Preparation and Evaluation of Phenol Formaldehyde-Montmorillonite and Its Utilization in the Adsorption of Lead Ions from Aqueous Solution.

In this study, phenol formaldehyde-montmorillonite (PF-MMT) was prepared and used for lead ion (Pb2+) adsorption. Batch adsorption experiments were conducted to determine the optimal conditions. The calculated adsorption equilibrium (q) revealed that pseudo-second-order (PSO) and Langmuir isotherm models best fit the experimental data, suggesting chemisorption as the main mechanism. An adsorption capacity (qmax) of 243.9 mg/g was achieved. Fourier transform infrared (FTIR) analysis showed new peaks in PF-MMT-Pb, indicating metal complexation. Scanning electron microscopy (SEM) imaging displayed distinct Pb2+ clusters on the adsorbent surface. Adsorption was rapid, attaining equilibrium within 90 min. Effects of time, dose, concentration, and pH were systematically investigated to optimize the process. Lead ion removal efficiency reached 98.33% under optimum conditions after 90 min. The adsorption process was chemisorption based on the Dubinin-Kaganer-Radushkevich model with a free energy of 14,850 J/mol. The substantial adsorption capacity, rapid kinetics, and high removal efficiency highlight PF-MMT's potential for effective Pb2+ removal from aqueous solution.

Phenol-Formaldehyde/Pyrazole Composite: Synthesis, Characterization, and Evaluation of its Chromate Removal Efficiency.

In this study, we report the successful synthesis of a phenol-formaldehyde-pyrazole (PF-PYZ) compound through the surface functionalization of phenol-formaldehyde (PF) with pyrazole (PYZ). The resulting mixture was subjected to comprehensive characterization using a range of analytical techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The newly synthesized PF-PYZ material effectively removes Cr(VI) ions. Notably, a substantial elimination efficiency of 96% was achieved after just 60 min of contact time. The strategic incorporation of pyrazole (PYZ) as the principal functionalizing agent contributed to this exceptional performance. Notably, the functionalized PYZ sites were strategically positioned on the surface of PF, rendering them readily accessible to metal ions. Through rigorous testing, the optimal sorption capacity of PF-PYZ for Cr(VI) ions was quantified at 0.872 mmol Cr(VI)/g, highlighting the material's superior adsorption capabilities. The practical utility of PF-PYZ was further established through a reusability test, which demonstrated that the chromate capacity remained remarkably stable at 0.724 mequiv Cr(VI)/g over 20 consecutive cycles. This resilience underscores the robustness of the resin, indicating its potential for repeated regeneration and reuse without a significant capacity loss. Our work presents a novel approach to functionalizing phenol-formaldehyde with pyrazole, creating PF-PYZ, a highly efficient material for removing Cr(VI) ions. The compound's facile synthesis, exceptional removal performance, and excellent reusability collectively underscore its promising potential for various water treatments, especially oil field and environmental remediation applications.

Efficient dye removal from industrial wastewater using sustainable activated carbon and its polyamide nanocomposite derived from agricultural and industrial wastes in column systems.

Sugar beet crown (SBC) waste was employed to produce sustainable activated carbon (AC) by a thermo-chemical activation procedure using a fixed ratio of H3PO4/SBC (1 : 1 w/w ratio) at 550 °C/2 h. An activated carbon/polyamide nano-composite (AC/PA) was also prepared through the polymerization of the fabricated AC (90%) with polyamide (PA, 10%) synthetic textile waste using a proper dissolving agent at a specified w/w ratio with the employed polymer (formic acid/PA = 82/18%). Both AC and its derivative AC/PA were employed in the remediation of dyes from industrial wastewater in column systems, and their efficiencies were compared at various applied experimental conditions. The adsorption of the industrial dye waste (IDW) was a pH-, flow rate-, and bed thickness-controlled process by the regarded adsorbents. Kinetic studies confirmed the suitability of the Thomas equation over the Yoon and Nelson model in predicting the dynamic adsorption process of IDW by AC and AC/PA as was assured by the close agreement among the calculated and experimental uptake capacities of both adsorbents at the same applied flow rates, suggesting the chemisorption nature of IDW adsorption. Additionally, electrostatic attraction was the leading mechanism of IDW adsorption by AC and AC/PA composite with some advantages of the former over the latter.

Synthetization and characterization of SnCaAl2O3 nanocomposite and using as a superior adsorbent for Pb, Zn, and Cd ions in polluted water.

