Simulated Dye Wastewater Research Articles

Ultrasound-enhanced catalytic degradation of simulated dye wastewater using waste printed circuit boards: catalytic performance and artificial neuron network-based simulation.

Recent developments of heterogeneous advanced oxidation for refractory organic contaminants and catalysts made of solid waste have attracted much attention. In this work, waste printed circuit board (wPCB) was used for catalytic degradation of simulated textile wastewater enhanced by ultrasound. Catalytic degradation of rhodamine B (RhB) and methylene blue (MB) was conducted in the presence of H2O2. Effect of ultrasound, wPCB, H2O2, pH, and dye concentration was investigated by single factor experiments. The growing catalytic efficiency was determined by ultrasound. The removal efficiency of MB and RhB are influenced by wPCB, H2O2, pH, and dye concentration. Degradation efficiency is accelerated with increasing wPCB dosage and H2O2 and decreasing dye concentration. Effective degradation of MB and RhB is obtained under broader pH region, attractively at neutral pH. Under optimal conditions, MB removal reaches 98.83% at 90min while RhB removal reaches 99.57% at 80min. Hydroxyl radicals play an important role in catalytic process. Tentative mechanism for catalytic degradation of MB and RhB are discussed based on multiple characterizations. Superior reusability of wPCB proves that wPCB is highly durable catalyst. Due to low cost and high efficiency, wPCB is attractive as effective catalyst for treatment of organic wastewater. Artificial neuron network-based (ANN) simulation, as a widely used artificial intelligence algorithm, was one of preferred methods for the wastewater treatment due to its unique properties in solving complex processes. An ANN model was designed for the prediction of the performance of ultrasound-enhanced catalytic degradation with a high R value (0.99).

Simultaneous production of clean water and organic dye from dyeing wastewater by reusable lignin-derived porous carbon

Porous carbon adsorption is regarded as a promising technology for addressing issues of organic dye wastewater remediation and fresh water production. However, there are critical challenges in existing porous carbon adsorbents, including the relatively poor adsorption capacity, low removal rate, large consumption of activator, weak recoverability of organic dye and adsorbent, which need to be further investigated. Herein, we develop a hierarchical porous carbon material directly derived from renewable lignin that can serve as a high-performance and reusable adsorbent for simultaneous production of clean water and organic dye from simulated dye wastewater. Benefitting from the inherent hierarchical microstructures, the lignin-derived porous carbon (LPC) exhibits excellent adsorption capacity (979.29 mg/g) and high removal rate (8.16 mg/(g·min)) for Orange II dye. In addition, the LPC offers an attractive advantage for wastewater treatment that the organic dye, eluting agent and water all can be easily recycled and reused through facile filtration and distillation. Notably, the as-synthesized LPC can significantly reduce wastewater treatment costs by reusing multiple times and thus exhibits infinite possibility to transform a dyeing factory from a wastewater discharger to a clean water and organic dye producer.

Investigation of photoelectrocatalytic degradation mechanism of methylene blue by α-Fe2O3 nanorods array

Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge. Herein, vertically oriented mesoporous α-Fe2O3 nanorods array (α-Fe2O3-NA) is directly grown on fluorine-doped tin oxide (FTO) glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater. The Ov sites on the α-Fe2O3-NA surface are the active sites for methylene blue (MB) adsorption. Electrons transfer from the adsorbed MB to Fe-O is detected. Compared with electrocatalytic and photocatalytic degradation processes, the photoelectrocatalytic (PEC) process exhibited the best degrading performance and the largest kinetic constant. Hydroxyl, superoxide free radicals, and photo-generated holes play a jointly leading role in the PEC degradation. A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis. This work demonstrates that photoelectrocatalysis by α-Fe2O3-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation. The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.

