Acid Red Research Articles

Magnetic coordination polymer for dye removal and antibacterial activity

BackgroundColor elimination from dye wastewater is one of the major environmental concerns, therefore, finding an eco-friendly, recyclable, and effective sorbent for dye treatment is very important. This work aims to scrutinize the performance of a new magnetic amino-coordinated metal–organic framework, namely NiFe2O4/[Zn4(BTC)2(Hbtc)(L-His)2(H2O)4] 1.5H2O (NF/LHTZn), in Acid Red 14 (AR14) and methylene blue (MB) elimination, and antibacterial activity. MethodHere, NiFe2O4 (NF), LHTZn, and NF/LHTZn materials were successfully constructed via the hydrothermal condition and checked via several characterizations (i.e., X-ray diffraction and Fourier transform infrared). Batch adsorption studies were performed to appraise the influence of operational factors like solution preliminary concentration (A), adsorbent dosage (B), contact time (C), temperature (D), and pH on the removal of MB and AR14 dyes. The response surface methodology (RSM) has helped to optimize two dye sorption processes. Significant findingsBased on experimental results, sorption kinetics were correctly matched by the pseudo 2nd order model for both dyes. Freundlich's isotherm indicated that the best fit for MB removal and maximal uptake capacity (Qmax) was 375.93 mg/g, while Langmuir was best fitted for AR14 (Qmax= 276.24). Thermodynamic results revealed that both dye adsorption was spontaneous in nature. According to RSM data, the maximum removal of MB was 292.61 mg/g under optimal conditions, A= 100 mg/L, B= 0.3 g/L, C= 140 min, D= 30 °C and, pH 7, and a maximum AR14 adsorption of 272.35 mg/g gained at an A= 100 mg/L, B= 0.3 g/L, C= 126 min, D= 40 °C and pH 2. Based on disk diffusion results, NF/LHTZn has also a proper antibacterial performance toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria.

Zwitterionic loose polyamide nanofiltration membrane with good antifouling properties for efficient removal of humic acid and dyes

Loose nanofiltration membrane exhibits significant advantages in removing organic pollutants due to its high selectivity at a lower operating pressure. Herein, a novel zwitterionic loose polyamide separation layer was designed and formed on the modified polyethersulfone substrate to obtain the zwitterionic loose nanofiltration (ZLNF) membrane with high water permeability and good antifouling properties. The BAPP-TMC polyamide layer was fabricated by the interfacial polymerization between 1,4-bis(3-aminopropyl)piperazine (BAPP) and trimesoyl chloride (TMC). Afterward, the BAPP-TMC polyamide layer was grafted with zwitterions by a facile surface modification. Owing to the fabrication of the relatively loose polyamide structure with zwitterions, the prepared ZLNF-0.2 membrane presented an ultra-high pure water permeability of 148.5 L m−2 h−1 bar−1 while maintaining relatively good removal capacities for organic pollutants. The removal rates for humic acid (HA, 100 ppm) and Congo Red (CR, 100 ppm) were 98.1 % and 97.6 %, respectively. Furthermore, the good hydrophilicity and strong surface hydration effect of zwitterions endowed the ZLNF membranes with excellent anti-organic fouling and antibacterial adhesion properties. The good antibacterial abilities of ZLNF membranes were also proved by the fluorescence staining results. Due to the effective separation performance and good antifouling properties, the fabricated ZLNF membranes present great application potential in removing natural organic matter and dyes.

Catalytic activation of persulfate by 3D Cd(II) coordination polymers based on a flexible cyclotriphosphazene-functionalized ligand

