In this paper, the dye removal ability of the acrylic grafted polysulfone nanomembrane using ultraviolet radiation was studied to remove dyes from colored textile wastewater. Acrylic acid was used to modify polysulfone ultrafiltration membrane. The effect of different operating parameters such as pressure, salt concentration and chemical structure of dyes was evaluated. Data indicated that the photografted membrane has acceptable performance both in terms of flux and rejection. The dye rejection and hydraulic permeability were 86–99.9% and 7.6Lm−2 h−1 bar−1, respectively. It was found that the rejection of dyes decreased with salt concentration due to a decrease of the Donnan effect. Also, the low molecular weight dyes and highly charged dyes were more sensitive in the presence of salts. Addition of 80mM Na2SO4 in dye solution decreased the dye rejection more than 15%. The rejection enhancement for all cases was negligible by increasing driving pressure from 1 to 4bar. Dyes with low charger were more sensitive to operating pressure than that of dyes with higher charges. All findings supported that acrylic grafted nanomembrane is potentially capable to separate dyes from colored textile effluent.
The decolorization and degradation of triazinic ring-containing azo dye by using TiO2-immobilized photoreactor is reported. A simple and easy method was used for the immobilization of photocatalyst. Reactive Red 198 (RR 198) was used as model compound. Photocatalytic degradation processes were performed using a 5L (bench scale) solution containing dye. Batch mode immersion type method was used for the treatment of dye solution. UV–vis, ion chromatography (IC) and chemical oxygen demand (COD) analyses were employed to evaluate the results of the photocatalytic degradation of RR 198. Dye solution was completely decolorized in relatively short time (35min) after UV irradiation in combination with hydrogen peroxide. The results verified that all of the dye molecules were destructed. Kinetics analysis indicates that the dye photocatalytic decolorization rates followed first order model (R 2 =0.99). Ion chromatography analysis was used to investigate the formation and destruction of aliphatic carboxylic acids and formation of inorganic anions during the process. Formate and oxalate anions were detected as main aliphatic carboxylic intermediates, which were further oxidized slowly to CO2. UV/TiO2/H2O2 process proved to be capable of successful decolorization and degradation of the RR 198.
Metal-organic frameworks (MOFs) have been extensively investigated as catalysts to synthesis of various chemical and eliminate toxic pollutants in water. Herein, MOF was used as an efficient catalyst for the halogenation of aromatic materials (aniline, b-naphthol, and naphthalene). The rod-like MIL-88A as an iron-based MOF was synthesized using Fe3+ with fumaric acid in water as a green solvent. The synthesized catalyst was characterized by FT-IR, XRD, SEM, and Raman. The rod-like MIL-88A is evaluated as the heterogeneous catalyst to activate KBr/I for the halogenation of aromatic compounds. 1HNMR and 13CNMR were used to characterize the halogenated aromatic materials. Halogenation of aromatic rings has been studied using potassium bromide (KBr) and potassium iodide (KI) as brominating and iodinating agents in the presence of rod-like MIL-88A as oxidant under solvent-free reaction (grinding) conditions. The halogenation yield of aromatics materials was 80–99%. The conversion yield of aniline to 4‑bromo aniline using 0, 10, 20, 30, 40, and 50 mg of rod-like MIL-88A at 25 min and room temperature (25 ºC) were 0%, 76%, 85%, 90%, 95%, and 88%, respectively. In addition, the conversion yield of B-naphthol to 1-Bromo-2-naphthol using a green catalyst was 97%. Also, the conversion yield of Naphthalene to 1-Bromonaphthalene using a rod-like catalyst. In most cases, mono-halogen derivatives were obtained in good yield without the aid of strong acids. In addition, the rod-like MIL-88A catalyst shows excellent stability and can be reused after proper washing treatments. It could be concluded that green synthesized rod-like MIL-88A could be used as an environmentally friendly catalyst for the halogenation of aromatics via grinding as a solvent-free reaction at room temperature.