Development of Co-Al LDH/GO composite photocatalyst for enhanced degradation of textile pollutant under visible light irradiation

Industrial wastewater contamination is a severe global issue due to the effective dosage of textile dyes that are directly exiting from the textile industries either without treatment or mild treatment. These dyes contain many organic pollutants severely damaging human beings along with aquatic environment and animals. Methylene blue (MB) dye is a carcinogenic that can cause acute diseases. In this regard, Photocatalysis proves an alluring approach because to its fascinating characteristics over ordinary technologies particularly economical and simple methodology. Layered double hydroxide (LDH) as a photocatalysts are exhibiting their promising performance for the treatment of organic pollutant in industrial wastewater. The present research displays a simple and facile co-precipitation method for the synthesis pure Co-Al LDH and its composite with graphene oxide (GO). A series of composites of GO and Co-Al layered doubled hydroxide with varied content of GO is successfully synthesized that enhanced the photocatalytic performance of Co-Al LDH in terms of MB dye degradation. With the optimized sample, 0.5 g GO loading onto Co-Al LDH termed as 0.5-CAL/GO, the MB dye degradation of 71 % was achieved under white LED light (10 W) irradiation. Synthesized photocatalysts are characterized by several analytical techniques such as (XRD, SEM, FTIR, Raman, UV Visible DRS, Photoluminescence spectroscopy). This research presents the flexible strategy for effective removal of MB dye simulated wastewater, acting as a textile industry wastewater employing a visible light active photocatalyst under white light (LED) illumination.

Study on degradation of alizarine reds in simulated dye wastewater by gas-liquid two-phase discharge plasma

In this paper, a gas-liquid two-phase discharge plasma water treatment device was designed for the degradation of alizarine reds in simulated dye wastewater. The effects of the solution circulation flow rate, carrier gas velocity, discharge power, initial concentration, solution pH, Fe2+ addition, H2O2 addition, and tert-butanol addition on the removal efficiency of alizarin red were investigated in the experiment. According to the treatment results of 50 mg/L and pH 7.21 alizarine reds in simulated dye wastewater, the removal efficiency reached 94.6%: the discharge power of 43.5 W, the circulation flow rate of 52 L/h, and the carrier gas velocity of 20 mm/s. Meanwhile, the mechanistic and reaction kinetics of the alizarine reds degradation process were investigated, and the economic feasibility of plasma discharge alizarine reds degradation.

Bioinspired photothermal sponge for simultaneous solar-driven evaporation and solar-assisted wastewater purification

Solar-driven evaporation (SDE) garners widespread attention for solving the freshwater shortage. However, most designed photothermal evaporators lack consideration of contaminants in bottom bulk water which seriously reduces their credibility in practical application. Inspired by the bump structure of Rafflesia arnoldii and truss building, a photothermal evaporator with secondary structure was constructed by embedding biochar loaded with UiO-66-NH2 (C@MOF) into chitosan/bamboo fibers (CS/BFs) matrix for simultaneous freshwater generation and dye adsorption. Due to the efficient light utilization, CS/BFs/C@MOF sponge exhibits an energy conversion efficiency of 86.84% under 1 sun illumination. In addition, CS/BFs/C@MOF sponge possesses the maximum adsorption capacities of 105.48 mg g−1 for methylene blue (MB) and 60.57 mg g−1 for methyl orange (MO). Importantly, the dye adsorption process on CS/BFs/C@MOF is essentially an endothermic reaction, which is more effective in sunlight. The good dye adsorption capacity allows CS/BFs/C@MOF to confine most contaminants to the bottom region during long time working in dye solution, ensuring an efficient SDE process. In outdoor practical application, a single evaporator can extract 6.72 kg m−2 purified water from 50 mg/L of simulated dye wastewater one day with a contaminant removal efficiency of 85.14%. This work achieves a good integration of separation and purification strategies through solar energy and offers a promising solution for solar-driven in-depth water treatment.

