Phenol In Aqueous Solution Research Articles

Zinc oxide (ZnO) Enhanced with Silver (Ag) is Used to Improve the Photocatalytic Degradation of Phenol in Aqueous Solutions

Silver-modified zinc oxide (Ag/ZnO) photocatalysts were synthesized and characterized to evaluate their efficiency in degrading phenol under UV irradiation. X-ray fluorescence, surface area analysis, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV-visible reflectance spectroscopy confirmed successful deposition of metallic silver (Ag0) nanoparticles on the ZnO surface. The abundance of silver particles correlated directly with Ag concentration. Surface plasmon resonance bands indicated silver nanoparticle formation. Photocatalytic testing showed increased phenol degradation with Ag/ZnO versus pure ZnO, with 0.88 wt% Ag being optimal. Further experiments found 50 mg/L initial phenol and 0.15 g/L photocatalyst dosage optimized performance. Finally, almost complete elimination of phenol from drinking wastewater occurred after 180 minutes with the enhanced Ag/ZnO photocatalyst under UV irradiation.

Effect of pore-forming agent on degradation of phenol by iron tailings based porous ceramics

In order to realize the resource utilization of solid waste and the treatment of phenol wastewater in China, a new porous ceramic granules (PCG) with the function of degrading phenol wastewater was prepared by using titanium-containing blast furnace slag, iron tailings and fly ash as raw materials, which realized the sustainable development of "treating waste with waste". The effects of different pore forming agents on the structure, morphology, ionic state of PCG samples and the adsorption behavior of phenol in aqueous solution were investigated. The results show that the change of pore forming agent has no obvious change on the crystal structure. When carbon powder (CP) and starch (SH) are used as pore forming agents, the internal pore structure is relatively dense and less porous, and it is not easy to form liquid channels. When ammonia bicarbonate (NH) is used as pore-forming agents, the internal pore structure is very developed and has many three-dimensional pore structures. Under the conditions of PH 2, phenol concentration 10 mg/L and solid-liquid ratio 3 g/L, TOC removal rates of CP-PCG, SH-PCG and NH-PCG samples after 72 h adsorption reaction were 39.10 %, 14.00 % and 93.29 %, respectively. In addition, the surface functional groups, hydrogen bonds and π-π interactions of PCG samples may be involved in the adsorption of phenol. This work not only provides a low-cost, environmentally friendly and simple technology for phenol-containing wastewater treatment, but also provides a new idea for the effective use of solid waste resources.

The Effectiveness of Carbonized Neem Leaves Adsorbent for the Removal of Phenol from Synthesized Effluent Using the Batch Process Method

The adsorption of phenol in aqueous solution was investigated using carbonized neem leaves adsorbents. The effect of various factors such as contact time, phenol concentration, pH, temperature, and amount of adsorbent on the adsorption capacity of the adsorbents was determined. The results show that maximum adsorption was obtained at a contact time of 150 minutes, at a phenol concentration of 50 mg/L, optimum adsorption temperature of 45⁰C, pH of 2 and adsorbent dosage of 3 g/L. The equilibrium data was well described by the Freundlich isotherm equation (R2= 0.955 ). This shows a heterogenous adsorption process. The kinetics of the process were explained by the intra-particle diffusion models (R2>0.9). This fitted data indicates a degree of boundary layer control and is not limited to intra-particle diffusion.

Investigation of the Influence of Structural Changes in Aqueous Solutions of Phenol on Its Ability to Be Extracted by Fe3O4 Magnetic Nanoparticles

Investigation of the Influence of Structural Changes in Aqueous Solutions of Phenol on Its Ability to Be Extracted by Fe3O4 Magnetic Nanoparticles

Surface accumulation and acid-base equilibrium of phenol at the liquid-vapor interface.

We have investigated the surfactant properties of phenol in aqueous solution as a function of pH and bulk concentration using liquid-jet photoelectron spectroscopy (LJ-PES) and surface tension measurements. The emphasis of this work is on the determination of the Gibbs free energy of adsorption and surface excess of phenol and its conjugate base phenolate at the bulk pKa (9.99), which can be determined for each species using photoelectron spectroscopy. These values are compared to those obtained in measurements well below and well above the pKa, where pure phenol or phenolate, respectively, are the dominant species, and where the Gibbs free energy of adsorption determined from surface tension and LJ-PES data are in excellent agreement. At the bulk pKa the surface-sensitive LJ-PES measurements show a deviation of the expected phenol/phenolate ratio in favor of phenol, i.e., an apparent upward shift of the at the surface. In addition, the Gibbs free energies of adsorption determined by LJ-PES at the bulk pKa for phenol and phenolate deviate from those observed for the pure solutions. We discuss these observations in view of the different surface propensity of phenol and phenolate as well as potential cooperative interactions between them in the near-surface region.

