,单一金属盐催化活性:Cu(NO3)2＞MnSO4＞CoCl2.考察了不同反应条件(温度、氧分压、进水有机物浓度)对铜盐均相催化湿式氧化的影响,结果表明,该工艺在200℃活性最高,在进水COD 48 400 mg/L,反应2 h时,COD去除率为86.6%;供氧量以初始氧分压0.93～1.16 MPa(25℃)为宜;该工艺在较宽进水浓度范围内有较高的去除率.     

催化湿式氧化法处理含酚废水

进行了CuO/Al2O3、CuO MnO2/Al2O3、CuO K2O/Al2O3、CuO/CeO2催化剂在160℃和1.6MPa的氧气压力条件下,催化氧化法处理含酚废水的实验,结果表明催化剂CuO/CeO2具有最高的催化活性,COD为3000mg/L左右含酚废水,反应50min后降解97%。并测定了在135～165℃和1.6MPa氧气压力下,加入催化剂CuO/Al2O3氧化含酚废水的COD与时间的的关系,求取了反应的动力学方程。初步探讨了氧分压和溶液的pH对催化氧化反应速率的影响。     

高浓度难降解有机废水湿式氧化可行性研究

选择四种高浓度难降解有机废水,在2L高压间歇反应釜中,研究了湿式氧化效果与技术可行性。结果表明:从氧化的容易程度来看,乳化液废水>丙硫咪唑废水>甲胺磷废水>分散蓝废水;各废水湿式氧化后可生化性得到显著改善;Cu2+有不同程度的催化作用;甲胺磷废水和丙硫咪唑废水对不锈钢反应釜腐蚀严重,乳化液废水最适宜湿式氧化。反应温度显著影响废水湿式氧化效果,温度越高氧化率越高。     

催化湿式氧化法处理噻螨酮生产废水的试验

采用CuO-MnO2-La2O3为催化剂,以催化湿式氧化技术处理噻螨酮生产过程中产生的的高浓度有机废水.试验结果表明,用该复合催化剂在处理此种有机废水时表现出较好的催化活性.在230℃,氧气分压为2.5MPa和pH值为7.3的条件下,当废水CODCr的质量浓度为15 730 mg/L,在120 min内,CODCr去除率达到96.1%,而在相同条件下未加催化剂的湿式氧化CODCr去除率只有50.3%.     

催化湿式氧化法治理H-酸母液废水的研究

H-酸母液是染料工业急需治理的高浓度有机废水,COD含量高,酸性强,一般的生化法尚不能有效治理。作者研制了具有高氧化活性的含贵金属-稀土金属双活性组分催化剂,对H-酸母液工业废水进行了催化湿式氧化(CWO)治理研究。CWO试验在固定床鼓泡式反应器连续反应装置上进行。试验考察了反应温度、反应压力、进水空速、废水pH值和气水比对催化湿式氧化法处理H-酸废水效果的影响。考虑反应工艺条件的影响和工厂实际情况以及对处理费用的要求,选定在248℃,4.0MPa,空速=2.0h-1,V(空气)∶V(水)=220∶1,废水pH=6.0的条件下,处理含CODCr46391mg/L,色度5600倍的H-酸母液废水,CODCr和色度的去除率分别达到95.4%和98.2%。处理后的废水可生化性有所提高,BOD/COD>0.3,可进一步用生化法降解排放,催化剂运转稳定性良好。根据小试结果初步估算治理H-酸废水费用约为(以COD计)0.6～0.7元/kg。     

芬顿催化氧化法在焦化废水处理中的应用

针对芬顿催化氧化工艺存在的问题进行了原因分析,在药品选择、药品投加方案、投加条件、刮泥机运行时间、pH值调节、混凝沉淀池增加挡板等方面进行改进。将芬顿催化氧化法应用到净化焦化废水中,出水指标达到国家一级排放标准。     

Regeneration of spent activated carbon by wet air oxidation

The regeneration of activated carbon was studied using the wet air oxidation process in the temperature range of 150–240°C and oxygen partial pressure range of 0.2 to 1.0 MPa. Phenol was used as substrate. The overall mechanism of regeneration has been analysed and the different steps taking place during the regeneration process were individually investigated. Kinetics of oxidation of phenol and oxygen mass transfer coefficients have been estimated in the ranges of temperature and pressure studied. Oxidative degeneration characteristics of activated carbon were also studied. The conditions of temperature and pressure have been found at which the extent of regeneration is favourable.