Dye removal in wastewater can be done by catalytic reaction with coordination polymers. Herein, Two 3D Cd(II) coordination polymers, namely, {[Cd3(L)(H2O)4].(H2O)(DMF)}n (GTU-1) and {[Cd3(L)(4,4-bpy))(H2O)2].(H2O)}n (GTU-2), were prepared with a novel hexapod-shaped molecular building block, hexakis(methyl-2-(4-phenoxyphenyl)acetatebenzene) cyclotriphosphazene (H6L), by solvothermal reactions in dimethylformamide with nitric acid as the modulator. Cd(II) coordination polymers were characterized by Fourier transform infrared spectroscopy, thermal analysis, scanning electron microscopy, powder X-ray diffraction analysis and single crystal X-ray diffraction technique. GTU-1 represents a 3D pillared-layered coordination polymer structure containing 2D Cd-carboxylate (Cd(COO)n)-based inorganic building unit (IBU) whereas GTU-2 is a 3D coordination polymer derived from 1D IBU bridged together by deprotonated L6- and judiciously chosen ancillary linker 4,4-bipyridine (4,4-bpy). In both complexes, the flexible multisite cyclotriphosphazene bridging ligand (H6L) is completely deprotonated. GTU-2 exhibited relatively good catalytic activity towards rhodamine B (RhB), Methylen Blue (MB) and Acid Red 17 (AR-17) removal in aqueous solution.

Design of separable magnetic chitosan grafted-benzaldehyde for azo dye removal via a response surface methodology: Characterization and adsorption mechanism

In this study, a magnetic chitosan grafted-benzaldehyde (CS-BD/Fe3O4) was hydrothermally prepared using benzaldehyde as a grafting agent to produce a promising adsorbent for the removal of acid red 88 (AR88) dye. The CS-BD/Fe3O4 was characterized by infrared spectroscopy, surface area analysis, scanning electron microscopy-energy dispersive X-ray, vibrating sample magnetometry, powder X-ray diffraction, CHN elemental analysis, and point of zero charge (pHPZC). The Box-Behnken design (BBD) was adopted to study the role of variables that influence AR88 dye adsorption (A: CS-BD/Fe3O4 dose (0.02–0.1 g), B: pH (4–10), and time C: (10–90 min)). The ANOVA results of the BBD model indicated that the F-value for the AR88 removal was 22.19 %, with the corresponding p-value of 0.0002. The adsorption profiles at equilibrium and dynamic conditions reveal that the Temkin model and the pseudo-first-order kinetics model provide an adequate description of the isotherm results, where the maximum adsorption capacity (qmax) with the AR88 dye was 154.1 mg/g. Several mechanisms, including electrostatic attraction, n-π interaction, π-π interaction, and hydrogen bonding, regulate the adsorption of AR88 dyes onto the CS-BD/Fe3O4 surface. As a result, this research indicates that CS-BD/Fe3O4 can be utilized as an effective and promising bio-adsorbent for azo dye removal from contaminated wastewater.

Green synthesis of ZnO nanoparticles using the aqueous extract of Platanus orientalis: Structural characterization and photocatalytic activity

In this study, zinc oxide nanoparticles (ZnO NPs) were prepared from the aqueous leaves extract of Platanus orientalis by a green route. To gain optimum synthesis terms for production of ZnO NPs, response surface methodology (RSM) with Box-Behnken design (BBD) was applied. The NPs were investigated by several techniques including Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), UV–Vis spectroscopy, photoluminescence (PL) spectroscopy, field emission scanning electron microscope (FE-SEM), energy dispersive x-ray (EDX), transmission electron microscopy (TEM) and Brunear-Emmet- Teller (BET) analysis. The average crystallite revealed a size of 23.48 nm measured by PXRD. The selected area electron diffraction (SAED) and PXRD analyses indicated the presence of the ZnO crystalline phase. Besides, FE-SEM and TEM analyses of biosynthesized ZnO NPs confirmed their spherical shape. Calculations showed that the optical band gap value of biosynthesized ZnO NPs is less than commercial sample, which can be attributed to the presence of some natural compounds of the plant extract in the ZnO structure. Biosynthesized ZnO NPs were also used as a photocatalytic material for the degradation of Acid Red 14, resulting in about 85% dye degradation under xenon lamp irradiation for 45 min. Due to their eco-friendly synthesis and non-toxic nature, ZnO NPs prepared from P. orientalis extract can be used as potential candidates for some environmental applications such as photocatalytic processes.

