Reactive Dye Wastewater Research Articles

Role of surfactants in the degradation and sustainable dyeing for reactive dyeing wastewater

To enhance the decolorization rate of thermally activated sodium persulfate in dye wastewater, C.I. Reactive Black 5 (RB5) was investigated in this study, which was evaluated by the decolorization of the dye solution. The effect of surfactant concentration (including anionic surfactant sodium dodecyl sulfate (SDS), nonionic surfactant Tween 80 (TW-80) and amphoteric surfactant (BS-12)), SPS concentration, and reaction temperature on the degradation of RB5 was studied. Furthermore, the relationship between free radicals and RB5 degradation was investigated. The results showed that the addition of SDS and TW-80 would inhibit the decolorization of RB5. Correspondingly, the effect would enlarge as the surfactant concentration increased. Nevertheless, the addition of BS-12 wouldn’t affect the final decolorization of RB5 dye solution, despite it could increase the decolorization rate in the initial stage. After 10 min of decolorization, compared to the dye liquor without BS-12, the decolorization could increase by 9.07 % and 0.69 %, respectively, after adding 0.5 and 1.0 CMC of BS-12. Besides, when reactive dyes were degraded by thermally activated sodium persulfate, the SO4-· and ·OH would work together, and SO4-· played a major role while ·OH played an auxiliary part. When the treated wastewater was used for dyeing, the addition of BS-12 could effectively regulate the dyeing rate. The fixation and K/S value were increased by 1.1 % and 0.20, respectively. Furthermore, the dyed fabrics also exhibited improved uniformity, with negligible differences in color fastness. The effects of adding SDS were similar to BS-12, while it decreased the exhaustion and fixation rate of RB5. In addition, non-ionic TW-80 was unfavorable to dyeing. This work provides a new way for efficient treatment of dyeing wastewater as well as reuse, opening an environmentally friendly treatment concept.

Multivariate optimization and application verification of electrochemical oxidation process for reactive dye wastewater generated by washing

At present, organic wastewater containing dyes has become one of the main threats to the environment, and wastewater pollution caused by dyes released from fabrics during home washing also accounts for a large proportion. In this study, Ti/IrO2 electrodes for dye waste degradation were designed and prepared with Reactive Yellow 210 (RY 210), Reactive Blue 19 (RB 19) and Reactive Blue 21 (RB 21) solutions, and a laboratory electrochemical reactor was constructed. Secondly, in the reactor, the effects of current density (20–60 mA cm−2), electrolyte concentration (NaCl, 0.01–0.03 M L−1), and initial dye concentration (30–70 mg L−1) on the COD degradation rate and energy consumption of the dye solution were explored, and the parameters were optimized by the Box-Behnken design, and the equipment was realized in the washing machine. The results showed that the effect of degradation parameters on the degradation of the three groups of dyes was: current density > initial dye concentration > electrolyte concentration. Through parameter optimization, the average COD degradation rates of the three groups of dyes, Reactive Yellow 210 (RY 210), Reactive Blue 19 (RB 19) and Reactive Blue 21 (RB 21), reached 50.71%, 41.65%, and 33.12%, respectively, and the degradation energy consumption decreased by the same trend as 29.91%, 26.49%, and 65.91%, respectively.

Decolorization Performance of a Methyl Benzyl Diallyl Quaternary Ammonium Salt Copolymer in a Simulated Reactive Dyeing Wastewater

The source of dyeing wastewater and the composition of pollutants are very complex, direct discharge will bring great harm to living environment, and cause waste of water resources. For the treatment of reactive dyeing wastewater, this work developed and synthesized a novel cationic flocculant called Poly (DMDAAC-co-DAMBAC), which was made by copolymerizing dimethyl-diallyl-ammonium chloride (DMDAAC) and methyl-benzyl-diallyl-ammonium chloride (DAMBAC). To assess its flocculation effects, flocculation decolorization studies with 3RF reactive yellow, KN−R reactive blue, and 3BF reactive red were conducted. The copolymers′ lipophilicity considerably increased once atyl groups were added. The experimental results showed that Poly(DMDAAC-co-DAMBAC) had an optimal decolorization rate of over 94 % for three reactive dyes and a maximum decolorization rate of roughly 80 % for CODMn, both of which were significantly higher than those of PDMDAAC and nearly on par with those of PDAMBAC with a comparable viscosity. Instead, Theoretical calculations of the binding energy of the results demonstrated the accuracy of the findings. The study illustrated the flocculation mechanism and laid the foundation for further application of Poly(DMDAAC-co-DAMBAC).

