Dye Wastewater Research Articles

Application and regeneration of magnetic material MgAlLDH@Fe3O4 humic acid with removal capacity for malachite green

Malachite green (MG), a dye in wastewater, pollutes the natural environment, and it is difficult to eliminate dyes from aquatic systems. MgAlLDH-magnetite humic acid (Mg3Al@M2HA) was prepared for MG adsorption via coprecipitation and hydrothermal methods. The adsorption was performed using the batch adsorption method at the pH of the point of zero charge (8.33), with an optimum contact time of 120 min and a maximum concentration of 100 mg/L of MG. Furthermore, the pseudo-second-order and Langmuir models were better fitted to the kinetic and isotherm models, respectively. The maximum monolayer adsorption capacity for MG on Mg3Al@M2HA at 313 K was 113.6 mg/g. The calculated thermodynamic parameters (Δ H = 18.524 kJ/mol, Δ S = 0.076 J/Kmol, Δ G = − 4.586 to − 6.111 kJ/mol) implied that the MG adsorption was spontaneous, endothermic, and had degrees of randomness in the temperature range of 303–323 K. Moreover, the ΔH was less than 40 kJ/mol, confirming that the combination of MG with Mg3Al@M2HAwas due to the physisorption with electrostatic interaction, hydrogen bonding, and π–π interaction. Recycling experiments showed that the MG removal rate was 82.55 % after 5 cycles. This study provides new insights into Mg3Al@M2HA and its potential applications for MG adsorption.

Direct conversion of resin button waste into adsorbent for efficient removal of dyes and heavy metals from aqueous solution

An eco-friendly and cost-effective solution was developed to solve the problem of resource waste and environmental pollution caused by dye wastewater and unsaturated polyester resin-based resin buttons. In this study, solvent degradation was utilized to directly convert waste resin buttons into selective adsorbents, and the degradation products showed good adsorption performance for methylene blue and Pb(II), with adsorption capacities up to 808.9mg/g and 380.5mg/g, and a removal rate of about 99%, respectively. The adsorption experiments showed that the kinetics of the adsorption process closely followed a quasi second-order model (R²＞0.999), and the interaction between the degradation products and the pollutants was governed by chemisorption. In addition, the adsorption process fits well with the Langmuir isotherm model (R² > 0.991), indicating that the adsorption process mainly involves uniform monolayer adsorption. Mechanistic analysis revealed that both electrostatic interactions and hydrogen bonding play important roles in the adsorption process. Notably, the material showed good cyclic stability for Pb(II), with the retention rate of the original adsorption capacity close to 98% after five cycles, while the results indicated that external factors such as pH, salinity and surfactant had a significant effect on the adsorption behavior. This “waste to treasure” recycling strategy not only provides an effective method for selective adsorption of water pollutants, but also improves the practical application of thermosetting resin recycling.

Self-cleaning micro/nano graded porous groove structure fiber membranes by coaxial spinning for purification of dye wastewater.

Adjusting the structure of the membrane and improving its performance proved to be an effective technique for accomplishing efficient dye wastewater purification. Water erosion of polyvinylpyrrolidone (PVP) core in polyacrylonitrile (PAN) nanofiber membrane modified with UiO-66-NH2 was successfully achieved, in this study, using coaxial electrospinning, and ZIF-8 with excellent performance was further epitaxy-grown in situ. Two differently shaped and positively charged MOFs confer strong adsorption capacity (adsorption capacity >2042mg/g) on cationic dyes. In addition, the multi-dimensional separation pores brought by the micro/nano graded porous groove structure and MOFs not only make the membrane have excellent static adsorption performance, but also have excellent dynamic separation performance under the influence of toxic heavy ions (separation efficiency >99 %; Flux >1666Lm-2 h-1 bar-1). More importantly, this special structure of the membrane has an excellent photocatalytic activity for the dye, so the membrane can be used for a long time in a green and environmentally friendly way. Together, membranes show a significant deal of potential for the treatment of wastewater containing dyes due to the combination of these outstanding characteristics.

