Ultrasonic assisted removal of sunset yellow from aqueous solution by zinc hydroxide nanoparticle loaded activated carbon: Optimized experimental design

Ponceau 4R elimination from fruit juice: An integrated optimization strategy utilizing artificial neural networks, least squares, and chitosan-nickel ferrite Nano Sorbent

The goal of present work is to examine the efficiency of aminated-chitosan/NiFe2O4 nanoparticles (AmCs/NiFe2O4 NPs) produced for removing Ponceau 4R (P4R) from fruit juice through an adsorption process. The resulting nanoparticles were characterized using various techniques. The modeling of results was done using least squares (LS) and Radial basis function-artificial neural network (RBF-ANN). The optimum removal of P4R (91.43 %) was obtained at the following optimum conditions: pH 4.47, adsorbent dosage 0.047 g/L, contact time approximately 57.78 min, and initial concentration P4R 26.89 mg/L. The highest adsorption capacity (qm) was found to be 208.33 mg g-1. The P4R adsorption mostly followed the Freundlich and pseudo-second-order isotherm kinetic models. Both LS-based models and RBF-ANN provided good predictions for independent variables. The dye elimination efficacy for juice samples were approximately 90.34 %. Therefore, based on the obtained results, it can be claimed that the prepared AmCs/NiFe2O4 NPs can be used to remove P4R.

DFT and comparative adsorption study of NiO, MnO, and Mn2NiO4 nanomaterials for the removal of amaranth dye from synthetic water

In the current study, NiO nanoparticles, MnO nanoparticles, and Mn2NiO4 nanocomposites (Ni-NPs, Mn-NPs and MN-NCs, respectively) were synthesized using a facile hydrothermal method, and their performance in the removal of amaranth (AM) dye from synthetic wastewater was compared. XRD, FTIR spectroscopy, SEM, BET analysis, and TGA were performed to characterize the produced catalysts. The effect of pertinent parameters, including pH, dosage of catalysts, temperature, and shaking speed on the uptake of AM was investigated through batch experiments. The MN-NCs showed ultrafast and high efficiency for AM removal compared to their counter parts Mn-NPs and Ni-NPs. Under ideal conditions, the highest adsorption efficiencies of AM onto Ni-NPs, Mn-NPs, and MN-NCs were calculated to be 80.50%, 93.85%, and 98.50%, respectively. The Langmuir isotherm fitted the experimental data of AM removal better as shown by the higher values of r 2, compared to the Freundlich isotherm, indicating monolayer type adsorption of AM. According to kinetic analyses, the adsorption of AM was best described by the pseudo-second-order kinetic model. Further, regeneration/recycling studies showed that MN-NCs retained 79% adsorption efficiency after four cycles. DFT experiments were also conducted to gain a deeper understanding of the process and behavior of AM adsorption. In conclusion, as Ni-NPs, Mn-NPs, and MN-NCs adsorb AM predominantly via electrostatic interaction, they can be applied for the removal of both cationic and anionic dyes by controlling the pH factor.

Modeling sunset yellow removal from fruit juice samples by a novel chitosan-nickel ferrite nano sorbent

Analysis of food additives is highly significant in the food industry and directly related to human health. This investigation into the removal efficiency of sunset yellow as an azo dye in fruit juices using Chitosan-nickel ferrite nanoparticles (Cs@NiFe2O4 NPs). The nanoparticles were synthesized and characterized using various techniques. The effective parameters for removing sunset yellow were optimized using the response surface methodology (RSM) based on the central composite design (CCD). Under the optimum conditions, the highest removal efficiency (94.90%) was obtained for the initial dye concentration of 26.48 mg L-1 at a pH of 3.87, a reaction time of 67.62 min, and a nanoparticle dose of 0.038 g L-1. The pseudo-second-order kinetic model had a better fit for experimental data (R2 = 0.98) than the other kinetic models. The equilibrium adsorption process followed the Freundlich isotherm model with a maximum adsorption capacity of 212.766 mg g-1. The dye removal efficiency achieved for industrial and traditional fruit juice samples (91.75% and 93.24%), respectively, confirmed the method's performance, feasibility, and efficiency. The dye adsorption efficiency showed no significant decrease after five recycling, indicating that the sorbent has suitable stability in practical applications. variousThe synthesized nanoparticles can be suggested as an efficient sorbent to remove the sunset yellow dye from food products.