Polyethylenimine-Crosslinked 3-Aminopropyltriethoxysilane-Grafted Multiwall Carbon Nanotubes for Efficient Adsorption of Reactive Yellow 2 from Water.

This research intended to report amine-functionalized multiwall carbon nanotubes (MWCNTs) prepared by a simple method for efficient and rapid removal of Reactive Yellow 2 (RY2) from water. EDS analysis showed that the N content increased from 0 to 2.42% and from 2.42 to 8.66% after modification by 3-Aminopropyltriethoxysilane (APTES) and polyethylenimine (PEI), respectively. BET analysis displayed that the specific surface area, average pore size, and total pore volume were reduced from 405.22 to 176.16 m2/g, 39.67 to 6.30 nm, and 4.02 to 0.28 cm3/g, respectively. These results proved that the PEI/APTES-MWCNTs were successfully prepared. pH edge experiments indicated that pH 2 was optimal for RY2 removal. At pH 2 and 25 °C, the time required for adsorption equilibrium was 10, 15, and 180 min at initial concentrations of 50, 100, and 200 mg/L, respectively; and the maximum RY2 uptake calculated by the Langmuir model was 714.29 mg/g. Thermodynamic studies revealed that the adsorption process was spontaneous and endothermic. Moreover, 0-0.1 mol/L of NaCl showed negligible effect on RY2 removal by PEI/APTES-MWCNTs. Five adsorption/desorption cycles confirmed the good reusability of PEI/APTES-MWCNTs in RY2 removal. Overall, the PEI/APTES-MWCNTs are a potential and efficient adsorbent for reactive dye wastewater treatment.

Modelling and Multi-Objective Optimization of Continuous Indirect Electro-Oxidation Process for RTB21 Dye Wastewater Using ANN-GA Approach.

A continuous indirect electro-oxidation (EO) process was developed using graphite electrode to investigate the treatability of reactive turquoise blue RTB21 dye wastewater under specific operating conditions of initial pH, current density, hydraulic retention time (HRT), and electrolyte (NaCl) concentration. The experiments were performed in accordance with the central composite design (CCD), and the findings were used to create a model utilizing artificial neural networks (ANNs). According to the predicted findings of the ANN model, the MSE values for colour and COD removal efficiencies were estimated to be 0.748 and 0.870, respectively, while the R2 values were 0.9999 and 0.9998, respectively. The Multi-objective optimization using genetic algorithm (MOGA) over the ANN model maximizes the multiple responses: colour and COD removal efficiency (%). The MOGA generates a non-dominated Pareto front, which provides an insight into the process's optimum operating conditions.

Charged modified tight ceramic ultrafiltration membranes for treatment of cationic dye wastewater

Tight ceramic ultrafiltration membranes have been proven to exhibit good rejection performance for reactive dye wastewater at high temperatures because of their high thermal and chemical resistance. However, the application of ceramic membranes for the treatment of cationic dye wastewater is challenging because of their surface charge. In this study, a ceramic membrane is modified by grafting aminosilane (KH-551) to enhance the positive charge of the membrane surface. The rejection performance of the charged modified ceramic membrane toward the methylene blue solution is significantly improved. The modification substance is bonded to the ceramic membrane surface via covalent bonding, which imparts good thermal stability. The modified ceramic membrane exhibits stable separation performance toward the methylene blue solution. Overall, this study provides valuable guidance for the adjustment of the ceramic membrane surface charge for treating industrial cationic dye wastewater.

