Dye Wastewater Treatment Research Articles

Removal of Acid Orange 7 dye using Makgeolli lees with ultrasonic assistance

AbstractThis study investigated the efficient removal of Acid Orange 7 (AO7) dye in water by using Makgeolli lees, a popular by‐product obtained during the production of traditional Makgeolli beverages in Korea. By incorporating ultrasound, the effects of contact time, Makgeolli lees dosage, initial AO7 dye concentration, and initial pH of the dye solution were investigated and comprehensively compared with the same experiment using the stirring method. The results consistently showed ultrasound not only enhances the excellent adsorption ability of Makgeolli lees but also accelerates the process compared to the stirring method. The Langmuir isotherm model best described the adsorption process for both methods, suggesting monolayer adsorption on the surface of Makgeolli lees, with maximum capacities of 25.13 mg/g for ultrasound at 40 kHz and 20.41 mg/g for stirring methods. Furthermore, the study showed that optimal dye removal efficiency can be achieved with ultrasound conditions at 28 kHz frequency, 125 W/L power density, and 100% ultrasound intensity. This research promises that the integration of low‐cost biomass coupled with ultrasound could provide a potential solution for dye wastewater treatment.

Efficient removal of high concentration dyes from water by functionalized in-situ N-doped porous biochar derived from waste antibiotic fermentation residue

Using biochar for dye wastewater treatment is attracting interest due to its excellent adsorption properties and low costs. In this work, a novel biochar derived from oxytetracycline fermentation residue (functionalized OFR biochar, FOBC) was investigated as a efficient adsorbent for typical dyes removal. At 25 °C, the maximum adsorption capacity calculated by Langmuir model of FOBC-3-600 for methylene blue (MB), malachite green (MG), and methyl orange (MO) reached 643.97, 617.89, and 521.03 mg/g, respectively. The kinetics and isotherm model fitting showed that the chemisorption and physisorption both occurred during the adsorption process. Dyes were efficiently adsorbed through pore filling, electrostatic attraction, π-π interactions, and surface complexation. And the cycling experiment and environmental risk assessment indicated that the FOBC-3-600 had excellent recyclability and utilization safety. Overall, this study provides a practical method to simultaneously treat the dyeing wastewater and utilize the antibiotic fermentation residue.

Slide-shaped cotton-based photocatalytic solar evaporator with dual mutually strengthening functions for simultaneous desalination and dynamic fast dye removal

High-salt dyeing wastewater would do harm to both the environment and people's health. Herein, a photocatalytic solar evaporator with bifunctions of photothermal evaporation and photocatalysis was prepared by loading MnO2 and TiO2 on the cotton fabric, aiming at simultaneous pure water derivation and dye degradation. The evaporator was positioned in a slide-shaped configuration that uses downward capillary force and gravity-assisted water transportation for a sufficient water supply, avoiding salt accumulation during photothermal evaporation and realizing a fast dynamic dye removal via photocatalysis. Interestingly, the loaded TiO2 enhances the photothermal activity of the loaded MnO2 by increasing light absorption. While MnO2 also enhances the photocatalytic activity of TiO2 by charge transfer and heat generation. It was exciting to find that the solution streaming down dynamically through the slide-shaped evaporator into the downstream container was completely colorless, which was in sharp contrast with the blue dye solution at the upstream. Under one sunlight, the evaporator showed a evaporation rate of 1.65 kg m−2 h−1, a photothermal conversion efficiency of 96.65 % and a methylene blue removal efficiency of >95 % during the 8-day evaporation. This study realizes the synergistic effect of photothermal evaporation and photocatalysis, providing a novel strategy for the treatment of high-salt dyeing wastewaters.

