The feasibility and performance of photocatalytic degradation and toxicity reduction of textile dye (Acid Blue 25) have been studied at pilot scale in an immobilized titania nanoparticle photocatalytic reactor. UV–Vis, Ion Chromatography (IC) and chemical oxygen demand (COD) analyses were employed to obtain the details of the photocatalytic dye degradation. The effects of operational parameters such as H2O2, pH and dye concentration on the photocatalytic degradation of Acid Blue 25 were investigated. The aliphatic carboxylic acid intermediates and inorganic anions generated during the dye degradation process were analyzed. Daphnia magna bioassay has been used to test the progress of toxicity during the treatment process. Total disappearance of dye was attained. During the photocatalytic treatment process, the residual acute toxicity was reduced. The results showed that immobilized titania nanophotocatalysis capable to degradation and toxicity reduction of acid dye textile wastewater.
Herein, Materials Institute Lavoisier (MIL-125(Ti))/carbon nanotube (CNT) nanoporous composites (MIL/CNT) were synthesized by hydrothermal method. Different amounts of CNT (0.01 g and 0.03 g) were used to synthesize nanocomposites (denoted as MIL/CNT(0.01) and MIL/CNT(0.03), respectively). The synthesized nanomaterials (MIL, MIL/CNT(0.01) and MIL/CNT(0.03)) were characterized by XRD, FTIR, TGA, BET, SEM, and zeta potential and used for photocatalytic dye degradation. Reactive Black 5 (RB5) was used as a model pollutant. The zeta potential of MIL and MIL/CNT (0.01) were −27.7 mV and 19.2 mV, respectively. The data showed that that MIL/CNT(0.01) nanocomposite had higher photocatalytic dye degradation due to the synergistic effect of CNT. Dye decolorization by the nanomaterials followed the zero-order kinetics reaction. The decolorization rate was 0.0015, 0.0019, 0.0024 mg/L min for MIL, MIL/CNT(0.01) and MIL/CNT(0.03), with the correlation coefficient of 0.9639, 0.9906, and 0.9757, respectively. The synthesized catalysts were reusable over two cycles.
This work aims to introduce new chelating materials based on lignocellulosic biomass from Gundelia Tournefortii (GT). In terms of functionalization, GT has been modified using ethylenediaminetetraacetic dianhydride (EDTAD). Functionalized/modified Gundelia Tournefortii (EGT) and GT were characterized by the Fourier Transform Infra-red (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), and X-ray Diffraction (XRD) analyses. In this regard, adsorption experiments (continuous fixed-bed column, batch) have been conducted using EGT to adsorb contaminants (Cu (II) and dye). The batch tests investigate the optimum condition, factors like: duration of experiment, the value of pH, EGT amount, and the initial concentration of the prepared solution. According to experimental data, sorption followed Langmuir isotherm. Besides, the most suitable kinetics model was pseudo-second-order. The capacity of this adsorbent reached 156.78 mg/g as the maximum amount. In terms of fixed-bed column study, functional items such as flow rate, bed depth, inflow concentration on EGT performance in the continuous adsorption column were assessed. Results confirmed that the enhancement in the inflow concentration and bed length, and flow rate decline, reinforced EGT removal capability. The dynamic capacity of this adsorbent is projected to reach 15.61 mg/g as the maximum amount in certain conditions. Modeling of experimental breakthrough curve demonstrated that the Thomas model is better described rather than Yoon-Nelson and Adams-Bohart models. Also, the results indicated that the Lignocellulosic biomass had dye (Direct Red 23: DR23) removal ability.