Integrated MnO2 nanosheet ultrafiltration ceramic membrane with micro-nano bubbles for catalytic treatment of dye wastewater

Membrane filtration integrated with micro-nano bubbles (MNBs) is an attractive technology for treating dye wastewater given its efficiency and environmental compatibility. However, the amount of ·OH generated during the disintegration of MNBs is insufficient in practical applications. This work presents the characterisation of a modified Al2O3 ceramic membrane (CM) with the MnO2 nanosheet (MnO2/Al2O3 CM), which provides dual functions of membrane filtration and MNB catalysis. Here, a novel MNB catalytic membrane reactor (MNB-CMR) was constructed by applying the modified MnO2/Al2O3 CM for treating the simulated dye wastewater, i.e., methylene blue (MB). The MB degradation showed that the MNB-CMR improved 17% decolorization rate and 20% total organic carbon removal rate compared to the integrated MNB process with the non-modified CM. The MNB-CMR exhibited excellent catalytic performance and fouling resistance. Besides, the effects of MNB-CMR operational parameters such as the initial methylene blue (MB) concentration, reaction temperature, solution flux, and solution pH on the MB degradation performance were investigated. Based on the scavenging experiments of reactive oxygen species (ROS), the reaction of singlet oxygen (1O2) or hydroxyl radicals (·OH) was elucidated as the primary ROS responsible for the oxidation of MB in the MNB-CMR. In addition, the XPS results showed that the redox couple of Mn(IV)/Mn(III) on the surface of the MnO2/Al2O3 CM was responsible for MNB catalysis. Finally, we proposed a possible degradation pathway of MB. This work shows an attractive alternative wastewater treatment process to relieve membrane fouling and enhance MNB catalysis concurrently.

Preparation and application of monodisperse, highly cross-linked, and porous polystyrene microspheres for dye removal

The porous materials as adsorbents play an important role in dye removal. In this paper, monodisperse, highly cross-linked porous microspheres with a specific surface area of 255.83 m²/g and average pore size of 8.5 nm were synthesized by seed swollen emulsion polymerization. The sulfonation reactions of porous microspheres were carried out to improve the hydrophilic performance and electronegativity of the microsphere surface. Cationic methylene blue (MB) and anionic methyl orange (MO) were employed as simulated dye wastewater to investigate the adsorption kinetics of porous microspheres. The experimental results demonstrate that porous sulfonate microspheres possess selective adsorption for MB due to electrostatic interaction between the negative charges on the surface of microspheres and the positive charges of MB molecules. Porous microspheres exhibit an adsorption capacity of 313.125 mg/g after 2 h. The adsorption kinetics of MB dyes in porous microspheres follow a pseudo-second-order model.

Conversion of waste bottle PET to magnetic microparticles adsorbent for dye-simulated wastewater treatment

Mass production and consequent accumulation of plastic wastes in the environment urges the development of technologies for the efficient plastic wastes utilization and valorization to materials and products to support circular economy. Here, we report a novel conversion of PET plastic to a magnetic microparticles adsorbent prepared by co-precipitation of Fe3O4 nanoparticles with oligomeric products of PET aminolysis. The obtained adsorbent represents highly water-dispersible oligo(terephthalamide) particles of several tens μm size embedding magnetic nanoparticles randomly distributed in the organic matrix. The PET-derived magnetic adsorbent was used for the rapid and facile magnetic separation of an anionic dye (Congo Red, CR) from dye simulated water samples. The adsorbent containing plenty of amine groups showed superb adsorption capacity for CR of ca. 780 mg/g which is pH dependent and optimal at pH 6.5. Furthermore, the microparticular, non-aggregative state of the adsorbent coupled with its magnetic functionality provided rapid saturation of the adsorbent with dye by ca. 70% of the equilibrium adsorption capacity within 5 min and possibility of instantaneous removal from solution by a magnet. The proposed here material design addresses simultaneously the problem of plastic wastes utilization and preparation of cost-effective and efficient adsorbents for environmental cleaning purposes.

