Optimizing Cu(II) removal from aqueous solution by magnetic nanoparticles immobilized on activated carbon using Taguchi method

Synthesis and Optimization of Cr (VI) Removal from Aqueous Solution by Activated Carbon with Magnetic Fe3O4Nanoparticles by Response Surface Methodology

In this study, the activated carbon with Fe3O4 nanoparticles was synthesized and employed as an effective tool to remove the Cr (VI) from the aqueous solution. The process inputs like concentration of Cr (VI), the dosage of Fe3O4 nanoparticles in activated carbon, and pH of the aqueous solution were optimized by response surface methodology, and their effects were studied. The statistical analysis by ANOVA showed that the process inputs were significantly affected the removal rate, with the maximum impact provided by the pH of the aqueous solution. The best parameters were identified to be pH of 3, aqueous solution concentration of 12 mg/L, the dosage of 1.5 g/L, and adsorption time of 40 min. SEM, EDS, and FTIR characterized the synthesized activated carbon/Fe3O4 samples with magnetic characteristics. Adsorption isotherms and adsorption kinetics analyzed the chemical stability of the synthesized nanocomposite.

New insight on some selected nanoparticles as an effective adsorbent toward diminishing the health risk of deltamethrin contaminated water

Deltamethrin is a widely used insecticide that kills a wide variety of insects and ticks. Deltamethrin resistance develops as a result of intensive, repeated use, as well as increased environmental contamination and a negative impact on public health. Its negative impact on aquatic ecology and human health necessitated the development of a new technique for environmental remediation and wastewater treatment, such as the use of nanotechnology. The co-precipitation method was used to create Zn-Fe/LDH, Zn-AL-GA/LDH, and Fe-oxide nanoparticles (NPs), which were then characterized using XRD, FT-IR, FE-SEM, and HR-TEM. The kinetic study of adsorption test revealed that these NPs were effective at removing deltamethrin from wastewater. The larval packet test, which involved applying freshly adsorbed deltamethrin nanocomposites (48 hours after adsorption), and the comet assay test were used to confirm that deltamethrin had lost its acaricidal efficacy. The kinetics of the deltamethrin adsorption process was investigated using several kinetic models at pH 7, initial concentration of deltamethrin 40 ppm and temperature 25°C. Within the first 60 min, the results indicated efficient adsorption performance in deltamethrin removal, the maximum adsorption capacity was 27.56 mg/L, 17.60 mg/L, and 3.06 mg/L with the Zn-Al LDH/GA, Zn-Fe LDH, and Fe Oxide, respectively. On tick larvae, the results of the freshly adsorbed DNC bioassay revealed larval mortality. This suggests that deltamethrin's acaricidal activity is still active. However, applying DNCs to tick larvae 48 hours after adsorption had no lethal effect, indicating that deltamethrin had lost its acaricidal activity. The latter result corroborated the results of the adsorption test's kinetic study. Furthermore, the comet assay revealed that commercial deltamethrin caused 28.51% DNA damage in tick cells, which was significantly higher than any DNC. In conclusion, the NPs used play an important role in deltamethrin decontamination in water, resulting in reduced public health risk. As a result, these NPs could be used as a method of environmental remediation.

Magnetic nanoparticles incorporation into different substrates for dyes and heavy metals removal-A Review

Substantial discharge of hazardous substances, especially dyes and heavy metal ions to the environment, has become a global concern due to many industries neglecting the environmental protocols in waste management. A massive discharge of contaminantsfrom different anthropogenic activities, can pose alarming threats to living species and adverse effect to the ecosystem stability. In the process of treating the polluted water, various methods and materials are used. Hybrid nanocomposites have attained numerous interest due to the combination of remarkable features of the organic and inorganic elements in a single material. In this regards, carbon and polymer based nanocomposites have gained particular interest because of their tremendous magnetic properties and stability. These nanocomposites can be fabricated using several approaches that include filling, template, hydrothermal, pulsed-laser irradiation, electro-spinning, detonation induced reaction, pyrolysis, ball milling, melt-blending, and many more. Moreover, carbon-based and polymer-based magnetic nanocomposites have been utilized for an extensive number of applications such as removal of heavy metal and dye adsorbents, magnetic resonance imaging, and drug delivery. This review emphasized mainly on the production of magnetic carbon and polymer nanocomposites employing various approaches and their applications in water and wastewater treatment. Furthermore, the future opportunities and challenges in applying magnetic nanocomposites for heavy metal ion and dye removal from water and wastewater treatment plant.

Synthesis of MnFe2O4 and Mn3O4 magnetic nano-composites with enhanced properties for adsorption of Cr(VI): artificial neural network modeling

This study reports adsorptive removal of Cr(VI) by magnetic manganese ferrite and manganese oxide nano-particles (MnF-MO-NPs) composite from aqueous media. The X-ray diffraction pattern of MnF-MO-NPs revealed a polycrystalline nature with nanoscale crystallite size. The prepared adsorbent with high Brunauer-Emmett-Teller specific surface area of 100.62 m²/g and saturation magnetization of 30.12 emu/g exhibited maximum Cr(VI) removal at solution pH 2.0 and was easily separated from water under an external magnetic field. Adsorption capacity as much as 91.24 mg/g is reported and electrostatic interaction between positively charged adsorbent surface and anionic metal ion species is the main driving force in this adsorption. Adsorption experimental data followed Langmuir isotherm and second order kinetics. Partial involvement of intra-particle diffusion was also observed due to the mesoporous nature of MnF-MO-NPs. The thermodynamic studies revealed that the process was favorable, spontaneous and exothermic in nature. An artificial neural network model was developed for accurate prediction of Cr(VI) ions removal with minimum mean squared error (MSE) of 15.4 × 10^-4 and maximum R² of 0.98. Owing to large surface to volume ratio, advantage of easy magnetic separation, and high adsorption capacity towards Cr(VI), the reported MnF-MO-NPs appear to be a potential candidate in Cr(VI) contaminated wastewater remediation.