The presence of heavy metals in drinking water or wastewater poses a serious threat to the ecosystem. Hence, the present study focused on synthesizing SnCaAl2O3 core-shell nanoparticles (C.N.P.s) in the α-Alumina phase by thermal annealing a stacked structure sandwiched between two Al2O3 layers at low temperatures. The obtained structure showed Sn N.P. floating gate with an Al2O3 dielectric stacked tunneling barrier to remove the excess of these heavy metals from polluted water. To characterize the prepared composites, X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM) were used. The synthesized SnCaAl2O3 C.N.P.s composite was examined to utilize it as an adsorbent for removing Zn, Cd, and Pb divalent cations. The removal efficiency was studied by various parameters such as adsorbent dose, pH, contact time, metal concentrations, temperature, and coexisting ions. The experimental results were tested via Langmuir and Freundlich isotherm models. The obtained results were convenient to the Freundlich isotherm model. Moreover, the adsorption thermodynamic behavior of Zn+2, Cd+2, and Pb+2 on the synthesized composite was examined, and the process is endothermic and spontaneous under experimental conditions. The results illustrated that the adsorption efficiency of the SnCaAl2O3 core-shell nanoparticles (C.N.P.s) ranged from 88% to about 100% for all cations.

Synthesis, nonlinear optical analysis and DFT studies of D-π-D and A-π-A configured Schiff bases derived from bis-phenylenediamine.

Herein, an integral approach has been made towards the exploration of electronic and structural parameters of four synthesized (DMA with an A-π-A configuration and DMM, DAM, and DMD with a D-π-D configuration) and one designed (DMB-D) novel Schiff base compounds. Bis phenylenediamine derivatives were prepared by condensation of 4,5-dimethyl-o-phenylenediamine (1) with various substituted benzaldehydes (2a-d). The structures of compounds were confirmed by spectroscopic techniques, i.e., UV-visible, FT-IR, and NMR spectroscopy. The DFT-based analysis of entitled compounds was performed via density functional theory utilizing the M06-2X functional in conjugation with the 6-311G(d,p) basis set to acquire geometrical parameters, natural bonding orbital (NBO), the density of states (DOS), non-linear optical (NLO), molecular electrostatic potential (MESP), and natural population analyses. The smallest band gap of (5.446 eV) was noted for DMAvia frontier molecular orbital (FMO) analysis. GRPs were obtained with the aid of E gap values as DMA with the lowest band gap displayed a small magnitude of hardness (2.723 eV) and a large magnitude of softness (0.183 eV). The ß tot values of DMA, DMM, DMB-D, DAM, and DMD were 56.95, 0.43, 2.53, 8.98, and 68.47 times larger than urea (ß tot = 3.71 × 10-31 e.s.u.), respectively. The observed fascinating NLO properties of these novel compounds might be helpful for further advancement in non-linear optics.

First theoretical probe for efficient enhancement of optical nonlinearity via structural modifications into phenylene based D-π-A configured molecules.

The design of nonlinear optical (NLO) materials using conjugated molecules via different techniques is reported in the literature to boost the use of these systems in NLO. Therefore, in the current study, designed phenylene based non-fullerene organic compounds with a D-π-A framework were selected for NLO investigation. The initial compound (PMD-1) was taken as a reference and its seven derivatives (PMDC2-PMDC8) were made by introducing different acceptor moieties into the chemical structure of PMD-1. To explain the NLO findings, frontier molecular orbital (FMO), transition density matrix (TDM), density of states (DOS), natural bond orbital (NBO) and UV-Vis study of the title compounds was executed by applying the PBE1PBE functional with the 6-311G(d,p) basis set. The descending order of band gaps (E gap) was reported as PMDC7 (2.656) > PMDC8 (2.485) > PMD-1 (2.131) > PMDC3 (2.103) > PMDC2 (2.079) > PMDC4 (2.065) > PMDC5 (2.059) > PMDC6 (2.004), in eV. Global reactivity parameters (GRPs) were associated with E gap values as PMDC6 with the lowest band gap showed less hardness (0.0368 E h) and high softness (13.5785 E h). The UV-Vis investigation revealed that the maximum λ max (739.542 nm) was exhibited by PMDC6 in dichloromethane (DCM) as compared to other derivatives. Additionally, natural bond orbital (NBO) based findings revealed that PMDC6 exhibited the highest stability value (34.98 kcal mol-1) because of prolonged hyper-conjugation. The dipole moment (µ), average linear polarizability 〈α〉, first hyperpolarizability (ß tot) and second hyperpolarizability (γ tot) were evaluated for the reference and its derivatives. Consequently, among the designed compounds, the highest ß tot (4.469 × 10-27 esu) and γ tot (5.600 × 10-32 esu) values were shown by PMDC6. Hence, it's concluded from said results that these structural modifications proved PMDC6 as the best second and third order NLO candidate for various applications like fiber optics, signal processing and data storage.

Synthesis, spectroscopic, SC-XRD/DFT and non-linear optical (NLO) properties of chromene derivatives.

