Comparison activity of pure and chromium-doped nickel oxide nanoparticles for the selective removal of dyes from water.

The current study involves a synthesis of a composite of nickel oxide nanoparticles (NiONPs) with a chromium dopant to yield (Cr/NiONPs). Synthesis of nickel oxide was performed by the co-precipitation method. The synthesis of the composite was conducted by the impregnation method. FTIR, EDX, SEM, and XRD were used to characterize the synthesized materials. The synthesised materials' point zero charges (PZC) were performed using the potentiometric titration method. The obtained results show that the PZC for neat nickel oxide was around 5, and it was around 8 for Cr/NiONPs. The adsorption action of the prepared materials was examined by applying them to remove Reactive Red 2 (RR2) and Crystal Violate (CV) dyes from solutions. The outcomes demonstrated that Cr/NiONPs were stronger in the removal of dyes than NiONPs. Cr/NiONPs achieved 99.9% removal of dyes after 1 h. Adsorption isotherms involving Freundlich and Langmuir adsorption isotherms were also conducted, and the outcomes indicated that the most accurate representation of the adsorption data was offered by Langmuir adsorption isotherms. Additionally, it was discovered that the adsorption characteristics of the NiONPs and Cr/NiONPs correspond well with the pseudo-second-order kinetic model. Each of the NiONPs and Cr/NiONPs was reused five times, and the results display that the effectiveness of the removal of RR2 dye slightly declined with the increase in reuse cycles; it lost only 5% of its original efficiency after the 5 cycles. Generally, Cr/NiONPs showed better reusability than NiONPs under the same conditions.

Simulation study of a practical approach to enhance cadmium removal via biological treatment by controlling the concentration of MLSS.

The fate of cadmium at the Muharram Aisha wastewater treatment plant in Karbala governorate, Iraq was studied using the TOXCHEM model. Cadmium, a known carcinogen, and is considered one of the most dangerous heavy metals and high concentrations, greater than permissible limits, were found in the treated wastewater. The plant operates using an activated sludge system and this was modeled via TOXCHEM with a sensitivity analysis carried out on the extended aeration system. Prior to analysis, the model was calibrated and validated for cadmium, with the adjustments leading to a mean square error (RMSE) and correlation coefficient (R) of 0.0001 and 0.81, respectively. The mass balance of cadmium in the Muharram Aisha treatment plant was found to be 4832.44 g/day (37.1726%) in the treated wastewater and 8164.52 g/day (62.804%) in the sludge, which indicated that the mix liquor suspended solid (MLSS) was the most sensitive factor. The sensitivity to cadmium was analyzed via MLSS in the extended aeration system and the results o indicated that the higher the MLSS concentration (mg/L), the greater the removal of cadmium in the treated wastewater. It was found that increasing the MLSS through a biological treatment method reduced the concentration of cadmium without the need for additional of any (potentially harmful) chemical treatments. The plant was subsequently operated for a period of 5 months with the MLSS increased from 1500 to 4500 mg/L, and this reduced the concentration of cadmium in the wastewater from 0.36 to 0.01 mg/L as a consequence. This research demonstrates how the novel application of TOXCHEM can be a useful tool in the reduction of heavy metal contamination in the environment.

Effect of Graphene Oxide and Temperature on Electrochemical Polymerization of Pyrrole and Its Stability Performance in a Novel Eutectic Solvent (Choline Chloride-Phenol) for Supercapacitor Applications.

