Synthesis of Fe3O4 Nanoparticles with Different Shapes Through a Co-Precipitation Method and Their Application

Magnetic Fe3O4 nanoparticles (NPs) were successfully synthesized via co-precipitation method using ferric chloride and ferrous sulphate as the starting materials. The shape and the size of Fe3O4 NPs were controlled by using different types of additive including ammonium hydroxide and sodium hydroxide. The results revealed that by adding ammonium hydroxide, the particles attained a spherical shape with a uniform size. On the other hand, the shape of the particles turned from spherical to cubic using sodium hydroxide. The magnetic results showed that both samples attained hysteresis loop, which indicated that both samples have ferromagnetic behavior. In addition, Fe3O4 NPs with cubic shape showed higher adsorptive behaviour towards Congo red compared to spherical Fe3O4 NPs, which is attributed to the enhancement of their magnetic properties. The adsorption of Congo red onto cubic Fe3O4 NPs was best described by Langmuir isotherm model, while spherical Fe3O4 NPs followed Freundlich isotherm model.Other Information Published in: JOM License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s11837-022-05380-3</p

Enhanced Removal of Diesel Oil Using New Magnetic Bentonite-Based Adsorbents Combined with Different Carbon Sources

In this work, new magnetic bentonite-based adsorbents combined with different carbon sources, namely, reduced graphene oxide and multiwall carbon nanotubes, were synthesized via co-precipitation method. The synthesized adsorbents were characterized using XRD, TGA, SEM, EDX, TEM, and BET analysis techniques. The adsorbents were then used to remove oil from aqueous solutions of water-in-oil emulsion by performing batch adsorption experiments. The experimental data were fitted to three isotherm models including Langmuir, Freundlich, and Sips models using non-linear regression and were compared using Akaike Information Criterion statistical model. The data analysis showed that Sips model best fits the experimental data for the adsorption of oil onto both adsorbents. The maximum adsorption capacity of oil from sips model were 81.65 mg/g and 77.12 mg/g for Fe3O4/Bent/rGO and Fe3O4//Bent/MWCNTs, respectively. The obtained kinetics data were fitted to pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. Pseudo-second order kinetic model best fitted the kinetic data of both adsorbents. Overall, both adsorbents showed high removal efficiency reaching equilibrium in less than 50 min indicating that both adsorbents can be successfully utilized in industrial adsorption process. Graphical abstractOther Information Published in: Water, Air, & Soil Pollution License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s11270-022-05641-6</p

Dynamic simulation of lead(II) metal adsorption from water on activated carbons in a packed-bed column

In this work, lead(II) adsorption on activated carbons, tire-derived activated carbon (TAC), and commercial activated carbon (CAC), in a packed-bed column, was simulated using the Aspen Adsorption® V11 flowsheet simulator. The simulator was used to model the fixed-bed adsorption column and to establish the breakthrough curves by varying the initial concentration of lead(II) ions (500 mg/L, 1000 mg/L, 2000 mg/L, and 3000 mg/L), the bed height (0.2 m, 0.3 m, 0.4 m, 0.5 m, and 0.6 m), and the flow rate (9.88 × 10−4 m3/s, 1.98 × 10−3 m3/s, 2.96 × 10−3 m3/s, 3.95 × 10−3 m3/s, and 4.94 × 10−3 m3/s), at constant temperature and pressure of 25 °C and 3 bar, respectively. At the optimum conditions of 500 mg/L lead(II) concentration, 0.6 m bed height, and 9.88 × 10−4 m3/s flow rate, the breakthrough times were 488 s and 23 s for TAC and CAC, respectively. Under the same conditions, the adsorption capacity obtained at t0.5 was 114.26 mg/g for TAC and 7.72 mg/g for CAC. The simulation results indicate the potential of TAC for the adsorption of lead(II) in comparison to CAC.Other Information Published in: Biomass Conversion and Biorefinery License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s13399-022-03079-8</p

Optimizing and control of effective synthesize parameters for Fe3O4 nanoparticles using response surface methodology

To control Fe3O4 nanoparticles (Fe3O4 NPs) size, different molar ratio of Fe2+ and Fe3+ as well as ammonium hydroxide (pH) was used to synthesize Fe3O4 NPs through co-precipitation method. The Box–Behnken design was selected to explore the interaction between process parameters (factors) such as Fe2+ molar ion, Fe3+ molar ion and pH on the final size. The interactive effect between the process variables was evaluated by analysis of variance (ANOVA). The quadratic model predicted by the Box–Behnken design was significant with a P value of Other Information Published in: Chemical Papers License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s11696-022-02320-y</p

Adsorption of 4-Nitrophenol onto Iron Oxide Bentonite Nanocomposite: Process Optimization, Kinetics, Isotherms and Mechanism

Despite its importance in chemical industry, 4-Nitrophenol (4-NP) is a persistent organic pollutant that has serious effects on the ecosystem. In the present study, Box–Behnken design in response surface methodology was used to optimize the adsorption process parameters for the maximum 4-NP removal at 30 ℃ using Fe3O4/Bt NC. The regression model results suggested that the optimum adsorbent dosage, initial concentration, pH and contact time were 0.3182 g, 85 mg/L, 11 and 137.2 min, respectively. The regression model showed an optimum removal of 100%, while 99.5% removal was obtained from batch experiments at the optimum conditions suggested by the regression model, which confirm the model validity. The adsorption data best fitted to Freundlich isotherm model and Pseudo second-order kinetic model suggesting the existence of physical and chemical interaction between the fabricated composite and 4-NP. FTIR analysis suggested that the adsorption mechanism included an electrostatic attraction and the formation of new chemical bonds. Obtained results suggest that Fe3O4/Bt NC can be an effective adsorbent for complete 4-NP removal at the indicated optimum conditions. Graphical AbstractOther Information Published in: International Journal of Environmental Research License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s41742-022-00402-z</p