新型杂化絮凝剂PAC-PDMDAAC对染料废水的脱色光谱分析

用新型杂化絮凝剂聚合氯化铝-聚二甲基二烯丙基氯化铵(PAC-PDMDAAC)处理分散紫和活性艳红两种染料废水。杂化絮凝剂投药量为400和450 mg·L-1时,分散紫和活性艳红的脱色率分别达到99%和86.8%,优于聚合氯化铝(PAC)和复配型PAC-PDMDAAC。杂化絮凝剂处理分散紫的最佳pH为7～12,而处理活性艳红的最佳pH为7～9。分别对两种染料及其杂化絮体进行傅里叶红外光谱扫描,结果表明杂化絮凝剂与两种染料分子的某些基团有络合作用,杂化絮体中羟基峰增大且宽化,杂化絮凝剂对染料废水的脱色以吸附电中和为主。对染料原水以及混凝后上清液进行紫外连续扫描,两种上清液的吸光度都大大降低,同时吸收曲线波峰偏移,进一步说明电中和与吸附架桥的协同作用是脱色的主要机理。同时,杂化絮凝剂对分散紫的脱色是通过破坏醚键以及与—NH₂反应,而对活性艳红的脱色则是通过对—SO₃的置换以及对Cl-的取代。为该新型无机-有机高分子杂化絮凝剂混凝脱色效能及脱色机理研究提供新方法,具有实际意义和应用价值。     

树脂吸附法D-核糖发酵液脱色的研究

首次考察了六种不同树脂对D－核糖发酵液的脱色作用,详细地研究了吸附工艺条件对树脂脱色能力的影响．试验结果表明,在25℃下,以1.0BV／h的流速进行吸附时,NKA－Ⅱ树脂对D－核糖发酵液具有良好的脱色效果,脱色率91％,处理量5.7BV;并对树脂再生的条件进行了较详尽研究。     

Ultrasound and heat enhanced persulfate oxidation activated with Fe0 aggregate for the decolorization of C.I. Direct Red 23

Effluents from the paper printing and textile industries are often heavily contaminated with azo dyes. Azo dyes are difficult to oxidize biologically. This work investigated the decolorization of an azo dye, C.I. Direct Red 23 (DR23), by persulfate (PS) activated with Fe⁰ aggregates (PS/Fe⁰). Ultrasound (US) and heat were used as enhancement tools in the PS oxidation system. Neither US-activated PS nor thermally activated PS was effective in oxidizing DR23. However, the decolorization was significantly enhanced by PS/Fe⁰ combined with US (PS/Fe⁰/US) or heat (PS/Fe⁰/55 °C). Approximately 95% decolorization of 1 × 10⁻⁴ M DR23 was achieved within 15 min in the PS/Fe⁰/US system at an initial pH of 6.0, PS of 5 × 10⁻³ M, Fe⁰ of 0.5 g/L and US irradiation of 106 W/cm² (60 kHz). Complete decolorization was achieved within 10 min in the Fe⁰/PS/55 °C system. The rate of decolorization doubled when US was introduced in the PS/Fe⁰ system during the treatment of different initial dye concentrations. The dependence of dye and true color (ADMI) depletion on PS concentration has been discussed. DR23 was completely degraded based on the disappearance of aromatic groups of UV–vis spectra and the variation of TOC mineralization. The observed pseudo-first-order decolorization rate was substantially enhanced by increasing temperature. The Arrhenius activation energy for the PS activated with Fe⁰ was estimated as 8.98 kcal/mol, implying that higher temperature is beneficial for the DR23 decolorization. The addition of US into the PS/Fe⁰ system did not incur a substantial increase in electricity, whereas the mineralization of DR23 occurred quickly. Thus, both PS/Fe⁰/US and heated PS/Fe⁰ systems are practically feasible for the effective degradation of the direct azo dye in textile wastewater.     

Decolorization of azo dyes Orange G using hydrodynamic cavitation coupled with heterogeneous Fenton process

The present work demonstrates the application of the combination of hydrodynamic cavitation (HC) and the heterogeneous Fenton process (HF, Fe⁰/H₂O₂) for the decolorization of azo dye Orange G (OG). The effects of main affecting operation conditions such as the inlet fluid pressure, initial concentration of OG, H₂O₂ and zero valent iron (ZVI), the fixed position of ZVI, and medium pH on decolorization efficiency were discussed with guidelines for selection of optimum parameters. The results revealed that the acidic conditions are preferred for OG decolorizaiton. The decolorization rate increased with increasing H₂O₂ and ZVI concentration and decreased with increasing OG initial concentration. Besides, the decolorization rate was strongly dependent on the fixed position of ZVI. The analysis results of degradation products using liquid chromatography–ESI–TOF mass spectrometry revealed that the degradation mechanism of OG proceeds mainly via reductive cleavage of the azo linkage due to the attack of hydroxyl radical. The present work has conclusively established that the combination of HC and HF can be more energy efficient and gives higher decolorization rate of OG as compared with HC and HF alone.     

