Mesoporous Magnetic/Polymer Hybrid Nanoabsorbent for Rapid and Efficient Removal of Heavy Metal Ions from Wastewater

Polymeric nanoparticle synthesis for biomedical applications: advancing from wet chemistry methods to dry plasma technologies

Nanotechnology has introduced a transformative leap in healthcare over recent decades, particularly through nanoparticle-based drug delivery systems. Among these, polymeric nanoparticles (NPs) have gained significant attention due to their tuneable physicochemical properties for overcoming biological barriers. Their surfaces can be engineered with chemical functional groups and biomolecules for a wide range of biomedical applications, ranging from drug delivery to diagnostics. However, despite these advancements, the clinical translation and large-scale commercialization of polymeric NPs face significant challenges. This review uncovers these challenges by examining the interplay between structural design and payload interaction mode. It provides a critical evaluation of the current synthesis methods, beginning with conventional wet chemical techniques, and progressing to emerging dry plasma technologies, such as plasma polymerization. Special attention is given to plasma polymerized nanoparticles (PPNs), highlighting their potential as paradigm-shifting platforms for biomedical applications while identifying key areas for improvement. The review concludes with a forward-looking discussion on strategies to address key challenges, such as achieving regulatory approval and advancing clinical translation of polymeric NP-based therapies, offering unprecedented opportunities for next-generation nanomedicine.

Efficacious Removal of Cd2+ and Pb2+ Ions from Wastewater Using a Novel Fe3O4/SiO2/PANI-SDBS Nanocomposite

The current work synthesizes and characterizes a new Fe3O4/SiO2/PANI-SDBS nanocomposite designed as an efficient adsorbent for the removal of Cd2+ and Pb2+ ions from contaminated water. The process includes the polymerization of aniline on the Fe3O4/SiO2 nanocomposite in the presence of SDBS. The Fe3O4/SiO2/PANI-SDBS nanocomposite was characterized by using a variety of techniques, including FT-IR, XRD, TEM, SEM, BET, TGA, zeta potential measurements, and particle size distribution analysis, to evaluate its magnetic, structural, and surface properties. For the elimination of both Cd2+ and Pb2+ ions, ideal adsorption parameters were examined, including pH, adsorbent dose, and contact duration. The solution medium's optimal pH for achieving the highest effectiveness of elimination for both metal ions was decided to be 7.0. The Fe3O4/SiO2/PANI-SDBS adsorbent demonstrated high adsorption capacities for both Pb2+ (72.20 mg g-1) and Cd2+ (67.84 mg g-1) at pH 7, with corresponding removal efficiencies of over 94.10% and 77.47%, respectively. This efficiency is attributed to the composite's large specific surface area and the strong binding affinity of its PANI and SDBS functional groups toward heavy metal ions. Multilayer adsorption on heterogeneous surfaces was shown by isotherm analysis that matched the Freundlich model and adsorption kinetic investigations that showed strong conformance with pseudo-second order for both metal ions. The thermodynamic study proves endothermic and spontaneous process for the removal of metal ions. Furthermore, the adsorbent may be readily recovered from solution thanks to the magnetic core, and regeneration by acid treatment enables reusability with consistent adsorption efficiency across several cycles, making it a cost-effective and sustainable option for continuous water purification processes. Its high adsorption capacity and reusability also make it suitable for use in emergency-response situations, such as the rapid cleanup of wastewater.

Enhancing Tannic Acid-Arginine Complex Loading in Ultraporous PA6 Nanofibers through NH3 Foaming for Efficient Heavy Metal Removal from Textile Wastewater

Metal-containing dyes in the textile industry release heavy metal ions into wastewater, posing significant environmental risks and complicating treatment processes. Among various removal methods, chemical adsorption through functional groups that form stable complexes is one of the most effective. Tannic acid (TA), renowned for its strong chelation of metal ions via phenolic hydroxyl groups, faces challenges in operation and recycling in its powdered form. Electrospun polyamide 6 (PA6) nanofiber membranes, characterized by high surface area and structural stability, offer a promising platform. However, achieving an optimal TA loading remains a technical hurdle for industrial applications. To address this, we developed an arginine (l-Arg) bridging strategy to enhance the TA loading on PA6 nanofibers. Additionally, we implemented an NH3 escape foaming technique to increase membrane porosity by 20% and quadruple pore size, enhancing surface roughness and resulting in a 70% increase in TA loading. The optimized adsorbent demonstrated the effective removal of various heavy metal ions, achieving over 95% removal efficiency for five different metals. Even after five adsorption-desorption cycles, the membrane retained over 92% efficiency, translating to a treatment capacity of 12.5 tons of wastewater per kilogram of foaming fiber, underscoring its potential for practical wastewater treatment applications.

