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In this work, the adsorption capacity of hydrotalcite on the Reactive Yellow 2 textile dye has been verified. Nanoclays are elements with a high capacity for adsorption of dyes and can be reusable as printing pigments. For this, the Lambert-Beer lines of each dye have been previously made. A dye concentration of 1 g/L and a clay concentration of 3 g/L have been used. Then the dye has been introduced into the clay by stirring for 24 hours in 100 mL of solution of the dye, to later filter it and allow to dry. The adsorption of the dye by the nanoclay has been almost absolute, leaving the initial solution very clean, which are excellent results from the point of view of cleaning wastewater. After drying and collecting the clay, a stamping paste in a substrate of PES/CO 50%/50% was made with the hybrid obtained, using a concentration of 1.5 g/kg and 7.5 g/Kg. They were then heat-set at 180ºC for 30 seconds. Finally, the samples obtained are analyzed on a Minolta CM-3600d reflection spectrophotometer to assess the color achieved. There is a difference in color when comparing the two samples, as expected, the printed sample with higher concentration of hybrid shows a greater intensity of colour. The color difference was calculated and the Kubelka-Munk theory was taken as a reference to make an assessment of the strength of the color obtained.

[Display omitted] A treatment process based on microfiltration followed by nanofiltration (MF-NF) is proposed for textile wastewater treatment. The NF concentrate is further treated by UV/H 2 O 2 , Fenton, and photo-Fenton processes. Results showed that the dye was efficiently retained by the MF membrane (>99.1%), which allowed its reuse. The MF-NF was able to reject 92% of the chemical oxygen demand (COD) and>98.5% of color. When the NF concentrate was treated by UV/H 2 O 2 , it was achieved a maximum COD removal of 63% in the condition C:H 2 O 2 1:3 (molar ratio of COD and hydrogen peroxide) and pH 3. The Fenton process, optimized through response surface methodology, achieved 84.7% of COD removal, which increased when combined with UV irradiation (92.2%). An analysis of the NF permeate physicochemical quality and its treated concentrate suggested that it can be reused in the textile industry for different purposes as yarn washing-off and equipment's washdown. The operating cost for MF-NF corresponded to 0.240 US$/m3 and, including the cost of NF concentrate treatment by photo-Fenton, 0.517 US$/m3, lower than currently practiced by the water distribution company. The system proposed for water reuse and NF concentrate treatment was able to increase the water recovery and decrease the environmental impacts that could be caused by the NF concentrate disposal. [ABSTRACT FROM AUTHOR]

Featured Application: Nanoclays can be used as adsorbent for waste water in several industries as textile. In addition the hybrid composites generated after the dye adsorption can be used as pigments in several applications as textile stamp, polymer composites (filature), 3d printing, ceramic, cosmetic or even food industries depending on the hybrid components (natural dyes). Finally the desorption of the dyes is also possible with the nanoclays, allowing their reuse in other applications as textile dyeing, closing the manufacture circle without residues. Wastewater recovery is one of the most pressing contaminant-related subjects in the textile industry. Many cleaning and recovery techniques have been applied in recent decades, from physical separation to chemical separation. This work reviews textile wastewater recovery by focusing on natural or synthetic nanoclays in order to compare their capabilities. Presently, a wide variety of nanoclays are available that can adsorb substances dissolved in water. This review summarizes and describes nanoclay modifications for different structures (laminar, tubular, etc.) to compare adsorption performance under the best conditions. This adsorbent capacity can be used in contaminant industries to recover water that can be used and be recontaminated during a second use to close the production circle. It explores and proposes future perspectives for the nanoclay hybrid compounds generated after certain cleaning steps. This is a critical review of works that have studied adsorption or desorption procedures for different nanoclay structures. Finally, it makes a future application proposal by taking into account the summarized pros and cons of each nanoclay. This work addresses contaminant reuse, where part of the employed dyes can be reused in printing or even dyeing processes, depending on the fixing capacity of the dye in the nanoclay, which is herein discussed. [ABSTRACT FROM AUTHOR]

