Regeneration Research of Porous Magnetic Microspheres during Treatment of Wastewater Containing Cationic Dyes

The application feasibility of porous magnetic microspheres in the removal of cationic dyes from wastewater was investigated. Various desorption solutions were employed for the recovery of cationic dyes from absorbents and regeneration of porous magnetic microspheres. The results showed that 1 M NaCl or 1 M KCl in water/methanol co-solvent had excellent desorption ability for methyl violet. This fact was further demonstrated in the removal cationic gold yellow from its aqueous solution. Overall, this provided a simple methodology for the treatment of wastewater containing cationic dyes and the regeneration of porous magnetic microspheres.     

Extraction and recovery of rhodamine B,methyl violet and methylene blue from industrial wastewater using D2EHPA as an extractant

The extraction behavior of cationic dyes namely rhodamine B (RB), methyl violet (MV) and methylene blue (MB) from industrial wastewater has been investigated using di-(2-ethylhexyl) phosphoric acid (D2EHPA) in hexane as a carrier. The extraction of cationic dyes increases with decreasing feed phase pH and increasing D2EHPA concentration in organic phase. The stripping percentage of dyes using acetic acid as the stripping agent from loaded D2EHPA was found to increase with increasing acid concentration. 98% stripping efficiency of dyes was achieved with 8.5 mol/L acetic acid solution at an organic:aqueous phase ratio (O/A) of 2:1. Parameters examined include D2EHPA concentration, effect of diluents, effect of pH, effect of initial dye concentration, equilibration time, and various stripping agents, aqueous to organic phase ratio in extraction and organic to aqueous phase ratio in stripping.     

混合染料的相互作用机理研究

利用模拟混合染料废水,分析了阳离子蓝FGL与酸性、活性、直接、阳离子、分散5种染料混合后的颜色变化机理和染料之间的作用。结果表明:阳离子蓝FGL基本上能与含磺酸基的酸性、活性和直接染料按电荷摩尔比发生作用,与同类的染料不会发生反应,与分散橙SE-B也会通过库仑力发生反应。混合液的色度在有沉淀生成时会变小,这样将节约废水处理的成本。     

In situ hypochlorous acid generation for the treatment of textile wastewater

An electrolytic process based on chlorine generation was adopted to treat wastewater containing textile dyes. In situ production of hypochlorous acid was achieved in an undivided electrolytic cell. The cell contained a graphite rod as the anode and a stainless steel sheet as the cathode. The generated chlorine reacts with water leading to the formation of hypochlorous acid and hydrochloric acid. The resultant hypochlorous acid, being an oxidising agent, oxidises the organic components present in the textile wastewater. In this study, the colour in wastewater containing Procion Navy and Procion Red dyes, respectively, was completely removed after 40 min of electrolysis at a constant current density of 39 mA/cm² (where the initial dye concentrations were 3700 and 3200 mg/l, respectively). In the case of the Procion Yellow and composite dyes, complete colour removal occurred after 50 min of electrolysis (with initial dye concentrations of 3500 mg/l). Even though colour removal occurred during the electrolysis process, it required up to 180 min of electrolysis to reduce the COD values for the four dyes (Procion Navy, Red, Yellow and the composite) from the initial levels of 4520, 4200, 4170 and 4283 mg/l to 70, 45, 39 and 52 mg/l, respectively. This clearly indicates that the process removes both colour and organic components present in textile wastewater.     

壳聚糖树脂在废水处理中的应用研究进展

综述了壳聚糖树脂在处理重金属离子废水、染料废水和其他废水的研究应用,总结了壳聚糖树脂处理废水的作用机理及其解吸、再利用方法.     

Supercritical carbon dioxide containing a cationic perfluoropolyether surfactant for dyeing wool

The phase behaviour of a cationic perfluoropolyether surfactant in supercritical carbon dioxide and its ability to solubilise ionic dyes has been investigated. This cationic surfactant was found to dissolve satisfactorily in supercritical carbon dioxide and was able to form micellar aggregates incorporating a small amount of water in their interior. Conventional anionic dyes such as acid and reactive dyes were solubilised satisfactorily in the cationic surfactant/water/supercritical carbon dioxide system. The surfactant was more effective in this respect than its anionic analogue.     