Slow-release of hydrogen peroxide from PDA-coated calcium peroxide for enhanced dye wastewater decolourisation removal

In Fenton-like systems, a slow-release of hydrogen peroxide (H2O2) is of great value in improving the sustainable treatment of pollutants. In this study, calcium peroxide (CaO2) was first synthesized by different methods, and its slow-release performance of H2O2 was evaluated. Then CaO2@PDA composites (referred to as CP-X, X represent the mass ratio of Polydopamine (PDA) to CaO2 were prepared by using a simple precipitation method. And the H2O2 slow-release experimental result indicates that the average release rate of the prepared CP-1.0 is 0.19 mmol·g-1·min-1 within 130 min. The release of H2O2 from CP-1.0 is consistent with the biexponential biphasic kinetic model, where water molecules and H2O2 osmotic diffusion are the main factors affecting the rate of H2O2 release. Decolourisation removal of crystalline violet (CV) solution was carried out using CP-1.0 as oxidants. Under the conditions of 0.02 g CP-1.0, pH = 6.5, and 20°C, more than 98.0% of CV solution (30 mg/L) was removaled within 30 min. Then, possible degradation pathways were postulated using a combination of density functional theory (DFT) and liquid chromatography mass spectrometry (LC-MS). Finally, the decolourisation degradation mechanism was proposed according to the active species quenching experiments and Electron Paramagnetic Resonance (EPR) analysis. This study presents novel insights into the removal of emerging pollutants in aqueous media by CaO2-based Fenton-like systems.

Oxygen vacancy-mediated MnVO cathode via assisted of vanadium in heterogeneous electro-Fenton degradation of dye wastewater

Oxygen vacancy-mediated MnVO cathode via assisted of vanadium in heterogeneous electro-Fenton degradation of dye wastewater

Enhanced dye wastewater treatment via PVDF membrane distillation: Influence of dye classes on performance and fouling

Enhanced dye wastewater treatment via PVDF membrane distillation: Influence of dye classes on performance and fouling

PEI-SiO2/GO Nanofiltration Membrane: Achieved high water permeability and dye rejection rate

Water pollution has long been a significant issue, and the purification of dye wastewater plays a crucial role in addressing this problem. Graphene oxide (GO) has found extensive applications in water treatment due to its unique two-dimensional (2D) structure and a surface rich in a large number of oxygen-containing functional groups. We introduced silica(SiO2) and polyethyleneimine(PEI) into GO to prepare a membrane. The experimental findings revealed that the 3-SiO2/GO binary composite membrane achieved a high water permeability of 45.6Lm-2 h-1 bar-1 while maintaining retention, which is nearly four times higher than that of the GO membrane (9.85Lm-2 h-1 bar-1).The water permeability of the PEI0.2-SiO2/GO ternary composite membrane achieved 42.37Lm-2 h-1 bar-1. The rejection rate for methyl orange dye reached 92.36%, with similar rejection rates all above 95% observed for other dyes.

Removal of dyes from aqueous solution using a magnetic graphene oxide nanocomposite: kinetic, isothermal, and thermodynamic characterization

The efficacy of utilizing graphene-magnetite nanocomposite for methylene blue and crystal violet adsorption treatment from aqueous samples was investigated in this study. The nanocomposite properties were evaluated by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and vibrating quantum magnetometry. Some adsorption parameters such as adsorption capacity, contact time, stirring rate, temperature, and pH of the aqueous solution were explored in the research too. Moreover, it was found that adsorption followed a pseudo-second-order kinetic model with an R2 value of 0.999 resulting in a maximum adsorption capacity of 240 mg/g for methylene blue and 203 mg/g for crystal violet respectively. Besides, different well-known isotherm models fit the equilibrium data well. Assessments of thermodynamic parameters showed that the removal of both dyes by GO-Fe3O4 nanocomposite is spontaneous. Also, the reuse ability of GO-Fe3O4 nanocomposite was studied and the result was shown to be recycled suitably and possessed adsorptive properties so that it can be developed as an inexpensive and alternative adsorbent for dye wastewater treatment.

Tailoring amino-functionalized n-alkyl methacrylate ester-based bio-hybrids for adsorption of methyl orange dye: Controllable macromolecular architecture via polysaccharide-integrated ternary copolymerization.

Controllable macromolecular architecture formation via polysaccharide integrated ternary copolymerization was explored in the design of amino-functionalized n-alkyl methacrylate ester-based biohybrids. Ternary poly(dimethylaminoethyl methacrylate-co-glycidyl methacrylate-co-hydroxypropyl methacrylate)/sodium-alginate, PDGH/ALG, hybrids were designed using anionic polysaccharide through in-situ radical polymerization. An insight into the effect of ALG on physicochemical structure of ternary hybrids, particularly the interactions between polymeric chains, was created. In addition to incorporation of ALG, the effect of polymerization under cryocondition on mechanical stiffness of hybrids was investigated. Adding 0.5 % ALG to ternary PDGH matrix resulted in a 4.2-fold increase in compressive modulus. Swelling of hybrid hydrogels prepared at 1 °C decreased by 5 times, while a 3.4-fold decrease was observed in hybrid cryogels formed at -18 °C. ALG-rich hybrids showed "salting-in" behavior with increasing salt concentration in NaCl, KCl and MgCl2 solutions, while hybrids with low ALG-content exhibited "salting-out" behavior. The hybrid gels were applied to adsorption of anionic dye methyl orange (MO) from simulated dye wastewater. The adsorption was found to follow Freundlich mechanism and a pseudo-second-order kinetic model. ALG-integrated hybrid gels showed a high desorption efficiency and a longer lifespan during the regeneration process, thus showing potential to be used for anionic dye removal from textile wastewater in industry.