The absorption capacity of calcined hydrotalcite at different concentrations in a solution of 0.05 g • L-1 of 4 different dyes has been compared; Direct Blue 199, Direct Red 23, Direct Blue 71 and Reactive Yellow. For this, the Lambert-Beer lines of each dye have been previously made. Two different concentrations of clay, 5 and 10 g • L-1, have been worked. Then the dye has been introduced into the clay by stirring for 24 hours in 100 ml of solution of each dye, to later filter it and allow to dry. In all cases, the absorption of the dye by the nanoclay has been almost absolute, leaving the initial solution very clean, which are excellent results from the point of view of cleaning wastewater. However, when obtaining very similar results when scaling it to an industrial production, it would be more optimal to use the lowest concentration in order to reduce costs. Finally, a color measurement was made using a Jasco V-670 spectrophotometer, double beam spectrophotometer between 190- 2700 nm and color differences are calculated and represented in a color chart. Again, no large differences are observed and reinforce the idea of using a low concentration.

In this study, a new kind of wholly-Tröger's base-based polyamide (w TB-PA) thin film composite (TFC) nanofiltration (NF) membrane was successfully fabricated for the separation application in strong acidic condition via the acid-induced segregation (AIS) effect. Firstly, the self-synthesized Tröger's base diamine monomer — 2,8-diamino-4,10-dimethyl-6H,12H-5,11-methanodibenzo [1,5]-diazocine (TBDA) was added in the polyethersulfone (PES) casting solution to prepare the TBDA-based PES substrate by synchronously coupling the non-solvent-induced phase transformation (NIPs) and AIS, and then the TBDA molecules on the PES substrate surface further reacted with trimesoyl chloride (TMC) via interfacial polymerization (IP) to obtain the w TB-PA TFC NF membranes. Meanwhile, the acid-induced segregation effect of on the microstructure and separation performance of the w TB-PA TFC NF membrane were systematically investigated. As compared with the conventional poly(piperazine amide) NF membrane (M PIP-TMC), the w TB-PA NF membranes exhibited thinner, smoother but more hydrophobic surface as well as lower isoelectric point, and especially showed much higher tolerance to 20 wt% H 2 SO 4 after soaking 63 days and favorable dye rejection (～99.9 %). Thereinto, the acid segregation agent of citric acid monohydrate (CA) endowed the w TB-PA TFC NF membrane with relatively optimal acid resistance and SO 4 2−/Cl− separation selectivity (about 11.8) than glacial acetic acid (AC), nitric acid (HNO 3) and hydrochloric acid (HCl). Moreover, this w TB-PA NF membrane based on CA-induced segregation had higher recovery of the cationic dye of crystal violet (CV) (＞98.0 %) in acidic condition. Therefore, the w TB-PA TFC NF membranes have great potential for the separation application in the strong acidic condition in the future. A new kind of wholly-TB-based polyamide (wTB-PA) thin-film composite (TFC) nanofiltration (NF) membrane was fabricated with a self-synthesized TB-based diamine monomer TBDA by coupling the non-solvent-induced phase transformation (NIPs), acid-induced segregation (AIS) and interfacial polymerization (IP) processes. The resultant wTB-PA TFC NF membrane exhibited thinner and smoother surface, and especially showed much higher tolerance to 20 wt% H 2 SO 4 after soaking for 63 days and high recovery of the cationic dye of crystal violet (CV) (＞98.0 %) in acidic condition. [Display omitted] • The new wholly-Tröger's base-based polyamide thin film composite nanofiltration membrane was fabricated successfully. • The acid-induced segregation was combined with NIPs and IP processes to fabricate the w TB-PA TFC NF membrane. • The w TB-PA TFC NF membrane exhibited much higher tolerance to 20 % H 2 SO 4 after soaking for 63 days. • The w TB-PA TFC NF membrane showed higher recovery rate of cationic dye of CV in acid condition. [ABSTRACT FROM AUTHOR]