Molecular simulation of adsorption behavior for phenol aqueous solution into layered graphene oxides

Graphene oxide (GO) adsorbents possess layered structures with nanoscale interlayer channels, which have been proposed as effective adsorbents for the removal of harmful phenol from aqueous solutions. However, the relevant adsorption process and behavior remain largely unexplored, and, particularly, the interlayer insertion and interaction mechanism need to be clarified. Herein, molecular dynamics simulation was performed to comprehensively investigate the dynamics process and interaction for phenol adsorption into GO interlayers. It is theoretically demonstrated that the adsorption process is thermodynamically spontaneous. The time evolution of molecular insertion amounts and interaction energy were applied to describe the dynamics process, in which different adsorption stages were revealed. Our simulation findings show that the interlayer phenol movement is the rate-limiting step in the adsorption process. Furthermore, by analyzing the interlayer structure and morphology, it is illustrated that the phenol molecules are discretely and disorderly scattered with a lying-down conformation within the GO interlayer. The adsorption interaction is the combination of the π–π and hydrogen-bonding interactions, in which the π-π interaction provides a dominant contribution. The effects of interlayer widths and surface oxidization degrees were thoroughly investigated. Our simulations provide new insight and useful guidance for the development of GO adsorbents.

Performance of Mesoporous Ceria-Supported Pt Catalysts for Oxidative Degradation of Aqueous Solution of Toxic Phenol in a Continuous Fixed Bed Reactor: Optimization of Reaction Conditions, Kinetics, Catalyst Stability, and Characterization

Performance of Mesoporous Ceria-Supported Pt Catalysts for Oxidative Degradation of Aqueous Solution of Toxic Phenol in a Continuous Fixed Bed Reactor: Optimization of Reaction Conditions, Kinetics, Catalyst Stability, and Characterization

Insights into the activation of peroxymonosulfate by ZIF-L@ZIF-67 derived CoCN catalyst for highly effective removal of phenol in the presence of chloride ions

A novel catalyst with cobalt and nitrogen-codoped porous carbon matrix (CoCN-900) was successfully prepared, characterized and applied for activating peroxymonosulfate (PMS) to remove phenol in aqueous solution. The CoCN-900 material exhibited superior performance in activating PMS for phenol degradation and could completely remove phenol within 60 min. Radical quenching tests and electron paramagnetic resonance (EPR) analysis showed that 1O2 and SO4•– played a major role in the phenol removal process over the CoCN-900/PMS system. In addition, the influences of catalyst/PMS dose, initial phenol concentration, reaction temperature, natural organic matter and coexisting anions on phenol degradation were systematically investigated. Particularly, it was found that the chloride ions (Cl–) had a significant accelerative effect, increasing the phenol degradation rate from 0.142 to 0.600 min−1. In the presence of Cl–, the phenol degradation efficiency was primarily ascribed to the effects of 1O2 and O2•–, which were significantly different from those in the absence of Cl–. Meanwhile, Cl– could also accelerate the deactivation of the catalyst. Findings in this study provided new insight for the fabrication of high-performance zeolitic imidazolate frameworks (ZIFs)-derived carbon materials and evaluating the influences of anions on the degradation of phenolic contaminants in PMS-based advanced oxidation processes (AOPs).

Degradation of binary mixtures of water pollutants in a photocatalytic microreactor: Competitive kinetics with explicit radiation absorption effects

The photocatalytic degradation of 17-α-ethinylestradiol (EE2) and phenol in aqueous solutions was studied using a continuous flow, planar microreactor under simulated sunlight. A TiO2 thin film was employed as photocatalyst. The degradation rates of single compounds and binary mixtures were well described by the Langmuir-Hinshelwood equation, including competitive terms for the companion pollutant and the intermediate products, and the effect of photon absorption by the photocatalyst. The absorbed radiation in the microreactor was calculated from the optical properties of the TiO2 film and the application of the Net Radiation method. The estimation of the kinetic parameters was carried out by numerical integration of coupled mass balance equations for EE2 and phenol employing the Runge-Kutta method, and adjusting the kinetics parameters with a nonlinear least-squares solver. The objective of this routine was to minimize the sum of the squares of the differences between the simulated and experimental outlet concentrations of EE2 and phenol under different operating conditions. Using this approach, intrinsic kinetic parameters were obtained. The model was able to predict the degradation of both organic pollutants under different inlet concentrations, irradiation levels, and fluid flow rates. This methodology can be extended to assess the simultaneous degradation of multi-component systems.

