Optimization of simultaneous removal of binary mixture of indigo carmine and methyl orange dyes by cobalt hydroxide nano-particles through Taguchi method

Utilization of battery waste derived ZnO in the removal of dye from aqueous solution: A waste to wealth approach

Every year a huge amount of zinc carbon batteries is discarded as waste and the management of such waste has become a growing concern all over the world. However, from these waste carbon batteries different kinds of valuable materials could be recovered. On the other hand, different industries discharged large volumes of dye wastewater into the environment which has a profound impact on environment and as well as human health. In this study, ZnO was recovered from the waste carbon batteries through pyrometallurgy process and utilized it for the treatment of methylene blue and methyl orange dye water. The batch adsorption process was carried out to observe the effect of adsorbent dosage, pH, contact time, stirring speed and temperature. Under the obtained optimal conditions adsorption kinetics (Pseudo-first order and pseudo-second order) and adsorption isotherms (Langmuir, Freundlich and Temkin) were analyzed. The results disclosed that 0.5 g and 0.6 g of ZnO showed maximum removal efficiency for MB and MO dye solution (50 ppm) whereas pH 13 and 6 were the optimal for MB and MO respectively. Kinetic studies indicate that both the adsorption processes were pseudo-second order. It was also revealed that based on regression coefficient R2 value the adsorption of MB and MO on ZnO is followed Langmuir model. Furthermore, the findings revealed that the MO adsorption on ZnO is a chemical adsorption process and MB adsorption is a physical adsorption process.

Utilizing Novel Lignocellulosic Material from Hart's-Tongue Fern (Asplenium scolopendrium) Leaves for Crystal Violet Adsorption: Characterization, Application, and Optimization

In this work, a new lignocellulosic adsorbent was obtained and tested for crystal violet dye removal from water. The material was obtained from hart's-tongue fern (Asplenium scolopendrium) leaves after minimal processing, without chemical or thermal treatment. The surface of the material was characterized using a variety of techniques, including FTIR, SEM, and color analysis. The effect of various factors on the adsorption capacity was then investigated and discussed. The kinetic and equilibrium studies showed that the general-order kinetic model and the Sips isotherm are the most suitable to describe the adsorption process. The equilibrium time was reached after 20 min and the maximum calculated value of the adsorption capacity was 224.2 (mg g-1). The determined values for the thermodynamic parameters indicated physical adsorption as the main mechanism involved in the process. The Taguchi method was used to optimize the adsorption conditions and identify the most influential controllable factor, which was pH. ANOVA (general linear model) was used to calculate the percentage contribution of each controllable factor to dye removal efficiency. Analysis of all the results shows that hart's-tongue fern (Asplenium scolopendrium) leaves are a very inexpensive, readily available, and effective adsorbent for removing crystal violet dye from aqueous solutions.

Hybrid lignin particles via ion-crosslinked for selective removal of anionic dyes from water

Hybrid lignin (HL) particles were synthesized by compounding lignosulfonate and carboxylated chitosan through a simple ionic cross-linking method, and modifying by polyvinylpolyamine. Due to the synergistic effect of recombination and modification, the material exhibits excellent adsorption performance for anionic dyes in water. The structural characteristics and adsorptive behavior were systematically investigated. The pseudo-second-order kinetic model and the Langmuir model were revealed to well describe the sorption procedure of HL for anionic dyes. The results exhibited that the sorption capacities of HL on sodium indigo disulfonate and tartrazine were 1099.01 mg/g and 436.68 mg/g, respectively. Simultaneously, the adsorbent behaved no significant adsorption capacity loss after five adsorption-desorption cycles, indicating its superb stability and recyclability. Additionally, the HL exhibited excellent selective adsorption of anionic dyes form binary dye adsorption systems. The interaction forces between adsorbent and dye molecules, such as hydrogen bonding, π-π stacking, electrostatic attraction and cation bonding bridge, are discussed in detail. The facile preparation process and superior dyes removal performance of HL were considered a potential adsorbent to remove anionic dyes from wastewater.