Preparation of Co x Mg y Cu(1- x - y )Fe2O4 nanoparticles and their adsorption mechanism of methyl blue

A facile rapid-combustion process was introduced for preparing magnetic Co x Mg y Cu(1- x - y )Fe2O4 nanoparticles, and to enhance their specific surface area and saturation magnetization, the optimization involved adjusting the element proportion, calcination temperature, and solvent amount. The optimal element proportion of x:y:(1-x-y) for Co x Mg y Cu(1- x - y )Fe2O4 nanoparticles was 0.1:0.7:0.2, and the effects of solvent amount, and calcination temperature were also investigated. The average particle size and specific surface area of Co0.1Mg0.7Cu0.2Fe2O4 nanoparticles calcined at 400 °C with 25 mL absolute alcohol were 17.9 nm and 56.96 m2/g, respectively; while demonstrating a saturation magnetization of 8.5 emu/g. To solve the increasingly severe issue of water pollution, these nanoparticles were employed to efficiently treat dye wastewater containing methyl blue (MB). After fitting kinetic and isotherm models, the adsorption process of magnetic Co0.1Mg0.7Cu0.2Fe2O4 nanoparticles for MB dominated by chemisorption and was a multilayer adsorption process. The adsorption isotherm experiments revealed a remarkable maximum adsorption capacity of methyl blue, reaching 2255.7 mg/g, within the concentration range of MB from 400 to 4000 mg/L. The thermodynamic analysis indicated the spontaneity of the exothermic adsorption process. The studies on the effect of pH also led to satisfying results; while the residual adsorption capacity could still remain 91.2% initial adsorbance after 12 times recycle. The outstanding recycling ability, resistance to ionic strength, and pH resistance distinguished the magnetic Co0.1Mg0.7Cu0.2Fe2O4 nanoparticles among vast adsorbents. These results highlight the significant potential of these nanoparticles for treating dye wastewater.

Study on Methylene Blue Adsorption Properties of Biochar/Montmorillonite Composites

The textile printing and dyeing industry, as one of the important pillars of the global economy, has become an environmental problem that needs to be solved because of the increasingly serious pollution of dye wastewater generated during its production process. Dye wastewater not only contains high concentrations of organic dyes, but also often accompanied by heavy metal ions, additives and salts and other pollutants, if discharged directly without effective treatment, will seriously pollute the water body, destroying the ecological balance, and affecting the survival and health of human beings and aquatic organisms. In order to deal with the problems of serious pollution, large discharge and high cost of dye wastewater, it is necessary to develop an efficient, economic and environmentally friendly wastewater treatment system. It is particularly important to develop efficient, economical and environmentally friendly wastewater treatment technologies. Adsorption is considered as a promising method for wastewater treatment. In this study, we focused on the development of new and efficient adsorbent materials. Taking methylene blue, a typical dye, as an example, we skillfully composited modified biochar with montmorillonite, a natural mineral material, through pyrolysis and intercalation strategies, and conducted in-depth investigations on the effects of the composites on the adsorption of methylene blue in water, the factors affecting the regeneration performance of the adsorbents, and the thermodynamic characteristics of the adsorption. The effect of the composite material on the adsorption of methylene blue in water, the factors affecting the regeneration performance of the adsorbent and the adsorption thermodynamic characteristics were investigated in depth, with a view to providing certain theoretical and practical references for the effective treatment of dye wastewater.

Heterologous expression and characterization of a dye-decolorizing peroxidase from Ganoderma lucidum, and its application in decolorization and detoxifization of different types of dyes.

Dye-decolorizing peroxidases (DyPs) belong to a novel superfamily of heme peroxidases that can oxidize recalcitrant compounds. In the current study, the GlDyP2 gene from Ganoderma lucidum was heterologously expressed in Escherichia coli, and the enzymatic properties of the recombinant GlDyP2 protein were investigated. The GlDyP2 protein could oxidize not only the typical peroxidase substrate ABTS but also two lignin substrates, namely guaiacol and 2,6-dimethoxy phenol (DMP). For the ABTS substrate, the optimum pH and temperature of GlDyP2 were 4.0 and 35°C, respectively. The pH stability and thermal stability of GlDyP2 were also measured; the results showed that GlDyP2 could function normally in the acidic environment, with a T50 value of 51°C. Moreover, compared to untreated controls, the activity of GlDyP2 was inhibited by 1.60 mM of Mg2+, Ni2+, Mn2+, and ethanol; 0.16 mM of Cu2+, Zn2+, methanol, isopropyl alcohol, and Na2EDTA·2H2O; and 0.016 mM of Fe2+ and SDS. The kinetic constants of recombinant GlDyP2 for oxidizing ABTS, Reactive Blue 19, guaiacol, and DMP were determined; the results showed that the recombination GlDyP2 exhibited the strongest affinity and the most remarkable catalytic efficiency towards guaiacol in the selected substrates. GlDyP2 also exhibited decolorization and detoxification capabilities towards several dyes, including Reactive Blue 19, Reactive Brilliant Blue X-BR, Reactive Black 5, Methyl Orange, Trypan Blue, and Malachite Green. In conclusion, GlDyP2 has good application potential for treating dye wastewater.