Study on non-linear equilibrium, kinetics and thermodynamic of deltamethrin removal in aqueous solution using modified magnetic iron oxide nanoparticles

The purpose of modification of magnetic iron oxide nanoparticles is an eco-friendly, emerging and economical method for removing deltamethrin in the aqueous solution and wastewater effluents when compared with other adsorbent methods. Modified magnetic iron oxide nanoparticles were synthesized by co-precipitation and then coupled with 3-hydroxytyraminium chloride. The nano-sorbent was characterized by thermogravimetric analysis, elemental analysis, transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectroscopy, zero point charge and surface area determination. Batch studies were conducted and adsorption equilibrium, kinetic and thermodynamic non-linear models were carried out. The resulting equilibrium data were tested with Langmuir and Freundlich non-linear isotherm models, and the results showed that the Langmuir isotherm fitted the data well. Kinetic studies were done with different initial deltamethrin concentrations, adsorbent dosage and temperature, and the data were assimilated with pseudo-first order, pseudo-second order and intra-particle diffusion kinetic equations, and it was found that the studied nano-sorbent processes followed the pseudo-second order kinetic equation. Thermodynamic analysis was also carried out to estimate the changes in free energy (ΔG⁰), enthalpy (ΔH⁰), and entropy (ΔS⁰). The thermodynamic parameters revealed that the adsorption of deltamethrin into the nano-sorbent was spontaneous, feasible and showed an endothermic process.

Adsorption of iron(III), cobalt(II), and nickel(II) on activated carbon derived from Xanthoceras Sorbifolia Bunge hull: mechanisms, kinetics and influencing parameters

Xanthoceras Sorbifolia Bunge hull activated carbon (XSA) was prepared and characterized by Brunauer-Emmett-Teller analysis, scanning electron microscopy and energy dispersive X-ray (EDX) spectroscopy. The ability of XSA as an adsorbent was investigated for the removal of the iron group ions Fe(III), Co(II), and Ni(II) from aqueous solution. Optimum adsorption parameters were determined based on the initial concentrations of the iron group ions, pH, adsorption temperature, and adsorption time in adsorption studies. The maximum monolayer adsorption capacities were 241.13 mg/g for Fe(III), 126.05 mg/g for Co(II), and 187.96 mg/g for Ni(II), respectively. Adsorption kinetics and isotherms showed that the adsorption process best fitted the nonlinear pseudo-second-order and Langmuir models, and the affinity of the ions for XSA decreased as follows: Fe(III) > Ni(II) > Co(II). Regeneration studies indicated that XSA could be used after several consecutive adsorption/desorption cycles using HNO₃. Fourier transform infrared and EDX spectra revealed the chemical adsorption value of XSA as an adsorbent for removing iron group ions from aqueous solutions.

Cadmium ion adsorption by amine-modified activated carbon

Cadmium (Cd) is one of the most toxic metals found in water and sediments. In the effort to develop an effective adsorbent for aqueous Cd removal, activated carbon (AC) was modified with an amino-terminated organosilicon (3-aminopropyltrimethoxysilane, APS). Response surface methodology was used to optimize selected operational parameters of adsorption of aqueous Cd by considering a central composite design with three input variables, temperature of the mixture solution, the contact time and feed ratio (APS/AC), on the surface modification. Results demonstrated that the strong Cd-binding amine ligands were effectively introduced onto the AC surfaces through the silanol reaction between carbon surface functional groups (-COOH, -COH) and APS molecules. The optimized preparation condition is 77 °C, 4 h and 2.1 ratio. The adsorbent presented a favorable adsorption of the aqueous Cd(II).

Which is better for optimizing the biosorption process of lead - central composite design or the Taguchi technique?

The aim of this study is to evaluate central composite design (CCD) and the Taguchi technique in the adsorption process. Contact time, initial concentration, and pH were selected as the variables, and the removal efficiency of Pb was chosen for the designated response. In addition, face-centered CCD and the L₉ orthogonal array were used for the experimental design. The result indicated that, at optimum conditions, the removal efficiency of Pb was 80%. However, the value of R² was greater than 0.95 for both the CCD and Taguchi techniques, which revealed that both techniques were suitable and in conformity with each other. Moreover, the results of analysis of variance and Prob > F < 0.05 showed the appropriate fit of the designated model with the experimental results. The probability of classifying the contributing variables by giving a percentage of the response quantity (Pb removal) made the Taguchi model an appropriate method for examining the effectiveness of different factors. pH was evaluated as the best input factor as it contributed 66.2% of Pb removal. The Taguchi technique was additionally confirmed by three-dimensional contour plots of CCD. Consequently, the Taguchi method with nine experimental runs and easy interaction plots is an appropriate substitute for CCD for several chemical engineering functions.