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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.

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.

The generation and accumulation of environmental pollutant of industrial contaminations gave it a big challenge to develop many removal strategies of pollution. Textile dyes as dispersive blue 26 dye affected by several decolorization parameters like as temperature, initial pH and initial concentrations of dye. These variables parameter were studied on ZnO-dye suspension solution in dark and photoreaction conditions. In dark reaction, with using thermodynamic and kinetic parameters such as ΔH°, ΔS°, ΔG° and Ea, the type of adsorption was determined and found as a physical adsorption, exothermic and fast reaction. Moreover, the results demonstrated that the photoreaction process under UV-light-A would elevated the rate of reaction, percentage of decolorization and accelerated the half-time of decolorization reaction in 50 ppm of dye. The photoreaction of decolorization of this dye acts as pseudo first order kinetics with endothermic, less random less, non spontenous and fast reaction.

Polyethylene glycols (PEGs) are increasingly found in wastewater due to their use in the production of non-ionic surfactants, pharmaceuticals, antifreeze agents, water soluble lubricants, and cosmetics. This has led to increased interest in determining the fate of this chemical species in wastewater treatment plants. For the first time, a detailed practical and theoretical study on the fate of PEG has been conducted at the Aoun sewage treatment plant (ASTP) and modeled using the TOXCHEM model. Data were collected and entered into the TOXCHEM model, after calibration and validation, and root mean square error (RMSE) and correlation coefficient (R) were 0.04 and 0.82, respectively, which is within acceptable limits. A sensitivity analysis showed that the most sensitive parameters were the wastewater influent flow rate, temperature, air flow rate, MBBR biofilm thickness, specific surface area of the MBBR media, and MBBR media fill fraction. The TOXCHEM model showed that emission of PEG varied according to the season. Emissions were greatest during the warmer months and summer and spring emissions were found to be 24% and 18.4%, respectively. During spring and summer 24% and results of the TOXCHEM model indicated that the fate of PEG during spring and summer (35°C) and autumn and winter (12°C) was that about 24 and 18.4%, 10 and 10%, 53.5 and 46.6%, and 12.5 and 25% was fated to be emitted into atmosphere, sorbed to sludge, biodegraded, and discharged with the outlet, respectively. The highest emission was 3.3 mg/m 3 during the summer season in the aeration basin. Excessive flow rate affects biodegradation and reduces treatment efficiency. Reducing air flow rate, and the effects of MBBR biofilm thickness, specific surface area of MBBR media, and MBBR media fill fraction all increase the biodegradation process, reduce emission rates, and improve the treatment process. Increasing temperatures increase biodegradation, but also increase emissions. Practically, air flow rate, MBBR media fill fraction, and return activated sludge (RAS) were chosen for their ease of application at ASTP. The practical enhancement contributed to the reduction of the concentrations of chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solid (TSS), nitrate (NO 3) , phosphate (PO 4 –P), ammonia (NH 4 ), hydrogen sulfide (H 2 S), PEG in summer, and PEG in winter, from 44, 35, 15, 35, 3, 0.15, 0.18, 0.8, and 1.9 to 20,11, 9, 8, 2, 0.12, 0.1, 0.35, and 0.6 mg/L, respectively. Overall improvements increased biodegradability from 47 to 75.4% and reduced emissions from 18 to 5.6%. The TOXCHEM model used in this study was found to be an excellent predictor of the enhancement process.

The emission and fate of methyl mercaptan from the residential complex treatment plant (RCTP) moving bed bioreactor (MBBR) process in the city of Al-Hur in Karbala governorate in Iraq were studied using the TOXCHEM 4.1 model. The release of odorous sulfur compounds from treatment plants harms workers and the surrounding area. Methyl mercaptan, in particular, is responsible for odors similar to rotten cabbage. The sensitivity analysis for the methyl compounds in the MBBR system was conducted based on the following factors: a large thick biofilm layer, the specific surface area of media, media fill fraction, and aeration flowrate. The model was validated via RMSE and R, which showed the model outputs are representatives of real-world observations. Degradation and emission were shown to be the two most important processes in the system. During the summer (32 °C) and winter (12 °C), about 13 and 10%, 2 and 4%, 0.5 and 1%, and 85 and 85% were emitted into the atmosphere, discharged with effluent, sorbed into sludge, and biodegraded, respectively. The overall concentrations of CH4S emitted in summer and winter were 1.78 and 1.38 ppm, respectively. Operating the MBBR system with a thick biofilm layer, a large specific surface area of media, a greater media fill fraction, and a low aeration rate contributed significantly to the decomposition of methyl mercaptan and thus decreased emission into the atmosphere. Finally, the TOXCHEM simulation accurately predicts the fate of CH4S and the emissions inherent to the MBBR system. The manipulation of the operating factors led to the improvement of the system and the reduction of methyl mercaptan gas emissions without the need to add units and chemical additives.