Degradation of Phenol Using Sonolysis and Photolysis by TiO2/RHAC Catalyst and Analysis with Spectrophotometer UV-VIS and HPLC

This study focuses on the degradation of phenol in aqueous solutions using photolysis and sonolysis methods. It investigates the impact of catalyst mass, types of light (UV-A, UV-C, and visible light), types of catalyst (RHAC, TiO2, and TiO2/RHAC), and processing time on phenol degradation. The phenol solutions are analyzed before and after degradation using Spectrophotometer UV-Vis and HPLC. The research aims to understand the factors influencing phenol degradation and provide a basis for further studies to enhance the efficiency of phenol removal. Results show significant improvements in degradation percentages of phenol by using TiO2/RHAC as the catalyst. Sonolysis achieves a degradation of 20.82% with a catalyst, which increases to 50.57% with the catalyst. Photolysis achieves a degradation of 29.06%, which rises to 91.99% with the catalyst. The highest degradation percentage is achieved using UV-A light for 5 hours with a catalyst mass of 30 mg of TiO2/RHAC catalyst. HPLC analysis confirms a decreased phenol concentration and the presence of intermediate compounds. The TiO2/RHAC catalyst demonstrates the promising potential for efficient phenol degradation in aqueous solutions.

Membrane assisted process intensification and optimization for removal and recovery of phenol from industrial effluents

The best method of preserving the environment is not to discharge any contaminant but to recover them as value from the effluent streams thereby adopting circular economy. This calls for developing new strategies including intensification of conventional processes to make the recovery of contaminants cost effective and environmentally friendly. In this context, experimental studies are reported with respect to conventional solvent extraction and membrane assisted solvent extraction for recovering phenol from effluent streams. Initial studies are carried out with aqueous solutions of phenol with concentrations up to 500 mg/L using hydrophobic polyvinylidene fluoride based hollow fiber membrane element in tandem with conventional solvent extraction using 1- hexanol as solvent. The operating parameters for the membrane assisted solvent extraction were optimized in parallel with conventional solvent extraction using the statistical tool, response surface methodology to provide a comparative assessment highlighting the advantages of membrane assisted solvent extraction in terms of energy consumption, operational simplicity and environmental friendliness. The studies were validated using real effluents obtained from a formaldehyde resin manufacturer. The comparative study highlights the specific advantages and demonstrates the superiority of membrane assisted solvent extraction using a real industrial effluent. It was observed that more than 98 % of phenol could be removed from effluent in membrane assisted solvent extraction and recover about 90 %, continuously allowing the recycle of the solvent. Being closed loop operation, no solvent is exposed to the environment making the process environmentally friendly operation. The mechanism of mass transfer in membrane contactors follows resistance in series model and the experimental values of mass transfer coefficient were estimated to be between 1.7 × 10 −7 and 2.2 × 10 −7 m/s, whereas the empirical values were around 1.3 × 10 −7 m/s.

Generalized Rapid Synthesis of Supported Nanocluster Catalyst for Mild Hydrogenation of Phenol toward KA Oil.

Homogeneous and nanometric metal clusters with unique electronic structures are promising for catalysis, however, common synthesis techniques for metal clusters suffer from large size and even metal nanocrystals attributing to their high surface energy and unsaturated configurations. Herein, a generalized rapid annealing strategy for synthesizing a series of supported metal clusters as superior catalysts is developed. Remarkably, TiO2 supported platinum nanoclusters (Pt NC/TiO2 ) exhibits the excellent catalytic activity to realize phenol hydrogenation under mild conditions. The complete phenol conversion rate and 100% selectivity toward KA oil are achieved in aqueous solution at room temperature and normal pressure. Semi-continuous scale up production of KA oil is successfully performed under mild conditions. Such excellent performance mainly originates from the partial reconstruction of Pt NC/TiO2 in aqueous phenol solution. Considering that the phenol can be produced from lignin, this study underpins a facile, sustainable, and economical route to synthesize nylon from biomass.

