In this paper, the surface of magnetic manganese ferrite nanoparticles (MFN) was modified using cetyl trimethylammonium bromide (CTAB). The modified MFN was studied using Fourier transform infrared spectroscopy (FTIR). The adsorption capacity of surface modified MFN (MFN-CTAB) was investigated for dye removal for single and ternary systems. Three anionic dyes, C.I. Direct Red 80 (DR80), C.I. Direct Red 31 (DR31), and C.I. Acid Blue 92 (AB92), were used as model compounds. The effects of operational parameters on dye removal (i.e. adsorbent dosage, dye concentration and salt) and the kinetic and isotherm of dye adsorption were studied. The adsorption kinetic for the dyes was found to be well described by the pseudo-second order model. The maximum dye adsorption capacity (Q ) of MFN-CTAB for DR80, DR31 and AB92 was 83 mg/g, 59 mg/g and 70 mg/g, respectively. The adsorption isotherm data were analyzed using the Langmuir, Freundlich, and Temkin equations. The results revealed that the Langmuir model fitted the adsorption data better. The results showed that the MFN-CTAB as a magnetic adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions.
In this paper, surface of novel biosorbent (Canola hull) was characterized and its dye removal ability at different cationic dye concentrations was studied. The isoelectric point, functional groups and morphology of Canola hull were investigated as biosorbent surface characteristics. Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and UV–Vis spectrophotometry were used. Basic Blue 41, Basic Red 46 and Basic Violet 16 were used as model textile cationic dyes. The presence of functional groups onto Canola hull were investigated using FTIR. The intraparticle diffusion, pseudo-first order and pseudo-second order kinetic models were examined to evaluate the kinetic data and the rate constants were calculated. The Langmuir, Freundlich and Tempkin adsorption isotherm models were applied to describe the equilibrium isotherms. Thermodynamic parameters such as free energy, enthalpy and entropy of dye adsorption were obtained. The FTIR spectrum proved the presence of functional groups such as hydroxyl and amino groups in adsorbent surface. Adsorption kinetic of dyes followed pseudo-second order kinetics. The thermodynamic studies showed that the dye adsorption onto Canola hull is spontaneous, endothermic and physical reaction. The results indicated that Canola hull could be used as a noval natural biosorbent for the removal of cationic dyes.
This study introduces synthesizing and utilizing a novel rGO-ZnO-CdSe composite for the visible-light-driven photocatalytic degradation of basic red 46 (BR46) dye. Employing a hydrothermal approach for synthesis, the composite underwent detailed characterization using FESEM, XRD, and FTIR. The process of photocatalytic degradation was systematically modeled and refined using response surface methodology (RSM). These conditions, including a 0.05 g photocatalyst loading, 14.05 mg/L initial dye concentration, and a pH level of 7.78, resulted in an average degradation yield of 94.59 %. Further investigations into the effects of different scavengers unveiled the dominant role of •OH radicals in the degradation mechanism. The composite demonstrated excellent recyclability, retaining most of its effectiveness over the fifth cycle with minimal efficiency loss. Additionally, significant TOC removal efficiency indicated thorough mineralization and safety assessments confirmed no significant release of hazardous heavy metals post-degradation. This study underscores the importance of optimizing operational parameters and highlights the composite's environmental safety and sustainability.