In the present study, we reported the efficient synthesis of novel, heterocyclic, coumarin-based pyrano-chromene derivatives, 2-amino-8-methyl-5-oxo-4-[2-(2-oxo-2H-chromen-3-ylmethoxy)-phenyl]-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile (4a) and 2-amino-8-methyl-5-oxo-4-[2-(2-oxo-2H-chromen-3-ylmethoxy)-phenyl]-4H,5H-pyrano[3,2-c]chromene-3-carboxylic acid methyl ester (4b). The chemical structures of synthesized compounds were resolved by employing various spectroscopic techniques like UV-Vis, FT-IR, 1H & 13C NMR, and single crystal X-ray diffraction (SC-XRD) analysis. The compounds; 4a and 4b, with appealing π-bonded skeleton were further analyzed in terms of their electronic and structural aspects using an integral approach of density functional theory (DFT) and time-dependent DFT (TD/DFT). The methodology: M06-2X/6-31G(d,p) level of theory was applied to compare their experimental data with theoretical outcomes using quantum chemical analysis. The frontier molecular orbitals (FMOs) study revealed that, 4a possesses a low band gap (5.168 eV) as compared to 4b (6.308 eV). Global reactivity parameters were associated with E gap values as 4a, with the lowest band gap showed the smaller value of hardness (0.094 eV) and a larger value of softness (5.266 eV). The non-linear optical (NLO) insight exhibited that, the average polarizability 〈α〉 and second hyperpolarizability (γ tot) were observed in 4a as 6.77005 × 10-23 and 0.145 × 104 esu, respectively. Overall, the computational studies suggest that the investigated compounds have distinct NLO properties.

Enhanced Nanofiltration Process of Thin Film Composite Membrane Using Dodecyl Phenol Ethoxylate and Oleic Acid Ethoxylate for Oilfield Calcite Scale Control.

This research studied the enhancing effect on the nanofiltration composite (TFCNF) membrane of two non-ionic surfactants on a thin-film composite nanofiltration membrane (TFCNF) for calcite scale (CaCO3) inhibition in oilfield application to develop a multifunctional filtration system: nanofiltration, antiscalant, and scale inhibitors. The effectiveness of dodecyl phenol ethoxylate (DPE) and oleic acid ethoxylate (OAE) as novel scale inhibitors were studied using the dynamic method. Scaling tests on the membrane were performed to measure the scaling of the inhibited membrane with and without scale inhibitors for salt rejection, permeability, and flux decline. The results revealed that the TFCNF membrane flux decline was improved in the presence of scale inhibitors from 22% to about 15%. The rejection of the membrane scales increases from 72% for blank membranes, reaching 97.2% and 88% for both DPE and OAE, respectively. These confirmed that scale inhibitor DPE had superior anti-scaling properties against calcite deposits on TFCNF membranes. Inhibited scaled TFCNF membrane was characterized using environmental scanning electron (ESEM), FTIR, and XRD techniques. The results of the prepared TFCNF membrane extensively scaled by the calcite deposits were correlated to its morphology.

Phragmites australis (Reed) as an Efficient, Eco-Friendly Adsorbent for Brackish Water Pre-Treatment in Reverse Osmosis: A Kinetic Study.

A cost-effective adsorbent was prepared by carbonization of pre-treated Phragmites australis reed at 500 °C. Phragmites australis was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface analyses. XRD of the as-prepared adsorbent exhibited a partially crystalline structure with a specific surface area of 211.6 m2/g and an average pore diameter of 4.2 nm. The biosorption potential of novel biosorbent Phragmites australis reed was investigated with a batch scale and continuous flow study. The study was conducted at different constraints to obtain optimum pH conditions, adsorbent dose, contact time, agitation speed, and initial TDS concentration. In order to analyze the properties of the procedure and determine the amount of sodium removal, Langmuir, Freundlich, and Dubinin-Radushkevich isotherms were tested. The optimal values of contact time, pH, and adsorbent dose were found to be 150 min, 4, and 10 g/L, respectively, with an agitation speed of 300 rpm at room temperature (27 °C). The three tested isotherms show that the adsorption of Na+ onto the prepared adsorbent is a hybrid process from physi- and chemisorption. For industrial application, the adsorbent was tested using the adsorbent column technique. Pseudo-first-order, pseudo-second-order, and diffusion models were connected, and it was discovered that the information fit best to the pseudo-second-arrange active model. According to the intraparticle diffusion model, the mechanism goes through four stages before reaching equilibrium. The periodicity test shows that the adsorption ability of Phragmites australis can be recovered by washing with 0.1 M HCl.

Enhanced Performance of Chitosan via a Novel Quaternary Magnetic Nanocomposite Chitosan/Grafted Halloysitenanotubes@ZnγFe3O4 for Uptake of Cr (III), Fe (III), and Mn (II) from Wastewater.