Sorghum-grown fungal biocatalysts for synthetic dye degradation

The synthetic dye discharge is responsible for nearly one-fifth of the total water pollution from textile industry, which poses both environmental and public health risks. Herein, a solid substrate inoculated with fungi is proposed as an effective and environmentally friendly approach for catalyzing organic dye degradation. Pleurotus ostreatus was inoculated onto commercially available solid substrates such as sorghum, bran, and husk. Among these, P. ostreatus grown on sorghum (PO-SORG) produced the highest enzyme activity and was further tested for its dye biodegradation ability. Four dye compounds, Reactive Blue 19 (RB-19), Indigo Carmine, Acid Orange 7, and Acid Red 1 were degraded by PO-SORG with removal efficiencies of 93%, 95%, 95%, and 78%, respectively. Under more industrially relevant conditions, PO-SORG successfully degraded dyes in synthetic wastewater and in samples collected from a local textile factory, which reveals its potential for practical usage. Various biotransformation intermediates and end-products were identified for each dye. PO-SORG exhibited high stability even under relatively extreme temperatures and pH conditions. Over 85% removal of RB-19 was achieved after three consecutive batch cycles, demonstrating reusability of this approach. Altogether, PO-SORG demonstrated outstanding reusability and sustainability and offers considerable potential for treating wastewater streams containing synthetic organic dyes.

Chitosan induced synthesis of few-layer MoS2/Fe-doped biochar and its dual applications in Cr(VI) removal

The removal of Cr(VI) from wastewater still faces many challenges. This study reports on chitosan-induced synthesis of few-layer MoS2/Fe-doped biochar (Mo-Fe0.5-CS) with dual applications in Cr(VI) removal. Using chitosan as a soft template, the MoS2 in the composite had only about 3 layers with an interlayer spacing greater than that of pure MoS2, while Fe was embedded in the carbon skeleton in the form of 6-coordination with O/N. The Mo-Fe0.5-CS composite showed high affinity for Cr(VI), with rapid adsorption reaching 100% removal within 15 min for a single solution of Cr(VI). It follows the Langmuir isotherm model with a maximum adsorption capacity of up to 180 mg/g. Furthermore, the Mo-Fe0.5-CS composite demonstrated catalytic activity for Fenton-like reactions, which allowed for the simultaneous removal of organic pollutants and Cr(VI). In a mixture solution of Cr(VI) and Acid Red 73 (AR73), the removal efficiencies using Mo-Fe0.5-CS and H2O2 in 30 min were 99.7% and 96.6%, respectively. The MoS2 acted as a cocatalyst to improve the reduction of Fe(III), and the catalysis of Cr(VI) also contributed to the removal of AR73 to a certain extent. Even at pH 10, the system was effective due to the 1O2 produced in the reaction and the acidic microenvironment constructed by unsaturated S atoms. These findings provide insights into the effective removal and utilization of Cr(VI) in wastewater treatment.

Preparation of highly porous nitrogen-doped biochar derived from birch tree wastes with superior dye removal performance

Heteroatom doping is a highly effective strategy that can be used to modify carbonaceous adsorbents to improve their chemical reactivity and increase their adsorptive properties. Herein, a simple method is reported for the preparation of nitrogen-doped biochar using a natural and abundant biowaste from birch trees and melamine as a nitrogen dopant for the adsorption of Acid red 18 (AR-18) dye from water. The doped biochars were also characterized for their performance during the treatment of synthetic effluents. The physicochemical characterization results showed that the N-doping process provoked remarkable chances on the biochar morphology, pore structure, and surface functionalities. N-doped biochar showed abundant nitrogen functional groups with 5.4 % of N in its structure while non-doped carbon showed traces with 0.47 %. Moreover, the specific surface area of doped biochar was dominated by mesopores (86.4 %) while non-doped was dominated by micropores (67.8 %). Raman analysis showed that the incorporation of N created more defects in the biochar structure. The adsorption experiments showed that the N-doping boosted the biochar adsorptive performance. The maximum adsorption capacity of the doped biochar was 545.2 mg g−1, while the non-doped exhibited 444.5 mg g−1, i.e., an increase of 22.6 %. The kinetic and equilibrium studies showed that Avrami fractional order and Liu models were the most suitable for describing the experimental AR-18 dye adsorption data. The equilibrium parameters were found to obey a nonlinear relationship with the temperature. Since the biochars are highly porous, pore filling was the main adsorption mechanism, however; AR-18 dye removal suggests that interactions such as electrostatic, hydrogen bonds, Lewis acid-base, and π-π between the adsorbent and the dye are involved. The thermodynamic studies showed that the removal of the AR-18 dye from the solution is dependent on temperature, exothermic, and spontaneous. The N-doped biochar showed excellent removal performances of contaminants from synthetic effluents confirming their high efficiency for color removal. This research shows that N-doping is an efficient strategy to design effective, low-cost, and sustainable adsorbents to remediate dye contamination in wastewater.

