A novel composite has been fabricated by using MOF and chitin as a natural and biocompatible compound. To this purpose, MOF was synthesized by using 2-aminoterephthalic acid and iron (III) chloride hexahydrate and then reacted with Cl-functionalized chitin. The resulting composite was characterized and utilized as a catalyst for degradation of methylene blue both in dark condition and under visible light irradiation. The results indicated superior catalytic activity under visible light irradiation. Furthermore, study of the reaction variables, including basicity, dye concentration and catalyst loading showed that the highest catalytic activity was achieved at basic condition. It was also found that both initial dye concentration and catalyst loading can affect the catalytic activity. To disclose the merits of the composite compared to its individual components, kinetic studies of the photo-degradation process in the presence of the composite, chitin and MOF have been performed. The results confirmed superior activity the composite compared to its components. The study of the mechanism of the reaction using scavengers confirmed that the created holes (h+) are the most effective species in the process of photocatalytic degradation of MB. Notably, the catalyst was recyclable and could be used for degradation of other dyes.
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In this paper, the adsorption of Acid Yellow 36 (AY36), and Acid Red 73 (AR73) onto Pine Cone (PC) was investigated in aqueous solution in a batch system with respect to initial dye concentration, pH, contact time, temperature, inorganic anions (salt) and biosorbent doses at 25 oC. Surface studies of PC were investigated by Fourier transform infrared (FTIR). Studies of dye concentration and salt effects exhibited that dye removal percentage by PC was decreased. The results indicated that acidic pH supported the adsorption of this dyes by PC. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetics data. The experimental data fitted well to the pseudo-second - order kinetics model for both dyes. Equilibrium isotherms were analyzed by Langmuir and Freundlich adsorption models. It was found that the isotherm data of AY36 and AR73 followed langmuir and Freundlich isotherms, respectively. Effective desorption of dyes were showed that adsorption of dyes on PC is physical process. The results indicate that PC could be employed as effective biomaterial for the removal of dyes from textile wastewater.
In this paper, the isotherm, kinetic, and thermodynamic of cationic dye removal onto inorganic adsorbent (Feldspar) were investigated in single and binary systems. Basic Red 18 (BR18) and Basic Blue 41 (BB41) were used as cationic dyes. The characterization of the Feldspar was carried out using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) techniques. The effect of operational parameters such as adsorbent dosage, initial dye concentration, pH, ionic strength, and temperature on dye removal was studied. It was found that the adsorption of BR18 and BB41 onto Feldspar followed with Langmuir and extended Langmuir isotherms in single and binary systems, respectively. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetic in single and binary system. The thermodynamic data showed that dye adsorption onto Feldspar was spontaneous, endothermic, and physisorption reaction. Based on the data of the present investigation, one could conclude that the Feldspar as an eco-friendly and low-cost adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions containing cationic dyes.
This study reports the facile, green synthesis of ternary magnetic photocatalyst composites (COF/HKUST/CoFe2O4) with tunable COF: HKUST ratios, integrating an amide-based covalent organic framework, the metal-organic framework (HKUST-1), and CoFe2O4 nanoparticles. The hybrid was comprehensively characterized by FTIR, XRD, SEM, MAP and EDX, TEM, VSM, AFM, PL and DRS. The optimized COF/HKUST/CoFe2O4 composite achieved 95% degradation of 90 mg/L doxycycline (DOX) within 180 min and 97% removal of 20 mg/L methylene blue (MB) in 150 min under visible-light irradiation. This efficacy stems from synergistic heterointerface interactions that promote efficient charge separation, accelerated electron transfer, and suppressed recombination. Kinetic modeling confirmed second-order degradation for DOX and first-order for MB, while scavenging assays identified photogenerated holes (h⁺) as the dominant oxidative species, followed by hydroxyl radicals and superoxide anions. Notably, the composite enables straightforward magnetic separation, and robust recyclability, retaining > 72% pollutant degradation efficiency over five consecutive cycles. This work advances sustainable wastewater remediation by providing a low-cost, scalable photocatalyst that aligns with circular economy principles and United Nations Sustainable Development Goal 6, offering a versatile platform for mitigating antibiotic resistance and dye-induced aquatic toxicity.
In this paper, the amine functionalized magnetic carbon nanotube (AFMCNT) was synthesized and used to remove anionic dyes from single and binary systems. The characteristics of AFMCNT were investigated using Fourier transform infrared and scanning electron microscope. Acid Blue 92 (AB92), Acid Red 14 (AR14), and Direct Red 31 (DR31) were used as anionic dyes. The effect of operational parameters (AFMCNT dosage and pH) on dye removal was investigated. The adsorption isotherm and kinetics were studied. The isotherm data in single and binary systems followed Langmuir isotherm. The maximum adsorption capacity (Q0) of AB92, AR14, and DR31 was 333, 370, and 323 mg/g, respectively. Dye adsorption kinetics in single and binary systems followed pseudo-second-order kinetics model. The results showed that AFMCNT was an effective adsorbent to remove cationic dyes from binary systems.