In this work, the adsorption capacity of hydrotalcite on the Reactive Yellow 2 textile dye has been verified. Nanoclays are elements with a high capacity for adsorption of dyes and can be reusable as printing pigments. For this, the Lambert-Beer lines of each dye have been previously made. A dye concentration of 1 g/L and a clay concentration of 3 g/L have been used. Then the dye has been introduced into the clay by stirring for 24 hours in 100 mL of solution of the dye, to later filter it and allow to dry. The adsorption of the dye by the nanoclay has been almost absolute, leaving the initial solution very clean, which are excellent results from the point of view of cleaning wastewater. After drying and collecting the clay, a stamping paste in a substrate of PES/CO 50%/50% was made with the hybrid obtained, using a concentration of 1.5 g/kg and 7.5 g/Kg. They were then heat-set at 180°C for 30 seconds. Finally, the samples obtained are analyzed on a Minolta CM-3600d reflection spectrophotometer to assess the color achieved. There is a difference in color when comparing the two samples, as expected, the printed sample with higher concentration of hybrid shows a greater intensity of colour. The color difference was calculated and the Kubelka-Munk theory was taken as a reference to make an assessment of the strength of the color obtained. [ABSTRACT FROM AUTHOR]

Wastewater recovery is one of the most pressing contaminant-related subjects in the textile industry. Many cleaning and recovery techniques have been applied in recent decades, from physical separation to chemical separation. This work reviews textile wastewater recovery by focusing on natural or synthetic nanoclays in order to compare their capabilities. Presently, a wide variety of nanoclays are available that can adsorb substances dissolved in water. This review summarizes and describes nanoclay modifications for different structures (laminar, tubular, etc.) to compare adsorption performance under the best conditions. This adsorbent capacity can be used in contaminant industries to recover water that can be used and be recontaminated during a second use to close the production circle. It explores and proposes future perspectives for the nanoclay hybrid compounds generated after certain cleaning steps. This is a critical review of works that have studied adsorption or desorption procedures for different nanoclay structures. Finally, it makes a future application proposal by taking into account the summarized pros and cons of each nanoclay. This work addresses contaminant reuse, where part of the employed dyes can be reused in printing or even dyeing processes, depending on the fixing capacity of the dye in the nanoclay, which is herein discussed.

The absorption capacity of calcined hydrotalcite at different concentrations in a solution of 0.05 g • L-1 of 4 different dyes has been compared; Direct Blue 199, Direct Red 23, Direct Blue 71 and Reactive Yellow. For this, the Lambert-Beer lines of each dye have been previously made. Two different concentrations of clay, 5 and 10 g • L-1, have been worked. Then the dye has been introduced into the clay by stirring for 24 hours in 100 ml of solution of each dye, to later filter it and allow to dry. In all cases, the absorption of the dye by the nanoclay has been almost absolute, leaving the initial solution very clean, which are excellent results from the point of view of cleaning wastewater. However, when obtaining very similar results when scaling it to an industrial production, it would be more optimal to use the lowest concentration in order to reduce costs. Finally, a color measurement was made using a Jasco V-670 spectrophotometer, double beam spectrophotometer between 190-2700 nm and color differences are calculated and represented in a color chart. Again, no large differences are observed and reinforce the idea of using a low concentration. [ABSTRACT FROM AUTHOR]

Nanofiltration (NF) is widely used to treat highly saline textile waters, but its efficiency in dye recovery is limited by low permeance. This study presents a novel class of Co-based metal-organic framework (Co-MOF) nanosheet membranes for efficient and selective dye recovery. The Co-MOF membranes have precisely regulated in-plane pore sizes and exhibit superior permeance and selectivity compared to non-porous nanosheet membranes. By adjusting the length of the ligand, the in-plane pore size was precisely tuned from 1.01 × 0.63 to 1.43 × 0.64 nm2. The Co-MOF membranes exhibited high selectivity for salts over dye in both diffusion and pressure-driven filtration modes, along with excellent and tunable pure water permeance and high rejection of the dye OII. The remarkable permeability and selectivity of the Co-MOF membranes were attributed to the in-plane pores on the nanosheets, which serve as extra fast "lifts" for water and salts while exhibiting high rejection to the dye molecules. Long-term filtration performance and Co leaching tests demonstrated the stability of the Co-MOF membranes, making them promising candidates for practical dye recovery applications. Overall, this work provides a new approach for the development of high-performance membranes for textile wastewater treatment. [Display omitted] • The Co-MOF nanosheet membranes with precisely regulated in-plane pores were successfully fabricated. • The Co-MOF membranes with the "lifts" structure showed the excellent selectivity and high water permeance of 615.8 ± 26.4 L m−2 h−1 bar−1. • Tunable in-plane pore sizes provide additional pathways for water and salt permeance, outperforming non-porous nanosheet membranes and commercial membranes. • The Co-MOF membranes showed high stability in water and low Co-leaching. [ABSTRACT FROM AUTHOR]