Mercury Ion Selective Adsorption from Aqueous Solution Using Amino-Functionalized Magnetic Fe2O3/SiO2 Nanocomposite

This study focuses on the development of new amino-functionalized magnetic Fe2O3/SiO2 nanocomposites with varying silicate shell ratios (1:0.5, 1:1, and 1:2) for the efficient elimination of Hg2+ ions found in solutions. The Fe2O3/SiO2-NH2 adsorbents were characterized for their structural, surface, and magnetic properties using various techniques, including Fourier transform infrared spectrum (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Braunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), zeta-potential, and particle size measurement. We investigated the adsorption circumstances, such as pH, dosage of the adsorbent, and duration of adsorption. The pH value that yielded the best results was determined to be 5.0. The Fe2O3/SiO2-NH2 adsorbent with a silicate ratio of (1:2) exhibited the largest amount of adsorption capacity of 152.03 mg g-1. This can be attributed to its significantly large specific surface area of 100.1 m2 g-1, which surpasses that of other adsorbents. The adsorbent with amino functionalization demonstrated a strong affinity for Hg2+ ions due to the chemical interactions between the metal ions and the amino groups on the surface. The analysis of adsorption kinetics demonstrated that the adsorption outcomes adhere to the pseudo-second-order kinetic model. The study of adsorption isotherms revealed that the adsorption followed the Langmuir model, indicating that the adsorption of Hg2+ ions with the adsorbent occurred as a monomolecular layer adsorption process. Furthermore, the thermodynamic analyses revealed that the adsorption of Hg2+ ions using the adsorbent was characterized by a spontaneous and endothermic process. Additionally, the adsorbent has the ability to selectively extract mercury ions from a complex mixture of ions. The Fe2O3/SiO2-NH2 nanocomposite, which is loaded with metal, can be easily recovered from a water solution due to its magnetic properties. Moreover, it can be regenerated effortlessly through acid treatment. This study highlights the potential use of amino-functionalized Fe2O3/SiO2 magnetic nanoparticles as a highly efficient, reusable adsorbent for the removal of mercury ions from contaminated wastewater.

Amino-Functionalized Lotus Stem Hydrochar for Rapid Adsorption and In Situ Detoxification of Cr(VI) from Water

The development of low-cost, efficient, and environmentally friendly adsorbents is the key to highly toxic hexavalent chromium [Cr(VI)] removal by adsorption. In this paper, amino-functionalized lotus stem hydrochar (ALSHC) was prepared from an agricultural waste lotus stem (LS) for the adsorption removal of Cr(VI) from water. The effects of the initial Cr(VI) concentration, contact time, temperature, coexisting anions, and reusability of ALSHC on Cr(VI) removal were examined in detail. The adsorption mechanism was further discussed by investigating the impact of the solution's initial pH, the relation between the pH change in solution and Cr(VI) removal during the process, the changes of chromium (Cr) species in solution and on ALSHC during adsorption, and the XPS characterization. The results demonstrated that ALSHC effectively removed Cr(VI) from water with rapid adsorption (the removal rate reached 80.90% in only 10 min) and in situ detoxification. Most importantly, ALSHC still had better adsorption performance (adsorption capacity of 30.95 mg g-1) than commercially activated carbon, even at pH = 9.00. The adsorption of Cr(VI) by ALSHC accorded with the pseudo-second-order kinetic model and Langmuir isotherm model, indicating a monolayer chemisorption process. The adsorption process was shown to be spontaneous and endothermic based on the thermodynamic characteristics (ΔG0 < 0, ΔH0 > 0, and ΔS0 > 0). The mechanism of Cr(VI) removal was mainly composed of three parts in sequence: Firstly, Cr(VI) in solution was quickly adsorbed onto ALSHC with protonated -NH2 through electrostatic attraction; subsequently, the adsorbed Cr(VI) on ALSHC was mostly detoxicated by in situ reduction; and finally, the reduced Cr(III) and the remaining Cr(VI) were fixed on the ALSHC surface by complexation. The prepared ALSHC displayed a certain superiority in Cr(VI) adsorption and had the prospect of further development.