Removal of basic dye (Astrazon Blue FGRL) using macroalga Caulerpa lentillifera

The macroalga Caulerpa lentillifera was found to have adsorption capacity for a basic dye, Astrazon Blue FGRL. For the whole range of concentrations employed in this work (20-1280 mgl(-1)), the adsorption reached equilibrium within the first hour. The kinetic data corresponded well with the pseudo second-order kinetic model where the rate constants decreased as initial dye concentrations increased. At low dye concentrations (20-80 mgl(-1)), an increase in the adsorbent dosage resulted in a higher removal percentage of the dye, but a lower amount of dye adsorbed per unit mass (q). The adsorption isotherm followed both the Langmuir and Freundlich models within the temperature range employed in this work (18-70 degrees C). The highest maximum adsorption capacity (q(m)) was obtained at 50 degrees C. The enthalpy of adsorption was estimated at 14.87 kJmol(-1) suggesting a chemical adsorption mechanism.     

Mechanisms and chemistry of dye adsorption on manganese oxides-modified diatomite

The investigations into structural changes which occur during adsorbent modification and the adsorption mechanisms are essential for an effective design of adsorption systems. Manganese oxides were impregnated onto diatomite to form the type known as δ-birnessite. Initial investigations established the effectiveness of manganese oxides-modified diatomite (MOMD) to remove basic and reactive dyes from aqueous solution. The adsorption capacity of MOMD for methylene blue (MB), hydrolysed reactive black (RB) and hydrolysed reactive yellow (RY) was 320, 419, and 204 mg/g, respectively. Various analytical techniques were used to characterise the structure and the mechanisms of the dye adsorption process onto MOMD such as Fourier transform infrared (FTIR), X-ray diffraction (XRD) and atomic absorption spectrometry (A.A.). A small shift to higher values of the d-spacing of dye/MOMD was observed indicating that a small amount of the dye molecules were intercalated in the MOMD structure and other molecules were adsorbed on the external surface of MOMD. Two mechanisms of dye adsorption onto MOMD were proposed; intercalation of the dye in the octahedral layers and adsorption of the dye on the MOMD external surface. Moreover, the results demonstrated that the MOMD structure was changed upon insertion of MB and RY with an obvious decrease in the intensity of the second main peak of the MOMD X-ray pattern.     

Endocrine disrupting compounds in municipal and industrial wastewater treatment plants in Northern Greece

The occurrence and fate of endocrine disrupting compounds (EDCs) in a sewage treatment plant and two industrial wastewater treatment plants from textile and tannery factories were investigated. EDCs of interest are 4-nonylphenol, 4-octylphenol, their ethoxylate oligomers (mono- and di-ethoxylates of nonylphenol and octylphenol), bisphenol A, triclosan and steroid estrogens. Target compounds were determined in dissolved fraction, total suspended solids and sludge by employing solid phase extraction and ultrasonication followed by gas chromatography–mass spectrometry.Nonylphenols and oligomers with one or two ethoxy groups were the most abundant compounds in raw wastewater as well as in effluents from all the treatment stages of sewage treatment plant, followed by triclosan and bisphenol A. Steroids were found at very low concentrations. Almost all phenolic EDCs compounds were predominantly associated to suspended solids in influents whereas the dissolved fraction dominated the treated effluents. High removal rates, ranging from 86% to 99%, were observed throughout the whole treatment process. Biodegradation was the main removal pathway of EDCs. Tannery wastewaters exhibited high concentrations of nonylphenolic compounds. This type of wastewaters could pose a significant risk to the aquatic and terrestrial environment.     

Degradation of a commercial textile biocide with advanced oxidation processes and ozone

The occurrence of significant amounts of biocidal finishing agents in the environment as a consequence of intensive textile finishing activities has become a subject of major public health concern and scientific interest only recently. In the present study, the treatment efficiency of selected, well-known advanced oxidation processes (Fenton, Photo-Fenton, TiO(2)/UV-A, TiO(2)/UV-A/H(2)O(2)) and ozone was compared for the degradation and detoxification of a commercial textile biocide formulation containing a 2,4,4'-trichloro-2'-hydroxydiphenyl ether as the active ingredient. The aqueous biocide solution was prepared to mimic typical effluent originating from the antimicrobial finishing operation (BOD(5,o) < or =5 mg/L; COD(o)=200 mg/L; DOC(o) (dissolved organic carbon)=58 mg/L; AOX(o) (adsorbable organic halogens)=48 mg/L; LC(50,o) (lethal concentration causing 50% death or immobilization in Daphnia magna)=8% v/v). Ozonation experiments were conducted at different ozone doses (500-900 mg/h) and initial pH (7-12) to assess the effect of ozonation on degradation (COD, DOC removal), dearomatization (UV(280) and UV(254) abatement), dechlorination (AOX removal) and detoxification (changes in LC(50)). For the Fenton experiments, the effect of varying ferrous iron catalyst concentrations and UV-A light irradiation (the Photo-Fenton process) was examined. In the heterogenous photocatalytic experiments, Degussa P25-type TiO(2) was used as the catalyst and the effect of reaction pH (3, 7 and 12) and H(2)O(2) addition on the photocatalytic treatment efficiency was examined. Although in the photochemical (i.e. Photo-Fenton, TiO(2)/UV-A and TiO(2)/UV-A/H(2)O(2)) experiments appreciably higher COD and DOC removal efficiencies were obtained, ozonation appeared to be equally effective to achieve dearomatization (UV(280) abatement) at all studied reaction pH. During ozonation of the textile biocide effluent, AOX abatement proceeded significantly faster than dearomatization and was complete after 20 min ozonation (267 mg O(3)). On the other hand, for complete detoxification, ozonation had to be continued for at least 30 min (corresponding to 400mg O(3)). Effective AOX and acute toxicity removal was also obtained after heterogeneous photocatalytic treatment (TiO(2)/UV-A and TiO(2)/UV-A/H(2)O(2)). The Fenton-based treatment experiments and particularly the dark Fenton reaction resulted in relatively poor degradation, dearomatization, AOX and acute toxicity removals.     