The present research is focused on the ultrasound assisted adsorption of Acid blue 92 (AB92) and Direct red 80 (DR80) as anionic dyes in single and binary systems onto zeolitic imidazolate framework (ZIF-8) functionalized with 3-Aminopropyltrimethoxysilane (APTES). Different techniques such as Fourier transform infrared (FTIR), scanning electron microscope (SEM), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and thermogravimetric analyses (TGA) were used to characterize the prepared adsorbent. The individual effects and possible interactions between the various parameters including adsorbent dosage, sonication time, initial dye concentrations and pH on dyes removal efficiency were investigated by response surface methodology (RSM). The optimized experimental conditions were fixed at adsorbent dosage 0.005g for AB92 and 0.01g for DR80, pH 2.1, sonication time 15min, and initial dyes concentration 15mgL-1 to get maximum removal percentage (>95.0%). A reliable and intelligent model based on least-squares support vector machine (LS-SVM) was developed to predict dye removal efficiency. The root mean square error (RMSE) of 0.604, 0.734 and 1.549 with high determination coefficient (R2) of 0.999, 0.996 and 0.997 for AB92, DR80 and binary system, respectively, were able to predict and model the adsorption process. The presented model illustrates better performance in predicting dye removal efficiency compared to the kinetic models. The results showed that the adsorption process had better conformation with pseudo-second order model. The adsorption equilibrium data was investigated by Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich isotherm models and the data were well fitted by Langmuir model with maximum adsorption capacity of 633.4 and 500.2mgg-1 for AB92 and DR80 dyes, respectively. APTES@ZIF-8 was regenerated and found to be reusable after four successive cycles without considerable loss in adsorption capacity.
In this paper, graphene oxide (GO) was prepared from graphite and used as an adsorbent to remove cationic dyes from single and binary systems of colored wastewater. The GO was prepared by Hummer method and characterized using Fourier transform infrared, scanning electron microscopy, and X-ray diffraction. Basic blue 41 (BB41), basic red 18 (BR18), and basic red 46 (BR46) were used as model dyes. It was found that the adsorption of dyes on GO followed the Langmuir isotherm and the pseudo-second-order kinetics. The capacity of GO to remove BB41, BR18, and BR46 was 1429, 1250, and 476 mg/g, respectively. The results show that the GO has a good capacity for dye adsorption from single and binary systems of colored wastewater containing cationic dyes.
This paper deals with the application of Soy Meal Hull (SMH), an agricultural by-product, for the removal of direct and acid dyes from aqueous solutions. Four textile dyes, C.I.Direct red 80 (DR80), C.I.Direct red 81 (DR81), C.I.Acid blue 92 (AB92) and C.I.Acid red 14 (AR14) were used as model compounds. Physical characteristics of SMH such as surface area, Fourier transform infra-red (FTIR) and scanning electron microscopy (SEM) were obtained. The surface area of SMH was found to be 0.7623m2/g and the presence of functional groups such as hydroxyl, amine and carbonyl groups were detected. The effect of initial dye concentration, pH, contact time and SMH doses were elucidated at 20±1°C. Results show that the pH value of 2 is favorable for the adsorption of all four dyes. The data evaluated for compliance with the Langmuir, Freundlich and BET isotherm models. It was found that data for DR80 and DR81 fitted well with Langmuir isotherm, for AB92, BET isotherm is preferred, while for AR14, the Freundlich isotherm is the most applicable. The adsorption capacities of SMH for DR80, DR81, AB92 and AR14 were, 178.57, 120.48, 114.94 and 109.89mg/g of adsorbent, respectively. Also, adsorption kinetics of dyes was studied and the rates of sorption were found to conform to pseudo-second order kinetics with good correlation (R 2 ≥0.9977). Maximum desorption of ≥99.8% was achieved for DR80, DR81 and AB92 and 86% for AR14 in aqueous solution at pH 10. Based on the data of present investigation, one could conclude that the SMH being a natural, eco-friendly and low-cost adsorbent with relatively large adsorption capacity might be a suitable local alternative for elimination of dyes from colored aqueous solutions.
In this research, the Date Seed (DS) was investigated to remove the anionic dyes from textile effluent as a biosorbent. Direct Blue 78 (DB78) and Acid yellow 36 (AY36) were used as anionic dyes. The surface characteristics of DS were investigated using Fourier Transform Infra-Red and Scanning electron microscope. The influence of process variables such as adsorbent dosage, initial dye concentration and pH were studied. The isotherm and kinetic of dye adsorption onto DS were studied. The results indicated that the data for adsorption of DB78 and AY36 onto DS fitted well with Langmuir isotherms. The rates of sorption were found to conform to pseudo-second order kinetic with good correlation. Results indicated that DS could be used as a biosorbent to remove the anionic direct and acid dyes from contaminated watercourses.