A critical review on the treatment of reactive dye wastewater

A critical review on the treatment of reactive dye wastewater

Comparative study of multifunctional properties of synthesised ZnO and MgO NPs for textiles applications

PurposeAmong various metal oxide nano particles, MgO NPs and ZnO nanoparticles (NPs) in particular are gaining increasing attention due to their multifunctional characteristics, low cost and compatibility with textile materials. Each type of nanoparticle excels over others in certain properties. As such, it is often crucial to carry out comparative studies of NPs to identify the one showing higher efficiency/output for particular applications of textile products.Design/methodology/approachIn the investigation reported in this paper, ZnO NPs and MgO NPs were synthesised via sol-gel technique and characterised. For comparative analysis, the synthesised NPs were evaluated for multiple properties using standard procedures before and after being applied on cotton fabrics by a dip-pad-dry-cure method.FindingsXRD and FTIR analyses confirmed the successful synthesis of ZnO and MgO NPs. Homogeneous formation of desired NPs and their dense and uniform deposition on the cotton fibre surface were observed using SEM. ZnO NPs and MgO NPs coatings on cotton were observed to significantly enhance self-cleaning/stain removal properties achieving Grade 5 and Grade 4 categories, respectively. In terms of ultraviolet (UV) protection, ZnO or MgO NP coated fabrics showed UPF values of greater than 50, i.e. excellent in blocking UV rays. MgO NPs exhibited 20% cleaning efficiency in treating reactive dye wastewater against ZnO NPs which were 4% efficient in the same treatment, so MgO was more suitable for such type of treatments at low cost. Both NPs were able to impart multifunctionality to cotton fabrics as per requirement of the end products. However, ZnO NPs were better for stain removal from the fabrics while MgO NPs were appropriate for UV blocking.Originality/valueIt was therefore clear that multifunctional textile products could be developed by employing a single type of cost effective and efficient nano particles.

Reuse of water from real reactive monochromic and trichromic wastewater for new cotton dyes after efficient treatment using H2O2 catalyzed by UV light

The textile industry widely uses reactive dyes to obtain cotton fabrics having good resistance to color removal despite frequent washing. This level of dye usage generates substantial volumes of wastewater containing significant quantities of residual dye requiring treatment before discharges from commercial dyeing operations to public waterways. As part of a study aimed at recycling/reusing rather than discharging reactive dye wastewater, well-known dyes Reactive Yellow 176, Reactive Red 241, and Reactive Blue 221 were used in dyeing cotton fabric, and the generated wastewater samples were decolorized with H2O2 catalyzed by UV light. The efficiency of UV/H2O2 decolorization for trichromic wastewater was determined by UV-Vis monitoring at 550 nm, wherein it was found that more than 91% of color removal in trichromic wastewater occurred at pH 4. The reuse of wastewater was investigated by a total of three sequential cycles of wastewater treatments. The quality of cotton dyed with reused wastewater was assessed through color measurements using CIELAB, fastness to light, and wash fastness testing. Results showed that MCT/VS-based reactive dye wastewater arising from UV/ H2O2 treatment could be used for two subsequent dyeing cycles without compromising the quality of the color of the dyed cotton fabrics. The proposed treatment can also save water and salt, enhancing the economy of the dyeing process.

Enhanced Removal of Organic Pollutants and Reactive Dye in Polyethersulfone Submerged Membrane Bioreactor (PES-SMBR) for Textile Wastewater

The present investigation was carried out to assess the operation of a pilot-scale submerged membrane bioreactor (SMBR) for the treatment of reactive dye and textile wastewater. The operation of SMBR model was conducted by using a polyethersulfone (PES) hollow fibre membrane with continuous flow mode at different HRTs at 8, 6 and 4 h, for 90 days. During the entire operation, the average permeate flux, TMP, F/M ratio and OLR was found to be 19 (L/m²/h), 2.6 (psi), 0.10 (g BOD/(g MLSS•d) and 0.89 (kg BOD/m³.d), respectively. The variations in the permeate flux, TMP, F/M ratio and OLR have not adversely effects on the operation of the SMBR model. Throughout the entire operation, despite the TP, TDS and conductivity, the high amount of COD (82%), BOD (86%), NO3-N (79%), TSS (98%), turbidity (97%) and colour (79%), removal was achieved. The permeate flux was declined by membrane fouling and it was recovered by chemical cleaning as well as regular backwashing during the entire operation. The results obtained from the study concluded that the hollow fibre ultrafiltration polyethersulfone (PES) membrane shows good performance while treating textile wastewater along with reactive dye solution.

