Novel Functionalized Polythiophene-Coated Fe₃O₄ Nanoparticles for Magnetic Solid-Phase Extraction of Phthalates

Free Fatty Acid from Waste Palm Oil Functionalized Magnetic Nanoparticles Immobilized on Surface Graphene Oxide as a New Adsorbent for Simultaneously Detecting Hazardous Polycyclic Aromatic Hydrocarbons and Phthalate Esters in Food Extracts

A newly synthesized free fatty acids from waste palm oil functionalized magnetic nanoparticles immobilized on the surface of graphene oxide (FFA@MNP-GO) was successfully synthesized and characterized in this research. The combinations of long alkyl chain of free fatty acid with graphene oxide that consists of large delocalized 77-electron systems and abundant of hydrophilic groups with hydroxyl, epoxide and carboxylic groups offer the determination of simultaneous wide range of polarities of organic pollutants in real matrices through hydrogen bonding, hydrophobic and 77-77 interactions. The fabricated adsorbent was successfully applied as a magnetic solid phase extraction (MSPE) adsorbent for the simultaneous separation of selected phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) in apple and cabbage extracts prior to their high performance liquid chromatography with diode-array detector (HPLC-DAD) determination. Factors affecting the extraction efficiency such as amount of adsorbent, desorption solvent, volume of desorption solvent, extraction time, desorption time, pH and sample volume were investigated and optimized. The results revealed that under optimal conditions, the detection limit of selected PAEs and PAHs were in the range of 0.56-0.97 ng mL^-1 and 0.02-0.93 ng mL^-1, respectively. The spiked recoveries of real apple and cabbage extracts for PAEs and PAHs were in the range of 81.5-117.6% with good relative standard deviation (RSD) (n = 5) less than 10% and 86.7-118.2% with acceptable RSDs (n = 5) ranging from 1.5 to 11.0%, respectively. This study reported for the first time the use of MSPE procedure for simultaneous determination of chosen PAHs and PAEs in real samples including apple and cabbage extracts by using new adsorbent, FFA@MNP-GO.

Removal of Hg2+ by carboxyl-terminated hyperbranched poly(amidoamine) dendrimers grafted superparamagnetic nanoparticles as an efficient adsorbent

In this research, carboxyl-terminated hyperbranched poly(amidoamine) dendrimers grafted superparamagnetic nanoparticles (CT-HPMNPs) with core-shell structure were synthesized by the chemical co-precipitation method, the core of superparamagnetic iron oxide nanoparticles and a shell of polyamidoamines (PAMAM) and carboxyl groups, as a novel adsorbent for removing Hg²⁺ from aqueous systems. The surface of the particles was modified by 3-(aminopropyl) triethoxysilane, and finally, PAMAM and carboxyl dendrimers were grown on the surface up to 5.5 generation. The synthesized polymer was characterized physically and morphologically using different techniques. Also, they were evaluated in terms of adsorption capacity to remove inorganic pollutants of Hg²⁺, selectivity, and reusability. The adsorption mechanism Hg²⁺ onto CT-HPMNPs was investigated by single-step and two-step isotherms that the adsorption capacity of Hg²⁺ obtained 72.3 and 32.88 mg g^-1 respectively at pH 5, adsorbent dosage 2 g L^-1, Hg²⁺ initial concentrations 20 mg L^-1, contact time 60 min, and temperature of 298 K by CT-HPMNPs. Also, the kinetics of Hg²⁺ followed the pseudo-second-order model and adsorption isotherms of Hg²⁺ onto CT-HPMNPs were fitted well by Freundlich (as a single-step) and two-step adsorption models with a correlation coefficient of 0.9997 and 0.9999 respectively. The results showed a significant potential of Hg²⁺ ions removing from industrial wastewater and spiked water by CT-HPMNPs.

A study on the removal of propyl, butyl, and benzyl parabens via newly synthesised ionic liquid loaded magnetically confined polymeric mesoporous adsorbent