A MoS2-based evaporator with porous structure and interlayer channels for solar desalination and photocatalytic degradation

The solar interfacial evaporator is a highly promising method for producing fresh water and has garnered significant attention due to its environmental friendliness and low energy consumption. MoS2, a frequently used semiconductor material for interfacial evaporation, has been the focus of research aimed at enhancing evaporation rate and efficiency, with less consideration given to its salt resistance and other potential capabilities. In this work, we introduce a novel ANF/MoS2@MXene evaporator that employs vertically aligned MoS2 nanosheets coated on MXene as the photothermal material and aramid nanofiber aerogel (ANF) as the substrate. The evaporator exhibits both photothermal and photocatalytic degradation effects. The existence of MXene and vertically oriented MoS2 nanosheets contributes to a broad light absorption spectrum, resulting in an evaporation rate of 1.42 kg m-2h−1 and an efficiency of 95.84 % under one sun. Additionally, the porous structure and interlayer channels within the ANF facilitate rapid water transfer and timely salt discharge. This leads to a stable evaporation rate of 1.28–1.37 kg m-2h−1, preventing salt crystal accumulation on the evaporator’s surface during 10 h of continuous operation in 3.5 % NaCl solution. The evaporator also demonstrated an effective degradation rate of 89.24 % in treating dye wastewater after 2-hour light exposure. This work presents a promising approach for constructing a photothermal evaporation/photocatalytic bifunctional system with enhanced salt resistance for MoS2-based evaporators.

Strongly tribocatalytic dye degradation of high-entropy powder through harvesting friction

The omnipresent friction can be harvested to generate electricity, thereby facilitating redox reactions to degrade dye wastewater, which can be named as tribocatalysis. Here, it’s experimentally found that the high-entropy CoCrFeMnNi powder synthesized via the Vacuum Induction Gas Atomization (VIGA) technique, can behave the obvious tribocatalytic Rhodamine B (RhB) dye degradation performance. In the tribocatalysis dye degradation process, friction occurs at the interface between the catalyst’s surface and the stirring Teflon rod. The tribocatalytic RhB dye degradation ratios of the high-entropy CoCrFeMnNi powder catalysts at stirring speeds of 200 rpm, 400 rpm, 800 rpm, 1000 rpm, and 1200 rpm are 14.7 %, 70.3 %, 93.2 %, 99.4 %, and 99.8 %, respectively. It’s also found that the RhB dye degradation ratio can be slightly enhanced under an external DC magnetic field provided by a commercial NdFeB magnet, which may be attributed to the magnetically-induced enhancement of separation efficiency of these positive and negative carriers. After being recycled for 3 times, the CoCrFeMnNi powder can still degrade 90.8 % RhB dye. The CoCrFeMnNi powder with the excellent tribocatalytic activity is potential for application in dye wastewater treatment through utilizing the friction energy in the environment.

Unleashing the potential of electrooxidation and PVDF/TiO2 photocatalysis for textile dye wastewater treatment

Unleashing the potential of electrooxidation and PVDF/TiO2 photocatalysis for textile dye wastewater treatment

Photocatalytic nanohybrid UV-light-driven PVDF/GO-NiFe@SiO2 membrane coupled with bentonite adsorption and ozonation process for a sustainable textile wastewater treatment