Photocatalytic Decomposition of Azo Dyes and Phenols Using Polymer Composites Containing Nanostructured Poly(Titanium Oxide) Doped with Gold or Silver Nanoparticles under Light Irradiation in a Wide Wavelength Range

The photocatalytic properties of poly(titanium oxide) (PTO) dispersed in optically transparent polymeric matrices of different natures under the action of both UV and visible light on aqueous solutions of azo dyes and phenols were investigated. PTO in materials forms clusters of mixed polymorphic modification—anatase and rutile—with an average size ~12 nm. With a one-electron transition Ti4+ + e− → Ti3+ accompanied by a reversible break of the Ti-O bond, the formation of electron-hole pairs and, consequently, active oxygen species occurs in PTO under UV irradiation. The PTO band gap in nanocomposites is 3.11–3.35 eV. Its doping with gold and silver nanoparticles with sizes from ~10 to ~30 nm reduces the PTO band gap by up to 2.11 eV, which leads to the operating wavelength range extension of the materials. It provides the enhancement of nanocomposites’ photocatalytic properties under UV irradiation and is the reason for their high activity under visible light action. It was found that azo dyes decompose by ~90% in this case. A phenol and para-nitrophenol conversion of 80–90% was proven at ~60 min upon their aqueous solutions’ visible-light irradiation at the nanocomposite concentration in a solution of 0.5 g/L.

Gram-Scale Room-Temperature Synthesis of Solid-State Fluorescent Carbon Nanodots for Bright Electroluminescent Light Emitting Diodes.

The reaction conditions of high temperature and high pressure will introduce structural defects, high energy consumption, and security risks, severely hindering the industrial application of organic carbon nanodots (CDs). Moreover, the aggregation caused quenching effect also fundamentally limits the CDs based electroluminescent light emitting diodes (LEDs). Herein, for the first time, a rapid one-step room temperature synthetic strategy is introduced to prepare highly emissive solid-state-fluorescent CDs (RT-CDs). A strong oxidizing agent, potassium periodate (KIO4 ), is adopted as a catalyst to facilitate the cyclization of o-phenylenediamine and 4-dimethylamino phenol in aqueous solution at room temperature for only 5min. The resultant organic molecule, 2-(dimethylamino) phenazine, will self-assemble kinetically to generate supramolecular-structure CDs during crystallization. The elaborately arranged supramolecular structure (J aggregates) endows CDs with intense solid-state-fluorescence. Density functional theory (DFT) calculation shows that the excited state of RT-CDs exhibits charge transfer characteristic owing to the unique donor-Π-acceptor structure. A high-performance monochrome RT-CDs based electroluminescent LEDs (2967cd m-2 and 1.38cd A-1 ) werefabricated via systematic optimizations of device engineering. This work provides a concrete and feasible avenue for the rapid and massive preparation of CDs, advancing the commercialization of CDs based optoelectronic devices.

Oxidative degradation of phenol in aqueous solution by using heat, ZVI, AC, heat/ZVI, or heat/AC activated persulfate

Oxidative degradation of phenol in aqueous solution by using heat, ZVI, AC, heat/ZVI, or heat/AC activated persulfate

Mesoporous LaVO4/MCM-48 nanocomposite with visible-light-driven photocatalytic degradation of phenol in wastewater

Dearomatization through photocatalytic oxidation is a swiftly rising phenolic compounds removal technology that works at trifling operations requirements with a special emphasis on the generation of nontoxic products. The study aims to develop a LaVO4/MCM-48 nanocomposite that was prepared via a hydrothermally approach assisting the employment of an MCM-48 matrix, which was then utilized for phenol degradation processes. Various techniques including UV–Vis DRS, FTIR, PL, Raman, TEM, and BET analyses are employed to characterize the developed photocatalyst. The developed photocatalyst presented remarkable characteristics, especially increased light photon utilization, and reduced recombination rate leading to enhanced visible-light-driven photodegradation performance owing to the improved specific surface area, specific porosities, and <2 eV narrow energy bandgap. The LaVO4/MCM-48 nanocomposite was experienced on aqueous phenol solution having 20 mg/L concentration under visible-light exposure, demonstrating exceptional performance in photodegradation up to 99.28%, comparatively higher than pure LaVO4. The conducted kinetic measurements revealed good accordance with pseudo first-order. A possible reaction mechanism for photocatalytic degradation was also predicted. The as-synthesized LaVO4/MCM-48 nanocomposite presented excellent stability and recyclability.