Crystal Violet Adsorption on Eco-Friendly Lignocellulosic Material Obtained from Motherwort (Leonurus cardiaca L.) Biomass

The performance of a new eco-friendly adsorbent, obtained from motherwort (Leonurus cardiaca L.) biomass after minimum processing, in crystal violet dye removal from aqueous solutions was studied. Firstly, the adsorbent material was characterized using several technics, such as FTIR, pH_PZC determination, SEM and color analysis. The next step was to determine the influence of initial dye concentration, contact time, temperature, pH, adsorbent dose and ionic strength on adsorbent adsorption capacity. Equilibrium, kinetic, thermodynamic, optimization and desorption studies were performed in a batch system for studying all aspects related to the adsorption process. The sips isotherm best fit the experimental data with a predicted maximum adsorption capacity of 125.6 (mg g⁻¹). The kinetic data indicate that equilibrium is reached at 50 min and that general order is the best kinetic model to describe the dye retention. The process is endothermic, spontaneous, favorable and supposed to be a physical adsorption. In addition to establishing the optimal adsorption conditions, Taguchi methods and ANOVA analysis showed that the pH is the most influencing parameter of the adsorption process, having a contribution of 61.64%. All the presented data show that the motherwort biomass powder is very suitable to be used as at low-cost, easy available and effective adsorbent for the crystal violet dye removal from aqueous solutions.

Removal of Methylene Blue from Aqueous Solutions Using a New Natural Lignocellulosic Adsorbent-Raspberry (Rubus idaeus) Leaves Powder

In this work, raspberry (Rubus idaeus) leaves were converted to powder and used as a new natural lignocellulosic low-cost adsorbent for methylene blue removal from aqueous solutions. Different techniques (FTIR, SEM, color analysis, and pH_PZC determination) were applied for adsorbent characterization. The effects of pH, ionic strength, contact time, adsorbent dose, initial deconcentration, and temperature on adsorption capacity were investigated. Equilibrium, kinetic, and thermodynamic studies have shown that the adsorption is best described by the Sips isotherm and pseudo-second-order kinetic model and that the process is spontaneous, favorable, and endothermic, involving physisorption as the main mechanism. The maximum adsorption capacity was 244.6 (mg g⁻¹) higher compared to other adsorbents based on plant leaves. The Taguchi method and the ANOVA analysis were used to optimize the adsorption conditions. The contact time was the factor with the highest influence on the process, while the temperature had the lowest influence. A desorption study was also performed to determine the possibility of adsorbent regeneration.

Sustainable Recovery of Valuable Nanoporous Materials from High-Chlorine MSWI Fly Ash by Ultrasound with Organic Acids

The new technology development for municipal solid waste incineration fly ash treatment and reuse is urgent due to landfill shortage and environmental effect of leached hazardous substances. Chlorine (Cl) is worth considering due to its high levels in fly ash. In this study, a treatment process of ultrasound combined with organic acid was used to eliminate Cl from fly ash to enhance its properties for reuse. Taguchi methodology was implemented to design the experiments by controlling four impact factors and the contribution of each factor was evaluated by the ANOVA analysis of variance. Following two treatment steps within 5 min with a solid/liquid ratio of 1:10 at 165 kHz, 98.8% of Cl was eliminated. Solid/liquid ratio was the most prominent factor that contributed to the Cl removal with more than 90%, according to the ANOVA analysis of variance. Tert-butyl alcohol (tBuOH), an •OH radical scavenger, was utilized to examine different effects of ultrasonic cavitation on Cl removal efficiency. A 20 kHz ultrasound was used to explore the influence of multi-frequency ultrasound with different mechanical and sonochemical effects on the fly ash dechlorination. This ultrasonic-assisted organic acid treatment was found to be a time and cost-effective pathway for fly ash Cl removal.

Enhanced adsorptive removal of indigo carmine dye by bismuth oxide doped MgO based adsorbents from aqueous solution: equilibrium, kinetic and computational studies

The IC adsorption mechanism on the Bi2O3 doped MgO nanosorbents occurred through the chemisorption process.

Bathurst Burr (Xanthium spinosum) Powder-A New Natural Effective Adsorbent for Crystal Violet Dye Removal from Synthetic Wastewaters

