A novel magnetic nanoadsorbent has been synthesized by the covalent immobilization of thiosalicylhydrazide on the surface of Fe3O4 nanoparticles. Size, structure, magnetic property, and porosity of the prepared magnetic nanoparticles (MNPs) were studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analysis. The ability of the prepared MNPs for removing heavy metals ions (Pb2+, Cd2+, Cu2+, Zn2+, and Co2+) from industrial wastes was studied, and the effects of different affecting parameters on the adsorption characteristics of the modified MNPs were investigated. The maximum adsorption capacities of Pb2+, Cd2+, Cu2+, Zn2+, and Co2+ were found to be 188.7, 107.5, 76.9, 51.3, and 27.7 mg g–1, respectively. Excellent adsorption capacity of the modified nanoadsorbent together with other advantages such as reusability, easy separation, environmentally friendly composition, and freedom of interferences of alkaline earth metal ions make them suitable adsorbents for removal of heavy metal ions from environmental and industrial wastes.

The aim of this work was to develop a superadsorbent for the removal of Hg2+ ions from aqueous solutions. In this regard, a porous covalent triazine ring-based nanoneedle was synthesized through a facile hydrothermal method. The structure and morphology of the synthesized covalent triazine ring-based adsorbent were characterized by different techniques. The structural stability of the synthesized superadsorbent was examined under different temperatures and pH conditions. The maximum adsorption capacity of the prepared organic framework is 1826 mg g–1 for removing Hg2+ ions at ambient temperature and an optimum pH of 5. Different linear and nonlinear models were applied for the fitting of the obtained adsorption data. It was found that the adsorption data can be well fitted to the linear Langmuir model (R 2 = 0.998). The adsorption kinetics can also be well described by the linear pseudo-second-order model. To make a portable, highly sensitive, and low-cost device for in situ sensing of trace amounts of Hg2+ ions, the smartphone colorimeter platform was developed using accessible equipment. The response of the developed system for the determination of Hg2+ ions was linear in the concentration range of 0.25–15 mg L–1, and the detection limit of the system is 0.063 mg L–1 Hg2+. The total cost of the developed system is lower than 400 US dollars, and the cost of each analysis is lower than 0.05 US dollars. Ultrahigh adsorption capacity, chemical stability, and fast adsorption kinetics make the synthesized triazine-based covalent organic framework a suitable candidate for the removal of Hg2+ ions from industrial effluents.

In this paper a novel sunlight activable photocatalyst system based on the synergistic effect between double Z-Scheme g-C3N4-WO3-Bi2WO6 nanocomposite and long-lasting phosphorescent SrAl2O4: Eu2+, Dy3+ nanoparticles has been designed, synthesized...

In this work, we report ultrasonic-assisted synthesis of layered double hydroxides (LDHs) containing biodegradable amino acid derivative, N,N′-(pyromellitoyl)-bis-L-isoleucine diacid, and their application for removal of cyanide ions from industrial wastes. The structure of the modified Mg−Al LDHs was studied using transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), FT-IR spectroscopy, and X-ray diffraction (XRD) techniques. The ability of the prepared LDHs for adsorption of cyanide ions from aqueous solutions was examined, and the effects of the different parameters were investigated. It was found that, under optimum conditions, the proposed LDHs adsorbent can remove 98.7% of cyanide content of the aqueous solution in less than 35 min. Compared to the recently reported methods for removal of cyanide; the proposed method has several advantages. First, the adsorbent particles (LDHs) are synthesized via an environmentally acceptable route; because water is used as solvent under ultrasonic irradiation. Second, cyanide ions are exchanged with biodegradable anions, thus the proposed method does not produce toxic waste. Third, the prepared adsorbent has high adsorption capacity and the fast adsorption kinetics, thus it can be used for lowering the concentration of cyanide in the wastes to below regulatory limits in practically acceptable times.

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In this work, the preparation and characterization of glutaraldehyde-crosslinked electrospun nanofibers of chitosan/poly(vinyl alcohol) (GCCPN) as a new adsorbent for tetracycline (TC) is reported. Electrospun nanofibers of chitosan/poly(vinyl alcohol) (PVA) were prepared by employing a 75:25 volumetric ratio of chitosan:PVA, voltage of 30 kV, collection distance of 10 cm, and injection flow rate of 2 mL/h. Then, the nanofibers were crosslinked via applying the glutaraldehyde on them for 3 h at 40 °C. The nanofibers were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction. Uniform beadless nanofibers with minimum diameters of 3-11 and 6-18 nm were obtained before and after crosslinking, respectively. Then the applicability of the synthesized GCCPN for removal of TC from aqueous solutions was investigated. The response surface method was applied to evaluate the influence of pH (6-12), TC concentration (50-250 mg/L) and the adsorbent dose (0.05-0.25 g in 20 mL solution) on the adsorption characteristics of GCCPN. The maximum adsorption capacity was 102 mg/g. The adsorption kinetics was explained most effectively by the pseudo-second-order model. The adsorption data of TC on the GCCPN surface was explained well by the Langmuir isotherm model.

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