Nitration Mechanism of Hot Plasma Pulsed Radiation for Electric Spark Discharge

The mechanism reaction of species formed in an aqueous solution under the action of a remote spark discharge on solutes was studied. The main active factor was radiation. To generate species, hot plasma radiation of electric spark discharge and, for comparison, a corona electric discharge was used. A solution of phenol in water with a concentration of 25 mg/L (2.65 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times \,\,10^{-4}$ </tex-math></inline-formula> mol/L) was chosen as a probe. A generator of hot plasma radiation had a discharge power of 0.4 J/s, and the volume of processed liquid was 10 mL. A generator of corona electric discharge had power released in the discharge power of 4.7 J/s, and the volume of the processed liquid was 50 mL. Degradation of phenol in aqueous solution was observed under the action of both sources of active species. It was found that under the action of a corona discharge, phenol is destroyed directly during treatment, and practically, no changes take place two days thereafter. Under the action of a hot plasma radiation, changes in phenol concentration during treatment were insignificant, but degradation of phenol took place after processing. The main product formed during degradation is 4-nitrophenol and phenol nitration takes up to 120 h. Oxidation of phenol under plasma radiation does not take place. The results obtained allow us to conclude that one of the possible mechanism reactions under hot plasma radiation is nitration.

Acylamino-functionalized hyper-cross-linked polymers for efficient adsorption removal of phenol in aqueous solution

Chemically functionalized hyper-cross-linked polymers (HCLPs) with high Brunauer-Emmett-Teller (BET) surface area (SBET) and pore volume (Vtotal) are efficient polymeric adsorbents for the adsorption of polar phenolic substances. Herein, chloromethylated polystyrene (CMPS) was used as the raw material and two consecutive Friedel-Crafts reactions were adopted to prepare the acylamino-functionalized HCLPs, and they were used to adsorb phenol in aqueous solution. In the first reaction, considerable acylamino groups were successfully loaded on the polymers, and the N and O contents were measured to be 1.03 wt% and 3.59 wt%, respectively. In particular, a great deal of rigid methylene joined the polymer chains in the second reaction as using dichloromethane as the novel external cross-linker, and hence acylamino-functionalized HCLPs with high SBET (up to 914 m2/g) and Vtotal (up to 1.01 cm3/g) were prepared. The resulting HCLPs exhibited excellent adsorption of phenol, the fitted maximum capacity (qmax) was measured to be 318.6 mg/g, and the adsorption reached the equilibrium within 120 min. The dynamic adsorption demonstrated that up to 79 BV (bed volume, 1 BV = 8 mL) of phenol could be removed at the initial concentration of 1000.5 mg/L and the dynamic capacity was scaled to be 316.1 mg/g, and ethanol could desorb phenol from the polymer column completely. The adsorption mechanism revealed that hydrogen bonding, π–π stacking, micropore-filling were the main driving forces for the adsorption.

Accurate Vertical Ionization Energy of Water and Retrieval of True Ultraviolet Photoelectron Spectra of Aqueous Solutions.

Ultraviolet (UV) photoelectron spectroscopy provides a direct way of measuring valence electronic structure; however, its application to aqueous solutions has been hampered by a lack of quantitative understanding of how inelastic scattering of low-energy (<5 eV) electrons in liquid water distorts the measured electron kinetic energy distributions. Here, we present an efficient and widely applicable method for retrieving true UV photoelectron spectra of aqueous solutions. Our method combines Monte Carlo simulations of electron scattering and spectral inversion, with molecular dynamics simulations of depth profiles of organic solutes in aqueous solution. Its application is demonstrated for both liquid water, and aqueous solutions of phenol and phenolate, which are ubiquitous biologically relevant structural motifs.

Study of Sonocatalytic Activity ZnO-WO3 Composite on Degradation Phenol in Aqueous Solution

Sonocatalysis was used to study phenol degradation using a ZnO/WO3 composite. The degradation was assisted by ultrasonic waves at 40 KHz and conducted using the sonocatalysis technique. The degradation percentage was calculated using data from the UV-Vis spectrophotometer. The composite characterization results showed that the samples containing WO3, ZnO and also contained a new structure ZnWO4. The morphological length and width of the composites were revealed by SEM examination. Furthermore, heterogeneous particle sizes were discovered. The surface area of composite was bigger than before combined. The optimum condition in degradation of phenol by ZnO-WO3 composite are 0,4 g of catalyst at 30 ppm of phenol, 7 min reaction time with the greatest phenol degradation at 92,5%. The catalyst can be reused 5 times to degrade phenol at 85%. The composite catalyst and assisted with ultrasonic as the sonocatalytic technique are one of the most environmentally and cost effective.