Membrane Fouling in the Reclamation of Secondary Effluent with an Ozone-Membrane Hybrid System

Abstract

The current research is a pilot scale study on membrane fouling in an ozone-ceramic membrane hybrid system, aiming at the reclamation of secondary effluent which contains abundant organic substances and bacteria. Compared with the microfiltration process with 30 mg O₃/L feed, the microfiltration without ozone sustained for a longer period of time and produced greater filtrate volume, while all other conditions were kept constant. The results of size exclusive chromatography (SEC) show that the number of large molecules increases after ozonation; this part of organic molecules may contribute more to 0.1 µm membrane fouling. Other evidence proves that ozone brings about the lysis of bacteria. This may account for the increase in the number of large organic molecules after ozonation.     

Surface modification of low density polyethylene films by homogeneous catalytic ozonation

Low density polyethylene films were treated by ozone to generate peroxides on the surfaces. The peroxides generated are capable of initiating radical graft polymerization of hydrophilic vinyl monomers onto the polymers, resulting in hydrophilic surfaces. Results of ozonation revealed that molecular ozone instead of hydroxyl radicals was the main oxidant for peroxide generation. A novel approach, aqueous ozonation with the addition of a soluble transitional metal salt, FeCl₃, as a homogeneous catalyst, was proposed and proved to be successful in this study. The addition of FeCl₃ could increase peroxide generation by 22.7%, compared to its non-catalyzed counterpart. An optimum catalyst concentration, 0.04 g/L, was determined. Also, the effects of pH, ozonation time and applied ozone dose on peroxide generation were investigated. The loss in tensile strength of the films would be 15% or less if the applied ozone dose was not over 2 wt.%. The functional groups generated on the film surfaces were characterized by FTIR, the contact angle and surface roughness of the film were also examined before and after ozonation.     

活性炭催化臭氧化处理含氰废水的试验研究

研究了活性炭催化臭氧化降解低质量浓度含氰废水,考察了臭氧投加量、活性炭用量、pH值等因素对处理效果的影响.试验结果表明:活性炭对臭氧有明显的催化作用,并可以提高臭氧的利用率;在CN-初始质量浓度150 mg/L、臭氧投加量30 mg/min、活性炭14 g/L、反应30 min条件下,CN-去除率为99.8%,相对于单...     

纳米金属氧化物催化臭氧氧化抑制溴酸盐形成的效能研究

通过纯水的模拟研究,探讨了纳米SnO2和纳米TiO2催化臭氧氧化抑制溴酸盐形成的情况及不同条件下纳米TiO2的抑制效能.结果表明,纳米SnO2催化及纳米TiO2催化均能有效抑制溴酸盐的形成,相对单独臭氧氧化条件溴酸盐生成量分别降低了45.81％和74.10％;光照对纳米TiO2催化抑制溴酸盐形成的效能影响不大;反应温度在10～26℃之间时,随着温度的升高,纳米TiO2催化抑制溴酸盐形成的作用越明显;纳米TiO2催化抑制溴酸盐生成的效能随着Br-初始质量浓度的增加和pH的上升而降低.     

负载型二氧化铈催化氧化对滤后水THMsFP的影响

考察了连续流体系中,滤后水经负载型二氧化铈(CeO2)催化臭氧氧化后的三卤甲烷生成势(THMsFP)情况.发现催化氧化后滤后水的THMsFP大幅降低,比单独臭氧氧化后的降低了57.0%.这主要和CeO2催化氧化所表现出来较高的TOC去除率及较高的卤代活性位破坏能力有关.考察了不同反应条件下(Br-质量浓度、接触氧化时间及臭氧投量),连续流催化氧化滤后水后THMsFP的变化规律.结果表明,在不同反应条件下,负载型CeO2催化氧化都能表现出明显控制THMsFP的优势.且低臭氧投量(0.7mg·L-1)下,CeO2催化氧化就能表现出明显控制THMsFP的优势,比单独臭氧氧化后的降低了64.9%.     