Laccase-catalyzed enzymatic dyeing of cotton fabrics

As some synthetic dyes are regarded to be toxic, mutagenic and carcinogenic, the search for eco-friendly alternatives for the synthesis of dyes and coloration has gained importance. For this reason, this study focused on finding new eco-friendly alternatives for coloring cotton. 100% cotton knitted fabrics were subjected to enzymatic coloration using a commercial laccase enzyme and various precursors. After determining the colors, the effect of pH on the enzymatic dyeing process was investigated. Then the optimization of reaction conditions was also realized statistically for the precursors giving the best results in terms of color. With the aim of obtaining further improvements in color-yield values obtained in enzymatic dyeings, the effect of the pretreatment process and the use of ultrasound were also investigated. Furthermore, the reaction pathways in enzymatic coloration were explained and results were confirmed by means of Fourier Transformed Infrared analysis. As a result of experimental studies, red and lilac colors could be successfully obtained on cotton for the first time in the literature. In this way, the theoretical basis of enzymatic dye synthesis and dyeing of cotton was clarified comprehensively. Furthermore, technical (color reproducibility; washing, rubbing, light and perspiration-fastness values; and UV protection factor), economical (chemical, energy and water consumption required for dyeing (including aftertreatments) of 1 kg fabric) and ecological aspects of enzymatic dyeings were compared with reactive dyeing. According to the experimental results it was found that biological treatment alone was enough for wastewater of enzymatic coloring, while chemical treatment will also be needed in reactive dyeing wastewater. Furthermore, color reproducibility, evenness and UV protection properties of dyed samples were comparable with that of reactive dyeings. However, in terms of the fastness levels achieved, the enzymatic coloring was far behind the reactive dyeing.

Utilization of cationic polymer-modified fly ash for dye wastewater treatment

Reuse of modified fly ash for treatment of dye wastewaters is a promising new technology with the potential to mitigate two waste streams currently having negative effects on the environment. In the present study, cationic fly ash adsorbent was prepared by immobilizing with poly-epichlorohydrin-dimethylamine for treating reactive dye wastewaters. Characterization analyses confirmed that poly-epichlorohydrin-dimethylamine had been immobilized onto fly ash, and this immobilization could change the Zeta potential of fly ash from negative to positive throughout the range of pH from 3 to 11, but could not alter its crystal structure. Static adsorption analyses demonstrated that dye adsorption process was spontaneous and endothermic, and the experimental data were better in accord with pseudo-second-order kinetic model. Column experiments showed that cationic fly ash displayed a dramatically high dye adsorption capacity, which was over 1.5 times more than that of commercial activated carbon. Reusability study confirmed that synthesized cationic fly ash can be used repeatedly in column. Especially, in order to avoid secondary pollution, the generated disabled cationic fly ash adsorbent can be reused to produce polymer concretes as a functional filler. The present work can provide new insight into the utilization of modified fly ash for treating wastewaters.

Floc formation and growth mechanism during magnesium hydroxide and polyacrylamide coagulation process for reactive orange removal

ABSTRACT Magnesium hydroxide is commonly used as a coagulant for treating reactive dyes wastewater. However, the flocs are relatively small and coagulation process needs longer sedimentation time. Large flocs and short operation time are important for good coagulation performance. Coagulation floc formation and growth processes using magnesium hydroxide and polyacrylamide (PAM) dual-coagulant were investigated with controlled experiments through flocculation index (FI), floc size distribution, zeta potential, scanning electron microscopy and Fourier transform infrared spectroscopy. The final average floc size reached 58.5 and 4.96 μm with and absence of PAM addition during slow mixing periods. PAM feeding time and magnesium hydroxide formation time can affect the floc formation and growth processes. The results showed that floc formed rapidly during magnesium hydroxide generation within 90 s and flocs aggregated together by PAM bridging function. Reactive orange removal efficiency reached 99.3% with rapid mixing 250 rpm at 90 s during 100 mg/L magnesium ion addition, then adding 6 mg/L PAM at the beginning of slow mixing period in dual-coagulant system.