To address the challenges posed by conventional water treatment technologies, it is essential to develop non-toxic adsorbents that are highly effective in removing pollutants. Herein, innovative, environmentally friendly chitosan-zeolitic imidazolate framework 67 (CSZ67) biocomposite beads were synthesized. They were used to remove the MG dye and Tetracycline. The Co2+ ions within the chitosan/Co2+ matrix serve as nucleation sites for the in-situ growth of ZIF-67. CSZ67 biocomposite beads with different [CS]:[Co] molar ratios named CSZ67-1 (1:0.5), CSZ67-2 (1:0.34), and CSZ67-3 (1:0.17) were synthesized. CSZ67-1 biocomposite exhibited the highest removal efficiency (96 %), and adsorption capacity (476 mg/g). The electrostatic interactions and π-π stacking are the dominant adsorption mechanisms. Dye removal follows the pseudo-second-order kinetic and Freundlich isotherm. The findings indicated that the biocomposite CSZ67-1, demonstrating a 75 % removal efficiency for tetracycline, not only exhibits high efficacy in adsorbing malachite green cationic dye but also performs effectively in the adsorption of tetracycline.
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Mesoporous polyvinyl alcohol/chitosan/silica composite nanofiber (PCSCN) as a dye adsorbent was prepared using electrospinning and used for removing Direct Red 80 (DR80). The PCSCN was characterized using SEM, FTIR, and AFM. Dye adsorption was an endothermic reaction and followed the Langmuir isotherm and pseudo‐second order kinetics. The effects of operational parameters were investigated. The optimum condition was initial pH 2, adsorbent dosage = 0.015 g, initial dye concentration = 15 mg/L, and the optimum adsorption capacity of 322 mg/g. The results showed that PCSCN was a promising adsorbent to remove dye from colored wastewater. © 2018 American Institute of Chemical Engineers Environ Prog, 38: S100–S109, 2019
Corrosion inhibitors are widely used in acid solutions during pickling and descaling. In this study, the inhibition performance of different alkaline metal salts in the concentration range 0-0.1 M has been found out. The corrosion behavior of low carbon steel in 1 M HCl in the presence of different metal cations and different anions is studied using weight loss and OCP (Open Circuit Potential) methods at 20 åC. It is found that the addition of these salts inhibits the corrosion markedly. The inhibition effect is in the following order Na2SO4 >NaI > LiCl > NaCl > KCl > NaNO3 > NaBr.
NiO‐MnO 2 nanocomposite was synthesized and its dye removal ability from single and binary systems was investigated. The characteristics of the synthesized nanocomposite were studied using scanning electron microscopy (SEM), X‐ray diffraction (XRD), and Fourier transform infrared (FTIR). Basic Blue 41 (BB41), Basic Red 18 (BR18), and Basic Red 46 (BR46) were used. Artificial neural network (ANN) as an intelligent system was used to model the dye removal process. The effect of operational parameters such as adsorbent dosage and initial dye concentration on dye removal was evaluated. It was found that adsorption of BB41, BR18, and BR46 on the nanocomposite followed the Langmuir, Freundlich, and Tempkin isotherms, respectively. The adsorption kinetics of dyes were found to conform to pseudo‐second‐order kinetics in both single and binary systems. The results showed that the predictions of the ANN models were in close agreement with experimental data. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 111–119, 2017
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The effect of ozonation on the decolorization and degradation of an anthraquinone dye (C.I. Reactive Blue 19), performed in a laboratory scale cylindrical batch reactor, was studied. UV–Vis, ion chromatography (IC), chemical oxygen demand (COD) and total organic carbon (TOC) analyses were employed. The effect of operational parameters on decolorization such as ozone dosage, pH, dye concentration and the electrolytes was studied. Results showed that the ozonation was a very effective method for reactive dye decolorization. A rapid decrease of pH during the ozonation process gave evidence for production of acidic by-products. Sulfate, nitrate, formate, and acetate were identified as main oxidation products by ion chromatography. The reduction of COD and TOC showed partial degradation and mineralization of this dye.
In this paper, the surface modification of zinc oxide nanoparticle (ZON) by amine functionalization was studied to prepare high capacity adsorbent. Dye removal ability of amine-functionalized zinc oxide nanoparticle (AFZON) and zinc oxide nanoparticle (ZON) was also investigated. The physical characteristics of AFZON were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Acid Blue 25 (AB25), Direct Red 23 (DR23) and Direct Red 31 (DR31) were used as model compounds. The effect of operational parameters such as dye concentration, adsorbent dosage, pH and salt on dye removal was evaluated. The isotherm and kinetic of dye adsorption were studied. The maximum dye adsorption capacity (Q 0) was 20mg/g AB25, 12mg/g DR23 and 15mg/g DR31 for ZON and 1250mg/g AB25, 1000mg/g DR23 and 1429mg/g DR31 for AFZON. It was found that dye adsorption followed Langmuir isotherm. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% AB25, 86% for DR23 and 90% for DR31 were achieved in aqueous solution at pH 12. Based on the data of the present investigation, it can be concluded that the AFZON being an adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored aqueous solutions.
