Herein, the green synthesis of heterogeneous dual functional MIL88A-on-MIL88B hybrids (MIL: Materials InstituteLavoisier) with different amounts of MIL88B compared to MIL88A, including 1:2, 1:1, and 2:1, has been carried out. The photocatalytic degradation of tetracycline and adsorption of tetracycline and dyes (Direct Red 80, Direct Red 23, Acid Blue 92, and Reactive Orange 14) were investigated. Although the ratio of MIL88A-on-MIL88B (1:1) hybrid displayed the best activity, there is a slight difference in the photocatalytic performance of the other mass ratios studied. The result revealed that after 70 min of forming MIL88A on MIL88B, the best pollutant removal performance is obtained. During the limited synthesis time, the lopsided growth of MIL88A on the MIL88B surface limits the formation of sufficient functional groups and new pores between MIL88B as the substrate and MIL88A, which are effective and decisive in the performance. In the photocatalytic studies, the synthesized composite had good compatibility with the zero-order kinetics, and hydroxyl radicals were recognized as the most active species in the photocatalytic reaction. In the adsorption process, the MIL88A-on-MIL88A composite followed pseudo-second-order kinetics and the Langmuir isotherm. Besides, mechanisms such as π-π interaction/stacking, hydrogen bonding, and π-metal interaction were proposed for the pollutant adsorption process.
Excessive discharge of hazardous azo dyes into the aquatic ecosystem is a global environmental concern. Here, we develop a green approach to remediate dye pollutions in water by fabricating an easy-separable bio-nanocomposite, based on whey protein concentrate, its nanofibrils, and montmorillonite nano-clay. To characterize the nanocomposite, we used SEM, FT-IR, XRD, and BET techniques. Nanofibrils lead to a uniform dispersion of montmorillonite in the whey protein matrix and also reinforce the nanocomposite. The adsorption efficacy was monitored in a batch system, using cationic dyes (Chrysoidine-G, Bismarck brown-R), reactive dyes (reactive black-5, reactive orange-16), acid dyes (acid red-88, acid red-114), and direct dyes (direct violet-51, Congo red). This nanocomposite adsorbed different dye classes, cationic dyes quicker (> 82%, after 4 h), and reactive dyes slower. Then, the effect of initial dye concentration, pH, contact time, adsorbent dose, and temperature on Chrysoidine-G adsorption was explored. The adsorbent showed a high removal (>93%) for a wide concentration range of Chrysoidine-G, also acidic pH and higher temperature are more favorable for the process. Equilibrium adsorption parameters were reasonably fitted with a linear (Nernst) isotherm model. The results indicated the existence of an unlimited number of absorption sites, i.e. no saturation was achieved under our experimental conditions (q max(Exp) = 731 mg/g). Kinetic data were fitted with pseudo-second-order and intra-particle diffusion models. We conclude that this nanocomposite is a green adsorbent with potential use for wastewater treatment and related purposes. Highlights We produced an easy-separable bio-nanocomposite using whey nanofibrils and MMT, with high adsorption capacity Nanofibrils help disperse MMT particles uniformly in the WP matrix The adsorbent’s performance was compared to the adsorbents in absence of MMT and nanofibrils This composite adsorbs cationic, anionic, direct and reactive azo dyes with different kinetics Adsorption isotherms and kinetics are studied in detail
No abstract is provided for this article.
In this paper, the preparation, characterization and dye adsorption properties of novel biocompatible composite (Chitosan–zinc oxide nanoparticle) (CS/n-ZnO) were investigated. Zinc oxide nanoparticles were immobilized onto Chitosan. Physical characteristics of CS/n-ZnO were studied using Fourier transform infra-red (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray spectroscopy (WDX). Two textile dyes, Direct Blue 78 (DB78) and Acid Black 26 (AB26), were used as model compounds. The effect of CS/n-ZnO doses, initial dye concentration, salt and pH were elucidated at 20±1°C. The isotherm and kinetics of dye adsorption were studied. The presence of functional groups such as hydroxyl, amino and carbonyl groups were detected. Results showed zinc oxide nanoparticles were immobilized onto Chitosan. The data were evaluated for compliance with the Langmuir, Freundlich and Tempkin isotherm models. It was found that AB26 and DB78 followed with Langmuir and Tempkin isotherms, respectively. In addition, adsorption kinetics of both dyes was found to conform to pseudo-second order kinetics. Based on the data of present investigation, one could conclude that the CS/n-ZnO being a biocompatible, eco-friendly and low-cost adsorbent might be a suitable alternative for elimination of dyes from colored aqueous solutions.