Characterization and application of poly-ferric-titanium-silicate-sulfate in disperse and reactive dye wastewaters treatment

A novel coagulant poly-ferric-titanium-silicate-sulfate (PFTS) was synthesized and employed to treat two typical kinds of dye wastewaters—disperse blue and reactive yellow. The results indicated that PFTS with a Si/Fe molar ratio of 0.02 exhibited superior coagulation performance, especially under alkaline condition. The residual turbidity after coagulation by PFTS was only half of that after coagulation by poly-ferric-titanium sulfate (T-PSF). The sludge volume index was also reduced by PFTS compared to T-PSF in reactive dye treatment. Through the structure and morphology investigation of PFTS, it was found that new bonds of Si–O–Fe, Si–O–Ti and Fe–OH (Si–OH) were formed, and multi-branched structures and expanded surface area were generated. Additionally, compared with T-PSF, the floc strength and the floc size were also enhanced by PFTS, which was attributed to the polymerization between polysilicic acid and Fe/Ti which formed multi-branched structures, and finally adsorption and bridging ability of the coagulant was improved. Furthermore, the floc formed in reactive yellow wastewater treatment was larger and looser than that formed in disperse blue wastewater, with poorer strength and recovery ability, which can also interpret the better coagulation efficiency in disperse dye water treatment. From the results of coagulant characterization, zeta potential and flocs properties, it can be inferred that charge neutralization by the positive charged hydrolysate of coagulant was identified as the critical effect in disperse dyes removal, while the sweep and adsorption of metal hydroxyl compound formed during the hydrolysis of coagulants were considered to play a key role in reactive dye removal.

A study on the exhaustion of reactive dyes as an influence factor on the colour of reactive dyeing wastewater

One of the most significant pollution factors in the dyeing of textile materials is the colour of wastewater. This feature is particularly pronounced as the dye exhaustion is low. This paper examines the exhaustion of 5 reactive dyes, dyes which are widely used and characterized by modest capacity of exhaustion. The exhaust capacity is analysed in correlation with the value of the liquor ratio and the dye concentration in the dyeing solution.

Brackish water recovery from reactive dyeing wastewater via ultrafiltration

In this study, brackish water recovery from a real reactive dyeing textile effluent for reuse of water and salt was investigated. With the aim of improving the overall retention of species that are partly retained in a single stage, three different two-stage ultrafiltration scenarios were considered: 5 kDa followed by 5 kDa, 5 kDa followed by 2 kDa and 2 kDa followed by 2 kDa. The 2 kDa + 2 kDa scenario reduced the total organic carbon (TOC) from 239 ± 9 mg/L to 41 ± 7 mg/L, at 2 bar of transmembrane pressure (TMP) until a volume reduction factor (VRF) of 2.5, while color was reduced to less than 1% of the feed. The first stage 2 kDa at 4 bar experienced slight flux decline, however, the fouling was fully reversible just with physical cleaning. With this scenario, when the VRF was increased to 10 to increase the water recovery and TMP was increased to 4 bar to increase the permeate flux, the permeate quality remained similar, even when the pollutant load in the feed stream was doubled. With the 5 kDa + 2 kDa scenario, while TOC and color removals were somewhat less, the average first stage flux was about four times higher than that of the first stage 2 kDa filtration, although flux decline and partial fouling irreversibility were still observed. On the other side, the 5 kDa + 5 kDa scenario was the poorest in performance as 5 kDa membrane showed slightly lower retention of color and TOC with higher flux decline and poorer fouling reversibility; although the permeate flux was high. Considering the advantages of high retention and high flux, the permeate samples from both 2 kDa + 2 kDa and 5 kDa + 2 kDa scenarios were tested in fabric dyeing and found to be successful even with a color that is different than the color of the wastewater. These findings suggest that the proposed treatment scenario to recover salty water for reuse can be applicable for wastewater of changing characteristics, which is typical for textile dyeing processes.

The application of electro coagulation process for decolorization of reactive dyeing wastewater

In this study, the application of bipolar electro coagulation (EC) using iron electrode has been assessed for the removal of Remazol Black B in the simulated dye wastewater. The influence of different parameters involving pH, initial dye concentration, sodium sulfate concentration, electrolysis time, and electric current was investigated. According to the results, the anode dissolution rate can be significantly affected by the electric current and it can be found that at high sulfate concentration, the decolorization process cannot be improved. The best color removal efficiency was obtained was 98.8 ± 0.9% at pH of 10, dye concentration of 30 mg/L, and electrical current of 6 A during electrolysis time of 8 minutes. This result indicates that EC can be used as an efficient and “green” method for color removal from reactive dye solution.

