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1.
The hydroxyapatite (HAP) is prepared by precipitation method and examined for the photocatalytic degradation of calmagite, a toxic and non-biodegradable azo-dye compound. The physicochemical properties of hydroxyapatite material were characterized using BET surface area, XRD, FT-IR, and SEM analysis. The FT-IR analysis of the hydroxyapatite revealed that the peak intensity due to absorbance of surface PO43− group centered at wave number 1030 cm−1 is drastically decreased upon exposure to UV for 1 h. The study includes dark adsorption experiments at different pH conditions, influence of the amount of catalyst, and effect of pH on photocatalytic degradation of dye, chemical oxygen demand (COD) removal, biological oxygen demand (BOD5) increase and SO42− and NO3 ions evolution during the degradation. At optimum photocatalytic experimental conditions the same is compared with commercial degussa P-25 TiO2. The photocatalytic treatment significantly reduced the COD (92% removal) and increased the BOD5/COD ratio to 0.78. Considerable evolution of SO42− (8.5 mg L−1) and NO3 (12.2 mg L−1) ions are achieved during the degradation process, thus reflecting the usefulness of the hydroxyapatite photocatalytic treatment in calmagite removal in wastewater.  相似文献   

2.
MBR-光催化氧化处理印染废水的试验研究   总被引:2,自引:0,他引:2  
利用MBR-光催化氧化的组合工艺处理某纺织园区综合废水,对反应装置进行了连续运行效果的考察.结果表明,MBR对废水COD、浊度,色度降解率分别达到93.5%、99.9%和98.9%;MBR中污泥沉降性能明显优于SBR,能有效控制污泥膨胀现象;出水的透光性大大提高,经光催化氧化后COD、BOD、浊度、色度分别稳定在35.0mg·L~(-1)、2.7 mg·L~(-1),2.3NTU、3倍,水质达到GB 18918-2002的一级A排放标准和CJ/T48-1999的生活杂用水要求.  相似文献   

3.
为给某企业的反渗透系统提供稳定的优质进水,采用一体式膜生物反应器对某城市污水处理厂二级出水进行了深度处理中试试验。研究结果表明:在进水COD的质量浓度为7~15 mg/L时,色度为20~50度,浊度为0.70~3.57 NTU,膜通量10.0~13.75 L/(m2.h)、跨膜压差0.019~0.038 MPa、曝气量20 m3/h、制水时间40min、停机时间3 min、HRT 3.6~5.0 h条件下,MBR系统出水COD质量浓度小于10 mg/L,色度小于30度,浊度小于1 NTU,SDI15小于3,满足反渗透系统进水水质要求;MBR系统出水水质稳定,具有较强的耐冲击负荷能力。另外,探讨了MBR系统的跨膜压差与膜通量之间的关系。  相似文献   

4.
垃圾渗滤液生化出水絮凝-纳滤处理及过程机理   总被引:2,自引:2,他引:0  
垃圾焚烧发电厂渗滤液是一种含高浓度腐殖酸类物质和高盐含量的复杂有机废水,传统生化处理后仍难达标排放。本工作围绕垃圾渗滤液生化出水的特性,开展了Ca(OH)2絮凝、臭氧氧化预处理与NF处理相结合的处理工艺,并对处理过程的机理进行了探讨。研究表明,渗滤液生化出水经过Ca(OH)2絮凝处理,可以有效地去除其中的杂环类化合物。生化出水经8 g·L-1的Ca(OH)2絮凝处理后,比MBR出水产水通量提高达8.2%。对Ca(OH)2絮凝出水进行臭氧氧化处理,虽然降低了它的COD,但并未进一步提高其NF膜通量,其主要原因可能是臭氧氧化生成的硅氧烷类物质造成了膜的污染;与RO处理垃圾渗滤液生化出水相比较,NF膜无法分离废水中的酮类、胺和酰胺类、杂环类化合物,使得NF产水的COD处在100~160 mg·L-1。NF平均膜通量的增大可导致产水COD略有上升;垃圾渗滤液生化出水及其预处理水在NF处理过程中,都没有表现出严重的膜污染。  相似文献   