Catalytic Activity of Zn(II) Coordination Polymer Based on a Cyclotriphosphazene-Functionalized Ligand for Removal of Organic Dyes

The 3D Zn(II) coordination polymer {[Zn3(L)(4,4′-bpy)]}n (GTU-3) was prepared with a novel hexapod-shaped molecular building block, hexakis(methyl-2-(4-phenoxyphenyl)acetatebenzene) cyclotriphosphazene (H6L1) by solvothermal reaction in dimethylformamide (DMF). Zn(II) coordination polymer was characterized by FTIR, thermal analysis, SEM-EDX, BET, powder X-ray diffraction analysis, and single crystal X-ray diffraction techniques. GTU-3 consists of six crystallographically independent Zn2+ ions, two fully deprotonated cyclophosphazene-based ligands, and two 4,4′-bipyridines (4,4′-bpy). In the complex, the flexible multisite cyclotriphosphazene bridging ligand (H6L) was completely deprotonated. GTU-3 exhibited relatively good catalytic activity toward Rhodamine B (RhB) removal in aqueous solution. A 0.4 g/L amount of GTU-3 could degrade the 10 mg/L solution of RhB up to 76.5% in the presence of peroxymonosulfate (PMS) oxidant in 1 h. The kinetic studies showed that the degradation process followed pseudo-first-order kinetic. By extending the degradation time to 5 h, the degradation efficiency reached 95.3%. Under the same conditions, Methylene Blue (MB) and Acid Red 17 (AR17) dyes were degraded by 86.2% and 52.8%, respectively.

Adsorption and photocatalytic degradation of dye contaminants in wastewater over W-doped titania nanotubes

BackgroundIn recent years, the degradation of dye contaminants discharged from industrial operations is considered a top priority in the environmental science and engineering field. MethodsIn this study, tungsten (W) doped titania nanotubes (TNs) were synthesized to advance their reactivity towards the degradation of basic violet 10 (BV10), acid blue 9 (AB9), acid orange 7 (AO7), and acid red 1 (AR1) under UV radiation. Significant findingsThe specific surface area of the W-TNs was 242.6 m2 /g. The XPS spectra presented peaks positioned at 35.5 and 37.6 eV endorsing the W6+ species, conforming to W 4f7/2 and 4f5/2, respectively. The reaction kinetics indicated that BV10, AB9, AO7, and AR1 photodegradation were all two-step reactions with rate constants being BV10: k1 / k2 = 31 min−1, AB9: k1 / k2 = 2 min−1, AO7: k1 / k2 = 1 min−1, and AR1: k1 / k2 = 3 min−1. The optimum photocatalytic efficacies for BV10 (49.77%, AB9 (14.95%), AO7 (2.12% and AR1 (0.54%) were acquired using W-doped TNs.

Quantum chemical and experimental studies on the extraction of acid blue 80 and acid red 1 from their aquatic environment using tetrabutylammonium bromide based deep eutectic solvents

In this study, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy, HOMO–LUMO energy gap, chemical potential (µ), electronegativity (χ), electrophilicity index (ω), global hardness (η), and global softness (s) of dyes; acid blue 80 (AB80), acid red 1 (AR1) and deep eutectic solvents: tetrabutylammonium bromide with glycerol {[TBAB][Gly]}, tetrabutylammonium bromide with decanoic acid {[TBAB][DA]} and tetrabutylammonium bromide with oleic acid {[TBAB][OA]} were predicted and calculated using quantum chemical calculation. The polarity of all the studied molecules also predicted in terms of screening charge density and plotted sigma profile and sigma potential. Further, the extraction experiment was conducted for the extraction of acid blue 80 (AB80) and acid red 1 (AR1) using tetrabutylammonium bromide with decanoic acid {[TBAB][DA]} and tetrabutylammonium bromide with oleic acid {[TBAB][OA]} as the potential solvent. The process was characterized by means of distribution coefficient and efficiency. Finally, the extraction process feasibility was studied and discussed in terms of and