Effects of papermaking sludge-based polymer on coagulation behavior in the disperse and reactive dyes wastewater treatment

In this study, papermaking sludge was used as the raw biomass material to produce the lignin-based flocculant (LBF) by grafting quaternary ammonium groups and acrylamide. LBF was used as a coagulant aid with polyaluminum chloride (PAC) to treat reactive and disperse dyes wastewater. Effects of dosing method, pH, hardness and stirring speed on the coagulation behavior and floc properties were studied. Results showed that the superior coagulation efficiency and recovery factor were achieved by PAC+LBF compared with PAC and LBF+PAC. The primary mechanisms of LBF in the treatment of disperse and reactive dye solutions were charge neutralization and bridging effect, respectively. In the dual-coagulation, the impact of pH on the coagulation efficiency was weak during pH range of 5–9. Moderate hardness could enhance the floc properties due to the decrease of electrostatic repulsion and the chelation of Ca(II) and LBF. Besides, flocs coagulated by PAC+LBF had a stronger anti-crush ability.

DECOLORIZING OF REACTIVE DYES WASTEWATER VIA DOWN-FLOW HANGING SPONGE (DHS) SYSTEM

This study was carried out to assess the efficiency of down-flow hanging sponge (DHS) system for decolorizing the reactive dyes wastewater. The reactor was operated at different hydraulic retention times (HRTs) of 1.7, 3.5 and 6 h., and organic loading rates (OLRs) of 3.6, 2.2 and 1.3 g COD/l.d., respectively. The results obtained indicated that increasing the HRT from 1.7 to 3.6 h., significantly increased color and CODt removal efficiencies from 81 6.7 to 91.7 8.7% and from 24.2 6.7 to 72 12.7% respectively. At an HRT of 3.5 h., the DHS system provided a residual CODt value of 217 140 mg/L and BOD5t of 80.3 46 mg/L in the treated effluent. However, CODt and BOD5t removal efficiencies were significantly dropped at increasing the HRT up to 6.0 h., and reducing the OLR to 1.3 g COD/l. d. This was mainly due to a high salinity (20.9 0.4 gCl/l) in the influent wastewater which negatively affected on the decolourization process in the DHS system. Nevertheless, the reactor achieved relatively high removal efficiencies of color (81 6.7%) and turbidity (88 7.9%) as well.

Synthesis and Scaling up of Fe3+ by Sol-gel Method Doped on Ceramic Foam for Decolorization of Reactive Red Dyeing Wastewater

Wastewater from the Batiktextile industry contains large amounts of dyestuff together with significant amounts of suspended solids (SS), dispersing agents, salts and trace amounts of me-tals. Since this can lead to severe environmental problems, proper wastewater treatment pro-cesses are essential. The synthesis of Fe3+by sol-gel method doped on a ceramic foam for reac-tive red and disperse dyes removal from synthetic dye wastewater. Inthis research, the effect of color concentration, amount of catalyst and volumetric flow rates for industrial scale were studied.The Fe3+catalyst was prepared by sol-gel method in which 3M of FeCl3was used as a pre-cursor. The synthesized catalyst was characterized by the EDX spectrum from an X-ray spectro-meter. The surface morphology of the catalyst was investigated using a scanning electron microscope (SEM). To determine optimum operating conditions for catalytic testing, variations of disperse and reactive red concentrations (10 to 200 mg L-1) were used. The results indicated that the highest color removal efficiency (up to 96%) was observed when using Fe3+catalyst; 4 piecesper literof solution, and initial pH of 6.0. These conditions were then scaled up for a continuous packed bed column study. It was found that the optimal operating conditions obtained from the mathematical model for reactive red wastewater were: concentration of reactive red in the syn-thetic wastewater20 to 80 mg L-1; amounts of catalyst 432.5 to 1,730 mg and volumetric flow rates of wastewater20 to 200 mL min-1. Up to 84.85% of color removal efficiency was achieved.