Use of superswelling acrylamide/maleic acid hydrogels for monovalent cationic dye adsorption

Acrylamide/maleic acid (AAm/MA) superswelling hydrogels prepared by irradiation with γ radiation were used in experiments on swelling, diffusion, and adsorption of some water‐soluble monovalent cationic dyes such as basic red 5 (BR‐5), basic violet 3 (BV‐3), and brilliant cresyl blue (BCB). The AAm/MA hydrogel containing 60 mg MA and irradiated at 5.20 kGy was used for swelling and diffusion studies in water and aqueous solutions of the monovalent cationic dyes. For this superswelling hydrogel the swelling studies indicated that swelling increased in the following order: BR‐5 > water > BV‐3 ≥ BCB. The diffusion of water and the dyes within the hydrogels was found to have a non‐Fickian character. The uptake of the cationic dyes to the AAm/MA superswelling hydrogels was studied by the batch adsorption technique at 25°C. The uptake of dyes within the hydrogel increased in the following order: BR‐5 > BV‐3 > BCB. In the experiments of the adsorption equilibrium, S‐type adsorption in Giles' classification system was found. The binding ratio of the hydrogel/dye systems was gradually increased with the increase of the MA content in the AAm/MA hydrogel and the irradiation dose. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1809–1815, 2001     

Colour fastness of optionally aftertreated acid levelling and milling dyes on nylon 6.6 during washing in an activated oxygen‐bleach containing detergent. Part 1: Fading observed in the UK‐TO test and after repeated domestic laundering†

Previous studies examining the fading exhibited by different classes of cellulosic dyes on cotton, during washing in an oxidative‐bleach containing detergent, have been extended to acid levelling and the higher wet fast acid half‐milling dyes and acid milling dyes on nylon 6.6. It has been shown that acid levelling dyes exhibit a much higher level of fading, both in the single cycle, stressed UK‐TO test and after repeated domestic laundering, than acid milling dyes. The observed fading in each case was due to wash‐down/desorption of dye rather than an oxidative‐bleaching effect.     

Encapsulation of hydrophilic dyes with polystyrene using double miniemulsion technique

Hydrophilic dyes, reactive brilliant red K‐2BP (C.I. Reactive red 24), acid fuchsin (C.I. Acid violet 19), and cationic brilliant red 5GN (C.I. Basic red 14), have been encapsulated into hydrophobic polystyrene (PS) latex particles using double miniemulsion technique. In this method, the water droplets containing dyes were first suspended in octane/styrene phase using lipophilic emulsifiers to form a primary miniemulsion. This miniemulsion was further dispersed in water and miniemulsified, followed by polymerization at high temperature to form dye/PS core‐shell colorants. Experimental results show that this technique can cause as high as 80% of encapsulation efficiency for all three dyes, and obviously improve the water‐proofing property and photostability of organic dyes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

季铵型阳离子活性染料

本文综述了季铵型阳离子活性染料的理论与实践纤维素纤维在染浴中解离出羟基负离子,阳离子型活性染料在静电作用下吸附,提高了活性染料的亲和力和直接性,这种作用正是普通活性染料染色过程中无机盐所起的作用,因而阳离子型活性染料在染色中可大量减少甚至不使用无机盐,并可以大幅度提高染料的固色率,降低印染成本,缩短和简化印染流程,大量降低染色废水的排出。阳离子型活性染料大致分为两类:一类是阳离子在活性染料分的母体上,另一类是阳离子在活性基上。染料中阳离子主要有芳胺类季铵盐和脂肪族季铵化合物:染料的的化学结构类型主要是偶氮类、蒽醌类和杂环类,其合成方法与普通活性染料大同小异阳离子型活性染料是普通活性染料性能改进与提高的主要途径之一有25篇参考文献。     

腐植酸树脂处理含重金属离子废水可行性探讨

利用泥炭为原料制备腐植酸树脂。在动态条件下,研究了腐植酸树脂对重金属离子Zn2+、Ni2+的吸附效果及吸附条件并探讨了吸附与解吸再生机理:主要吸附形式为离子交换吸附和络合吸附。实验结果表明,在20℃,流速为4mL/min,pH值为5.0～7.0条件下,含Zn2+、Ni2+质量浓度均为70mg/L的废水,经腐植酸树脂处理后,Zn2+、Ni2+去除率可达98%以上,且处理后废水近中性。含Zn2+、Ni2+质量浓度分别为32.5mg/L和29.4mg/L,pH值为5.9的电镀废水,经腐植酸树脂处理后,废水中Zn2+、Ni2+含量显著低于国家排放标准允许值。     

离子交换树脂法吸附醋酸工艺

采用离子交换树脂法吸附醋酸溶液,并对该过程进行系统的研究. 通过树脂选型确定大孔弱碱性阴离子交换树脂D311,其对醋酸吸附容量较大,且膨胀收缩率较小. 用D311树脂对醋酸含量为1.5%(w)的醋酸溶液进行了吸附和脱附工艺优化研究,考察了体系温度、进料流量等对吸附和脱附过程的影响,在优化条件为温度30.0℃、进料流量4.0 mL/min时,吸附率达93.97%;温度50.0℃、洗脱剂3.98 mol/L NaOH、流量1.0 mL/min时,脱附率达100%. 树脂再生循环结果表明,D311重现性及机械强度较好.     