Polydopamine modified coconut shell biochar decorated with ZIF-8 for improved adsorption of malachite green and rhodamine B from aqueous solution.

Although various biochars from different biomass materials have been developed to remediate dye-contaminated environments, the removal capabilities of pristine biochar for dyes urgently require further enhancement due to insufficient surface adsorption sites. To introduce more adsorption sites, this work proposes a simple approach to fabricate coconut shell biochar (CSB) based adsorbent by anchoring zeolitic imidazolate framework-8 (ZIF-8) via the active sites provided by polydopamine (PDA)-coated CSB. The nucleation sites provided by the PDA layer promote the dispersion of ZIF-8 on the surface of CSB, resulting in sufficient adsorption sites for removing malachite green (MG) and rhodamine B (RB) from wastewater. The resulting CSB/PDA/ZIF-8 demonstrates a large specific surface area (749.54 m2∙g-1) and outstanding adsorption capacities for MG (1568 mg∙g-1) and RB (1496 mg∙g-1). Furthermore, CSB/PDA/ZIF-8 adsorbents can maintain a satisfactory removal rate for MG (91%) and RB (77%) even after five reuses. The analysis of the adsorption mechanism exhibits that electrostatic interactions, hydrogen bonds, coordination bonds, and π-π stacking are of significance for adsorbing MG and RB. Therefore, CSB/PDA/ZIF-8 is a promising candidate for dye wastewater treatment, while this work provides guidance for the high-quality utilization of biomass materials.

Rapid adsorption of industrial cationic dye pollutant using base-activated rice straw biochar: performance, isotherm, kinetic and thermodynamic evaluation

This work intends to effectively remove methylene blue (MB) dye from wastewater using an agricultural waste-derived sorbent made from pyrolyzing rice straw to generate biochar. This is done while keeping the sustainability idea in mind and tackling the crises arising from environmental contamination with dyes. The physicochemical scrutinization of the non-activated and the base-activated biochar materials showed that the materials have promising textural properties and surface functionalization, leading to high and fast capability to retrieve MB from aqueous solutions in alkaline conditions. The adsorption equilibrium for all the biochar was reached within a time span of 15 min, but 90 percent of the dye removed at equilibrium was already eliminated in less than 5 min. The behaviour of the equilibrium adsorption for the biochar materials was thoroughly assessed using Langmuir and Freundlich adsorption isotherms. Interestingly, the adsorption process for the base-activated biochar follows both Langmuir and Freundlich isotherms at higher pH. The base-activated biochar exhibited a maximum adsorption capacity of 129.87 mg/g at alkaline pH. The adsorption data analysis with various kinetic models revealed that the adsorption process follows a pseudo-second-order kinetics for all the biochar materials. The Gibbs free energy and activation energy studies clearly revealed the adsorption of MB on biochar to be spontaneous and physiosorption in nature. The adsorption mechanism of the fast and efficient removal of MB by the base-activated biochar involves electrostatic interactions, hydrogen bonding, n-π and π-π interactions. Overall, the base-activated biochar with higher and faster adsorption capacity in alkaline conditions is a promising low-cost bioadsorbent with a simple production process for the removal of cationic dyes from aqueous environments and practical dyeing wastewater purification.

Electrospinning Membrane with Polyacrylate Mixed Beta-Cyclodextrin: An Efficient Adsorbent for Cationic Dyes.

A simple and non-chemical binding nanofiber (β-CD/PA) adsorbent was obtained by electrospinning a mixture of β-cyclodextrin (β-CD) and polyacrylate (PA). The cationic dyes in wastewater were removed by the host-guest inclusion complex of the β-cyclodextrin and the electrostatic interaction between the polyacrylate and the dyes groups. The influence of the content of β-cyclodextrin on the surface morphology and adsorption capacity of the nanofiber membrane was discussed, and the optimized adsorption capacity of nanofiber adsorption material was determined. The adsorption capacity of nanofiber adsorbents for basic red 9, basic red 14, basic red 46, basic blue 9, basic yellow 19 and basic yellow 28 was 86.71 mg/g, 21.513 mg/g, 18.926 mg/g, 44.525 mg/g, 116.516 mg/g and 155.206 mg/g, respectively. The effects of different initial concentrations and pH values on the adsorption properties of adsorbent materials were studied. The kinetic analysis showed that the adsorption process of nanofibers for cationic dyes was more in line with the pseudo-second-order kinetic adsorption model. Moreover, nanofiber adsorbent could be easily separated from the dye solution and showed high recycling efficiency. These results indicated that the β-cyclodextrin/polyacrylate composite nanofibers are expected to be recyclable adsorbents in dye wastewater treatment.