Influence of inorganic salt on aerobic biodegradability of dyestuffs

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｄｕｓｔｒｉａｌｗａｓｔｅｗａｔｅｒｏｆｔｅｎｃｏｎｔａｉｎｓｈｉｇｈｌｙ ｃｏｎｃｅｎｔｒａｔｅｄｉｎｏｒｇａｎｉｃｓａｌｔｓ.ＣｏｍｍｏｎｃａｔｉｏｎｓｉｎｃｌｕｄｅＫ ,Ｎａ ａｎｄＣａ2 ,ａｎｄｃｏｍｍｏｎａｎｉｏｎｓｉｎｃｌｕｄｅＣｌ-,ＳＯ42 -ａｎｄＮＯ3-.Ｆｏｒｅｘａｍｐｌｅ ,ｗａｓｔｅｗａｔｅｒｆｒｏｍｔｈｅｐｒｏｃｅｓｓｏｆｄｙｅｓｔｕｆｆｓ,ｓｕｃｈａｓｃａｔｉｏｎｉｃｂｌｕｅＸ ＧＲＲＬ ,ｂａｓｉｃｂｒｏｗｎ ,ｂａｓｉｃｏｒａｎｇｅ,ｂａｓｉｃｖｉｏｌｅ…     

膜技术在废水处理中的应用

着重介绍了膜技术在生活污水、油田采出水、造纸废水、纺织印染废水、高浓度有机废水和重金属废水中的应用。膜技术处理废水与传统的废水处理方法相比具有处理效果好，可实现废水回用和有用物质回收的优点。并展望将膜技术应用于废水处理，特别是近年来新发展起来的纳滤膜分离技术应用于含低分子量污染物的分离，与传统的废水处理过程相结合等技术均将产生较大的社会效益与经济效益。     

Formation of organic chloride in the treatment of textile dyeing sludge by Fenton system

In the oxidation treatment of textile dyeing sludge, the quantitative and transformation laws of organic chlorine are not clear enough. Thus, this study mainly evaluated the treatment of textile dyeing sludge by Fenton and Fenton-like system from the aspects of the influence of Cl⁻, the removal of polycyclic aromatic hydrocarbons (PAHs) and organic carbon, and the removal and formation mechanism of organic chlorine. The results showed that the organic halogen in sludge was mainly hydrophobic organic chlorine, and the content of adsorbable organic chlorine (AOCl) was 0.30 mg/g (dry sludge). In the Fenton system with pH=3, 500 mg/L Cl⁻, 30 mmol/L Fe²⁺ and 30 mmol/L H₂O₂, the removal of phenanthrene was promoted by chlorine radicals (•Cl), and the AOCl in sludge solid phase increased to 0.55 mg/g (dry sludge) at 30 min. According to spectral analysis, it was found that •Cl could chlorinate aromatic and aliphatic compounds (excluding PAHs) in solid phase at the same time, and eventually led to the accumulation of aromatic chlorides in solid phase. Strengthening the oxidation ability of Fenton system increased the formation of organic chlorines in liquid and solid phases. In weak acidity, the oxidation and desorption of superoxide anion promoted the removal and migration of PAHs and organic carbon in solid phase, and reduced the formation of total organic chlorine. The Fenton-like system dominated by non-hydroxyl radical could realize the mineralization of PAHs, organic carbon and organic chlorines instead of migration. This paper builds a basis for the selection of sludge conditioning methods.     

固定化微生物处理印染废水

对固定化微生物技术处理印染废水的控制条件进行了研究,并进行了实际运行的考察。印染废水经表曝处理后,COD_(cr)约为145mg/l,色度约为40倍,再经固定化微生物处理后,出水COD_(cr)<50mg/l,色度<4.5倍。处理后的水可回收利用。     

三价铁盐对染料水的脱色研究及机理探讨

三价铁盐在pH5～6的范围内,能有效地支队水溶性活性、酸性染料等阴离子染料。脱色机理是由于形成的氢氧化铁对染料的吸附所致,吸附过程能很好地吻合Langmuir吸附等温线。     

电絮凝-催化氧化法去除染料工业废水COD的研究

我们对电絮凝 -催化氧化法处理染料工业废水COD进行了研究。实验结果表明 ,此方法对废水的COD具有良好的去除效果 ,并确定了相应的处理条件 :电解电压 4V ,电解时间 1.5h ,H2 O2 为 0 .6 % ,MO(含 75 %以上的TiO2 )为 2 .5g/L。平均COD去除率达到 77.5 %。电絮凝 -催化氧化法具有能耗低、操作简便等特点 ,为进一步深化处理奠定了基础