3D-printing of Fe-Ni bimetallic particles and their application in removal of arsenic from water

Arsenic is a hazardous element found in water sources, and removing it is crucial for ensuring a safe environment and water quality. Iron-based metal oxides efficiently remove arsenic; however, their small particle sizes make separation from water difficult after arsenic removal. Furthermore, the growing global issue of polymer waste further complicates environmental concerns. Combining three-dimensional (3D) printing and adsorption technology by incorporating nanosized functional materials into supporting polymers offers a potential solution to address both challenges. In this study, we developed a 3D-printed adsorption material through the incorporation of synthesized Fe-Ni bimetallic particles into a supporting polymer using selective laser sintering (SLS) technology. This adsorbent's properties were examined through scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and zeta potential. Furthermore, its performance in removing As(III) and As(V), even at trace levels, was assessed under varied conditions. The 3D-printed adsorbent demonstrated excellent removal of As(III) at pH 6, and As(V) at pH 4, lowering their concentration below 10 μg/L, thereby adhering to the limit established by the World Health Organization (WHO). Both As(III) and As(V) fitted the Freundlich isotherm and pseudo-second-order model, suggesting potential heterogeneous and chemisorption processes. FT-IR indicated that the exchange of the -OH group of Fe-OH with oxyanions of As(III) and As(V) could be the adsorption mechanism. Additionally, thermodynamic evaluation unveiled an endothermic and non-spontaneous adsorption reaction. The 3D-printed adsorbent exhibited excellent reusability across recurring adsorption cycles. The combination of SLS 3D printing with Fe-Ni bimetallic particles produces structures that retain their functionality in removing both arsenic species present in water. This indicates the potential of the 3D-printed adsorbent for effective treatment of arsenic-contaminated water, offering remedies to challenges like handling small particle sizes, mitigating polymer waste, and addressing environmental concerns.

Selective recovery of copper from copper tailings and wastewater using chelating resins with bis-picolylamine functional groups

Industrial and mining wastewater, along with copper tailings, are typically highly acidic and contain copper and other heavy metals, which may contaminate and damage the environment. Copper (Cu) is, however, a valuable metal, making its removal and recovery from such wastewater and tailings environmentally and economically advantageous. Chelating ion exchange resins featuring bis-picolylamine functional groups are especially suitable for application requiring selective recovery of Cu(II) from highly acidic media. In this study, and for the first time, the kinetics, binding capacity and selectivity of Lewatit MDS TP 220 chelating resin towards Cu(II) are reported. The resin was characterized by Zeta potential, scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Factors including pH, initial concentration, contact time, temperature, and selectivity were investigated to assess the adsorption performance of the chelating resin. The adsorption kinetics tests revealed fast adsorption within the first 5-30 min and fitted the pseudo-second-order model, signifying chemisorption process. The adsorption isotherm followed the Langmuir model, implying monolayer adsorption process. The maximum adsorption capacity (qm) for Cu(II) determined by the Langmuir model was 103.9 mg/g. The adsorption thermodynamics showed an endothermic and spontaneous adsorption. FTIR and XPS studies suggested coordination or chelation as the possible adsorption mechanism. Lewatit MDS TP 220 exhibited excellent Cu(II) adsorption, desorption with 2 M ammonium hydroxide (NH4OH), and selectivity in multi-metal ions solution. Additionally, the resin demonstrated excellent reusability after five regeneration steps. This chelating resin is a potential adsorbent for effective and recurrent recovery of Cu(II) from copper tailings and wastewater, thereby contributing to environmental remediation.

A magnetic activated sludge for Cu(ii) and Cd(ii) removal: adsorption performance and mechanism studies

In the present study, a novel magnetic activated sludge (MAS) was successfully synthesized and applied for heavy metal removal.