A new natural adsorbent material, Bathurst burr powder, was used to remove crystal violet dye from synthetic wastewaters. Particle size distribution and SEM and FTIR analyses were performed to characterize it. The effect of the operational adsorption process parameters (pH, ionic strength, initial dye concentration, adsorbent dose, contact time, temperature) onto the adsorption process was evaluated in a batch system. Equilibrium, kinetic, and thermodynamic studies were performed in order to understand the adsorption process. Taguchi method and ANOVA test were used to optimize the dye adsorption conditions and to establish the percentage contribution of each factor, respectively. The accuracy of the Taguchi prediction method was analyzed by correlating the predicted dye removal efficiency with the experimentally determined one. The particle size distribution analysis showed that 82.15% of the adsorbent particles have an average size below 0.5 mm. The adsorption process followed the Langmuir isotherm and pseudo-second order kinetic model. Maximum adsorption capacity value (164.10 mg·g⁻¹) was higher compared to many similar adsorbents. The process was endothermic, spontaneous, and favorably involving a physisorption mechanism. The Taguchi method showed that the most influential controllable factor was pH (65% contribution in adsorption efficiency) and the data analysis indicates a very good accuracy of the experimental design (R² = 0.994). The obtained results demonstrated that Bathurst burr powder can be used as a cheap and efficient adsorbent for crystal violet dye removal from aqueous solution.

Optimization, Equilibrium and Kinetic Modeling of Methylene Blue Removal from Aqueous Solutions Using Dry Bean Pods Husks Powder

In this research, dry bean pods husks (DBPH) were used as an adsorbent material after minimum processing (without chemical substances consumption and without thermal treatment) to remove methylene blue from aqueous solutions. The adsorbent surface characteristics were investigated using SEM and FTIR analysis. For maximum removal efficiency, several parameters that influence the dye adsorption were optimized using the Taguchi method. Equilibrium and kinetic modeling, along with thermodynamic studies, were conducted to elucidate the adsorption mechanism. Taguchi experimental design showed that the factor with the highest influence was the adsorbent dose, with a percent contribution established by the ANOVA analysis of 40.89%. Langmuir isotherm and pseudo-second order kinetic model characterizes the adsorption process. The maximum adsorption capacity, 121.16 (mg g⁻¹), is higher than other similar adsorbents presented in scientific literature. Thermodynamic parameters indicate a spontaneous, favorable and endothermic adsorption process, and their values show that physical adsorption is involved in the process. The obtained results, and the fact that adsorbent material is inexpensive and easily available, indicate that DBPH powder represents an effective absorbent for treating waters containing methylene blue. Additionally, the Taguchi method is very suitable to optimize the process.

Potential low-cost carbon-based adsorbent from gold mine tailings for anionic dye removal

In this study, a mesoporous carbon (CMK-3) was successfully synthesized using mesoporous silica (SBA-15) prepared from gold mine tailings (sample C_GMT) for removal of anionic dye from aqueous solution. For comparison, CMK-3 was prepared by the same method from pure silica (sample C_T), and the other CMK-3 sample was prepared by a one-pot route mixing with Pluronic P123 (sample C_P). The effect of the carbonization time on the synthesis of all CMK-3 samples was investigated, and the samples were characterized by X-ray diffraction and N₂ adsorption-desorption. The sample with the highest surface area was chosen as an adsorbent, for each CMK-3 obtained from different methods. Batch adsorption experiments were studied to determine the influence of pH, contact time, and initial dye concentration. The adsorption kinetics obeyed the pseudo-second-order model. All carbon-based adsorbents were observed to be quite effective for the removal of dye with adsorption percentage in the order of C_P > C_T > C_GMT. The maximum adsorption capacities were 188.99 and 204.57 mg·g^-1 for C_T and C_GMT, respectively. The comparative results of all carbon-based adsorbents show that C_GMT can be applied as a low-cost alternative to C_T for dye removal.

Glycerol mediated solution combustion synthesis of nano magnesia and its application in the adsorptive removal of anionic dyes

This study reports solution combustion synthesis of magnesia nanoparticles (nMgO) using magnesium nitrate as oxidiser and glycerol as fuel. Size, morphology, crystal structure and surface properties of synthesised nMgO were analysed by PXRD, SEM, TEM, FTIR and Point of Zero Charge. The XRD pattern of nMgO confirmed prepared samples were single cubic-phase without any impurities. TEM analysis proved nMgO was in nano regime with an average particle diameter of 20–40 nm. FTIR spectra show the presence of characteristic peaks of nMgO and support the XRD results. The prepared nMgO was employed as an adsorbent for the removal of two anionic dyes viz. Indigo Carmine (IC) and Orange G (OG). Furthermore, various adsorption isotherms and kinetic models were performed to understand the kinetics and mechanism of the adsorption process. Experimental results demonstrated that the adsorption equilibrium data fit well to Sips isotherm (R2 > 0.98) and the saturated adsorption capacities of nMgO were found to be 262 mg g−1 for IC and 126 mg g−1 for OG. Adsorption kinetics analysis revealed that the adsorption followed pseudo-first-order model, with both film and pore diffusion governing the rate of adsorption. Excellent adsorption capacity combined with efficient regeneration proved the potential of the prepared nMgO as an adsorbent for the removal of harmful dyes from industrial effluent.