The textile industries face significant environmental challenges due to the presence of complex pollutant dyes in its wastewater, making it one of the world's major sources of industrial water pollution. Numerous studies have been employed to overcome this problem, including physical, chemical, and biological treatments. However, most of those methods still suffered to achieve higher dye removal performance. This study provides new insight regarding textile wastewater treatment containing indigo red as the main colorant by carrying out a hybrid process combining bentonite adsorption, ozonation, and photocatalytic membrane filtration. For the membrane, we propose a modified polyvinylidene fluoride (PVDF) membrane incorporated with graphene oxide (GO) and nickel-iron doped silica (NiFe@SiO2) photocatalyst, which is named PVDF/GO-NiFe@SiO2 membrane. The membrane was employed under different sets of filtrations (dark and under ultraviolet irradiation) to treat natural dye wastewater from textile industry effluent. Further improvement was achieved when UV light irradiation was subjected to the process. This sequential adsorption-ozonation-membrane process under UV exposure exhibited improved dye removal from 55.11 % to 97.22 %. The results show that the proposed hybrid process successfully improved the membranes' antifouling behavior, thus boosting the membranes' performance and durability. From a broader perspective, our work promotes new insights for the integration of other physical, chemical, and biological treatment methods to improve the performance and durability of membrane-based processes, particularly for dye wastewater treatment.

Synthesis, characterization, wastewater treatment & plant growth application of ZnFe2O4/Bi2O3 nanocomposite

Vital for the prospective and sustainable environment, Bi2O3, ZnFe2O4 and ZnFe2O4/Bi2O3 (BZF) nanocomposite was synthesized in the present study by utilizing conventional combustion technique by green approach fueling with Aloe vera extract. The crystallite size calculated using Debye-Scherrer formula from X-Ray Diffraction (XRD) spectrum of BZF nanocomposite is ∼27 nm validated by XRD spectrum. Band gap of the nanocomposite is estimated using UV-Vis Diffuse Reflectance Spectra (DRS) analysis and was found to be 2.73 eV. The findings of the investigations have been validated by applications in photocatalytic degradation of acid green dye. The usage of Bi2O3, ZnFe2O4 and BZF nanocomposite as a catalyst for the degradation of acid green (AG) dye being subjected to visible light at ambient temperature results in improved photocatalytic response for Bi2O3, ZnFe2O4 and BZF nanocomposite was 88 %, 93 % and 97 % for 120 min respectively. Notably, the environmental impact of the entire technique has been examined in terms of the development of green gram plants displaying effective plant growth using the treated dye wastewater.

N-doped lignin-based activated carbon aerogel derived from bamboo black pulp liquor for efficient removal of malachite green in wastewater.

In this study, a lignin-based aerogel (LA) was prepared through acid precipitation of BPBL, followed by sol-gel method and freeze-drying. Additionally, a one-step activation-carbonization method was used to acquire nitrogen-doped lignin-based activated carbon aerogel (NLACA). The adsorption and catalytic degradation performance for malachite green (MG) were examined. The specific surface area of NLACA after N-doping was 2644.5 m2/g. The adsorption capacity for MG was increased to 3433mg/g with the presence of nitrogenous functional groups on surface of NLACA compared without N-doping. Meanwhile, non-radical singlet oxygen is the primary active substance and degradation efficiency arrives at 91.8% after the catalytic degradation within 20min and it has good stability and reuse. Three possible degradation pathways during degradation were analyzed by LC-MS technique. The adsorption isotherm and kinetic data demonstrated conformity with both the Langmuir model and the pseudo-second-order kinetic model. The primary mechanisms of the adsorption for MG dyes on NLACA include hydrogen bonding, π-π interactions, attraction of electrostatic and pore filling. Hence, NLACA derived from BPBL acts as a cost-effective and high-performance adsorbent and catalyst for removal of MG in dye wastewater. This concept introduces an innovative approach of "treatment of waste with waste" for developing a low-consumption, high-efficiency dye wastewater treatment and provides significant reference to treatment dye wastewater.

Efficient removal of direct dyes by SA-Er biopolymer gel spheres: Equilibrium isotherms, kinetics and regeneration performance study