Decolorization and toxicity evaluation of simulated textile effluent via natural microbial consortia in attached growth reactors

Textile wastewater is heterogeneous in nature with multiple types of dyes and other chemicals. Considering this point, attached growth bioreactors were constructed, using sludge (SD), alkalophilic (AK), and thermophilic (TH) bacterial consortia to develop an effective dye biodegradation system. Simulated dye wastewater, containing a 50 ppm mixture of three reactive azo dyes, viz. Reactive Blue (RB 221), Reactive Yellow (RY 145), and Reactive Red (RR 195) were treated under batch mode operation for up to 192 h. Overall, the color removal efficiency of the reactors varied from 85 to 94 % in 192 h. The thermophilic consortium achieved maximum decolorization (93.5 %), operated at 50 °C, while the alkalophilic consortium attained maximum COD reduction (93.0 %). Nitrites and nitrates were reduced to (14.7 – 79.3) – (84 – 239.4) mg/L, while sulfates ranged from 624.7 – 1003 mg/L. In addition, scanning electron microscopy (SEM) analysis revealed the biofilm community structure, indicating diverse bacterial interactions among each consortium. The biodegradation of dyes was further confirmed through Fourier-transform infrared spectroscopy (FTIR). Phytotoxicity and cytotoxicity analyses revealed that the dye mixture became non-toxic after treatment. This study outlines that natural microbial consortia are efficient dye decolorizers and confers the possibility of using microbial consortia for upscale biological treatment of dyeing effluents.

Preparation of Copolymer of 2-Methacryloyloxyethyldimethyl-3-sulfonic Acid Propylammonium Hydroxide and 3-(Methacryloyloxy) Propyltrimethoxysilane and Its Dye Adsorption Properties

While printing and dyeing bring us huge economic benefits, it also brings us huge challenges. Printing and dyeing will produce a large amount of wastewater, and the treatment of printing and dyeing wastewater has always been a concern. This work uses 2-methacryloxyethyl dimethyl-3-sulfonic acid propyl ammonium hydroxide, 3-(methacryloxy) propyl trimethoxysilane, and N, N’-methylene bispropylene as raw materials, and a photoinitiator is used to initiate polymerization under an ultraviolet lamp to prepare a copolymer gel. Taking the aqueous solution containing soap yellow as simulated dye wastewater, the adsorption performance of the prepared polymer for dyes was investigated. An ultraviolet spectrophotometer was used to investigate the effects of adsorption time, initial dye concentration, and polymer dosage on the adsorption performance. The performance test results show that the prepared polymer has high adsorption and removal efficiency for dyes containing soap yellow simulation, and has a potential application value.

Polymerization mechanism of polyferric aluminum phosphatic sulfate (PFAPS) and its flocculation effect on simulated dye wastewater

Polymerization mechanism of polyferric aluminum phosphatic sulfate (PFAPS) and its flocculation effect on simulated dye wastewater

Simultaneously enhanced treatment efficiency of simulated hypersaline azo dye wastewater and membrane antifouling by a novel static magnetic field membrane bioreactor (SMFMBR)

Operation performance and membrane fouling of a novel static magnetic field membrane bioreactor (SMFMBR) for treatment of hypersaline azo dye wastewater was investigated. The results showed that SMFMBRs possessed higher efficiency of dye decolorization, COD removal and detoxification than the control MBR without SMF. The (3#) SMFMBR equipped with 305.0 mT (the highest intensity) SMF displayed the best treatment performance among all the four reactors (named as 0#–3#, equipped with SMFs of 0 mT, 95.0 mT, 206.3 mT and 305.0 mT, respectively). Potentially effective microbes belonging to Rhodanobacter, Saccharibacteria genera incertae sedis, Defluviimonas, Cellulomonas, Cutaneotrichosporon, Candida and Pichia were enriched in three SMFMBRs, in both of suspended sludge and bio-cakes. The relative abundance of Candida and Pichia in suspended sludge of 3# SMFMBR was the highest among all the four reactors, suggesting their successful colonization and potentially persistent effect of bioaugmentation. On the other hand, SMF of higher intensity effectively mitigated membrane fouling. Less production of soluble microbial products (SMP) and extracellular polymeric substances (EPS), lower protein/polysaccharide (PN/PS) ratio in SMP and EPS, looser structure of bio-cakes on membrane surface, as well as lower relative abundance of potential fouling causing microbes (mainly bacteria) in microbial communities were determined in 3# SMFMBR than the other three groups.