Degradation and mineralization of two agricultural organic pollutants (Diazinon and Imidacloprid as N-heterocyclic aromatics) in aqueous solution by nanophotocatalysis using immobilized titania nanoparticles were investigated. Insecticides, Diazinon and Imidacloprid, are persistent pollutants in agricultural soil and watercourses. A simple and effective method was developed to immobilization of titania nanoparticles. UV–vis, ion chromatography (IC) and chemical oxygen demand (COD) analyses were employed. The effects of operational parameters such as H2O2 and inorganic anions (NO3 −, Cl− and SO4 2−) were investigated. The mineralization of Diazinon and Imidacloprid was evaluated by monitoring of the formed inorganic anions. The selected pollutants are effectively degraded following first order kinetics model. Results show that the nanophotocatalysis using immobilized titania nanoparticle is an effective method for treatment Diazinon and Imidacloprid from contaminated water.
The unique properties of graphene oxide (GO) nanosheets were integrated with the superparamagnetic characteristics of the CuFe2O4 nanoparticles to synthesize the magnetic graphene oxide (MGO), which was chemically modified with 3-amino propyl trimethoxy silane (APTMS) to functionalize the amine group on MGO (MGO-NH2). Afterward, MGO-NH2 was activated with glutaraldehyde (GLU) as a crosslinking agent to synthesize the functionalized MGO (fMGO) and its capability toward covalent Laccase immobilization was investigated. The comprehensive structural analysis using various characterization techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) clearly confirmed the covalent attachment of laccase onto MGO. The response surface methodology (RSM), based on Central Composite Design (CCD), was applied to optimize the immobilized Laccase (nanobiocatalyst)-mediated biodegradation of Direct Red 23 (DR23), as an azo dye, by considering independent variables such as nanobiocatalyst dosage, dye concentration, and pH. The optimal conditions to obtain the maximum decolorization yield (95.33%) were nanobiocatalyst dosage = 290.23 mg/L, dye concentration = 19.60 mg/L, and pH = 4.23. The obtained correlation coefficient and the adjusted one of 0.9651 and 0.9336, respectively, imply the nice model fitness. Therefore, structural characterization along with the experimental decolorization results introduced the synthesized superparamagnetic GO as an environmentally friendly nanobiocatalyst for effective decolorization purposes.
Novel chitosan-tailored graphene oxide (CSGO)-embedded poly(ether-b-amide) (PEBA) thin film nanocomposite (TFN) membranes have been fabricated and coated on ultraporous polyethersulfone. To synthesize the nature-friendly CSGOs, covalent functionalization of GO have been done by carbohydrate polymer, chitosan. The green nanofillers were then incorporated in the PEBA selective layer at different loadings up to 2 wt.%. The structural studies were performed using FTIR, XRD, SEM, AFM and contact angle analyses, which confirmed the appropriate filler dispersion and enhanced hydrophilicity of the TFN membranes. Moreover, using nanofiltration (NF) for malachite green (MG) dye rejection, the effects of CSGO loadings, transmembrane pressure, feed concentration and duration on the membranes separation performance were also assessed. The membrane loaded with 0.1 wt.% of CSGO showed the highest permeate flux, 3.2 times higher than that of TFC membrane. The surface-decorated CSGO-filled TFN membranes also represented improved antifouling performance, because the CSGO nanofillers had positive charge due to the protonation of chitosan N-H groups in acidic medium of this work.
Herein, binary and ternary MOF/carbon based composites (MOF/Carbon nitride/Graphene oxide) (novel binary (NH2-MIL-88B(Fe)/g-C3N4) (MOF/Carbon nitride) and ternary (NH2-MIL-88B(Fe)/g-C3N4/GO) (MOF/Carbon nitride/Graphene oxide) composites) were synthesized and used as photocatalysts for the elimination of Direct Red 23 (D-Red23) and Tetracycline Hydrochloride (TC-H). NH2-MIL-88B(Fe)/g-C3N4/GO (MILB/g/GO) ternary composites with three different amounts of GO including 3, 7, and 11 wt% were synthesized and denoted as MILB/g/(3%)GO, MILB/g/(7%)GO, and MILB/g/(11%)GO. g-C3N4 and GO (with three different amounts 3, 7, and 11 wt%) were incorporated to synthesize MILB/g/(3%)GO, MILB/g/(7%)GO and MILB/g/(11%)GO ternary composites. Several analyses were used to characterize the materials. The MILB/g/(3%)GO demonstrated the highest pollutant degradation efficiency. The degradation rate of dye and Tetracycline after 70 min of light radiation using MILB/g/(3%)GO in a photo-Fenton-like reaction was about 99% and 96%, respectively. The creation of a heterojunction structure using g-C3N4, and the simultaneous incorporation of the optimum amount of GO led to a remarkable amelioration in photocatalytic properties and the extraordinary performance of MILB/g/(3%)GO in the pollutants degradation process.