Biomass-based adsorbent materials are characterized by their low cost, environmental friendliness, and ease of design and operation. In this study, biomass-based hydrogel microspheres erbium alginate (SA/Er) with high stability and adsorption properties were prepared by a one-step synthesis method. The prepared materials were characterized and analyzed by SEM-EDS, XRD, TGA, FT-IR, UV–Vis, BET-BJH and XPS, and the adsorption performance of SA/Er was investigated for high concentrations of azo dyes in water. The results showed that the adsorption performance of SA/Er on the azo dyes of direct violet N (DV 1) and direct dark green NB (DG 6) with concentrations of 850 mg/L and 1100 mg/L under the optimal conditions was very high, and the adsorption amount could be up to 692 mg/g and 864 mg/g, respectively. The adsorption process was in accordance with the quasi-secondary kinetic model, which was accomplished by physical and chemical adsorption; the Langmuir isothermal model was able to better respond to the adsorption equilibrium, and the adsorption was dominated by the adsorption of surface monolayers; after seven desorption cycles, the removal of both azo dyes by the adsorbent material could reach >79.7 %. Combined with the results of FT-IR, UV–vis and XPS analysis before and after the adsorption, it was revealed that the adsorption of SA/Er with the dye molecules mainly consisted of hydrogen bonding, electrostatic adsorption and surface complexation, which resulted in the significant adsorption effect on the two azo dyes, and the above results can provide a reference for the treatment of dye wastewater.

Fabrication of a reusable carbon quantum dots (CQDs) modified nanocomposite with enhanced visible light photocatalytic activity

In awareness of industrial dye wastewater, carbon quantum dots (CQDs) and cobalt zinc ferrite (CZF) nanocomposites were synthesised for the making of carbon quantum dots coated cobalt zinc ferrite (CZF@CQDs) nanophotocatalyst using oxidative polymerization reaction. The results of TEM, zeta potential value, and FTIR confirm highly dispersed 1–4 nm particles with the − 45.7 mV carboxylic functionalized surface of CQDs. The results of the synthesised CZF@CQDs photocatalyst showed an average particle size of ~ 15 nm according to TEM, SEM, and XRD. The photocatalyst showed a 1.20 eV band gap, which followed the perfect visible light irradiation. TGA and DTA revealed the good thermal stability of the nanophotocatalyst. VSM was carried out, and the saturation magnetisations for CZF and CZF@CQDs were 42.44 and 36.14 emu/g, respectively. A multipoint study determined the BET-specific surface area of the CZF@CQDs photocatalyst to be 149.87 m2/g. Under visible light irradiation, the final CZF@CQDs nanophotocatalyst demonstrated remarkable efficiency (~ 95% within 25 min) in the photocatalytic destruction of Reactive Blue 222 (RB 222) and Reactive Yellow 145 (RY 145) dyes, as well as mechanical stability and recyclability. Even after the recycling of the degradation study, the nanophotocatalyst efficiency (~ 82%, 7th cycles) was predominantly maintained. The effects of several parameters were also investigated, including initial dye concentration, nanophotocatalyst concentration, CQD content, initial pH of the dye solution, and reaction kinetics. Degradation study data follow the first-order reaction rate (R2 > 0.93). Finally, a simple and low-cost synthesis approach, rapid degradation, and outstanding stability of the CQD-coated CZF nanophotocatalyst should make it a potential photocatalyst for dye wastewater treatment.

Excellent photocatalytic performance of PAA/Na2MoO4-Fe3+ hydrogel with Na2MoO4 as sacrificial agent for dye removal

Currently, the majority of photocatalytic materials primarily consist of insoluble semiconductors, whereas soluble semiconductor materials have limited applications in photocatalysis. In this study, it is proposed for the first time to use the soluble semiconductor sodium molybdate (Na2MoO4) as a sacrificial agent to fabricate a polyacrylic acid/sodium molybdate-Fe3+ hydrogel photocatalyst (PAA/Na2MoO4-Fe3+) through polymerization with Fe3+ ions and acrylic acid (AA) monomer. The hydrogel photocatalyst was thoroughly characterized and the results revealed that the presence of Na2MoO4 in ionic form within the hydrogel significantly enhanced its adsorption capacity for pollutant molecules. Additionally, Fe3+ ions coordinated with -COOH (L) groups on PAA to form [Fe(L)6]3+ ions, which acted as active sites of photocatalytic. Moreover, the PAA/Na2MoO4-Fe3+ hydrogel exhibited promising potential as a photocatalyst for the remove of dye pollutants (e.g. MB, MG, RhB and MO) from wastewater. Finally, we also explored and analyzed the photocatalytic mechanism of the hydrogel. It is noteworthy to conclude that the hydrogel possesses immense potential for the practical application of photocatalytic techniques in the treatment of dyes wastewater.