Photocatalytic Azo Dye Degradation Using Graphite Carbon Nitride Photocatalyst and UV-A Irradiation

The photocatalytic degradation of Acid Red 26 was examined utilizing a graphitic carbon nitride (g-C3N4) catalyst and a UV-A light in this study. We investigated how successfully the photocatalytic approach removed Acid Red 26 from synthetic and actual municipal wastewater. Both aqueous matrices allowed for extremely high clearance rates. Wastewater degraded at a slower rate than the other matrices, this might be ascribed to the wastewater’s complicated chemical composition. Using a liquid chromatography-mass spectrometry (LC-MS), the IPs in both synthetic and actual municipal effluent were determined. The photocatalytic degradation mechanisms of Acid Red 26 are hypothesised to comprise oxidation, dealkylation, and methoxy group cleavage based on the observed intermediate products (IPs). Using proven scavengers, we were also able to investigate the role of reactive species in the degradation process and illustrate the significance of h+ and O2• in the reaction. Chlorococcum sp. and Dunaliella tertiolecta microalgae were also utilised to assess the development of ecotoxicity. We observed low toxicity throughout the process when clean water was used as the matrix, with no production of hazardous IPs. In the case of actual municipal wastewater, there was an early rise in toxicity, which scientists believe was caused by the matrix’s chemical make-up. To lower the toxicity, a heterogeneous photocatalysis was used, and at the end of the treatment, nearly full detoxification was obtained.

A Carbonized Zeolite/Chitosan Composite as an Adsorbent for Copper (II) and Chromium (VI) Removal from Water.

To address Cu(II) and Cr(VI) water pollution, a carbonized zeolite/chitosan (C-ZLCH) composite adsorbent was produced via pyrolysis at 500 °C for two hours. C-ZLCH was characterized using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and zeta potential measurements. The batch experiments were performed by varying the initial pH, concentration, and contact time. The optimal pH values for Cu(II) and Cr(VI) were 8.1 and 9.6, respectively. The highest adsorption capacities for Cu(II) and Cr(VI) were 111.35 mg/g at 60 min and 104.75 mg/g at 90 min, respectively. The effects of chemicals such as sodium (Na+), glucose, ammonium (NH4+), and acid red 88 (AR88) were also studied. Statistical analysis showed that sodium had no significant effect on Cu(II) removal, in contrast to Cr(VI) removal. However, there was a significant effect of the presence of glucose, ammonium, and AR88 on both Cu(II) and Cr(VI) removal. The adsorption isotherm and kinetic models were fitted using Langmuir and pseudo-second-order models for Cu(II) and Cr(VI), respectively.

Transcriptome analysis reveals self-redox mineralization mechanism of azo dyes and novel decolorizing hydrolases in Aspergillus tabacinus LZ-M

Bio-degradation is the most affordable method of azo dye decontamination, while its drawbacks such as aromatic amines accumulation and low degradation efficiency must be overcome. In this study, a novel mechanism of azo dye degradation by a fungus was discovered. At a concentration of 400 mg/L, the decolorization efficiency of Acid Red 73 (AR73) by Aspergillus tabacinus LZ-M was 90.28%. Metabolite analysis and transcriptome sequencing analysis revealed a self-redox process of AR73 degradation, where the electrons generated in carbon oxidation were transferred to the reduction of -C-N = and –NN. The metabolites, 2-hydroxynaphthalene and N-phenylnitrous amide were mineralized into CO2 through catechol pathway and a glycolytic process. Furthermore, the mineralization ratio of dye was computed to be 31.8% by the carbon balance and electron balance. By using comparative transcriptome, a novel decoloring enzyme Ord95 was discovered in unknown genes through gene cloning. It hydrolyzed AR73 into 2-hydroxynaphthalene and N-phenylnitrous amide, containing a glutathione S-transferase domain with three arginines as key active sites. Here the new mechanism of azo dye degradation was discovered with identification of a novel enzyme in Aspergillus tabacinus LZ-M.