Adsorption Studies on the Removal of Anionic and Cationic Dyes from Aqueous Solutions Using Discarded Masks and Lignin

The carbon materials derived from discarded masks and lignin are used as adsorbent to remove two types of reactive dyes present in textile wastewater: anionic and cationic. This paper introduces the results of batch experiments where Congo red (CR) and Malachite green (MG) are removed from wastewater onto the carbon material. The relationship between adsorption time, initial concentration, temperature and pH value of reactive dyes was investigated by batch experiments. It is discovered that pH 5.0-7.0 leads to the maximum effectiveness of CR and MG removal. The equilibrium adsorption capacities of CR and MG are found to be 232.02 and 352.11 mg/g, respectively. The adsorption processes of CR and MG are consistent with the Freundlich and Langmuir adsorption models, respectively. The thermodynamic processing of the adsorption data reveals the exothermic properties of the adsorption of both dyes. The results show that the dye uptake processes follow secondary kinetics. The primary adsorption mechanisms of MG and CR dyes on sulfonated discarded masks and alkaline lignin (DMAL) include pore filling, electrostatic attraction, π-π interactions and the synergistic interactions between the sulphate and the dyes. The synthesized DMAL with high adsorption efficiency is promising as an effective recyclable adsorbent for adsorbing dyes, especially MG dyes, from wastewater.

Environmental remediation by tea waste and its derivative products: A review on present status and technological advancements

The rising consumption of the popular non-alcoholic beverage tea and its derivative products caused massive growth in worldwide tea production in the last decade, leading to the generation of huge quantities of waste tea residues every year. Most of these wastes are usually burnt or disposed in landfills without proper treatment which results in serious environmental issues by polluting water, air and soil. In the recent times, 'waste to wealth' is a fast-growing concept for environment friendly sustainable development. Utilization of the large amount of tea wastes for the production of low-cost adsorbents to reduce the expenses of water and wastewater treatment can be a sustainable way of management of these wastes which at the same time will improve circular economy also. This review endeavours to evaluate the potential of both raw and modified tea wastes towards the adsorption of pollutants from wastewater. The production of various adsorptive materials such as biochar, activated carbon, nanocomposites, hydrogels, nanoparticles from tea wastes are summarized. The advancements in their applications for the removal of different emerging contaminants from wastewater as well as potable water, air and soil are exhaustively reviewed. The outcome of the present review reveals that tea waste and its derivatives are appropriate candidates to be used as adsorbents that show tremendous effectiveness in cleaning the environment. This article will provide the readers with an in-depth knowledge on the sustainable utilization of tea waste as adsorbent materials and will assist them to explore this abundant cheap waste biomass for environmental remediation.

Design and Preparation of Imidazole Ionic Liquid-Based Magnetic Polymers and Its Adsorption on Sunset Yellow Dye

Magnetic polymers are often used as loading materials for ionic liquids because of their excellent magnetic separation properties. In this study, a novel imidazolium-based ionic liquid-modified magnetic polymer was synthesized by suspension polymerization and grafting, denoted as γ-Fe₂O₃@GMA@IM, and this magnetic polymer was used for the adsorption of the acid dye FCF. The magnetic polymer was characterized by SEM, FTIR, XRD, VSM and TGA. These techniques were used to reveal the overall physical properties of magnetic polymers, including the presence of morphology, functional groups, crystalline properties, magnetism and thermal stability. Studies have shown that γ-Fe₂O₃@GMA@IM can adsorb FCF in a wide pH range (2–10), with a maximum adsorption capacity of 445 mg/g. The adsorption data were more in line with the pseudo-second-order kinetic model and the Freundlich isotherm. In order to investigate its reusability, this study used 10% NaCl as the desorption solution, and carried out five batches of adsorption–desorption cycles. After five cycles, the adsorption effect was maintained at 98.3%, which showed a good recycling performance.