Facile Synthesis of Hypercrosslinked Hollow Microporous Organic Capsules for Electrochemical Sensing of CuII Ions

A very simple and facile methodology is used to prepare dithiocarbamate-functionalized hollow microporous organic capsules (HMOCs-DTC), which exhibit excellent stability, a high surface area, and appropriate microporous architecture. In this strategy, SiO₂ particles are used as templates to construct PS-DVB-MAA microspheres, and then dithiocarbamate groups are grafted onto them. The dithiocarbamate-functionalized hypercrosslinked microporous organic capsules (HMOCs-DTC/GC) are then used as an electrode material for the detection of Cu^II ions. Cyclic voltammetry (CV) and electron impedance spectroscopy (EIS) are exploited to study the electrochemical potential of the designed material. The placement of functional groups (dithiocarbamate) at the mesopore interface effectively enhances the mass transfer, which facilitates the more selective detection of Cu^II ions. The high sensitivity of the modified electrode is expressed in terms of current (I_p ) enhancement at extremely low concentrations of Cu^II ions. Thus, a functional and robust porous material (HMOCs-DTC) presents a sensitive sensing ability, displaying the calibration response over a wide linear range (2.50×10^-11 -3.50×10^-10  m), with a lowest limit of detection of 1.02×10^-11  m. Indeed, these HMOCs present a new class of porous polymers possessing extraordinarily high scalability but avoiding complex and expensive synthetic methodologies, promoting its practical utilization.

Solar light efficient photocatalytic activity degradation of emergent contaminants by coated TiO2 nanoparticles

The photocatalytic degradation of different emergent contaminants in aqueous solutions has been studied by using oligomer-coated TiO₂ nanoparticles under solar light irradiation.

Cooking can decrease mercury contamination of a mushroom meal: Cantharellus cibarius and Amanita fulva

Mushrooms (Cantharellus cibarius and Amanita fulva) were blanched (parboiled) and pickled using different treatment conditions with the aim of carrying out the study into effect on removal of toxic mercury (Hg) accumulated in flesh. Blanching of fresh sliced C. cibarius caused leaching of Hg by approximately 15%, while loss of up to 35% was observed for sliced, deep-frozen fruit bodies. The rate of Hg leaching from the C. cibarius in practice was the same when blanched for 5 or 15 min irrespective of potable or deionized water used. Pickling of blanched C. cibarius with a diluted vinegar marinade had only a minor, if any, effect on removal of Hg and was without effect on blanched caps of A. fulva. Mercury was better extracted by boiling water from the fresh caps of A. fulva (56 ± 2% of the initial level in fresh caps) than from the fresh or frozen fruit bodies of C. cibarius. Total leaching rate of Hg from a pickled C. cibarius when fresh fruit bodies were processed was between 15 ± 5 and 37 ± 7% (median range 13-34%), and when deep-frozen fruit bodies were processed, it was between 37 ± 7 and 39 ± 8% (median range 34-39%). Pickling of the caps of A. fulva with diluted vinegar did not increase leaching of Hg. Blanching of mushrooms before future culinary use is a simple procedure recommended in reduction of contamination with Hg of cooked mushroom meal. Pickling had little if any effect on further removal of Hg from the initially blanched mushrooms.

Highly efficient simultaneous adsorption of Cd(ii), Hg(ii) and As(iii) ions from aqueous solutions by modification of graphene oxide with 3-aminopyrazole: central composite design optimization

Efficient simultaneous adsorption of heavy metal ions from solutions by modified graphene oxide with 3-aminopyrazole using central composite design modeling.

Synergistic effects of ion exchange and complexation processes in cysteine-modified clinoptilolite nanoparticles for removal of Cu(ii) from aqueous solutions in batch and continuous flow systems

In this work, clinoptilolite tuff was pre-treated and converted to microparticles (CMP) and nanoparticles (CNP) by a mechanical method.

Comparison of Co(ii) adsorption by a crosslinked carboxymethyl chitosan hydrogel and resin: behaviour and mechanism

This article studies the possible chemical and physical adsorption mechanism for Co(ii) onto the crosslinked carboxymethyl chitosan hydrogel and resin.

Preparation of 4-vinylpyridine (4VP) resin and its adsorption performance for heavy metal ions

The study focused on the preparation of a chelating resin with pyridine ring as the functional group.

Uptake of Fe(iii), Ag(i), Ni(ii) and Cu(ii) by salicylic acid-type chelating resin prepared via surface-initiated atom transfer radical polymerization

With chloromethylated PS being the base material, a new type of ASA/PGMA/PS resin with high capacity was prepared by grafting GMA on the surface of the resin via surface-initiated atom transfer radical polymerization and followed by the derivatization with 5-ASA.