Abstract One of the main challenges of dyes adsorption technology application wide-spreading is the fate of the generated dyes-loaded-biomasses, which in certain cases could represent a serious threat to the environment. In this research work, an innovative and eco-friendly approach was established for the management of a lignocellulosic material (alkaline treated orange tree sawdust: ATOS) loaded with methylene blue (MB) at a concentration of 107 mg g−1. This approach consists first of all to a rapid and important MB desorption (more than 91%) from fixed bed depth columns by low cost saline solutions (NaCl: 0.5 M). The issued solutions contained high MB concentrations (>3400 mg L−1) permitting a partial recovery of the dye as a solid phase with a purity of 93% that could be reused again in the industrial process. The second step concerns the treatment of the remaining dissolved MB in the desorbed solutions through anodic oxidation process by using bipolar Si/BDD (Boron Doped Diamond) electrodes. The presence of chlorides anions in the desorbed solutions enhances considerably their discoloration and organic carbon removal efficiencies and kinetics and significantly reduces the related consumed energy. The quality of the resulting treated wastewaters allows its possible reuse in the industrial process. Finally, five consecutive adsorption/desorption cycles experiments showed that ATOS could be reused several times for the MB adsorption without significant efficiencies decrease. All these results confirm the validity of our strategy aiming to turn dyes-loaded-lignocellulosic-biomasses from pollution source to values. Graphical abstract Image 1 Highlights • Methylene blue desorption was studied in fixed bed column mode. • Methylene blue desorption was governed by an ion exchange mechanism. • Dye recovery was achieved with a high purity level of more than 92%. • Biomass ability for reuse was confirmed after five successive regeneration cycles. • High efficiency and low energy consumption when degrading MB by anodic oxidation. [ABSTRACT FROM AUTHOR]

To meet surging water demands, water reuse is being sought as an alternative to traditional water resources. Direct contact membrane distillation (DCMD) has been increasingly studied in the past decade for its potential as an emerging cost effective wastewater treatment process and subsequent water reuse. This review presents a comprehensive overview of the current progress in the application of DCMD for textile wastewater treatment based on the available state of the art. There are already published review papers about the membrane distillation process, but the difference in the present work is that it focuses on the textile area, which consumes a lot of water and generates large amounts of wastewater, and still needs innovations in the sector. A review focused on the textile sector draws the attention of professionals to the problem and, consequently, to a solution. Current issues such as the influences of feed solution, membrane characteristics and membrane fouling and new insights are discussed. The main performance operating conditions and their effects on the separation process are given. Likewise, challenges associated with the influence of different dyes on the DCMD results are explained. This review also highlights the future research directions for DCMD to achieve successful implementation in the textile industry. [ABSTRACT FROM AUTHOR]

Treatment of polluted water has been considered as one of the most important aspects in environmental sciences. Present study explores the decolorization potential of a low cost natural adsorbent Xanthium strumarium L. seed hull for the adsorption of a toxic xanthene dye, Rhodamine B (RHB). The characterization of the adsorbent revealed the presence of high amount of carbon, when exposed to Electron Dispersive Spectroscopy (EDS). Further appreciable decolorization took place which was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) analysis noticing shift in peaks. Isothermal studies indicated multilayer adsorption following Freundlich isotherm. The rate of adsorption was supported by second order kinetics directing a chemical phenomenon during the process with dominance of film diffusion as the rate governing step. Moreover paper aims at correlating the chemical arena to the mathematical aspect providing an in-depth information of the studied treatment process. For proper assessment and validation of the observed data, experimental data has been statistically treated by applying different error functions namely, Chi-square test (χ 2 ), Sum of absolute errors (EABS) and Normalized standard deviation (NSD). Further practical applicability of the low cost adsorbent was evaluated by continuous column mode studies with 72.2% of dye recovery. Xanthium strumarium L. proved to be environment friendly low cost natural adsorbent for decolorizing RHB from aquatic system. [ABSTRACT FROM AUTHOR]