Dye removal from water and wastewater by nanosized metal oxides - modified activated carbon: a review on recent researches

The conventional water and wastewater treatment methods are unable to provide up-to-data organized standards for drinking water and discharging effluents into natural ecosystems. Therefore, developing advanced and cost-effective methods to achieve published standards for water and wastewater and population needs are nowadays necessity. The important parts of this article are providing literature information about dyes and their effects on the environment and human health, adsorption properties and mechanism, adsorbent characteristics, and recent information on various aspects of modified activated carbons with nanosized metal oxides (AC- NMOs) in the removal of dyes. This review also summarized the effect of main environmental and operational parameters such as adsorbent dosage, pH, initial dye concentration, contact time, and temperature on the dye adsorption using AC-NMOs. Furthermore, the applied isotherm and kinetic models have been discussed.

Thermally reduced graphene oxide as green and easily available adsorbent for Sunset yellow decontamination

The release of synthetic food dyes, like Sunset yellow, into industrial effluents can cause serious environmental and health problems. Due to its aromatic structure, it is recalcitrant towards degradation into non-toxic intermediates and its removal by efficient adsorption represents a cheap and efficient method. Herein we propose the use of thermally reduced graphene oxide (TRGO) as effective Sunset yellow dye adsorbent with an adsorption maximum capacity comparable with other sophisticated, chemically synthesized carbon-based nanomaterials. The reduced graphene oxide and the Sunset yellow adsorbed one were characterized by FT-IR, XPS and XRD spectroscopy, N₂ adsorption-desorption isotherm and TGA analysis. BET surface area reduced from 274.1 m²/g (for TRGO) to 39.9 m²/g (for TRGO-SY) showing that Sunset Yellow molecules occupied the corresponding active sites while the number of sheets resulted from the XRD spectra - from 3 to 8 in TRGO to 5 in TRGO-SY indicates the ordered intercalations in the graphene structure. The adsorption isotherm experimental data were better fitted with the Langmuir model than the Freundlich model, with the maximum adsorption capacity of the SY dye monolayer of 243.3 mg/g at pH = 6.0 and 189.0 mg/g from synthetic wastewater. The kinetic study revealed a perfect fit following the Pseudo-second order model with an equilibrium achieved within 30 min. The lack of adsorption on the starting graphene oxide is indicative for π-π interactions between the adsorbate and adsorbent.

The synergistic effect of ultrasound power and magnetite incorporation on the sorption/desorption behavior of Cr(VI) and As(V) oxoanions in an aqueous system

Though abundant studies have targeted the sorption of Cr(VI) and As(V) anions by organic polymers or magnetic metal oxides, there is no research literature on the sorption characteristics of Cr(VI) and As(V) by thiourea-formaldehyde resin (TF) and its magnetic derivative (MTF). TF resin is a strong chelating agent, which has several practical applications. This paper reports on the removal of Cr(VI) and As(V) oxoanions by TF and MTF sorbents. The sorbents were characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, zetametry, Brunauer-Emmett-Teller (BET) analysis, and differential light scattering (DLS). The synergistic influence of magnetite incorporation and ultrasonic power on sorption kinetics, isotherms, and oxoanion desorption were investigated, including the analysis of the uncertainty in the study results. The relationship between kinetic and equilibrium constants of the two sorbents under normal shaking and ultrasound shaking was analysed. Ultrasound power improved the mass transfer and makes the sorption ultra-fast while magnetite enhanced the sorption capacity. The MTF particles sorbed 4.28 and 1.97 mmol g^-1 of Cr(VI) and As(V), respectively, under optimum conditions. Further, desorption kinetics and efficiency of Cr(VI) and As(V) were estimated using normal shaking and ultrasonic agitation. Ultrasound power reduced the time and the concentration of NaCl required for the stabilization of desorption efficiency.

