Application of amine-functioned Fe3O4 nanoparticles with HPEI for effective humic acid removal from aqueous solution: Modeling and optimization

Modeling and optimization of direct dyes removal from aqueous solutions using activated carbon produced from sesame shell waste

Today, there is a significant concern in the industry regarding the disposal of wastewater containing dyes into the environment, so the management and appropriate disposal of these wastes in the environment are considerable. The main aim of this study is to assess the efficiency of activated carbon (AC) prepared from sesame shells to remove direct dyes from aqueous solutions. According to the results, AC prepared from sesame shell had a high specific surface area (525 m2/g) and porous structure. The results demonstrated that the adsorbent had high potential to remove direct dyes as 84.5% of direct brown 103 (DB103), 93.08% of direct red 80 (DR80), 93.37% of direct blue 21 (DB21) and 98.39% of direct blue 199 (DB199) under the optimal conditions of adsorbent dose 4.8 g/L, contact time 19 min, pH 3 and initial dye concentration 12 mg/L. The experimental results showed that kinetic data were best described by the pseudo-second-order model (R2 = 0.989) while isotherm data were best fitted by the Freundlich model (R2 = 0.994). In the present study, not only was the produced waste used as a useful and economically valuable material, but it was also applied as an effective adsorbent to remove direct dyes from industrial effluents and reduce environmental pollution.

PEI-based functional materials: Fabrication techniques, properties, and biomedical applications

Cationic polymers have recently attracted considerable interest as research breakthroughs for various industrial and biomedical applications. They are particularly interesting due to their highly positive charges, acceptable physicochemical properties, and ability to undergo further modifications, making them attractive candidates for biomedical applications. Polyethyleneimines (PEIs), as the most extensively utilized polymers, are one of the valuable and prominent classes of polycations. Owing to their flexible polymeric chains, broad molecular weight (MW) distribution, and repetitive structural units, their customization for functional composites is more feasible. The specific beneficial attributes of PEIs could be introduced by purposeful functionalization or modification, long service life, biocompatibility, and distinct geometry. Therefore, PEIs have significant potential in biotechnology, medicine, and bioscience. In this review, we present the advances in PEI-based nanomaterials, their transfection efficiency, and their toxicity over the past few years. Furthermore, the potential and suitability of PEIs for various applications are highlighted and discussed in detail. This review aims to inspire readers to investigate innovative approaches for the design and development of next-generation PEI-based nanomaterials possessing cutting-edge functionalities and appealing characteristics.

Treatment of cardboard factory wastewater using ozone-assisted electrocoagulation process: optimization through response surface methodology

Cardboard factory wastewater is usually known by high chemical oxygen demand (COD), color, phenols, lignin, and its derivatives, and usual treatment techniques are not able to treat such wastewaters. This study aimed to investigate the efficiency of ozone-assisted electrocoagulation process (EC/O₃) for the treatment of real cardboard wastewater. The parameters influencing COD removal in the EC/O₃ process were optimized using response surface methodology. Regard to the statistical model, the optimum conditions were obtained at current density 9.6 mA/cm², time 20 min, and pH 12. At optimal condition, EC/O₃ process removed 74.7% and 97.5% of COD and color, which was higher compared to ozonation and EC processes separately. The COD removal followed pseudo-first-order kinetic with the coefficient correlation of 0.97 and the reaction rate constant of 0.073 1/min. To sum up, the combined electrocoagulation process with ozonation could be used satisfactorily for removing pollutants from real cardboard wastewater.

Synthesis and characterizations of hybrid PEG-Fe3O4 nanoparticles for the efficient adsorptive removal of dye and antibacterial, and antibiofilm applications

PURPOSE

Dyes are highly toxic coloured compounds in nature that are largely applied in paper, food, textile and printing industries. Here, the adsorption technique was performed to remove methyl orange (MO) dye from water by polyethylene glycol (PEG) modified iron oxide nanoparticles (Fe₃O₄ NPs).

METHODS

The method used for Fe₃O₄ NPs synthesis was chemical precipitation. The particles were analyzed by transmission electron microscope, magnetometer, BET analyzer, fourier-transform infrared spectroscopy, X-ray powder diffraction, zetasizer and particle size analyzer. The influence of pH (4.0 to 10.0), NaCl concentration (0.01 mM to 2 M), adsorbent dosage (1 to 10 mg), and the role of surface charge on adsorptive removal were investigated.

RESULTS

The NPs size, zeta potential and surface area was found to be 26 ± 1.26 nm, 33.12 ± 1.01 mV and 119 m²/g respectively. The adsorption of MO on Fe₃O₄ NPs agreed best to Freundlich model (R² = 0.965) when compared with Langmuir model (R² = 0.249). By comparing pseudo-first-order kinetic model (R² = 0.937), kinetic adsorption study was better followed by pseudo-second-order kinetic model (R² = 1). The adsorption rate decreased with increasing NaCl concentration. At pH 4, maximum adsorption was noted. The particles were also exhibited excellent antibacterial and antibiofilm activities. The ROS formation, lipid peroxidation and oxidative stress were increased with increase in NPs concentration. The NPs precoated slides exhibited more than 50% growth inhibition.

CONCLUSION

The investigation denotes the versatile applications of the prepared particles for removing the dye stuffs from industrial effluents and as antibacterial and antibiofilm agent.

Enhanced removal of humic acid from aqueous solution by combined alternating current electrocoagulation and sulfate radical

Application of alternating current in electrocoagulation and activation of persulfate (AEC-PS) for the effective removal of humic acid (HA) from aqueous solution was evaluated. In order to optimize the removal efficiency HA by the AEC-PS process, several influencing parameters such as pH, reaction time, PS dose, current density (CD), concentration of NaCl, initial concentration of HA, and coexisting cations and anions influence were investigated. From the batch experiments, the highest HA removal efficiency obtained was 99.4 ± 0.5% at pH of 5, reaction time of 25 min, CD of 4.5 mA/cm2, PS dose of 200 mg/L, and NaCl concentration of 0.75 g/L for an initial HA concentration of 30 mg/L. When CD increased from 1.25 to 4.5 mA/cm2, the HA removal efficiency was improved from 88.8 ± 4.4% to 96.1 ± 1.5%. In addition, the type of coexisting cations and anions exerted a significant role, leading to a reduction in the removal efficiency of HA. To investigate the dominant free activated radical, radical scavengers such as tert-butyl alcohol and ethanol were employed. It was observed that both OH and SO4- radicals substantially contributed to the removal of HA, and the contribution of SO4- radical was higher than that of OH radical, suggesting that AEC-PS process could serve as a novel and effective treatment technique for the removal of organic matters from aqueous sources.