Calcined biomass-bentonite composites as eco-friendly adsorbents for the treatment of toxic anionic and cationic dye wastewater

Adsorption is a suitable technique for decontamination of organic dye wastewaters. Herein, we comparatively investigated the adsorption performance of bentonite (BEN) and its modification with groundnut shell (BGS) and palm kernel shell (BPS) for methylene blue (MB) and congo red (CR) dyes removal from aqueous solution. BGS and BPS were prepared by calcination at 300 °C for 6 h and were characterized using BET, SEM, EDS and FTIR to determine their textural properties, morphologies, elemental compositions, and functional groups. The BET surface examination revealed that the surface area of BEN was enhanced from 78 m2/g to 195 m2/g and 141 m2/g after modification with groundnut shell (BGS) and palm kernel shell (BPS), respectively. The adsorption process in a batch system was subjected to comprehensive experimentation to investigate the effect of adsorbent dosage, contact time, temperature, initial concentration, and pH. The adsorption was fitted to adsorption isotherm and kinetic models and the results revealed that the adsorption process of BEN, BGS, and BPS towards MB and CR adsorption can be best described by Temkin, Freundlich and pseudo-second order kinetic models. The adsorption capacities (qmax) for uptake of MB by BEN, BGS and BPS are 10.61, 10.85 and 10.93 mg, while CR exhibited 8.83, 6.87 and 5.86 mg/g, respectively. The thermodynamics study revealed that the adsorption process was spontaneous, feasible, endothermic in nature. The adsorption process is governed by electrostatic attraction with the involvement of physical and chemical adsorption. This study suggests that biomass-modified bentonite is a sustainable, cost-effective, non-toxic, and greener approach for eliminating MB and CR from aqueous solution. Furthermore, the modification method does not only achieve substantial removal of MB and CR dyes, but also offers considerable energy savings and operational cost reductions in real-time based on water quality data. This study does present a novel, sustainable approach to improve natural water treatment efficiency and compliance.

Monte Carlo Simulation, Artificial Intelligence and Machine Learning-based Modelling and Optimization of Three-dimensional Electrochemical Treatment of Xenobiotic Dye Wastewater

The present study investigates the synergistic performance of the three-dimensional electrochemical process to decolourise methyl orange (MO) dye pollutant from xenobiotic textile wastewater. The textile dye was treated using electrochemical technique with strong oxidizing potential, and additional adsorption technology was employed to effectively remove dye pollutants from wastewater. Approximately 98% of MO removal efficiency was achieved using 15 mA/cm2 of current density, 3.62 kWh/kg of energy consumption and 79.53% of current efficiency. The 50 mg/L MO pollutant was rapidly mineralized with a half-life of 4.66 min at a current density of 15 mA/cm2. Additionally, graphite intercalation compound (GIC) was electrically polarized in the three-dimensional electrochemical reactor to enhance the direct electrooxidation and.OH generation, thereby improving synergistic treatment efficiency. Decolourisation of MO-polluted wastewater was optimized by artificial intelligence (AI) and machine learning (ML) techniques such as Artificial Neural Networks (ANN), Support Vector Machine (SVM), and random forest (RF) algorithms. Statistical metrics indicated the superiority of the model followed this order: ANN > RF > SVM > Multiple regression. The optimization results of the process parameters by artificial neural network (ANN) and random forest (RF) approaches showed that a current density of 15 mA/cm2, electrolysis time of 30 min and initial MO concentration of 50 mg/L were the best operating parameters to maintain current and energy efficiencies of the electrochemical reactor. Finally, Monte Carlo simulations and sensitivity analysis showed that ANN yielded the best prediction efficiency with the lowest uncertainty and variability level, whereas the predictive outcome of random forest was slightly better.Highlights• In-depth analysis of various artificial intelligence optimization techniques.• Prediction efficiency of artificial intelligence and machine learning algorithms.• 98% dye removal and 100% regeneration of graphite intercalation compound.• Advanced statistical analysis of targeted responses and data fitting techniques.• Analysis of uncertainties and variability using Monte Carlo simulation.