Modeling of azo dyes adsorption on magnetic NiFe2O4/RGO nanocomposite using response surface methodology

BACKGROUND

Azo group dyes are the largest group of synthetics dyes that widely used in industries, especially in textile industry. The presence of these organic compounds in wastewaters and their discharge into environment without efficient treatment may cause adverse effect on human, living and aquatic environment. The purpose of this study was to optimize the adsorption of azo dye of Direct Red 81 (anionic dye) and Basic Blue 41 (cationic dye) from aqueous solution onto magnetic NiFe₂O₄/RGO nanocomposite.

METHODS

In this study the response surface methodology (RSM) based on the central composite design (CCD), was used to optimization and modeling of adsorption process DR81 and BB41 dye on NiFe₂O₄/RGO. in order to investigating the effect of the operating parameters on the adsorption efficiency DR81 and BB41, four influential factors were chosen that includes of pH (3-9), contact time (5-25 min), adsorbent amount (0.02-0.05 g) and initial dye concentration (40-200 mg/L). A total of 30 experiments were performed for each dye in this study. The concentration of dye in solution was measured by spectrophotometer. The structure of synthesized adsorbent was investigated using Scanning Electron Microscope (SEM), X-ray diffraction (XRD), Fourier transform irradiation (FTIR), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM).

RESULTS

Analysis of variance (ANOVA) showed that regression model for both dye adsorption with value of P value <0.001 is significant statistically. The correlation coefficient (R²) for DR81 (R² = 0.9968) and BB41 (R² = 0.9948) indicated which there is a good agreement between predicted values and the results of the experiments and the model also well predict the adsorption efficiency. Furthermore, the factors of pH, dye concentration and adsorbent dose, have the greatest effect on adsorption, respectively, while contact time have the lowest effect on adsorption of both dyes. The adsorption behavior of the DR81 and BB41 onto NiFe₂O₄/RGO was best described by the Langmuir and Freundlich isotherm, respectively. The optimum conditions for maximum removal of DR81 (96.41%) was found to be at pH 3, contact time 19.68 min, adsorbent dose 0.02 g and initial dye concentration 40 mg/L. However, the optimum conditions for maximum removal of BB41 (97.87%) was found to be at pH 9 contact time 18.16 min, adsorbent dose 0.02 g and initial dye concentration 40 mg/L.

CONCLUSION

The present study shows that magnetic NiFe₂O₄/RGO nanocomposite have much potential as a powerful adsorbent for the rapid adsorption of anionic (DR81) and cationic dyes (BB41) from aqueous solution.

Comparison of activated carbon and iron/cerium modified activated carbon to remove methylene blue from wastewater

The methylene blue (MB) removal abilities of raw activated carbon and iron/cerium modified raw activated carbon (Fe-Ce-AC) by adsorption were researched and compared. The characteristics of Fe-Ce-AC were examined by N₂ adsorption, zeta potential measurement, FTIR, Raman, XRD, XPS, SEM and EDS. After modification, the following phenomena occurred: The BET surface area, average pore diameter and total pore volume decreased; the degree of graphitization also decreased. Moreover, the presence of Fe₃O₄ led to Fe-Ce-AC having magnetic properties, which makes it easy to separate from dye wastewater in an external magnetic field and subsequently recycle. In addition, the equilibrium isotherms and kinetics of MB adsorption on raw activated carbon and Fe-Ce-AC were systematically examined. The equilibrium adsorption data indicated that the adsorption behavior followed the Langmuir isotherm, and the pseudo-second-order model matched the kinetic data well. Compared with raw activated carbon, the maximum monolayer adsorption capacity of Fe-Ce-AC increased by 27.31%. According to the experimental results, Fe-Ce-AC can be used as an effective adsorbent for the removal of MB from dye wastewater.