5.
This study describes the treatment of composting leachate by the combination of coagulation and nanofiltration process.Poly ferric sulfate(PSF) was used as coagulant,and the effect of p H value and PSF dosage on the coagulation performance was investigated.The results indicated that the chemical oxidation demand(COD)and turbidity removal efficiency could reach to 62.8% and 75.3%,respectively at an optimum dosage of1200 mg·L~(-1)at p H 6.0.During the nanofiltration process,the operation conditions such as temperature and pressure were optimized,89.7% of COD,78.2% of TOC,72.5% of TN,83.2% of TP,and 78.6% of NH3-N were retained when tested at 0.6 MPa at 25 °C.The final leachate effluent concentration of COD,BOD5,NH3-N,TOC,SS was92 mg·L~(-1),31 mg·L~(-1),21 mg·L~(-1),73 mg·L~(-1)and 23 mg·L~(-1),respectively,which reached the local discharge standard.The combination of coagulation-filtration is useful for composting leachate treatment.  相似文献   

6.
7.
The use of hybrid advanced oxidation processes(AOPs) for the removal of pollutants from industrial effluents has been extensively studied in recent literature. The aim of this study is to compare the performance of the photo,Fenton, photo-Fenton and ozone–photo–Fenton processes in terms of color removal and chemical oxygen demand(COD) removal of distillery industrial effluent together with the associated electrical energy per order. It was observed from the experimental results that the O_3/UV/Fe~(2 +)/H_2O_2 process yielded a 100% color and95.50% COD removals with electrical energy per order of 0.015 k W·h·m~(-3) compared to all other combinations of the AOPs. The effects of various operating parameters such as H_2O_2 and Fe~(2+) concentration, effluent pH, COD concentration and UV power on the removal of color, COD and electrical energy per order for the ozone–photo–Fenton process was critically studied and reported. The color and COD removals were analyzed using a UV/Vis spectrometer and closed reflux method.  相似文献   

8.
Investigations are presented on the effect of the preliminary ozonation on ultrafiltration (UF) and powdered activated carbon (PAC) /UF process performance, especially on permeate flux decline and the effectiveness of model organics removal. Flat membranes from regenerated cellulose were used. A model solution was prepared as a mixture of humic acids and phenol. PAC dosage was equal to 100 mg/l−1. The ozone dosages were in the range of 1–3 mg O3 l−1 (0.2–0.6 mg O3/mg TOC). It was found that the most advantageous configuration was preliminary ozonation with an ozone dosage of 0.4 mgO3/mg TOC–UF. The permeate flux reached a value equal to the pure water flux value. Moreover, a very high effectiveness of model organics removal was obtained: TOC was reduced by about 96% and UV254 absorbance was removed completely. When PAC was added to the feed containing humic acids without ozonation, a drop in a permeate flux was observed compared to UF. Similarly, the addition of PAC to feed treated with ozone resulted in a significant drop in the permeate flux in comparison with pure water flux, regardless of ozone dosage applied.  相似文献   

9.
This paper investigates the microfiltration of unfiltered red and white wines through organic polyvinylidene difluoride membranes in plate and frame systems. Various pore sizes between 0.1 and 3 μm were first tested using a small laboratory unit and it was found that 0.4 μm pores gave the best comprise between turbidity and flux requirements. Tests with membrane areas between 1 and 2 m2 were carried out i a modular plate and frame system in which both gasket thickness and parallel vs. series arangements of compartments can be modified. With red wine the permeate flux is almost independent of fluid velocity but increases linearly with transmembrane pressure, reaching 50 1 h−1 m−2 at 3 bar. The permeate flux is larger in a turbulent regime than in a laminar one at the same velocity. With white wine, the permeate flux is higher and increases almost linearly with velocity reaching 170 1h−1 m−2 at 2 bar and 3.6 m s−1. The turbidity of the permeate was generally below 0.5 NTU for both white and red wines while initial turbidity was above 150 NTU for red and above 50 NTU for white. When several membrane compartments are placed in series, the output of the downstream compartment is reduced by 10%–15% compared with that of the upstream one owing to the drop in transmembrane pressure.  相似文献   

10.
Polymeric catalysts to be applied in the Diels–Alder cycloaddition of hexachlorocyclopentadiene and maleic acid have been prepared via molecular imprinting with template molecules immobilized on silica particles. These enzyme mimicking polymers exhibit specific catalytic effects compared to non-imprinted control polymers or polymer-free solutions. It could be demonstrated that the activity of the molecularly imprinted material rises when increasing the temperature. By this means, the reduction of the activation energy (as expected for catalysts) from 63 to 55 kJ mol−1 could be observed. Furthermore, the reaction was characterized based on the Michaelis–Menten model. For the diene compound a Michaelis constant of KM=5.8 mmol l−1 and an effective reaction rate of rmax,eff=0.4 μmol l−1 s−1, leading to a reaction rate constant keff=1.1×10−3 s−1, were determined.  相似文献   

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