In this study, MnO2 nanoparticle was synthesized by a simple method. Dye removal ability of the synthesized nanoparticle was investigated. Basic Blue 41 (BB41), Basic Red 46 (BR46), and Basic Red 18 (BR18) were used as model compounds. The structure of the synthesized adsorbent was characterized by scanning electron microscopy and Fourier transform infrared techniques. Least square support vector machine (LSSVM) was used to model the dye removal. The graphical plots and the values of statistical parameter showed LSSVM as an intelligent model suitable for modeling of dye adsorption. The effect of adsorbent dosage and initial dye concentration on dye removal was investigated. The kinetic and isotherm of the adsorption process were studied. The studies confirmed that the adsorption of BB41, BR46, and BR18 followed the Freundlich, Langmuir, and Freundlich isotherms, respectively. Adsorption kinetic of dyes was found to conform to pseudo-second-order kinetic model.
Corrosion inhibition effect of cationic surfactant DTAB (Dodecyl Threemethyl Ammonium Bromide) on low carbon steel in 1M HCl was studied using weight loss and OCP (Open Circuit Potential) methods. Inhibition efficiency increases with increasing of surfactant concentration. Also synergistic effect between surfactant and different alkaline metals salts (KCl, NaCl, NaBr, NaI, LiCl, Na2SO4, and NaNO3) in 1 M HCl is investigated. The effect of different anions and different metal cations on inhibition efficiency is discussed. The inhibition efficiency increases with increasing of salts concentration and reaches the maximum value near 0.1 M. The results show that the synergistic effects of salts are in this order Na2SO4 >NaI > LiCl > NaCl > KCl > NaBr > NaNO3. This inhibitor system containing cationic surfactant and an alkaline metal salt is efficient and low-cast for steel corrosion inhibition in HCl medium, even when the concentration of DTAB is as low as 0.5 × 10-4 M.
Herein, Materials Institute Lavoisier (MIL) metal-organic framework (MOF) including NH2-MIL-101(Fe): NM-101), and NH2-MIL-101(Fe)/phosphotungstic acid (PA) composite with different amounts of PA (1, 2, and 3 g denoted as NMP-1, NMP-2, and NMP-3, respectively) were synthesized and used for light-emitting diode (LED) visible-light degradation of dye (Methylene Blue: MB) solution. The materials were characterized using FTIR, SEM, TEM, TGA, XRD, and PL. The data presented that the NMP-2 composite had the highest degradation ability. The degradation efficiency of NMP-2 for 50 and 110 mg/L of pollutant concentration was 99 % and 55 %, respectively. The degradation kinetics for 0.006 g of NMP-2 followed the zero-order kinetics with 0.0179 min−1 rate constant with high correlation (0.9558).
Degumming is a surface modification process of natural fibers such as silk. In this paper, the feasibility of degumming with ultrasonic, ultrasonic–soap, and ultrasonic–enzyme (alcalase, savinase, and mixtures of these enzymes) processes as cleaner and environmentally friendly surface modification techniques of Persian silk were investigated. The effectiveness of parameters such as sonication time, soap, ultrasound–enzyme, enzyme concentration, degumming time and enzymes mixture on silk degumming were studied. The evaluation of the data was carried out through the measurement of the weight loss, strength, and elongation of the samples. In addition, the enzymatic treatment improved the properties of silk yarn such as strength and elongation. The scanning electron microscope images were obtained for degummed silk samples. The findings of this research support the potential production of new environmentally friendly textile fibers.
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