Synthetic dye is one of the major pollutants in saline wastewater. This demands emerging approaches for reuse of wastewater and inclusive management of water systems towards sustainability of water and environmentally beneficial ecosystem. We report here a fabrication process scalable for large-scale manufacturing of antifouling hollow fiber membrane with mean pore size of 1 nm, that can selectively allow permeation of water and NaCl (>95 %) from the salty (NaCl) dye wastewater and concentrate Reactive Black-5 dye (>99 %). The membrane exhibited antifouling property as the membrane flux recovered to almost its initial flux (~97 %) with intermittent washing with water and the flux was almost constant over a long period of separation experiment using dye wastewater feed. Thus, this hollow fiber membrane has potential for recovery/reuse of valuable dyes/NaCl as well as water reclamation from the wastewater. [Display omitted] • Spinning with surface coating process to make antifouling hollow fiber membrane • Surface reaction aided the formation of 'water channel' nanopores. • Surface COOH and OH groups imparted membrane hydrophilicity. • High endurance with 97 % flux-recovery-ratio in dye wastewater treatment [ABSTRACT FROM AUTHOR]

Dye recovery is of great significance for a circular economy and sustainable development. However, green recovery strategies without secondary pollution remain a significant challenge. To resolve this issue, a light-responsive smart material (citric acid-modified BiOCOOH (m-BOCH)) was synthesized and applied for dye recovery through adsorption in the dark, and desorption under visible light. With the modification of citric acid, the adsorption level of methylene blue (MB) on m-BOCH (43.4%) was more than six times that of pure BiOCOOH (7.1%). The desorption rate was ∼90% in 120 min under 420 nm light irradiation (there was no desorption for pure BOCH). Further, the adsorption rate was improved to 83.9% and the desorption rate remained stable at an optimal pH of 10.09. Characterization results indicated that carboxyl groups were modified onto the surface of BiOCOOH and served as adsorption sites for MB. Under visible light exposure, the connections between the carboxyl groups and BiOCOOH were damaged, which led to the desorption of MB from the surface of the m-BOCH. The recovered MB exhibited a good staining effect on hepatic stellate cells (HSC) as a fresh dye. The regeneration of m-BOCH was achieved through a moderate hydrothermal process, and the adsorption and desorption capacities were restored to 80.8% and 85.7%, respectively. This research provides a novel environmentally compatible strategy for dye recovery without secondary pollution. This is a very promising treatment technique for dye effluents, which highlights the application of smart materials resource recycling for environmental remediation. • The citric acid modified BiOCOOH (m-BOCH) was synthesized by a simple hydrothermal method. • The m-BOCH exhibited good adsorption and photo-induced desorption property to MB. • Carboxyl was modified onto the surface of BOCH and acted as adsorption site to MB. • The connection between carboxyl and BOCH was damaged with light and MB released into solution. [ABSTRACT FROM AUTHOR]

In this paper, industrial dyes, Disperse Red and Disperse Orange, were studied as model pollutants to show the excellent performance of olive pomace (OP) in sequestering and recovering these dangerous dyes from wastewater. The nature of interactions involved between dyes and OP were inferred by changing several parameters: contact time, pomace dosage, pH and temperature values. Visible spectroscopy was mainly used to obtain the percentage of the removed dyes, while SEM (scanning electron microscopy), FTIR-ATR (Fourier transform infra-red spectroscopy in total attenuated reflectance), TG (thermo gravimetric) and XPS (X-ray photoelectron spectroscopy) analyses were used to carefully investigate the systems. The recovery of dyes was also obtained using glacial acetic acid, the auxiliary solvent used during the dyeing processes, enabling the recycling of both of the adsorbent material and dyes presenting a green and a wide-ranging strategic approach.