Anion Exchange Resins as Effective Sorbents for Acidic Dye Removal from Aqueous Solutions and Wastewaters

Purification of wastewaters, particularly those containing dyes, has become increasingly important. The aim is to avoid a potential threat to the environment. Various sorbents have been used in the treatment of wastewaters contaminated by the Acid Orange 7 dye (AO7). In this article, the three anion exchange resins–weakly basic (Lewatit MonoPlus MP 62), intermediate (Lewatit MonoPlus MP 64), and strongly basic (Lewatit MonoPlus MP 500) were applied for AO7 removal from the aqueous solutions and wastewater. The most effective anion exchanger in wastewater purification proved to be Lewatit MonoPlus MP 500. AO7 sorption was not affected by the presence of Na₂SO₄ and CH₃COOH even at relatively high concentrations. The dye retentions were almost unchanged in the presence of non-ionic and anionic surfactants. AO7 sorption by Lewatit MonoPlus MP 62, MP 64, and MP 500 sharply decrease when the cationic surfactant is present in the solution. The monolayer adsorption capacity (Q₀ ) for MP 62 was found to be 79.9 mg/g at 25°C. At 45°C this value was almost ten times higher (769.5 mg/g). The increase of Q₀ values from 568.5 to 896.8 mg/g for MP 64 and from 979.0 to 1004.4 mg/g for MP 500 was observed with the rise in temperature. The optimal desorption conditions were found as follows: 1 M KSCN in 80–90% methanol for MP 62 (95–100% desorption) and MP 64 (～88% desorption) as well as 1 M HCl in 90% methanol for MP 500 (87% desorption).     

从工业废水中回收乙酸的方法研究进展

随着我国工业水平的不断提高, 含有乙酸的废水产生量越来越大。乙酸的含量一般在1%～30%(质量分数), 使废水不仅表现为强酸性, 而且化学耗氧量高, 不易直接排放。乙酸与水不易分离也使乙酸废水在工业上难以处理, 研究从废水中回收乙酸的方法具有重要意义。本文简要介绍了近几年国内外从工业废水中回收乙酸的进展, 主要包括膜分离法、吸附法、萃取法、萃取酯化法、精馏法, 并分析了每种方法的优缺点以及当前的研究水平。指出:双极膜电渗析和渗透汽化法适合乙酸质量分数在1%左右的废水处理;吸附法和反应萃取法适用于乙酸含量在10%以下的废水处理, 30%以下的乙酸废水可以借助反应精馏进行分离。最后分析了膜分离法和吸附法处理含乙酸废水的工业应用尚需解决的关键问题。     

Adsorption Behavior of Methylene Blue from Aqueous Solution by the Hydrogel Composites Based on Attapulgite

A series of carboxymethyl cellulose-g-poly (acrylic acid)/attapulgite hydrogel composites were synthesized for the removal of cationic dye methylene blue. Various factors affecting the uptake behavior were investigated. Adsorption rate of the hydrogel was quite fast, and adsorption equilibrium could be reached within 30 min. Adsorption kinetics well followed the pseudo-second-order equation for all systems. The Langmuir isotherm was found to best represent the data for the dye uptake. Even when 20 wt% attapulgite was introduced into the hydrogel, the corresponding maximum adsorption capacity reached 1979.48 mg/g at 30°C. The as-prepared adsorbents exhibited excellent affinity for the dye, and can be applied to treat wastewater containing basic dyes.     

Treatment of effluents from textile-rinsing operations by thermally stable nanofiltration membranes

Thermally stable nanofiltration membranes were used to recover hot water from rinsing effluents from acid and reactive dyeing operations. Two types of flat-sheet membranes, MPF-34 (MWCO 200) and MPF-36 (MWCO 1000), were tested at 60°C and 10 bar. Experiments carried out with the made-up feeds containing acid dye and acetic acid showed that both membranes were able to retain more than 99% of dye. MPF-36 suffered from substantial flux decline due to the dye and acid in the feeds but still provided higher fluxes than MPF-34. Furthermore, reactive dye rejection of MPF-36 was acceptable, ranging from 97 to 99.5%, while the fluxes, 105-140 1/m².h, were exceptionally high. MPF-36 was then further tested with the wastewater from industrial processes. The membrane could recover hot water by removing more than 98% of acid dye and 90% of reactive dyes. Despite severe fouling by acid dye, the membrane was still able to provide 40-50 1/m².h of permeate fluxes. For the reactive dye rinsing effluents, remarkably high fluxes of 120-1501/m2.h were obtained. Chemical cleaning of the used membrane with 0.2% wt. HNO₃ and subsequently 0.5% wt. NaOH recovered 80-100% of the flux.     