A Multifunctional Synergistic Solar-Driven Interfacial Evaporator for Desalination and Photocatalytic Degradation.

The scarcity of freshwater resources and the treatment of dye wastewater have emerged as unavoidable challenges that need to be addressed. The combination of solar-driven interfacial evaporation, photocatalytic degradation, and superhydrophobic surface provides an effective approach for seawater desalination and the treatment of organic dyes. In this study, we fabricated a multifunctional synergistic solar evaporator by depositing cupric oxide nanoparticles onto polypyrrole (PPy) coating and subsequently modified it with a hydrophobic agent successfully. The evaporator achieved an evaporation rate of 1.48 kg m-2 h-1 under 1 kW m-2 irradiation. Importantly, the evaporator exhibited a degradation efficiency of 95.9% toward the organic dye methylene blue. It is important to mention that PPy promotes the separation of photogenerated electron-hole pairs, thus improving the photocatalytic performance of cupric oxide. The salt resistance of the evaporator is evidenced by the absence of significant salt deposits on its surface even after 300 min of operation due to its superhydrophobic property. The evaporator also presents excellent resistance to acidic/alkaline/high-temperature/organic solvent environments. This solar evaporator offers a sustainable solution for water purification.

Synthesis of novel magnetic carboxyl-functionalized crosslinked copolymer microspheres for methylene blue removal from water

Magnetic carboxyl-functionalized crosslinked copolymer microspheres of α-methyl styrene and maleic anhydride (MCPMs) with a uniform particle size were synthesized based on self-stabilized precipitation polymerization. Magnetic crosslinked copolymer microspheres (MPMs) were prepared by in situ polymerization using oleic acid-modified Fe3O4 as the magnetic source, α-methyl styrene and maleic anhydride as monomers and divinylbenzene as the crosslinking agent, and MCPMs were then obtained by hydrolyzing the anhydride groups of MPMs into carboxyl groups. The as-prepared MCPMs were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, vibrating sample magnetometry and the Brunauer–Emmett–Teller method. The adsorption behavior, adsorption kinetics and adsorption isotherms of MCPMs for methylene blue (MB) removal from water were systematically investigated. It was found that MCPMs manifested good MB removal ability from water with a maximum MB adsorption capacity of 315 mg/g. The kinetic and isothermal data of MCPMs for MB removal followed the pseudo-second-order model and the Langmuir isothermal model, respectively. In addition, MB-loaded MCPMs could be separated easily by magnets, and the MB removal rate of MCPMs still reached more than 90.0% after five cycles. These results indicate that MCPMs have great potential in cationic dye wastewater treatments.

Synthesis, characterisation and photocatalytic activation of zinc nanoparticles via. biogenic methods

ABSTRACT Zinc nanoparticles (ZnNPs) were synthesised using a biogenic method from Hypericum calycinum leaves and characterised by UV-Vis spectroscopy, FTIR, TEM, and XRD to assess their optical, structural, and morphological properties. The ZnNPs exhibited absorbance peaks at 274 nm and 370 nm, with an average particle size of 29.066 ± 10.561 nm and a crystalline size of 16 nm. Their photocatalytic efficiency was evaluated by degrading methylene blue (MB) dye under sunlight, achieving 70% degradation in 150 minutes. This study represents the first use of H. calycinum for ZnNP synthesis and demonstrates their potential for photocatalytic dye removal and wastewater treatment applications.

Preparation and characterization of Ru-TiO2/PC/Fe3O4 composite catalyst with enhanced photocatalytic performance and magnetic recoverability under simulated solar light.