Synthesis, characterization, and azo dye degradation performance of mechanically alloyed Mg65Cu20Y13La2 nanocrystalline powders

This research describes the synthesis of the multicomponent Mg65Cu20Y13La2 alloy by mechanical alloying (MA) to investigate the influence of milling times on the microstructure of alloy and degradation performance of methyl orange. The structural evolution of this alloy was investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDX) techniques. The thermal behavior of the alloys was investigated by differential scanning calorimetry (DSC). The crystallite size of the Mg65Cu20Y13La2 alloys was calculated using the Debye Scherrer equation with broadening of the XRD peaks. The methyl orange degradation efficiencies of the Mg65Cu20Y13La2 alloys were evaluated by using ultraviolet–visible (UV–Vis) spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), and gas chromatography–mass spectrometry (GC–MS) techniques. The XRD and SEM results showed that the microstructure of the powders changed during MA. After 10 h milling time, three intermetallic phases were obtained as Mg2Cu2La, Mg24Y5, and Mg2Cu. The results also showed that a solid solution phase, α-Mg(Cu, Y, La), with an average crystallite size 21 nm was formed after 100 h milling time. DSC trace of the Mg65Cu20Y13La2 powders showed two exothermic peaks for the 10 h milling time, while it did not show any peaks for the 100 h milling time. Photocatalytic decomposition of the methyl orange solution by the Mg65Cu20Y13La2 alloy was evaluated by UV–Vis spectra with a decrease in absorbance at a wavelength of 465 nm. After a 20 min exposure, UV–Vis, FT-IR, and GC–MS analysis showed that the methyl orange samples were almost completely degradation by using the Mg65Cu20Y13La2 powders. The Mg65Cu20Y13La2 alloy exhibits a good reusability of 92% by the four cycle and a high efficiency was achieved in all the pH values in the range of 5–9. The results prove that the Mg65Cu20Y13La2 alloy is an efficient and promising material for dyeing wastewater treatment.

Waste newspaper as cellulose resource of activated carbon by sodium salts for methylene blue and congo red removal

The work was aimed at evaluating the adsorptive properties of waste newspaper (WN) activated carbons chemically produced using sodium salts for methylene blue (MB) and congo red (CR) removal. The activated carbons, designated as AC1, AC2, AC3 and AC4 were prepared through impregnation with NaH2PO4, Na2CO3, NaCl and NaOH, respectively and activation at 500 °C for 1 h. The activated carbons were characterized for surface chemistry, thermal stability, specific area, morphology and composition. The AC1 with a surface area of 917 m2/g exhibits a greater MB capacity of 651 mg/g. Meanwhile, a greater CR capacity was recorded by AC2 at 299 mg/g. The pseudo-second order model fitted well with the kinetic data, while the equilibrium data could be described by Langmuir model. The thermodynamic parameters, i.e.., positive ΔH°, negative ΔG° and positive ΔS° suggest that the adsorption of dyes is endothermic, spontaneous and feasible at high solution temperature. To conclude, WN is a potential cellulose source for producing activated carbon, while NaH2PO4 activation could be employed to convert WN into activated carbon for effective dye wastewater treatment.

Experimental study on dynamic adsorption properties of methylene blue onto coal-based activated carbon using a hydrocyclone

To address the issues of low adsorption efficiency of activated carbon in dyeing wastewater treatment, a dynamic adsorption process using activated carbon for wastewater treatment was proposed. A hydrocyclone was used as the carrier, and the adsorbent separation process was integrated into the same single device. Methylene blue (MB) was used to simulate printing and dyeing wastewater. The effects of initial concentration of MB solution, ratio of activated carbon quality to wastewater flow, and adsorption temperature on the adsorption efficiency were investigated. The results showed that the optimal adsorption efficiency of MB by activated carbon was 95.2 % when the initial concentration of MB solution was 12 mg/L, the ratio of activated carbon quality to wastewater flow was 0.5 mg/mL, and the adsorption temperature of MB solution was 44.5 °C. In addition, compared with the water bath oscillation method, the removal efficiency of MB was increased by 731 % under the same adsorption conditions. The research shows that it is feasible to treat printing and dyeing wastewater by using a hydrocyclone to enhance activated carbon adsorption. The research aims to provide a practical basis for future optimization of the structure and operation parameters of hydrocyclone and to reveal their wide application prospects.