This paper deals with the removal of textile dyes from aqueous solutions by poly(propylene imine) dendrimer (PPI). Direct red 80 (DR80), Acid Green 25 (AG25), Acid Blue 7 (AB7), and Direct Red 23 (DR23) were used as model dyes. The effects of operational parameters on dye removal such as dendrimer concentration, dye concentration, salt (inorganic anions), and pH have been studied at 25°C. The Langmuir and Freundlich isotherm models were investigated. In addition, dye desorption of dendrimer was studied. The results indicated that acidic pH supported the adsorption of dyes by dendrimer. Furthermore studies of dye concentration and salt effects exhibited that dye removal percentage by dendrimer was decreased. It was found that the isotherm data of DR80, AG25, and DR23 followed Langmuir isotherm and isotherm data of AB7 followed Freundlich isotherm models. Desorption tests showed that maximum dye releasing of 76.5% for DR80, 84.5% for AG25, 87% for AB7, and 93% for DR23 were achieved in aqueous solution at pH 12. Based on the data of present study, one could conclude that the dendrimer being an environmentally friendly adsorbent with relatively large adsorption capacity might be a suitable alternative for elimination of dyes from colored textile wastewater.
Urethane sodium carboxylate (USC) was synthesized and its dye removal ability was investigated. USC characteristics were studied using FTIR and SEM. Basic Blue 41 (BB41), Basic Red 18 (BR18), and Basic Violet 16 (BV16) were used. The effect of adsorbent dosage, dye concentration and salt on dye removal was evaluated. Adsorption kinetics followed pseudo-second order. The USC adsorption capacity was 474, 538 and 298mg/g for BB41, BR18 and BV16, respectively. Adsorption isotherm followed with Langmuir isotherm. The results showed that the USC might be a suitable adsorbent to remove dyes from colored wastewater.
In this study, zeolitic imidazolate framework (ZIF-8) as a metal-organic framework (MOF) and its hybrid nanocomposites based on graphene oxide (GO) and carbon nanotubes (CNTs) were synthesized by facile method at an ambient temperature. The sufficiency of GO and CNT substrates as the main components of the composites to grow nanoscale MOFs and increase dispersive forces were investigated. The characteristics of the MOF and hybrid nanocomposites were studied using FTIR, SEM, XRD, BET and TGA techniques. The prepared nanomaterials applied as adsorbents to remove malachite green (MG) as a cationic dye from colored wastewater. The removal rates of the hybrid nanocomposites were greater than that of the sole MOF. The maximum adsorption capacities were 1667, 2034 and 3300mgg−1 for ZIF-8, ZIF-8@CNT and ZIF-8@GO respectively at 20°C, which could be enhanced at the higher temperatures. The effect of several influential parameters such as MOF loading dosage, adsorbent dosage, solution pH, initial dye concentration and temperature were well studied and optimized using batch adsorption study. The adsorption kinetics, isotherm, activation and thermodynamics were also determined. ZIF-8 and its hybrid nanocomposites were regenerated by a simple ethanol-washing method. The hybrid nanocomposites exhibited stable and high reusability over four cycles. Overall, the simple synthesis, highly-effective, regenerable and stability in aqueous phase features enable prepared hybrid nanocomposites as excellent candidates to adsorptive removal processes.
In this paper, the degradation and mineralization of Butachlor in aqueous solution by nanophotocatalysis using immobilized TiO2 nanoparticles were investigated. Butachlor (N-butoxymethyl-2-chloro-2′,6′-diethylacetanilide) is a persistent organic pollutant in agricultural soil and watercourses. A simple and effective method was used for immobilization of titanium dioxide nanoparticles. UV–vis and Ion Chromatography (IC) analyses were employed to obtain the details of the photocatalytic degradation and mineralization of Butachlor. The effects of operational parameters such as H2O2, inorganic anions (NO3 −, Cl− and SO4 2−) and pH were investigated. The lack of any absorbance in 254nm was indicative of the complete degradation of aromatic intermediates. The mineralization of Butachlor was evaluated by monitoring of the formed inorganic anions (NO3 − and Cl−). Butachlor is effectively degraded following first order kinetics model. Results show that the immobilized titanium dioxide nanoparticle photocatalysis is an effective method for treatment Butachlor from contaminated water.