This research focuses on the development of a novel Ru-doped TiO2/grapefruit peel biochar/Fe3O4 (Ru-TiO2/PC/Fe3O4) composite catalyst, which exhibits exceptional photocatalytic efficacy under simulated solar light irradiation. The catalyst is highly effective in the degradation of rhodamine B (RhB), methylene blue (MB), methyl orange (MO), as well as actual industrial dye wastewater (IDW), and can be recovered magnetically for multiple reuse cycles. Significantly, the PCTRF-100 sample exhibited degradation efficiencies of 99.4% for RhB and 99.8% for MB within 60 min, and 98.04% for MO within 120 min. In the case of actual dye wastewater, a reduction in chemical oxygen demand from 1540 mg L-1 to 784 mg L-1 was achieved within 300 min, corresponding to a degradation rate of 46.81%. The remarkable photocatalytic activity observed is primarily attributed to the synergistic interactions among Ru-TiO2, biochar, and Fe3O4, which effectively facilitate the separation and migration of electron-hole pairs in TiO2.

Facile Preparation of Sulfonated Polysulfone Composite Membranes with High Hydrophilicity and Visible-Light Driving Self-Cleaning Performance.

The photo-Fenton reaction can efficiently degrade organic pollutants and thus is applied intensively for clearing out membrane fouling. However, the pollutant removal efficiency is greatly limited by the redox cycle rate of Fe2+/Fe3+ and the rapid recombination rate of the photogenerated electrons and holes. In order to overcome these drawbacks, a sulfonated polysulfone composite membrane was designed and prepared by incorporating titanium dioxide (TiO2) nanoparticles into a sulfonated polysulfone membrane and sequentially forming β-FeOOHs on the membrane surface. It was found that the synergy of TiO2 and β-FeOOH enhanced the hydrophilicity and improved the pure water flux of the composite membrane. As a result, the composite membrane exhibited superior separation performance for methylene blue and rhodamine B cationic dyes. The rejection rate was larger than 99.5%, and the pure water flux was larger than 125.7 L m-2 h-1, largely surpassing that of nanofiltration membranes. Meanwhile, the composite membrane exhibited an excellent self-cleaning performance, achieving a flux recovery rate over 99.7% after visible-light driving Fenton reaction treatment. The rejection rate still remained above 97.2% after 5 cycles of filtration and recovery, indicating the strong treatment ability of the membrane for dye wastewater.

Preparation of Porous Novel QuEChERS Adsorbent ZIF‐67/PAA/PES Composite Microspheres and Their Application for Rapid Adsorption of Triphenylmethane Dyes in Wastewater and Fish

ABSTRACTTriphenylmethane dyes have a wide range of applications in textiles, pharmaceuticals, food, and other fields. Malachite green (MG), fuchsin acid (FA), and crystalline violet (CV) were typical representatives of triphenylmethane dyes, and they are carcinogenic and mutagenic to aquatic organisms and environment. However, they need to be separated and enriched for their accurate quantification due to their low content. Therefore, it is important to develop a rapid and accurate enrichment method to monitor these dyes in aquatic systems for human health. In this paper, a novel QuEChERS adsorbent porous ZIF67/PAA/PES composite microspheres were prepared and applied for the rapid adsorption of triphenylmethane dyes in wastewater and fish samples, which improved the adsorption capacity and the analytical sensitivity of the targets. The experimental results demonstrated that the porous ZIF‐67/PAA/PES composite microspheres exhibited excellent selective adsorption capacity of MG, FA, and CV, and after six adsorption–desorption cycles, the material adsorption amount can reach more than 90% of its original adsorption amount in wastewater. In addition, the porous ZIF67/PAA/PES composite microspheres were applied as QuEChERS adsorbents for the enrichment of MG and CV dyes in fish, and the adsorption rates of the dyes were 99.11% and 99.03%, with the RSDs of 1.58% and 1.27%, respectively. The limits of detection were 0.0093 and 0.0127 mg/L for MG and CV. Through the Langmuir adsorption isotherm models to predict the MG, FA, and CV of the maximum adsorption capacity were 5417.3622, 2119.9011, and 1654.1026 mg/g, respectively. Thus, the novel porous ZIF67/PAA/PES composite microspheres are more advantageous as QuEChERS adsorbents for sample pre‐treatment and have very important research significance.

Study of adsorption efficiencies of biopolymer-based composites of chitosan with a sulfonic acid functionalized imidazolium ionic liquid for elimination of organic dyes in wastewater

Bio-polymer based composites of chitosan and a N-SO3H functionalized imidazolium ionic liquid were developed as sustainable adsorbent materials for adsorption of dyes from aqueous solution.

Multifunctional quaternary ammonium-modified TEMPO-oxidized cellulose nanofibers and MIL-100 with encapsulated laccase for efficient removal of anionic arund cationic dyes in wastewater

Multifunctional quaternary ammonium-modified TEMPO-oxidized cellulose nanofibers and MIL-100 with encapsulated laccase for efficient removal of anionic arund cationic dyes in wastewater