Indigo is one of the most consumed dyes in the textile sector, as it is widely used for the dyeing of denim clothes. About 15% of indigo used in the dyeing process is discharged to the wastewater treatment plants or sometimes into rivers, in countries where regulations are not strictly applied. In this work, real effluents that contained indigo dye were treated by means of 4 different ultrafiltration membranes. The feasibility to recover the concentrated dye with lab and semi-industrial pilots was also investigated. The studied membranes achieved up to 99% colour removal and 80% chemical oxygen demand (COD) decrease. Finally, the concentrates containing 20 g L −1 of indigo dye were reused in new dyeing processes. Colour differences (DE CMC ) and rubbing and washing fastnesses were evaluated. Fabrics dyed with the recovered indigo concentrates exhibited similar characteristics than the ones obtained with the commercial dye. [ABSTRACT FROM AUTHOR]

Hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) was explored to recover weak acid blue 6B from dyeing wastewater via liquid-liquid extraction protocol. A recovery efficiency of ca. 95% was achieved when 1.0 mL of 0.016 g/L dye solution was directly extracted by 0.2 mL ionic liquid [BMIM][PF6] without using any extractions. Investigations of UV-Vis and FTIR spectra indicated that structure of weak acid blue 6B did not change after weak acid blue 6B was extracted into ionic liquid phase. The main driving force of extraction was that solubility of weak acid blue 6B in ionic liquid phase was more than that in aqueous phase. The collected [BMIM][PF6] including weak acid blue 6B was sequentially applied in Tussah silk dyeing process. The dyeing performances of silk with 0.5% w/w ionic liquid [BMIM][PF6] as retarding agent were the same as that with 10% w/w inorganic salt, which indicated that ionic liquid [BMIM][PF6] was an excellent retarding agent and could be used to displace traditional inorganic salt in silk dyeing. In the aspect of environmental protection, the used [BMIM][PF6] dosage was only twentieth of traditional inorganic salt, which shown great promise as an attractive alternative or replacement to traditional inorganic salts in silk dyeing.Photographs of an aqueous-[BMIM][PF6] two-phase system: (left) before extraction; (right) after extraction. Eleven dyes were directly extracted by using ionic liquid [BMIM][PF6] as extraction solution. The main driving force of extraction was the higher solubility of weak acid blue 6B in ionic liquid as in the aqueous phase. [ABSTRACT FROM AUTHOR]

The effluent of textile industries containing synthetic dyes contributed to substantial pollution to water bodies. The biosorption process of Congo Red dye was successfully performed by integrating ultrasonication in the adsorption step with spent brewery yeast as a novel and renewable biosorbent. The adsorption process was hindered when ultrasonication was employed together with the biosorbent, indicating that desorption process had occurred. The adsorption process showed that 4 g/L of biosorbent was the optimum dosage for adsorption of 50 mg/L of Congo Red dye, and that the adsorption equilibrium fitted to the Langmuir model, with kinetics best fitted with pseudo-second order model. The maximum capacity of the adsorption was 52.6 mg/g, showing the potential of spent brewery yeast to aid in removing wastewater pollutants. Maximal Congo Red dye recovery (100%) was achieved in the sonication-assisted desorption studies using 0.01M NaOH as the eluting agent. The ultrasonication effects contributed to the efficient recovery of dye and good conversion of spent brewery yeast to biosorbent can be beneficial for treating pollution from textile wastewater. • Spent brewery yeast exhibited adsorption affinity towards Congo Red. • Cavitation bubbles and microjets were responsible for desorption of CR. [ABSTRACT FROM AUTHOR]

Organic dyes, which are contained in industrial effluents, should be removed to avoid health hazards and destruction of the ecosystem. In this study, the extraction of methylene blue from aqueous solution into AOT/isooctane reversed micellar solution was investigated. It was found that methylene blue was solubilized into the waterpool within reversed micelles by electrostatic interaction with AOT. The extraction ratio of methylene blue increased with an increase in AOT concentration and a decrease in salt concentration. The methylene blue extracted reversed micelles could be recovered into fresh salt solution with high concentration. It is considered that the main driving force of forward and backward extraction of methylene blue is electrostatic interaction between cationic dye, methylene blue, and anionic surfactant, AOT. The deterioration of the forward and backward extraction behavior by using AOT/isooctane reversed micellar solution reused was not observed. [ABSTRACT FROM AUTHOR]