In this paper, the adsorption of Acid Black 26 (AB26), Acid Green 25 (AG25) and Acid Blue 7 (AB7) onto Pine Cone (PC) was investigated in aqueous solution. Surface study of PC was investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The effect of operational parameters such as adsorbent dosage, dye concentration, inorganic anion (salt), pH and temperature onto dye removal was studied. The intraparticle diffusion model, the pseudo-first order and the pseudo-second order were used to describe the kinetics data. Equilibrium isotherms were analyzed using Langmuir, Freundlich and Tempkin adsorption models. Thermodynamic parameters of dye adsorption were obtained. The experimental data fitted well to the pseudo-second order kinetics model for dyes. The results indicated that isotherm data of AB26 and AG25 followed Langmuir isotherm and isotherm data of AB7 followed Freundlich isotherm models. The thermodynamic data indicated that the adsorption was endothermic process. Dye desorption studies in aqueous solution at pH 12 showed that maximum desorption of 93%, 97% and 94.5% were achieved for AB26, AG25 and AB7, respectively. It can be concluded that PC could be effectively employed as an effective biosorbent for the removal of dyes.
In this paper, primary–secondary amino silica nanoparticle (PSASN) was synthesized, and its dye removal ability from single and binary systems containing printing dyes was investigated. The synthesized PSASN was characterized by means of Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and BET analyses. Acid blue 92 (AB92), Direct Black 22 (DB22), Direct Red 31 (DR31), and Direct Red 80 (DR80) were used. The kinetics and isotherm of dye adsorption were studied. The effects of PSASN dosage, pH, salt, and initial dye concentration on dye removal were evaluated. Adsorption kinetic was found to conform to pseudo-second-order kinetics. The maximum dye adsorption capacity (Q0) of PSASN for AB92, DB22, DR31, and DR80 were 113.636, 37.453, 114.943, and 41.152 mg/g, respectively. It was found that dye adsorption on PSASN followed Langmuir isotherm. The results showed that the PSASN as an adsorbent with dye adsorption capacity might be a suitable alternative to remove dyes from colored printing wastewater.Keywords: Primary–secondary amino silica nanoparticleSynthesisDye removalBinary systemPrinting wastewater
In this paper, the removal of two anionic dyes from textile effluent in single and binary systems was investigated. Direct Red 23 and Acid Green 25 were used as anionic dyes. The surface characteristics of chitosan were investigated using Fourier transform infrared. The effects of operational parameters such as chitosan dosage, initial dye concentration, salt and pH on dye removal were studied. The isotherms of dye adsorption were investigated. It was found that the isotherm data of Direct Red 23 and Acid Green 25 in single and binary systems followed Tempkin isotherm. In addition adsorption kinetics of dyes was studied in single and binary systems and rate sorption was found to conform to pseudo-second order kinetics with a good correlation. Results indicated that chitosan could be used as a biosorbent to remove the anionic dyes from contaminated watercourses in both single and binary systems of pollutants.
In this work, magnetic alginate was synthesized by encapsulating of Nickel Zinc Ferrite nanoparticle within Ca-alginate.The synthesized magnetic alginate was modified by ethylenediamine using microwave radiation to remove anionic dye from wastewater.The characteristics of magnetic nanoparticle, magnetic alginate and magnetic alginate amide (MAA) were studied using Fourier transform infrared (FTIR) and Scanning electron microscope (SEM).FTIR analysis confirmed the amidation of alginate.Direct Red 31 (DR31) was used as model compound.The effect of operational parameters such as adsorbent dosage, pH and dye concentration on dye removal was evaluated.The kinetic, isotherm, and thermodynamic of dye adsorption was studied.Adsorption kinetic of DR31 was found to conform to pseudo-second order kinetics.It was found that adsorption of DR31 on MAA followed Langmuir isotherm.The thermodynamic study showed that dye removal using MAA was spontaneous, endothermic, and a physisorption reaction.The results indicate that MAA could be employed as a suitable alternative to remove dyes from wastewater.
In this paper, gemini polymeric nanoarchitecture (GPN) as a novel adsorbent was synthesized, and its dye removal ability from single and multicomponent (ternary) systems was investigated. The physical characteristics of GPN were studied using Fourier transform infrared (FTIR). Acid Blue 92 (AB92), Direct Green 6 (DG6), and Direct Red 31 (DR31) were used as model compounds. The isotherm and kinetic of dye adsorption from single and multicomponent (ternary) systems were studied. The effect of operational parameter such as adsorbent dosage, dye concentration, and salt on dye removal was evaluated. The maximum dye adsorption capacity (Q 0) of GPN was 1000mg/g, 1428mg/g, and 1250mg/g for AB92, DG6, and DR31, respectively. It was found that adsorption of AB92, DG6, and DR31 onto GPN followed with Langmuir, Freundlich, and Langmuir isotherms, respectively. Adsorption kinetic of dyes followed pseudo-second order kinetics. The results showed that the GPN as an insoluble polymeric adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored wastewater.