In this study, Silica aerogel/Polyacrylonitrile/Polyvinylidene fluoride (SAPPF) webs were fabricated using the electrospinning method and used for the removal of Basic Red 18 (BR18). The characteristics of the SAPPF membrane webs were evaluated using SEM, FTIR, TGA, XRD, and tensile strength. The results indicated successful fabrication of the SAPPF webs with porous morphology of nanofibers and higher thermal resistance in comparison to the Polyacrylonitrile/Polyvinylidene fluoride (PAN/PVDF) membrane webs. In addition, the tensile properties of nanofibers were enhanced by adding silica aerogel to the structure of nanofiber webs. Moreover, the influence of operational parameters such as contact time, dosage of adsorbent, and initial dye concentration was investigated. The equilibrium data were fitted by the Langmuir isotherm.
In this paper, three metal-organic frameworks (Materials of Institut Lavoisier: MILs-100 (Fe)) as porous nanomaterials were synthesized using FeCl3, Fe(NO3)3 and Fe2(SO4)3 and denoted as MIL-100-1, MIL-100-2 and MIL-100-3, respectively. The synthesized MILs-100 (Fe) were characterized by FTIR, SEM, TEM, XRD, UV–vis DRS and zeta potential. Basic Blue 41 (BB41) was used as a model dye to study the photocatalytic dye degradation ability of the synthesized metal organic frameworks. The results showed that the synthesized nanomaterials decolorized BB41. The decolorization kinetics followed first-order kinetic model. The rate constant was 0.0034, 0.0041, 0.0091 and 0.0289 (1/min) for 0.01, 0.02, 0.03 and 0.04 g of photocatalyst. The data indicated that MIL-100-1 had higher photocatalytic activity. The photocatalytic activity of MIL-100 did not decrease significantly for three cycles. It can be concluded that the synthesized MILs-100 (Fe) could be used as alternative catalysts for photocatalytic decolorization of colored wastewater.
No abstract is provided for this article.
In this paper, copper oxide nanoparticle was synthesized, and its surface was modified using N-(2aminoethyl)-3-(trimethoxysilyl)propylamine.The bi-amino surface functionalized nanoparticle (BASFN) was used to remove anionic dyes from single and binary systems.The scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDAX) and X-ray diffraction were used to characterize the nanoparticle.Direct Red 80 (DR80) and Direct Green 6 (DG6) were used as anionic dyes.The effect of adsorbent dosage, dye concentration and pH on dye removal was evaluated.Kinetic of dye adsorption on BASFN followed pseudo-second order.The results showed that the experimental data were correlated reasonably well by Langmuir and Freundlich isotherm in single and binary system, respectively.The maximum dye adsorption capacity (Q 0 ) of BASFN was 217 and 250 mg/g for DR80 and DG6, respectively.
Some graphene-based adsorbents such as mesoporous graphene oxide/TiO2 nanocomposite, thermally treated graphene nanosheets, holey graphene frameworks and 3-D graphene-based porous adsorbent have recently been introduced as promising adsorbents for post-combustion CO2 capture while, their CO2 adsorption kinetics and mechanisms have not sufficiently been reported by the scholars. To begin, in this study, CO2 capture kinetics of these adsorbents are investigated by different adsorption kinetic models including pseudo-first order model, pseudo-second order model, Avrami model, and the fractal-like exponential kinetic model. Subsequently, the Eyring and Arrhenius equations are used to determine the activation parameters related to the CO2 adsorption on these adsorbents. Furthermore, a mechanism is proposed to describe the negative activation energy assessed for CO2 adsorption on the studied adsorbents. Eventually, the rate-limiting kinetic models including interparticle diffusion model, intraparticle diffusion model and Boyd’s film diffusion model are applied to determine CO2 capture mechanisms on the mentioned graphene-based adsorbents.