Polypyrrole (Ppy)-modified graphene oxide (GO) electrodes were synthesized for the first time in a choline chloride-phenol-based deep eutectic solvent at various temperatures via electrochemical methods without the addition of any inorganic or organic catalysts. The surface morphologies and structures of the modified films were assessed via scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction techniques. The electrochemical properties and stability of the modified electrodes were investigated via cyclic voltammetry and impedance spectroscopy at various temperatures and scan rates. The results showed that the specific capacitance of the nanocomposites decreased with increasing scan rate during cycling. Additionally, the specific capacitances of the pure Ppy and Ppy/GO films increased with increasing temperature of the electrolyte (monomer-free), attributed to the reduction in viscosity at elevated temperature. The specific capacitances at 5 mV s-1 were found to be 1071.78 and 594.79 F g-1 for Ppy/GO (20 wt %) at 50 and 25 °C, respectively. It was also observed that the resistance in the cell decreased with increasing electrolyte temperature. Ppy/GO at 50 mV s-1 was found to have the highest capacitance retention of 85% after 2000 cycles, showing better cycling stability than the pure Ppy film. Herein, the incorporation of GO in the Ppy matrix led to improved specific capacitance and cyclic stability, suggesting that Ppy/GO could represent a promising electrode material for supercapacitor applications.

Voltammetric Determination of Hg2+, Zn2+, and Pb2+ Ions Using a PEDOT/NTA-Modified Electrode.

A novel electrochemical sensor for determining trace levels of Hg2+, Pb2+, and Zn2+ ions in water using square wave voltammetry (SWV) is reported. The sensor is based on a platinum electrode (Pt) modified by poly(3,4-ethylenedioxythiophene) and N α,N α-bis-(carboxymethyl)-l-lysine hydrate (NTA lysine) PEDOT/NTA. The modified electrode surface (PEDOT/NTA) was prepared via the introduction of the lysine-NTA group to a PEDOT/N-hydroxyphthalimide NHP electrode. The (PEDOT/NTA) was characterized via cyclic voltammetry (CV), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The effects of scan rates on the electrochemical properties of the polymer electrode were also investigated. The electrochemical results were used to estimate the coverage of the electrode polymer surface and its electrostability in background electrolyte solutions. Several analytical parameters, such as polymer film thickness, metal deposition time, and pH of the electrolyte, were examined. Linear responses to Hg2+, Pb2+, and Zn2+ ions in the concentration range of 5-100 µg L-1 were obtained. The limits of detection (LODs) for the determination of Hg2+, Pb2+, and Zn2+ ions were 1.73, 2.33, and 1.99 µg L-1, respectively. These promising results revealed that modified PEDOT/NTA films might well represent an important addition to existing electrochemical sensor technologies.

A multifunctional α-Fe2O3@PEDOT core-shell nanoplatform for gene and photothermal combination anticancer therapy.

Exploration of versatile nanoplatforms within one single nanostructure for multidisciplinary treatment modalities, especially achieving a synergistic therapeutic efficacy of combinational gene/photothermal cancer therapy is still a great challenge in biomedicine and nanotechnology. In this study, a unique photothermal nanocarrier has successfully been designed and developed for a combination of gene therapy (GT) and photothermal therapy (PTT) of cancer cells. Surface-engineered iron oxides (α-Fe2O3) nanoparticles (NPs) with poly(3,4-ethylenedioxythiophene) (PEDOT) polymer coatings are synthesized using a one-pot in situ oxidative polymerization method. The results show that the as-prepared α-Fe2O3@PEDOT core-shell NPs with a uniform particle size exhibit positively charged surfaces, facilitating efficient siRNA Bcl-2 (B-cell lymphoma-2) uptake for delivery to breast cancer cells. More importantly, α-Fe2O3@PEDOT core-shell NPs not only display good biocompatibility and water dispersibility but also strong optical absorption enhancement in the Vis-NIR region as compared to α-Fe2O3 NPs. The obtained α-Fe2O3@PEDOT core-shell NPs show an efficient photothermal conversion efficacy (η = 54.3%) and photostability under NIR laser irradiation. As a result, both in vitro and in vivo biological studies on two types of breast cancer cells/tumors treated with α-Fe2O3@PEDOT-siRNA nanocomplexes demonstrate high cancer cell apoptosis and tumor inhibition induced by synergistic GT/PTT therapy under mild conditions compared to an individual GT or PTT alone. Taken together, this is the first example of the use of an α-Fe2O3@PEDOT core-shell nanoagent as a siRNA delivery nanocarrier for highly effective gene/photothermal combination anticancer therapy.