Quantitative Phosphorus-31 NMR Analysis of Six Soluble Lignins

By using a set of lignin samples, which have been subjected to thorough analyses by the international wood chemistry community, the recently developed quantitative method of ³¹P NMR spectroscopy was comprehensively examined. The values of total phenolic hydroxyl groups and those of total hydroxyl groups were found to favourably compare with those obtained by other laboratories, applying independent methods of analysis. Furthermore, the application of quantitative ³¹P NMR spectroscopy offered additional detailed structural information for the examined lignins which was in accord with literature accounts for similar wood species and lignin preparations. More specifically, the steam explosion lignins from aspen and yellow poplar woods and that produced by ball milling/enzyme hydrolysis of cottonwood were found to contain relatively high amounts of β-O-4 structures. In contrast, the kraft, organosolv, and the acid hydrolysis processes were found to induce significant chain scission on the resulting lignins. Ball milled cottonwood lignin contained the highest frequency of β-O-4 bonds and the lowest amount of free phenolic hydroxyls. The erythro form of β-O-4 structures were invariably predominant in the lignins from aspen, yellow poplar and cottonwood, in accord with the conclusions of previous reports on hardwood lignins. Thus, the application of quantitative ³¹P NMR spectroscopy offered the detailed chemical composition of the examined lignins.     

Degradation of 1‐amino‐4‐bromoanthraquinone‐2‐sulfonic acid using combined airlift bioreactor and TiO2‐photocatalytic ozonation

BACKGROUND: Traditional treatment systems failed to achieve efficient degradation of anthraquinone dye intermediates at high loading. Thus, an airlift internal loop reactor (AILR) in combination with the TiO₂‐photocatalytic ozonation (TiO₂/UV/O₃) process was investigated for the degradaton of 1‐amino‐ 4‐bromoanthraquinone‐2‐ sulfonic acid (ABAS). RESULTS: The AILR using Sphingomonas xenophaga as inoculum and granular activated carbon (GAC) as biocarrier, could run steadily for 4 months at 1000 mg L^?1 of the influent ABAS. The efficiencies of ABAS decolorization and chemical oxygen demand (COD) removal in AILR reached about 90% and 50% in 12 h, respectively. However, when the influent ABAS concentration was further increased, a yellow intermediate with maximum absorbance at 447 nm appeared in AILR, resulting in the decrease of the decolorization and COD removal efficiencies. Advanced treatment of AILR effluent indicated that TiO₂/UV/O₃ process more significantly improved the mineralization rate of ABAS bio‐decolorization products with over 90% TOC removal efficiency, compared with O₃, TiO₂/UV and UV/O₃ processes. Furthermore, the release efficiencies of Br^? and SO₄^2? could reach 84.5% and 80.2% during TiO₂/UV/O₃ treatment, respectively, when 91.5% TOC removal was achieved in 2 h. CONCLUSION: The combination of AILR and TiO₂/UV/O₃ was an economic and efficient system for the treatment of ABAS wastewater. © 2012 Society of Chemical Industry     

臭氧氧化-BAC深度处理鲁奇炉煤制气废水

采用臭氧氧化-BAC工艺深度处理鲁奇炉煤制气废水,对影响处理效果的主要因素进行了研究,并考察了工艺的稳定运行效果。结果表明,当臭氧发生器电流为0.5 A,两级反应柱臭氧投加体积比为2∶1时,臭氧氧化对废水COD_(Cr)、色度和UV_(254)的去除效果最佳;适当延长BAC滤池的水力停留时间有利于污染物质的去除。稳定运行期间,废水COD_(Cr)平均可从298 mg/L下降到57 mg/L,平均COD_(Cr)去除率为81%;NH_3-N和TN的去除主要依靠BAC滤池中生物膜的硝化和反硝化作用,平均NH_3-N和TN去除率分别为26%和37%。     

O3/BAC工艺应用于城市污水深度处理

为使再生水适合不同用途,对经过混凝沉淀和砂滤处理的再生水进行了臭氧-生物活性炭的深度处理.在臭氧消耗量和反应时间分别为5 mg/L和10 min,BAC空床停留时间(EBCT)为10 min的条件下,臭氧-生物活性炭工艺对CODMn、DOC、UV254和色度平均去除率为32.4%、29.2%、48.6%和80.1%,出水CODMn、DOC、UV254和色度的平均值分别为3.3 mg/L、4.0mg/L、0.05 cm-1和2.0倍;臭氧生物活性炭工艺出水SDI《4,从而满足了反渗透系统的进水要求.