A novel chitosan/grafted halloysitenanotubes@Znγmagnetite quaternary nanocomposite (Ch/g-HNTs@ZnγM) was fabricated using the chemical co-precipitation method to remove the ions of Cr (III), Fe (III), and Mn (II) from wastewater. The characteristics of the synthesized Ch/g-HNTs@ZnγM quaternary nanocomposite were investigated using FTIR, SEM, XRD, GPC, TGA, TEM, and surface zeta potential. The characterization analysis proved that the mentioned nanocomposite structure contains multiple functional groups with variable efficiencies. Additionally, they proved the existence of magnetic iron in the nanocomposite internal structure with the clarity of presentation of gaps and holes of high electron density on its surface. The results showed that the pH and time to reach an equilibrium system for all the studied metal ions were obtained at 9.0 and 60 min, respectively. The synthesized Ch/g-HNTs@ZnγM nanocomposite exhibited maximum adsorption removal of 95.2%, 99.06%, and 87.1% for Cr (III), Fe (III), and Mn (II) ions, respectively. The pseudo-second-order kinetic model and, for isotherm, the Langmuir model were best fitted with the experimental data. The thermodynamic parameters indicated the exothermic and spontaneous nature of the adsorption reaction as proven by the ΔH° and ΔG° values. Additionally, chemical adsorption by the coordination bond is supposed as the main mechanism of adsorption of the mentioned metal ions on the nanocomposite. Finally, Ch/g-HNTs@ZnγM displays prospected advantages, such as a low-expense adsorbent, high efficiency and availability, and an eco-friendly source, that will reduce the environmental load via an environmentally friendly method.

Investigation the Effects of Green-Synthesized Copper Nanoparticles on the Performance of Activated Carbon-Chitosan-Alginate for the Removal of Cr(VI) from Aqueous Solution.

In the present investigation, green nano-zerovalent copper (GnZVCu), activated carbon (AC), chitosan (CS) and alginate (ALG) nanocomposites were produced and used for the elimination of chromium (VI) from a polluted solution. The nanocomposites GnZVCu/AC-CS-alginate and AC-CS-alginate were prepared. Analysis and characterization were performed by the following techniques: X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The SEM analysis revealed that the nanocomposites are extremely mesoporous, which leads to the greatest adsorption of Cr+6 (i.e., 97.5% and 95%) for GnZVCu/AC-CS-alginate and AC-CS-alginate, respectively. The adsorption efficiency was enhanced by coupling GnZVCu with AC-CS-alginate with a contact time of 40 min. The maximum elimination of Cr+6 with the two nanocomposites was achieved at pH 2. The isotherm model, Freundlich adsorption isotherm and kinetics model and P.S.O.R kinetic models were discovered to be better suited to describe the exclusion of Cr+6 by the nanocomposites. The results suggested that the synthesized nanocomposites are promising for the segregation of Cr+6 from polluted solutions, specially the GnZVCu/AC-CS-alginate nanocomposite.

Synthesis and Characterization of Silica-Coated Oxyhydroxide Aluminum/Doped Polymer Nanocomposites: A Comparative Study and Its Application as a Sorbent.

The present investigation is a comparison study of two nanocomposites: Nano-silica-coated oxyhydroxide aluminum (SiO2-AlOOH; SCB) and nano-silica-coated oxyhydroxide aluminum doped with polyaniline (SiO2-AlOOH-PANI; SBDP). The prepared nanocomposites were evaluated by monitoring the elimination of heavy metal Ni(II) ions from aquatic solutions. The synthesized nanocomposites were analyzed and described by applying scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) techniques, as well as Zeta potential distribution. In this study, two adsorbents were applied to investigate their adsorptive capacity to eliminate Ni(II) ions from aqueous solution. The obtained results revealed that SBDP nanocomposite has a higher negative zeta potential value (-47.2 mV) compared with SCB nanocomposite (-39.4 mV). The optimum adsorption was performed at pH 8, with approximately 94% adsorption for SCB and 97% adsorption for SBDP nanocomposites. The kinetics adsorption of Ni ions onto SCB and SBDP nanocomposites was studied by applying the pseudo first-order, pseudo second-order, and Mories-Weber models. The data revealed that the adsorption of Ni ions onto SCB and SBDP nanocomposites followed the pseudo second-order kinetic model. The equilibrium adsorption data were analyzed using three models: Langmuir, Freundlich, and Dubinin-Radusekevisch-Kanager Isotherm. It was concluded that the Langmuir isotherm fits the experimental results well for the SCB and SBDP nanocomposites. Thermodynamic data revealed that the adsorption process using SCB nanocomposites is an endothermic and spontaneous reaction. Meanwhile, the Ni ion sorption on SBDP nanocomposites is exothermic and spontaneous reaction.