Syringa vulgaris leaves powder a novel low-cost adsorbent for methylene blue removal: isotherms, kinetics, thermodynamic and optimization by Taguchi method

In this study, the potential of a new low-cost adsorbent, Syringa vulgaris leaves powder, for methylene blue adsorption from aqueous solution was investigated. The adsorbent surface was examined using SEM and FTIR techniques. The experiments were conducted, in batch system, to find out the effect of pH, contact time, adsorbent dose, initial dye concentration, temperature and ionic strength on dye adsorption. The process is best described by Langmuir isotherm and the pseudo second order kinetic model. Maximum adsorption capacity, 188.2 (mg g⁻¹), is better than other similar adsorbent materials. Thermodynamic parameters revealed a spontaneous and endothermic process, suggesting a physisorption mechanism. A Taguchi orthogonal array (L₂₇) experimental design was used to determine the optimum conditions for the removal of dye. Various desorbing agents were used to investigate the regeneration possibility of used adsorbent. Results suggest that the adsorbent material is very effective for removal of methylene blue from aqueous solutions.

Eco-Efficient Green Seaweed Codium decorticatum Biosorbent for Textile Dyes: Characterization, Mechanism, Recyclability, and RSM Optimization

Biosorption using natural waste has emerged as a potential and promising strategy for removal of toxic dyes from wastewaters in comparison to conventional ones. Herein, the Codium decorticatum alga (CDA) was biologically identified and used as a biosorbent for anionic and cationic dyes from aqueous solutions. SEM analysis showed a rough surface with an irregular edge and shape while hydroxyl, amine, sulfur and carboxyl functional groups were identified using FTIR analysis. TGA/DTG confirmed the stability of CDA and the adsorption process. Batch studies were conducted to investigate the effect of operational factors such as initial pH, biosorbent dosage, temperature, initial concentration, and solid/liquid contact time on the biosorption of crystal violet (CV) and Congo red (CR) dyes. For both CV and CR dyes, the biosorption kinetics was accurately described by the pseudo-second-order model and the Langmuir isotherm was found to be best fitted for equilibrium data. Maximum uptake capacities have attained up to 278.46 mg/g for CV and 191.01 mg/g for CR. The CV and CR dye biosorption mechanism was ultimately manifested through the electrostatic interactions. The regeneration study showed that the CDA presents excellent reuse performance up to four consecutive cycles. The process optimization was performed using the response surface methodology based on Box-Behnken design (RSM-BDD). Accordingly, the optimum predicted removal efficiencies using RSM-BBD for CV and CR were obtained, respectively, at 96.9 and 89.8% using a CDA dose of 1.5 g/L, dye concentration of 20 mg/L, pH of 10 for CV, and pH of 4 for CR. Overall, CDA behaves as an efficient, recyclable, cheap, and eco-friendly adsorbent for cleaning-up of dyed effluents.

A Review of Different Types of DOE Methods as a Useful Platform for Improving the Performance of Nano Adsorbents in Removal Systems of Pollutants

Background:

In recent years, the Design of Experiments (DOE) is used for removing pollutant from wastewater by nano-adsorbent. Some methods are Taguchi, Response Surface Methodology (RSM) and factorial design. The aim of this paper is to review different used methods of DOE in removing pollutant to suggest some notations to scholars.

Methods:

The reviewed papers were searched in Google Scholar, Scopus, and Web of Science randomly and categorized based on DOE methods.

Results:

Number of factors and responses in DOE for removing pollutants from wastewater are between 2-6 and 1-4, respectively. There are several computer software programs that provide simple use of these methods, such as Qualitek, Design Expert, Minitab, R and Matlab Programming. All models have a coefficient of determination R-sq more than 0.9.

Conclusion:

All the mentioned methods are appropriate because of the high R-sq value. Since the largest number of runs are used in RSM, it is not suitable for the experiments which are conducted by expensive materials and process. Furthermore, Design Expert and Minitab are the most popular software used by scholars in DOE methods for the removal of pollutant.