No abstract is provided for this article.
Herein, ZIF-8 composite (g-C3N4@ZIF-8/Ag3PO4) was synthesized and used for the degradation of Malachite Green (MG) and tetracycline. The catalyst was characterized using XRD, SEM, DRS, FTIR, and TGA. The degradation rates of MG under various conditions to determine the optimal operating parameters for water treatment was investigated. The results demonstrated that the MG degradation fit well with a second-order kinetic model. ZIF-8 composite achieved an impressive 90 % degradation of MG (20 mg/L), outperforming g-C3N4@ZIF-8 and Ag3PO4, with the highest rate constant. As the initial concentration of MG increased to 80 mg/L, the rate of degradation exhibited a substantial reduction, while it increased with a higher dosage (0.004 g) of the catalyst and the best results were achieved in a natural pH environment. In addition, the g-C3N4@ZIF-8/Ag3PO4 composite had tetracycline degradation ability in wastewater.
In this paper, polyacrylonitrile (PAN)–polyamidoamine (PAMAM) composite nanofibers were synthesized using electrospinning technique and their dye removal ability was investigated. The functional groups, morphology, total surface area and pore diameter distribution of nanofibers were studied by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), the Brunauer–Emmett–Teller (BET) and the Barret–Joyner–Halend (BJH) methods, respectively. Direct red 80 (DR80) and Direct red 23 (DR23) were used as the model compounds. The effects of adsorbent dosage, initial dye concentration, and solution pH on dye removal were evaluated. Kinetics and isotherm of dye adsorption were found to conform to pseudo-second order kinetics and Langmuir model, respectively. The maximum dye adsorption capacity (Q 0) of PAN/PAMAM composite nanofiber was 1666.66 and 2000 mg/g for DR80 and DR23, respectively.
In this article, adsorption modeling and sensitivity analysis were presented to describe the adsorption of textile dyes, Solophenyl Red 3BL (SR) and Pergasol Red 2B (PR), from colored wastewater onto the natural adsorbent (soy meal hull). The numerical model was used to solve the mathematical equations governing the adsorption procedure. The experimental results of SR and PR removal were compared with those results predicted by the numerical model. A sensitivity analysis of dye removal from solution phase has been carried out. The model predictions were compared to those results obtained from experimental tests for adsorption of dyes, and a close agreement was achieved. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
In this paper, poly(vinyl alcohol) (PVA)–triethylenetetramine (TETA) nanofiber was prepared and crosslinked using glutaraldehyde (GA). Dye removal ability of the modified nanofiber (PVA–TETA–GA) from colored wastewater was studied. Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to investigate the characteristics of the modified nanofiber. The effect of operational parameters (adsorbent dosage, pH, and the initial dye concentration) on dye removal was studied. The dye adsorption isotherm and kinetics on the nanofiber follows the Langmuir isotherm and pseudo-second-order kinetics, respectively. The results showed that the PVA–TETA–GA nanofiber is a suitable adsorbent with high dye adsorption capacity.
This paper deals with the degradation of Fenitrothion (an agricultural organophosphorous pollutant) in aqueous solution by titania nanophotocatalysis. The immersion type method was used for the treatment of polluted water. UV-Vis, ion chromatography and chemical oxygen demand analyses were employed to obtain the details of the photocatalytic degradation and mineralization of Fenitrothion. The numerical model was used to solve mathematical equation describing pollutant degradation process. The simulation results were compared to those results obtained from experimental tests and close agreement was achieved. Results show that the immobilized titania nanophotocatalysis is the effective method for removing Fenitrothion from contaminated water.