Study on synthesis of rare earth tungsten heteropoly acid glycine composite catalyst and degradation of dyes

Using glycine molecules as the carrier, a 1:11 rare earth tungsten heteropoly acid glycine composite catalyst was prepared by hydrothermal synthesis and characterized by XRD, TG, TEM, XPS and other methods. The effects of catalyst dosage, initial dye concentration, initial pH and other factors on the decolorization rate of Congo red simulated dye wastewater were investigated. The experimental results show that when the initial pH is 4, the amount of catalyst is 10 mg, and the dye concentration is 10 mg/L, the catalyst has good degradation performance on Congo red simulated dye wastewater, and the degradation can reach 90.9%.

Effect of Urea Addition on Anatase Phase Enrichment and Nitrogen Doping of TiO2 for Photocatalytic Abatement of Methylene Blue

TiO2-based materials are commonly employed as photocatalysts for industrial wastewater treatment. The primary reasons of employing TiO2 include cost effectiveness, ready availability, eco-friendliness, non-toxic behavior, and exceptional resistance towards photo-corrosion. However, the wider band gap of pure TiO2 restricts its performance because of its optical absorption of solar light to the ultraviolet (UV) region only, and to some extent of photo-excited charge recombination. In the present work an attempt is made to develop a facile synthesis approach by using urea, a cheap chemical precursor, to form nitrogen doped TiO2 with the key objective of extended light absorption and thus enhanced photocatalytic performance. It was also observed that the urea-induced anatase phase enrichment of TiO2 is another key factor in promoting the photocatalytic performance. The photocatalysts prepared by varying the amount of urea as a nitrogen dopant precursor, are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) to evaluate their crystallinity, morphology, functional groups, and charge separation properties, respectively. Moreover, the surface area was also estimated by physicochemical adsorption. The maximum nitrogen-doped sample yielded >99% photodegradation efficiency of methylene blue (MB) dye-simulated wastewater as compared to a pure TiO2 sample which exhibited 6.46% efficiency. The results show that the simultaneous factors of nitrogen doping and anatase phase enhancement contributes significantly towards the improvement of photocatalytic performance.

Effect of PO43- on the polymerization of polyferric phosphatic sulfate and its flocculation characteristics for different simulated dye wastewater

Introducing PO43- into the molecular structure of polyferric sulfate (PFS) can improve its flocculation performance and stability. In order to explore the mechanism of PO43- impacting on the polymerization and flocculation of polyferric phosphatic sulfate (PFPS), PFPS with different ratios of PO43-/Fe and OH–/Fe were prepared, and their particle size distributions and flocculation performances were obtained in this paper. The microstructures of the PFPS samples were characterized by SEM, XRD and FTIR. The molecular dynamics (MD) simulation on the mechanism of PO43- impacting on polymerization of PFPS was carried out. The results show that the proper addition of PO43- can promote the polymerization of PFPS, raise the Fe particle size and the content of active flocculant components, improve its ability of electric neutralization and adsorption bridging, and enhance the flocculation performance finally. Although the addition of OH– can also raise the Fe-polymer particle size in the PFPS sample, it will reduce the active flocculant components and increase uncharged precipitation, then reduce PFPS flocculation effect.