Adsorption of indigo carmine on functional chitosan and β-cyclodextrin/chitosan beads: Equilibrium, kinetics and mechanism studies

The present study was designed to produce novel cross-linked Chitosan and Chitosan/β-Cyclodextrin beads and study the adsorption of Indigo Carmine. Both adsorbents were characterized by SEM and FTIR techniques. Batch experiments were conducted in order to evaluate the effect of initial adsorbent's concentration, dye's initial concentration, initial pH and temperature. In all cases Chitosan/β-Cyclodextrin crosslinked beads exhibited higher removal efficiency of Indigo Carmine. Higher removal rates of Indigo Carmine were observed at low values of dye's initial concentration, pH and temperature, and high concentrations of adsorbent. The equilibrium adsorption data were a good fit for both Langmuir and Freundlich models and maximum adsorption capacity was 500.0 and 1000.0 mg_IC/g_adsorbent for Chitosan and Chitosan/β-Cyclodextrin crosslinked beads, respectively. Adsorption of Indigo Carmine was found to follow the pseudo-second order. The negative values of ΔG^o, ΔH^o and ΔS^o indicate that the adsorption process is exothermic, spontaneous and favorable at low temperatures.

High-Speed and High-Capacity Removal of Methyl Orange and Malachite Green in Water Using Newly Developed Mesoporous Carbon: Kinetic and Isotherm Studies

A novel mesoporous carbon nanostructured material was prepared and characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, thermogravimetry, and X-ray diffractometry. The material demonstrated high-speed and high-adsorption capacities of 827.5 and 2484.5 mg g^-1 for methyl orange (MO) and malachite green (MG) dyes in 10 min. The kinetic data were fitted to pseudo-first- and pseudo-second-order, external and intraparticle diffusion, and Elovich models, whereas the isotherm data were adjusted to the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Langmuir-Freundlich isotherms (Sips). It was found that MO and MG adsorption was limited by chemical interactions and mixed diffusion. Besides, the physical process was elucidated through free energy values (E = 2.56 and 0.049 kJ mol^-1 for the MO and MG, respectively). Methyl orange adsorption mostly occurred through ion exchange and electrostatic interactions, and at lower MO concentrations, through chemical interactions and surface complexation as well. Malachite green adsorption took place only on lower-energy sites. Thus, it can be concluded that the adsorbent proposed herein possessed high-speed and high-adsorption capacity. Therefore, it can be considered as promising in removing the reported dye pollutants.

Simultaneous elimination of Malachite Green, Rhodamine B and Cresol Red from aqueous sample with Sistan sand, optimized by Taguchi L16 and Plackett-Burman experiment design methods

The purpose of this study was to investigate the feasibility of simultaneous optimization and removal of dyes, Malachite green (MG), Rhodamine B (RhB) and Cresol Red (CR) from aqueous solutions by using Sistan sand as an extremely low cost adsorbent. Factors affecting adsorption of the analytes on the sorbent were investigated experimentally and by using Taguchi and Plackett–Burman experimental design methods. In most cases, the results of these two models were in agreement with each other and with experimental data obtained. Taguchi method was capable to predict results with accuracies better than 97.89%, 95.43%, and 97.79% for MG, RhB, and CR, respectively. Under the optimum conditions, the sorbent could remove simultaneously more than 83% of the dyes with the amount of adsorbed dyes of 0.132, 0.109, and 0.120 mg g⁻¹ for MG, RhB and CR on sand, respectively. Kinetic studies showed that pseudo second order is the best model of adsorption for all analytes. Thermodynamic parameters revealed that this process is spontaneous and endothermic.

Flower Buds Like MgO Nanoparticles: From Characterisation to Indigo Carmine Elimination

Here, we demonstrate a pyrolysis route for the synthesis of flower buds like magnesium oxide nanoparticles using a magnesium carbonate precursor without additional chemicals. The effect of heating at different time intervals upon the structure and morphology of the acquired nanostructures were investigated via X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and Fourier transformation infrared spectroscopy. Nitrogen adsorption was employed to study its porosity. The obtained data confirmed the formation of target nanoparticles that exhibited increasing sizes as pyrolysis time was lengthened. As a consequence a high surface area up to 27 m2 g−1 was recorded for the sample heated for 1 h duration. Furthermore, Indigo Carmine dye adsorption was carried out using the largest surface area species which showed an adsorption capacity of 158 mg g−1. The adsorption was found to comply with the Langmuir isotherm and it follows the pseudo-second-order kinetics. The diffusion process showed intra-particle along with film diffusion mode.