Removal of textile dyes in wastewater using polyelectrolytes containing tetrazole groups

Textile dyes are some of the pollutants which have received the most attention because of the large volume of wastewater generated by the textile industry. Removal by means of adsorption is one of the most versatile alternatives to treat these effluents. Even though different adsorbents such as activated carbons and mineral materials have been proposed, polymeric adsorbents are a viable alternative. This work reports for the first time the use of polyelectrolyte PTZ and macroelectrolyte MTZ containing tetrazole groups as adsorbents useful in the textile dyes removal present in aqueous solutions and wastewater. Because of the anionic character of the tetrazole group, MTZ exhibits selective adsorption capabilities for cationic dyes of up to 156.25mg·g^-1. The kinetic study of the process of adsorption shows that PTZ and MTZ fit a pseudo second-order model. MTZ also shows utility as a flocculant agent in the treatment of wastewater containing dyes Indigo Blue and Reactive Black. The results showed that PTZ and MTZ may be used in the treatment of wastewater in a process of coagulation-flocculation followed by the treatment by adsorption. This two-stage treatment removed up to 95% of the dye present in the wastewater. As well as removing the dyes, the values for COD, suspended solids, pH, and color of the wastewater decreased, thus significantly improving its quality.     

Synthesis,characterization, and flocculation performance of a sulfonated polytriazine

A novel sulfonated polytriazine (SP) is synthesized by the condensation polymerization reaction of 2‐(4,6‐dichloro‐1,3,5‐triazin‐2‐ylamino)benzene‐1,4‐disulfonic acid (Compound I) and 1,4‐diaminobenzene. The structure of SP is characterized by FTIR spectroscopy, ¹H‐NMR, and gel permeation chromatography (GPC). The flocculation performances for the cationic dyes are evaluated. The experimental results show that SP can efficiently remove the color of wastewater containing cationic dyes. The rates of color removal from C.I. Basic red 18 and C.I. Basic blue 9 reach as high as 99.6% and 98.5%, respectively. The synthesized SP shows high adsorption capacities of 1719 and 1988 mg/g for C.I. Basic blue 9 and C.I. Basic red 18, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39669.     

Selective filtration of dye by tannic acid-molybdenum disulfide composite nanofiltration membrane

Dye-selective nanofiltration membranes have great potential for chemical dye separation and purification as well as dye wastewater treatment. Two-dimensional materials such as molybdenum disulfide (MoS₂) with excellent physical and chemical properties are ideal nanofiltration membrane materials. MoS₂ with few layers is used in combination with polyphenols to prepare highly selective filtration nanofiltration membranes for cationic dyes. The tannic acid (TA)-MoS₂ composite material is constructed on the surface of a micro-porous Mixed Cellulose Ester membrane by a vacuum filtration method, and the nanofiltration membrane exhibits good flexibility and excellent film-forming properties. The maximum filtration efficiency of TAMoS₂ nanocomposite film for R6G can reach 80%, while for EY and MO, it is only 9.6% and 6.1% respectively. Filtration studies on mixtures of two different types of dyes show that the composite nanofiltration membrane has excellent separation performance. The separation characteristics and mechanism of the composite nanofilm on dyes are carefully studied, showing good selectivity for cationic dyes, which can be ascribed to the synergistic effect of non-covalent interactions and steric hindrance. This work paves the way for the use of eco-friendly membranes for water and wastewater treatment and provides an environmentally friendly solution for various applications.     

Analysis of impedance on platinum and gold anodes in glacial acetic acid

The analysis of impedance with an adsorbed intermediate for the Kolbe reaction was studied on platinum and gold in glacial acetic acid saturated with potassium acetate. The analysis by the complex impedance plane and complex capacitance plane plot showed that the rate-determining step of the Kolbe reaction is the process of the electrochemical desorption of radical-ion for both anodes, and that the value of double layer capacity C_dl is 7–10 μF/cm² at more noble potentials than 2.00 V where the Kolbe dimer products are obtained. It was found that the capacity peak at around 1.50 V for platinum and capacity hump for gold appear in the parallel capacity—potential curves in acetic acid containing small amounts of water, respectively. These phenomena are considered to be caused by the competitive adsorption reaction of CH₃COO⁻ and water.