Construction of high-performance CeO2 ultrafiltration membrane for high-temperature dye/salt separation

CeO2 is an alternative membrane material for precise separation under harsh conditions because of its single fluorite structure and outstanding high-temperature stability. In this study, uniform and stable CeO2 colloidal sols were successfully prepared using an ultrasound-assisted precipitation method with an average particle size of approximately 5 nm. To prepare crack-free CeO2 membranes with a controllable thickness, concentration of polyvinyl alcohol in the colloidal sol and the coating time were investigated. An integrated membrane layer was fabricated by adjusting the sol to PVA solution mass ratio to 1:1 with a coating time of 30 s. After calcination at 500 °C, a thin CeO2 membrane (approximately 200 nm thick) was obtained. In addition, the CeO2 material derived from the as-prepared sol showed a fluorite structure and lattice fringes corresponding to different crystal planes, indicating the formation of a pure CeO2 thin membrane. The CeO2 membrane exhibited a high performance, with a molecular weight cut-off of 3.9 kDa and a high water permeance of 100 L m−2 h−1·bar−1. It showed excellent thermal stability, promising good potential applicability at high temperatures. Additionally, it exhibited the dye rejection rates of >99% for Direct Red 80 and 95.5% for Congo Red, and salt rejection rates of <1% at 60 °C in the simulated dye wastewater treatment. Overall, this study presents a new tight ultrafiltration membrane material that has good potential for high-temperature dye wastewater treatment.

Study on the Performance of Pd-Catalyst Based on Decolorization Rate

The simulated azo dye waste-water was treated by Catalytic Wet Oxidation. The catalyst was prepared by impregnation method, and FSC (main component: γ-Al2O3) was used as the catalyst carrier, and 6wt%Cu, Fe, Pd and La were added. The catalyst was dynamically impregnated at 35 °C for 8 h, dried at 110 °C for 10 h, and roasted at 450 °C for 3h to prepare the supported catalyst. Based on the decolorization rate of treated waste-water, the effect of component composition on catalyst performance was investigated. In the CWAO treatment of waste-water, the pH of the treated effluent first decreased and then increased with the extension of reaction time; with the extension of reaction time, organic matter degrades continuously, the absorbance of waste-water decreases and the decolorization rate increases. Cu-Fe-Pd-La/FSC (ratio 0.75:0.75:1.5:3) has the best treatment effect; the metal dissolution concentration of the waste-water increases with the reaction time. Cu and Al are relatively stable, and the dissolution concentration in treated effluent is between 0.5 and 3.0 mg/L. The results showed that the Cu-Fe-Pd-La/FSC catalyst composed of Cu: Fe: Pd: La=1:1:1:3 had good catalytic activity and stability.

Treatment of Biorefractory Organic Compounds in Dyeing and Printing Process Textile Wastewater with Electron Beam Radiation

Abstract The biodegradability improvement of simulated textile dyeing (reactive), printing, and overall wastewater was carried out by electron beam (e-beam) radiation for an activated sludge proces...

Photocatalytic purification of simulated dye wastewater in different pH environments by using BaTiO3/Bi2WO6 heterojunction photocatalysts

Abstract To reveal the photodegradation process of mixture dye solutions in different pH environments by photocatalysts is a key point to promote the practical application of potocatalysis technology in purifying industrial dye wastewater. Herein we report the photocatalytic degradation of various organic dyes (MO, RhB, MB) and MO/RhB/MB mixture solutions in different pH environments by using novel BaTiO3/Bi2WO6 (BTO/BWO) heterojunction composites as the photocatalyst and simulated sunlight as the light source. The BTO/BWO heterojunction photocatalysts were prepared by immobilizing BTO particles onto rose flower-like BWO hierarchical architectures. Among the as-derived samples, the 15 wt%BTO/BWO composite is determined to have the highest photodegradation performance, which is ascribed to the efficient separation of photoexcited electron/hole pairs due to the Z-scheme electron transfer mechanism. The photodegradation of the dyes is found to be highly dependent on the acidic–alkaline environments. Moreover, an interesting competitive photodegradation phenomenon between the dyes is observed in the MO/RhB/MB mixture solutions. Superoxide (•O2−) and hydroxyl (•OH) radicals are suggested to be the direct reactive species causing the dye photodegradation in the present photocatalytic system.