In the current study, poly( p -aminophenol) (P p AP), with starch and graphene oxide (GO), was successfully synthesised by oxidative polymerisation from p -aminophenol monomer in an aqueous alkaline medium using ammonium persulfate (APS) as an oxidising agent. The synthesised polymers were characterised using UV–Vis spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction (XRD), and Brunauer–Emmett–Teller and zeta potential techniques. These techniques confirmed the presence of site-selective interaction between the conjugated P p AP chain and π-bonded surface, and thus the H-bonding of starch and GO. Further, the enhanced dye removal efficiency was ascribed to the improved morphology and the pore volume created by the entangled P p AP/Starch/GO. The influences of experimental conditions, such as the polymer composite content, dye concentration, time, pH of the bath solution, and temperature on cationic dye adsorption, were investigated. The adsorption data were fixed to the Langmuir isotherm (R 2 in the range between 0.997 and 0.9995) and showed a pseudo-second order (R 2  = in the range of 0.996 to 0.9996) kinetic model. Moreover, the polymer ternary composite was able to remove a large proportion (96.7%) of the cationic dye from water at pH 7. The thermodynamic investigation found that the adsorption process was spontaneous and endothermic. In addition, the synthesised adsorbent showed good reusability at six cycles. The data acquired suggest that the P p AP/Starch/GO composite can be effectively applied and reused as an inexpensive adsorbent material for removal of MB dye from water.

Novel polyaniline (Pani) and/or graphite (Gr)/molybdenum dioxide (MoO 2 ) composites have been successfully synthesised via an in situ chemical polymerisation method using a Deep Eutectic Solvent (DES) as the electrolyte. The chemical structure and properties of the Pani composites were characterised using various analytical techniques such as Raman, FTIR and UV–Vis spectroscopies, Thermo-Gravimetric Analysis (TGA), X-ray diffraction (XRD) and conductivity measurements, confirming its semi-crystalline nature. The results show shifts in the Raman, XRD and FTIR spectral features associated with the Pani composites, indicating that a matrix of metal oxide and/or graphite had formed in the polymer. Higher electrical conductivity was observed for the Pani/Gr (5.58 S cm −1 ) and Pani/Gr/MoO 2 (9.87 S cm −1 ) composites compared to pure Pani (1.25 S cm −1 ). The homogenous growth of Pani chains on the graphite and MoO 2 network were clearly observed by Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis by X-ray (EDAX). A larger surface area and greater porosity were achieved in the Pani/MoO 2 , Pani/Gr/MoO 2 and Pani/Gr samples, while a more compact structure was obtained for the Pani sample. These findings support that the idea that the polymer/graphite composites would be more useful for electrochemical charge transport, supercapacitance and energy storage applications compared to those using the pure polymer alone.

Physical properties of pure DESs and DESs mixed with different amounts of water were investigated by different techniques, including, rotational viscometer, Quartz Crystal Microbalance (QCM) and conductivity meter. In order to study heterogeneity of those liquids in nature. Analysis of these data showed some characteristics of heterogeneity, the extent of which depends on the number of hydrogen bond donors in the pure DES.

In this investigation, deep eutectic solvent based on propionic acid and choline chloride was used to prepare polyaniline, polypyrrole, and poly(aniline- co -pyrrole) samples using chemical oxidation and polymerization. Quantum mechanical calculations were conducted using time-dependent density functional theory to determine the electronic, spectroscopic properties and structure of homopolymers and the copolymer which were compared with the respective experimental data. Furthermore, the synthesized materials were characterized using Fourier transform IR spectroscopy, scanning electron microscopy (SEM), UV-visible spectroscopy, and thermogravimetric analysis. IR and UV-visible spectra confirmed copolymerization, and SEM revealed that the copolymer had a mixed morphology uniting features of both polyaniline and polypyrrole. Furthermore, the copolymer composite was more thermally stable than both homopolymeric materials. The quantum-chemical investigation revealed significant variations in the electron affinities and ionization energies of three polymers. The copolymer has the highest HOMO electronic density, indicating its superior electron-donating capability, while also having the highest LUMO density, suggesting a strong electron-accepting potential. Further, it also exhibits the smallest energy gap (2.384 eV), implying its high chemical reactivity, low stability, and high degree of polarization. The findings suggest that a larger energy gap correlates with greater molecular hardness and lower electronic softness, with polyaniline exemplifying these properties.

The electrodeposition of cobalt from alternative electrolytes, including ionic liquids and deep eutectic solvents (DES), has become a topic of great interest to the scientific community, with a significant impact in both academic circles and in the development of commercial industrial electrochemical processes. However, very few studies have considered the effects of water on the electrodeposition of metals from deep eutectic solvents. In this work, the electrodeposition of Co from a choline chloride (ChCl) ethylene glycol (EG)-based deep eutectic solvent (DES) containing 10%, 20% and 30% water has been studied, and for the first time a uniform and bright Co deposit has been obtained when the deposition was achieved from an electrolyte containing 20% water. The speciation of Co in a mixed 1:2 ChCl:EG-based liquid ( Ethaline 200 ) has been studied in both the absence and presence of water. The conductivities of the Co electrolyte were increased with increasing amounts of water. The electrochemical properties of the Co electrolytes have been studied using cyclic voltammetry, where it was found that the redox peak current gets larger and shifts in a positive direction when water was included in the Co solution. The resultant surface morphologies, topography, and roughness of the Co deposits were revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), which demonstrated that a highly uniform and smooth cobalt coating had been produced when the deposition occurred in Ethaline 200 containing 20% water.