Preparation and application of red mud-based heterogeneous Fenton catalyst

The zero-valent iron (ZVI) heterogeneous Fenton catalyst based on red mud (RM) was synthesized by direct reducing iron oxide in RM using H2 at 800 °C (RMH-800). X-ray diffraction analysis showed that Fe2O3 in RM was reduced to Fe0. Brunauer -Emmett-Teller, scanning electron microscopy and high-resolution transmission electron microscopy show that RMH-800 is a ZVI-loaded porous material. The catalysts were characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Under the conditions of 2.86 mM H2O2, 100 mg/L Acid Red G (ARG) and 1 g/L RMH-800, 95 % of ARG was removed within 10 min. The RMH-800/H2O2 system also showed excellent degradability to antibiotics (Sulfamethoxazole, Ibuprofen and Primidone). •OH is the main species responsible for pollutants degradation. RMH-800 showed low iron leaching during the reaction process and excellent catalytic performance even after 6 repeats, indicating it a stable and low-cost material with great potential for wastewater treatment.

Waste lignin-based cationic flocculants treating dyeing wastewater: Fabrication, performance, and mechanism

Lignin is often considered to be a complex polymeric structural material with excellent scalability. Reduced pressure distillation, a novel effective way, was proposed to recover reusable waste lignin from textile degumming black liquor. The structure of the recovered material was determined by Fourier Transform Infrared Spectroscopy (FT-IR), Gel Permeation Chromatography (GPC) and Klason Component Analysis. Recycled lignin (RL) was used as the basis for the synthesis of a cationic recycled lignin-based polymers (CRLM) through graft polymerizing cationic monomer (DMC). The optimum synthesis conditions were obtained by conducting orthogonal experiments using the cationicity as the studied parameter, while selecting pH, DMC/RL, reaction temperature and time as independent variables. Recovery experiments showed that the maximum recovery concentration of RL in the black liquor was 5 g/L, with a purity of approximately 83 %. Orthogonal experiments showed that a low DMC/RL ratio was crucial for the synthesis of flocculants. When the molar ratio of DMC/RL was 3:1, the cationicity of the prepared CRLM was as high as 11.32 %. Zeta potential and decolorization experiments also confirmed the stable decolorization performance of CRLM in three kinds of anionic dye wastewater. The experimental results showed that charge neutralization, chemical bonding forces and auxiliary effects play great role to remove anionic dyes, resulting in 94 %, 89 % and 94.9 % removal against Reactive Red 195 (RR195), Acid Red 18 (AR18) and Direct 168 (DB168) respectively. Therefore, this study demonstrated the potential of using recycled waste lignin as synthesize lignin-based flocculants in the field of printing and dyeing wastewater by treating waste with waste.

Preparation of poly (PVP/acrylamide/glycerol/bentonite clay) nanocomposite films by gamma radiation for removal of Sandolane Rubinole Acid Red 37 dye

ABSTRACT The present study focuses on utilising gamma irradiation to prepare Poly (PVP/acrylamide/glycerol/bentonite clay) nanocomposite film poly(PVP/AAm/Glyc/BNTN) with composition (40/60/5/0.25 wt %) at different doses of 10, 20, 30 and,40 kGy. The FTIR analysis shows the successful preparation and modification of the different irradiated poly(PVP/AAm/Glyc/BNTN) nanocomposite film at different doses. The film irradiated at 40 kGy is a stable film that has higher water resistance properties than other prepared films as shown in the swelling study. The bentonite nano clay was found to be homogeneously and well distributed in the surface of the nanocomposite film modified at 40 kGy, which led to the chemical stability of the synthesised poly(PVP/AAm/Glyc/BNTN) with composition (40/60/5/0.25 wt %) as shown in the swelling study, and field emission scan electron microscope (FESEM). Also, the bentonite nanoparticles have an average particle size of 76.5 nm. The impacts of the different factors which include pH, contact time (h.), and temperature (k) on the uptake of Acid red 37 (AR 37) dye from its aqueous solution were investigated. The Langmuir model was established as the suitable model for this work and the uptake of AR 37 dye was designated by the pseudo-second-order kinetic model to be spontaneous and endothermic. Furthermore, the adsorption capacity was enhanced with the temperature and time and reduced with increasing the pH of the dye solution. The maximum adsorption capacity of Poly(PVP/AAm/Glyc/BNTN) samples to the anionic AR 37 dye was found to be 136.13 mg/g at pH 4, contact time 8 hrs, and amount of adsorbent 0.3 g/100 ml of the dye solution.