蔗汁酒精废液色素的提取及其抗氧化活性研究

针对蔗汁酒精废液中含有的大量色素物,采用大孔树脂吸附提取色素,对蔗汁酒精废液中色素的提取工艺及其抗氧化活性进行了研究。通过静态吸附实验筛选出吸附树脂D101及对应的洗脱溶剂乙醇。最佳流速为3BV/h,最佳洗脱条件为40%的乙醇在pH6～7范围内进行洗脱。经测定,色素的黄酮含量为茶多酚的27.2%,但对自由基的抑制率却为茶多酚的88.06%,表明蔗汁酒精废液中提取的色素具有较高的抗氧化活性。     

Efficient photocatalytic treatment of sugar mill wastewater with 2%Ag3PO4/Fe/GTiP nanocomposite

The large amount of colored substances exist in the sugar mills wastewater that give higher organic load to the effluent. Therefore, a novel study of sugar mill wastewater treatment was carried out under photocatalysis by using a nanocomposite of silver phosphate-iron-graphene oxide-titanium phosphate (Ag₃PO₄/Fe/GTiP). The catalyst was prepared by simple chemical process with 2% content of Ag₃PO₄ to Fe/GTiP. The light, catalyst dosage, pH, and scavenger impacts on the decolorization and chemical oxygen demand (COD) removal from the sugar mill wastewater were observed. The highest decolorization and COD removal of 85.02% and 80.3% was achieved under pH-1 by using 50 W visible halogen light at catalyst dosage of 100 mg/75 ml in 200 min. The excellent recycled results were observed up to four cycles. The obtained results proves that this catalyst has high photocatalytic efficiency to treat the sugar mill wastewater.     

交联聚苯乙烯氨基树脂的结构与脱色性能研究

通过改变交联度、致孔剂以及胺化试剂合成了一系列大孔氨基吸附树脂。详细研究了树脂孔结构、功能基结构与树脂脱色性能的关系。     

Ultrasonic-assisted ozone degradation of organic pollutants in industrial sulfuric acid

In this work, a combination of ozone (O₃) and ultrasound (US) has been firstly used to decolorize black concentrated sulfuric acid with high organic content. The effect of different reaction factors on the transparency, extent of decolorization, H₂SO₄ mass fraction, and organic pollutants removal is studied. In addition, the systematic interaction between ultrasound and ozone on the decolorization process is reviewed through comparative experiments of O₃, US and US/O₃. A sulfuric acid product that meets the requirements for first-class products in national standards, with an extent of decolorization of 74.07%, transparency of 70 mm, and a mass fraction of 98.04%, is obtained under the optimized conditions. Under the same conditions, it has been established that the treatment time can be saved by 25% using the US/O₃ process compared to using O₃. Further, the production of oxidative free radicals (•OH) in a concentrated sulfuric acid system is enhanced using the US/O₃ process compared with O₃. In addition, the degree of effectiveness of different oxidizing components on the decolorization process is revealed by adding different free radical shielding agents when the US/O₃ process is used.     

A New <Emphasis Type="Italic">Stenotrophomonas maltophilia</Emphasis> Strain Producing Laccase. Use in Decolorization of Synthetics Dyes

Laccase activity was detected in a soil bacterium Stenotrophomonas maltophilia AAP56 identified by biochemical and molecular methods. It was produced in cells at the stationary growth phase in Luria Bertani (LB) medium added by 0.4 mM copper sulfate. The addition of CuSO₄ in culture medium improved production of laccase activity. However, one laccase enzyme was detected by native polyacrylamide gel electrophoresis. The enzyme showed syringaldazine (K _m = 53 μM), 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (K _m = 700 μM), and pyrocatechol (K _m = 25 μM) oxidase activity and was activated by addition of 0.1% (v/v) Triton-X-100 in the reaction mixture. Moreover, the laccase activity was increased 2.6-fold by the addition of 10 mM copper sulfate; the enzyme was totally inhibited by ethylenediaminetetraacetic acid (5 mM), suggesting that this laccase is a metal-dependant one. Decolorization activity of some synthetic dyes (methylene blue, methyl green, toluidine blue, Congo red, methyl orange, and pink) and the industrial effluent (SITEX Black) was achieved by the bacteria S. maltophilia AAP56 in the LB growth medium under shaking conditions.     

ZnO-based ternary nanocomposite for decolorization of methylene blue by photocatalytic dynamic membrane

In this article, novel Ag–ZnO/g-C₃N₄/GO ternary nanocomposites were prepared via co-precipitation method by 1%w Ag, 50% w g-C₃N₄, 10% w GO concentration and applied in dynamic membranes. The characteristics of Ag–ZnO/g-C₃N₄/GO nanocomposite were evaluated by various techniques such as X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray map, transmission electron microscopy, X-ray photoelectron spectroscopy, photocatalyst. The photocatalytic degradation of methylene blue was investigated under visible light. The photocatalytic efficiency of 93.43% for methylene blue degradation was obtained for Ag–ZnO/g-C₃N₄/GO nanocomposite after 50 min of irradiation, which was remarkably higher than that of pure ZnO, bare g-C₃N₄, Ag–ZnO, and Ag–ZnO/g-C₃N₄ at the same irradiation time. Likewise, in self-forming and pre-coated membranes, ternary nanocomposites can play a vital role in the membrane surface properties, as well as their decolorization performance. The rejection of methylene blue was 30% in pure polyethersulfone membrane, while the photocatalytic degradation of methylene blue in Ag–ZnO/g-C₃N₄/GO nanocomposites was 88.46% and 98.86% after 10 and 15 min of irradiation in both self-forming and pre-coated dynamic membranes, respectively. Experimental results show that the dynamic membrane possesses a higher ability for degradation of MB in a shorter period of time than the static system.