Abstract: Here we report a separation of a cationic dye, acridine orange (AO), by use of magnetic nanoparticles (γ-Fe2O3). The particles were showed to capture 98% of the dye within the first 20min of contact time. The maximum sorption capacity of the magnetic nanoparticles (MNPs) for AO was 59mg/g. The sorption isotherms fit well with the Freundlich model. The sorption kinetics fits well the pseudo-second-order rate equation model. 60–90% dye recovery was achieved by rotary evaporating the dye bearing nanoparticles in acetone. The nanoparticles were recycled for additional dye removal. [Copyright &y& Elsevier]

Abstract: The transport of cationic dyes methyl violet and rhodamine B from aqueous synthetic dye solution through flat type supported liquid membranes (SLM) using di (2-ethylhexyl) phosphoric acid (D2EHPA) as carrier was studied and the parameters affecting the dyes transport were determined. The extraction was carried out from the aqueous feed phase with pH 4 ± 0.2 to a more acidic strip phase of acetic acid (AcOH) with pH 2.5. The proton gradient between the feed and the strip phase was the main driving force of the mass transfer in this system. The influence of various parameters such as pH of the feed phase, strip phase concentration, carrier concentration, stirring speed and the concentration of dyes on the extraction efficiency was studied. Kinetics of transport was also studied. The optimum conditions of transport are feed phase pH 4 ± 0.2, acetic acid as stripping phase with pH 2.5, stirring speed at 600 rpm. The maximum recovery under optimum conditions was observed as 94.2% for methyl violet and 90.0% for rhodamine B. [Copyright &y& Elsevier]

Thirty species of fungi (filamentous and yeast) and bacteria were tested for their ability to remove C.I. Reactive Black 5, Reactive Blue 19 and Leuco Sulfur Biack 1 textile dyes from simulated plant waste effluents. Both dead and live forms of each of the species were tested. Species were ranked according to dye binding efficiencies (unit weight of dye bound per unit weight of biomass) and predicted biomass cost to completely decolorize a unit volume of dye-containing effluent. The results describe a potential biomass-based industrial process for recovering and reusing textile dyes. [ABSTRACT FROM AUTHOR]

In this work, a novel combined forward osmosis (FO)-extraction process is applied for resource recovery and dye wastewater treatment simultaneously. FO process is utilized to concentrate the dye wastewater, to achieve a higher concentration factor and lower energy consumption compared with NF process. The FO pre-treatment can increase the dye concentration and reduce the stream volume, thereby reducing the reagent consumption in the subsequent extraction process and lowering the processing cost. In the extraction process, the compositions of the extractant and stripping agent are also optimized, and the recovery rates for congo red, fuchsin acid, orange acid and methyl blue are 97.8%, 82.1%, 80.1% and 76.1%, respectively. In addition, the FO process is driven by the simulated seawater (0.6 M NaCl) draw solution, which can avoid the energy-intensive operation for the draw solution regeneration. Therefore, this study provides a sustainable strategy for the dye wastewater treatment in the coastal areas. Image 1 • FO pre-treatment can reduces the reagent consumption in extraction process. • Hybrid process achieves high dye recovery from dye wastewater. • FO shows a higher concentration factor and lower energy consumption compare to NF. • Seawater-driven FO avoids energy-intensive regeneration of draw solution. [ABSTRACT FROM AUTHOR]

Abstract: Hazardous dye removal and recovery from wastewater requires efficient capturing material. We report a phase change material (PCM) with phase change temperature of 16°C giving up to 98% removal of crystal violet in few minutes. The PCM was found to collect 54 times of its weight soluble dye. The dye adsorption kinetics obeys a second order pseudo rate. Upon cooling the PCM to below 16°C it gels and enabled solid removal of the captured dye. [Copyright &y& Elsevier]