This study investigated the effectiveness of ionic liquids (ILs) loaded onto the surface of a polymeric adsorbent (βCD-TDI) grafted with modified magnetic nanoparticles (MNPs) via an analysis of water treatment, which resulted in high removal of selected endocrine-disrupting chemicals (parabens). The syntheses of MNPs, MNP-βCD-TDI, and IL-MNP-βCD-TDI were characterised and compared using Fourier transform infrared (FT-IR) spectroscopy, carbon-hydrogen-nitrogen (CHN) analysis, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET) method, thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The results of SEM and TEM indicated that the pore size distribution exhibited mesoporous characteristics with a small surface area (BET analysis: 42.95 m2 g-1). Furthermore, a preliminary sorption experiment demonstrated the ability of IL-MNP-βCD-TDI to enhance not only the sorption capacity, but also the removal of propyl paraben (PP), butyl paraben (BP), and benzyl paraben (ArP). The adsorption process appeared to be pH-dependent, and hence the optimum pH of 6 was selected for a subsequent batch adsorption study of all the studied parabens with an equilibrium time of 80 min. Next, in an attempt to investigate the interactions that occur between the adsorbent and the adsorbates, adsorption kinetics and isotherm studies were performed. All the studied parabens were found to best fit pseudo-second-order kinetics and the Freundlich isotherm with R 2 > 0.98 at room temperature (298 K). The interaction of the host-guest inclusion complex and the π-π interaction between βCD and a selected paraben compound (ArP) were identified by performing 1H nuclear magnetic resonance (NMR), together with ultraviolet-visible (UV-vis) spectroscopic analysis. Finally, the adsorption efficiency of the developed material was practically tested on tap water, drain water, and industrial wastewater, which revealed a significant removal of parabens of up to 60-90% in comparison with a prior analysis.

Facile Synthesis, Characterization of Poly-2-mercapto-1,3,4-thiadiazole Nanoparticles for Rapid Removal of Mercury and Silver Ions from Aqueous Solutions

Industrial pollution by heavy metal ions such as Hg2+ and Ag⁺ is a universal problem owing to the toxicity of heavy metals. In this study, a novel nano-adsorbent, i.e., poly-2-mercapto-1,3,4-thiadiazole (PTT), was synthesized and used to selectively adsorb mercury and silver ions from aqueous solutions. PTT nanoparticles were synthesized via chemical oxidative dehydrogenation polymerization under mild conditions. Oxidant species, medium, monomer concentration, oxidant/monomer molar ratio, and polymerization temperature were optimized to obtain optimum yields. The molecular structure and morphology of the nanoparticles were analyzed by ultraviolet-visible (UV-Vis), Fourier transform infrared (FT-IR), matrix-assisted laser desorption/ionization/time-of-flight (MALDI/TOF) mass and X-ray photoelectron (XPS) spectroscopies, wide-angle X-ray diffraction (WAXD), theoretical calculations and transmission electron microscopy (TEM), respectively. It was found that the polymerization of 2-mercapto-1,3,4-thiodiazole occurs through head-to-tail coupling between the S(2) and C(5) positions. The PTT nanoparticles having a peculiar synergic combination of four kinds of active groups, S⁻, ⁻SH, N⁻N, and =N⁻ with a small particle size of 30⁻200 nm exhibit ultrarapid initial adsorption rates of 1500 mg(Hg)·g-1·h-1 and 5364 mg(Ag)·g-1·h-1 and high adsorption capacities of up to 186.9 mg(Hg)·g-1 and 193.1 mg(Ag)·g-1, becoming ultrafast chelate nanosorbents with high adsorption capacities. Kinetic study indicates that the adsorption of Hg2+ and Ag⁺ follows the pseudo-second-order model, suggesting a chemical adsorption as the rate-limiting step during the adsorption process. The Hg2+ and Ag⁺-loaded PTT nanoparticles could be effectively regenerated with 0.1 mol·L-1 EDTA or 1 mol·L-1 HNO₃ without significantly losing their adsorption capacities even after five adsorption⁻desorption cycles. With these impressive properties, PTT nanoparticles are very promising materials in the fields of water-treatment and precious metals recovery.

Polyaniline modified magnetic nanoparticles coated with dicationic ionic liquid for effective removal of rhodamine B (RB) from aqueous solution

Polyaniline (PANI) modified magnetic nanoparticle (MNP) nanocomposites coated with newly synthesized dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesized as a potential material for the removal of Rhodamine B (RB) from water samples. The synthesized material was successfully characterized using a few techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), thermo gravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and transmission electron microscopy (TEM) analysis. Several parameters have been optimized to enhance the efficiency of the removal process. The adsorption kinetics were investigated and the results showed that MNP-PANI-DICAT was best fitted to a pseudo-second order model for the adsorption of RB. As for the isotherm studies, Temkin's model was found to fit well with the adsorption isotherm of RB on MNP-PANI-DICAT. Other than that, thermodynamics results showed negative values of ΔG° for the adsorption of RB, which indicated that the process is thermodynamically feasible, spontaneous and chemically controlled at lower temperature. The negative value of enthalpy ΔH° (−40.41) indicated that the adsorption was an exothermic process. The percentage removal of RB was found to be 94.7% by MNP-PANI-DICAT under optimized conditions.

Schematic diagram of the removal procedure of RB on MNP-PANI-DICAT.