Herein, an eco-friendly biocomposite (metal-organic framework (MIL-53)/Chitosan (biological macromolecule)) was synthesized. MIL-(Fe) (Material Institute of Lavoisier: metal-organic framework) was synthesized and denoted as MIL-53A. The material was modified with different amounts of 3-amino propyl trimethoxy silane for preparing different MILs-53A/NH2. Finally, the surface functionalized metal-organic framework and biological macromolecule (SFMOF/BM) biocomposite was synthesized and characterized using XRD, FESEM, TEM, EDS, BET, TGA, FTIR, and Raman and used to remove emerging pollutants (Direct Red 23 and pharmaceuticals (tetracycline and doxycycline)). Adsorption obeyed a pseudo-second-order kinetic model. The adsorption capacity of the MIL-53A and MIL-53A/NH2 was 3,333 and 10,000 mg/g, respectively. SFMOF/BM had the highest adsorption capacity (12,500 mg/g). Adsorption performance remained high even after five regeneration cycles. The results indicated that SFMOF/BM biocomposite could be used as an environmentally friendly adsorbent of dye and pharmaceuticals. The SFMOF/BM could provide multiple non-covalent interactions to remove different organic pollutants, in which both π-π interactions/stacking and H-bonding are suggested to be responsible for the adsorption of dye, tetracycline, and doxycycline.
No abstract is provided for this article.
Herein, Graphene Oxide (GO), CoFe2O4, CoFe2O4/GO nanocomposite, aluminum fumarate (AlFum), and AlFum-CoFe2O4/GO (ACG) eco-friendly nanocomposites with different amounts of CoFe2O4/GO nanocomposite (5, 10, and 15 wt% denoted as 5ACG, 10ACG, and 15ACG, respectively) were green synthesized and characterized using FTIR, SEM, XRD, TEM, XRD, EDX, and BET. The XRD patterns of ACGs indicate that AlFum is fixed onto the surface of CoFe2O4/GO and its structure is well maintained. The SEM and TEM images indicated the 10ACG with good size distribution and shape. The EDX spectrum of ACG showed the homogeneous distribution of O, Fe, and Co in the synthesized materials. The synthesized ACG nanocomposite dispersed in water could be effortlessly separated from wastewater by an external magnet within several seconds. The dye (Direct Red 23: DR23) adsorption capacity of AlFum, 5ACG, 10ACG, and 15ACG was 120, 145, 230, and 167 mg/g, respectively. The Langmuir isotherm is a more adequate isotherm for characterizing the adsorption (R2 = 0.9998, 0.9918, 0.9997, and 0.9996 for AlFum, ACG-5, ACG-10, and ACG-15 respectively). Adsorption followed the pseudo-second-order kinetic. In addition, the synthesized composite had pharmaceuticals (tetracycline and doxycycline) removal ability.
In this research, decolorization and aromatic ring degradation of colored textile wastewater was investigated by indirect electrochemical process in a batch reactor. The graphite and sodium chloride were used as electrode and supporting electrolyte, respectively. Reactive Yellow 3 (RY3) was used as model compound. The effects of influential variables governing the efficiency of the process such as initial dye concentration, pH, current density, and electrolyte concentration were studied. The decrease of absorbance at UV region in UV–Vis spectra was indicative of the aromatic ring degradation. Kinetic analysis indicates that the electrochemical decolorization rates might be obeyed as a first order model. The UV–Vis data supported the decolorization and degradation of aromatic intermediates of RY3.
In this paper, dye removal ability of sodium alginate (SA) as a biopolymer from ternary systems was investigated. Physical characteristics of SA were studied using Fourier transform infra-red (FTIR) and scanning electron microscopy (SEM). Three textile basic dyes were used as model compounds. The adsorption kinetics, isotherms and thermodynamics were studied. The effect of SA dosage, initial dye concentration and pH on dye removal was elucidated. It was found that adsorption kinetics of dyes followed with pseudo-second order kinetics. In addition, dyes followed with Langmuir, and extended Langmuir isotherm in single and ternary systems, respectively. The thermodynamic data showed that the dye adsorption onto SA was a spontaneous, endothermic and physisorption reaction. Based on the data of present investigation, one could conclude that the alginate being a biocompatible, eco-friendly and low-cost adsorbent might be a suitable alternative for elimination of dyes from colored aqueous solutions.