Enhanced Sonophotocatalytic Degradation of Acid Red 14 Using Fe3O4@SiO2/PAEDTC@MIL-101 (Fe) Based on Metal-Organic Framework

Here, the magnetic Fe3O4@SiO2/PAEDTC@MIL-101 (Fe) with a new core-shell structure was synthesized, and its sonophotocatalytic properties were evaluated for acid red 14 (AR14) degradation. Particle characterizations were determined by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and vibrating-sample magnetometer (VSM), and the analysis results offered an excellent synthesis of mesoporous particles. Fe3O4@SiO2/PAEDTC@MIL-101 (Fe)/UV/US showed high degradation kinetics rate (0.0327 min−1) compared to sonocatalytic processes (0.0181 min−1), photocatalytic (0218 min−1), sonolysis (0.008 min−1), and photolysis (0.005 min−1). Maximum removal efficiencies of AR14 (100%) and total organic carbon (69.96%) were obtained at pH of 5, catalyst mass of 0.5 g/L, initial AR14 concentration of 50 mg/L, and ultrasound power of 36 W. Evaluation of BOD5/COD ratio during dye treatment confirmed that the sonophotocatalysis process can be useful for converting major contaminant molecules into biodegradable compounds. After recycling eight times, the prepared composite still has sonophotocatalytic degradation stability above 90% for AR14. Scavenging tests confirmed that holes (h+) and hydroxyl (•OH) were the pivotal agents in the decomposition system. Based on the results, the synthesized sample can be suggested as an excellent and promising sonophotocatalyst for the degradation of AR14 dye and its conversion into biodegradable compounds.

Adsorption Properties of Anionic Dyes on Quaternized Microcrystalline Cellulose.

Efficient removal of dyes in the wastewater of dyeing and printing industries is challenging, especially the anionic dyes with strong stability, serious environmental pollution, and difficult degradation. In the present work, a novel cationic adsorbent was synthesized through the quaternization of 2,3-epoxypropyltrimethylammonium chloride (GTA) onto microcrystalline cellulose and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, specific surface and pore size analysis, and scanning electron microscopy. Acid Yellow 128 (AY-128) and Acid Red 1 (AR-1) were selected to investigate their adsorption on quaternized microcrystalline cellulose (QMCC). The experimental adsorption results indicated that (1) the adsorption kinetics of AY-128 and AR-1 on QMCC could be consistent with the pseudo-second-order and Freundlich models, respectively; (2) the adsorption process was spontaneous and feasibly endothermic. The removal efficiency of AY-128 and AR-1 was up to 99 and 95%, respectively. After five times of reuse, the removal efficiency of AY-128 and AR-1 was still 97 and 95%. In conclusion, quaternized microcrystalline cellulose was a promising adsorbent for AY-128 and AR-1.

One-pot synthesis of novel 3D graphene/Fe3O4/agro-based waste material (Sesamum indicum) nanocomposite for wastewater treatment and artificial neural network modeling

A One-Step hydrothermal process was applied in this study to synthesize magnetic Fe3O4/3D graphene/Sesamum indicum nanocomposite (M3DGSN). Acid Red 88 (AR88) was set at the target pollutant to be adsorbed and removed by the synthesized nanocomposite from the aqueous media. Field Emission scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometery, and X-Ray diffraction analyses were applied to characterize the product. Artificial neural network modeling has also been employed in the adsorption process of AR88 using M3DGSN. Adsorption studies were performed in the dye concentration range of 5–30 mg L-1 with the adsorbent weight of 25–100 mg. It was observed that the dye removal efficiency using M3DGSN was dependent on different operational parameters and increased with rising pH, time, and weight of M3DGSN. Also, decreasing the dye concentration demonstrated the enhancement of dye removal efficiency. The optimum adsorbent amount and dye concentrations were observed to be 100 mg and 5 mg L-1, respectively. Also, the optimum removal performance was seen at the pH of 9.