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In this article, surface modification of feldspar using hexadecyltrimethyl ammonium bromide (HDTMA) and its dye removal ability in single and binary systems was studied. Acid Black 1 (AB1) and Acid Red 14 (AR14) were used as model dyes. The monocomponent Langmuir isotherm model was applied to experimental data and the isotherm constants were calculated for both dyes. The monolayer coverage capacities of surfactant‐modified feldspar (HDTMA‐feldspar) for AB1 and AR14 dyes in single solution system were found as 6.369 mg/g and 3.984 mg/g, respectively. It was observed that the equilibrium uptake amounts of AB1 and AR14 dye in binary mixture onto sorbent decreased with increasing concentrations of the other dye resulting in their antagonistic effect. Equilibrium adsorption for binary systems was analyzed by using the Extended Langmuir and Jain and Snoeyink Modified Extended Langmuir models. The rate of kinetic processes of single and binary dye systems onto adsorbent was described by using two kinetics adsorption models. The pseudo‐second‐order model was the best choice among the kinetic models to describe the adsorption behavior of single and binary dyes onto HDTMA‐feldspar. Thermodynamic parameters showed that dye adsorption on HDTMA‐feldspar were exothermic and unspontaneous in nature. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Herein, Fe based metal-organic framework (Materials Institute Lavoisier: MIL100) and its nanocomposites with different titania nanofiber (TNF) amounts (0.05, 0.07 and 0.09 g denoted as MIL100/TNF5, MIL100/TNF7 and MIL100/TNF9) were synthesized using a facile and green procedure at room temperature and atmospheric pressure. The TNF inorganic nanofiber was synthesized using the electrospinning method. The nanomaterials were fully characterized. They were used for visible-light photocatalytic degradation of Methylene Blue (MB). The surface area of MIL100/TNF7 was 1194.48 m2/g. The data indicated the MIL100 diameters ranging from 22 to 72 nm. The decolorization percentage of the synthesized materials at different dosages including 0.003, 0.004, 0.005, and 0.006 g was 39.80, 54.96, 63.31, and 72.10% for MIL100, 25.50, 26.81, 29.23, and 35.62% for TNF and 46.42, 70.85, 88.3, 97.96 and 99.40% for MIL100/TNF7, respectively. The MIL100/TNF7 nanomaterial had higher dye degradation ability, reusability, and stability over five cycles. Dye degradation followed first-order kinetics.
In this paper, the blend nanofiber (poly(vinyl alcohol) (PVA)/chitosan (CS)/diethylenetriamine (DETA)/ethylenediamine (EDA): PVA/CS/DETA/EDA) was prepared by electrospinning and cross‐linked by glutaraldehyde. The cross‐linked blend nanofiber by glutaraldehyde (CBNG) was characterized by FTIR and SEM. The homogenous surface diffusion model (HSDM) was used for expressing the dye adsorption on CBNG from colored wastewater. Experimental data were used to calculate the isotherm parameters as well as the kinetic parameters describing mass transfer resistances due to film diffusion (k f ) and diffusion coefficient (D s ). The sum square error (SSE) values for the adsorption of Acid Red 18 (AR18), Direct Blue 78 (DB78), and Direct Red 23 (DR23) were 0.0221, 0.0632, and 0.0038, respectively. Thus, the experimental and theoretical data showed a good agreement. Dye removal by CBNG followed the Langmuir isotherm and pseudo‐second order kinetics models. Thermodynamic studies indicated dye adsorption onto the nanofiber was an endothermic, spontaneous, and physisorption process. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1634–1642, 2017
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This article deals with the dye adsorption and desorption properties of Mentha pulegium ( MP ) from single and binary (mixture of dyes) systems. Direct Red 80 (DR80) and Acid Black 26 (AB26) were used as model dyes. The Fourier transform infrared (FTIR) was used to investigate the biosorbent characteristics. The effects of biosorbent dosage, contact time, dye concentration, salt, and pH on dye removal were studied. The biosorption isotherms, kinetics, and thermodynamic were studied. In addition, dye desorption was carried out to study adsorbent recovery. The results showed that the isotherm data of single and binary systems of dyes followed the Langmuir isotherm. The adsorption kinetic of the dyes was found to conform to a pseudosecond order kinetic model. Desorption tests showed maximum dye releasing of 97% for DR80 and 95% for AB26 in single system and 92% for DR80 and 94% for AB26 in binary system of dyes at pH 12. The thermodynamic data showed that the biosorption process is spontaneous, endothermic, and a physisorption reaction. It can be concluded that MP is an ecofriendly biosorbent to remove dyes from single and binary systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