Ion Pairing and Adsorption of Azo Dye/C16TAB Surfactants at the Air-Water Interface

Mixed layers of 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonate (Sunset Yellow, SSY) and cetyltrimethylammonium bromide (C16TAB) at the air-water interface were studied using vibrational sum-frequency generation (SFG) and dynamic surface tension measurements. In the bulk, addition of C16TAB to SSY aqueous solution causes substantial changes in UV/vis absorption spectra, which originate from strong electrostatic interactions between the anionic SSY azo dye with the cationic C16TAB surfactant. These interactions are a driving force for the formation of SSY/C16TAB ion pairs. The latter are found to be highly surface active while free SSY molecules show no surface activity. Dynamic SFG as well as surface tension measurements at low SSY concentrations reveal that free C16TAB surfactants adsorb at the air-water interface on time scales <1 s where they initially form the dominating surface species, but on longer time scales free C16TAB is exchanged by SSY/C16TAB ion pairs. This causes a dramatic reduction of the surface tension to 35 mN/m but also in foam stability. These changes are accompanied by a substantial loss in SFG intensity from O-H stretching bands around 3200 and 3450 cm-1, which we relate to a decrease in surface charging due to adsorption of ion pairs with no or negligible net charges. For SSY/C16TAB molar ratios >0.5, the O-H bands in SFG spectra are reduced to very low intensities and are indicative to electrically neutral SSY/C16TAB ion pairs. This conclusion is corroborated by an analysis of macroscopic foams, which become highly instable in the presence of neutral SSY/C16TAB ion pairs. From an analysis of SFG spectra of air-water interfaces, we show that the electrostatic repulsion forces inside the ubiquitous foam films are reduced and thus remove the major stabilization mechanism within macroscopic foam.

Highly efficient simultaneous adsorption and biodegradation of a highly-concentrated anionic dye by a high-surface-area carbon-based biocomposite

Mesoporous high-surface-area activated carbon (MHSA-AC), which has a honeycomb structure, was produced from coconut shells by simultaneous chemical and physical activation and used for the rapid adsorption of an anionic dye, namely acid orange 10 (AO10), from water. Owing to its porosity and high Brunauer-Emmett-Teller surface area (2283.91 m²g^-1), MHSA-AC is a highly efficient adsorbent. It also has good biocompatibility and is a good immobilization carrier; the grooves on the MHSA-AC surface facilitate immobilization. Here, a new, highly efficient, and environmentally friendly simultaneous adsorption and biodegradation (SAB) process was developed. Highly concentrated AO10 (6000 mg L^-1, 20 mL) was removed with an efficiency of 100% (pH = 7, 35 °C) by SAB using cells immobilized on MHSA-AC (500 mg). The immobilized cells were used directly, without pretreatment; the SAB process is therefore simple and has good potential for application in the treatment of dyes in industrial wastewater.

Experimental design and modeling of ultrasound assisted simultaneous adsorption of cationic dyes onto ZnS: Mn-NPs-AC from binary mixture

The manganese impregnated zinc sulfide nanoparticles deposited on activated carbon (ZnS: Mn-NPs-AC) which fully was synthesized and characterized successfully applied for simultaneous removal of malachite green and methylene blue in binary situation. The effects of variables such as pH (2.0-10.0), sonication time (1-5min), adsorbent mass (0.005-0.025g) and MB and MG concentration (4-20mgL(-1)) on their removal efficiency was studied dy central composite design (CCD) to correlate dyes removal percentage to above mention variables that guides amongst the maximum influence was seen by changing the sonication time and adsorbent mass. Sonication time, adsorbent mass and pH in despite of dyes concentrations has positive relation with removal percentage. Multiple regression analysis of the experimental results is associated with 3-D response surface and contour plots that guide setting condition at pH of 7.0, 3min sonication time, 0.025g Mn: ZnS-NPs-AC and 15mgL(-1) of MB and MG lead to achievement of removal efficiencies of 99.87% and 98.56% for MG and MB, respectively. The pseudo-second-order model as best choice efficiency describe the dyes adsorption behavior, while MG and MB maximum adsorption capacity according to Langmuir was 202.43 and 191.57mgg(-1).